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Sample records for raney ni catalyst

  1. Hydrodeoxygenation of bio-derived phenols to hydrocarbons using RANEY Ni and Nafion/SiO2 catalysts.

    Science.gov (United States)

    Zhao, Chen; Kou, Yuan; Lemonidou, Angeliki A; Li, Xuebing; Lercher, Johannes A

    2010-01-21

    A simple, green, cost- and energy-efficient route for converting phenolic components in bio-oil to hydrocarbons and methanol has been developed, with nearly 100% yields. In the heterogeneous catalysts, RANEY Ni acts as the hydrogenation catalyst and Nafion/SiO(2) acts as the Brønsted solid acid for hydrolysis and dehydration.

  2. Hydrogenolysis of 2-tosyloxy-1,3-propanediol into 1,3-propanediol over Raney Ni catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Zhi, Zheng; Jianli, Wang; Zhen, Lu; Min, Luo; Miao, Zhang; Lixin, Xu; Jianbing [Zhejiang Province Key Laboratory of Biofuel, The State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou (China)

    2013-03-15

    2-Tosyloxy-1,3-propanediol (TPD), a potential precursor for 1,3-propanediol (1,3-PD) production, is produced by the tosylation of glycerol with the help of protecting group techniques. In this work, the hydrogenolysis of TPD into 1,3-PD over Raney Ni catalyst is discussed at different reaction parameters to optimize the reaction conditions for selective formation of 1,3-PD. The mechanisms of the hydrogenolysis of TPD and the side reactions were also confirmed by gas chromatography-mass spectrometry (GC-MS) technique (author)

  3. One step hydrogenation–esterification of model compounds and bio-oil to alcohols and esters over Raney Ni catalysts

    International Nuclear Information System (INIS)

    Xu, Ying; Zhang, Limin; Chang, Jiamin; Zhang, Xinghua; Ma, Longlong; Wang, Tiejun; Zhang, Qi

    2016-01-01

    Highlights: • Fe–RN and Mo–RN showed excellent inhibition of alkylation and hydrogenation activity of phenol respectively. • The esterification activity of alcohols with acetic acid was followed as methanol > THFA > ethanediol. • After OHE of bio-oil, the total content of alcohols and esters reached to 87.27% in the product. - Abstract: Acids, aldehydes, ketones and phenols, which are the main components of bio-oil, have negative effects on the properties. In this paper, the mixture of acetic acid, furfural, hydroxyacetone, ethanediol, phenol and water were chosen as hybrid model compounds of bio-oil (MCB). To convert these compounds into stable and combustible oxygenated organics (alcohols and esters), one step hydrogenation–esterification (OHE) was carried out over Raney Ni catalyst (RN) and Mo, Sn, Fe, Cu modified Raney Ni catalysts (RNs) in the presence of methanol. 100% conversions of furfural and hydroxyacetone were achieved over RNs with high selectivity to desired products. The acetic acid conversion was only 35.1% with no methanol addition, while within 6 g/8 g methanol/MCB addition, the conversion of acetic acid increased to 81.1%. The esterification activity of alcohols was followed by methanol > tetrahydrofurfuryl alcohol (THFA), the hydrogenation product of furfural > ethanediol. Among the RNs, the addition of Fe catalyst restrained the aqueous-phase reforming of methanol and promoted the esterification of methanol and acetic acid. The Mo–RN showed the most favorable performance in the hydrogenation of phenol among the RNs. But the RN modified by both Fe and Mo did not give a good performance. After the OHE of light fraction of raw bio-oil over Mo–RN, there was no ketone & aldehyde detected and the contents of acids and phenols decreased from 49.04% and 7.35% to 8.21% and 3.84%. The conversion of acids could reach to 85.01% which was nearly to the conversion of acetic acid in MCB. The contents of alcohols and esters increased from 5

  4. Hydrogenation and hydrodeoxygenation of difurfurylidene acetone to liquid alkanes over Raney Ni and the supported Pt catalysts

    International Nuclear Information System (INIS)

    Li, Yuping; Huang, Xiaoming; Zhang, Qian; Chen, Lungang; Zhang, Xinghua; Wang, Tiejun; Ma, Longlong

    2015-01-01

    Highlights: • The C_8−C_1_4 alkane yield of 82.9% was obtained in the two-step hydrogenation/HDO process. • Protonation effect from methanol solvent increased F_2A conversion in the two-step process. • The rate-determining step was acyl C=O bond hydrogenation in the first step of F_2A hydrogenation. • The acidic centers from SiO_2−ZrO_2 activated the acyl and oxygen atoms of intermediates. • Acidity of SiO_2−ZrO_2 and Pt active centers of 1 wt%Pt/SiO_2−ZrO_2 resulted stable HDO performance. - Abstract: Direct HDO process for difurfurylidene acetone dimer (F_2A) conversion to liquid alkanes (C_8−C_1_4) at 260 °C in a batch reactor was investigated over different material supported 1 wt%Pt catalysts, including SAPO-11, HZSM-5, SiO_2−Al_2O_3, MCM-22, and home-made SiO_2−ZrO_2. C_8−C_1_4 alkanes of 55.8% was obtained over the optimized 1 wt%Pt/SiO_2−ZrO_2 due to its proper pore size of 9.0 nm and moderate acidic centers, together with more than 10% carbon yield of the oxygenated hydrocarbons, including C_1_1−C_1_3 chain alcohols & ketones and the hydrogenated F_2A dimers with furan ring (H-F_2A dimers). To improve the liquid alkane yield, a two-step process for F_2A conversion was also investigated, which included low-temperature hydrogenation at 50 °C over Raney Ni catalyst in a batch reactor and the subsequent high-temperature hydrodeoxygenation (HDO) at 280 °C over 1 wt%Pt/SiO_2−ZrO_2 in a fixed-bed reactor. The selectivity of 1,5-di(tetrahydro-2-furanyl)-3-pentanol (II-c) was the highest of 83.0% among the hydrogenated intermediates of H-F_2A dimers due to the protonation effect of methanol as the solvent and the hydrogenation of C=C bonds by Ni active centers. In the same time, the high content of this saturated alcohol H-dimer of II-C increased the solubility and stability of the intermediates in methanol solvent. High carbon yield of C_8−C_1_4 alkanes of 82.9%(mol) was obtained after oxygen atom removal from H-F_2A dimers via

  5. TOTAL HYDROGENATION OF BIOMASS-DERIVED FURFURAL OVER RANEY NICKEL-CLAY NANOCOMPOSITE CATALYSTS

    Directory of Open Access Journals (Sweden)

    Rodiansono Rodiansono

    2013-08-01

    Full Text Available Inexpensive Raney Ni-clay composite (R-Ni/clay catalysts exhibited excellent activity and reusability in the total hydrogenation of biomass-derived furfural into tetrahydrofurfuryl alcohol under mild conditions. For the Raney Ni-bentonite (R-Ni/BNT catalysts, the complete reaction was achieved at 393 K, 180 min giving almost 99% yield of tetrahydrofurfuryl alcohol. The R-Ni/BNT catalyst was found to be reusable without any significant loss of activity and selectivity for at least six consecutive runs.

  6. Polymer-Supported Raney Nickel Catalysts for Sustainable Reduction Reactions

    Directory of Open Access Journals (Sweden)

    Haibin Jiang

    2016-06-01

    Full Text Available Green is the future of chemistry. Catalysts with high selectivity are the key to green chemistry. Polymer-supported Raney catalysts have been found to have outstanding performance in the clean preparation of some chemicals. For example, a polyamide 6-supported Raney nickel catalyst provided a 100.0% conversion of n-butyraldehyde without producing any detectable n-butyl ether, the main byproduct in industry, and eliminated the two main byproducts (isopropyl ether and methyl-iso-butylcarbinol in the hydrogenation of acetone to isopropanol. Meanwhile, a model for how the polymer support brought about the elimination of byproducts is proposed and confirmed. In this account the preparation and applications of polymer-supported Raney catalysts along with the corresponding models will be reviewed.

  7. A nanostructural study of Raney-type nickel catalysts

    NARCIS (Netherlands)

    Devred, F.

    2004-01-01

    Raney-type nickel catalysts have been applied in commercial hydrogenation reactions for decades. They are relatively cheap and have proven to be very efficient in hydrogenation. The preparation process is relatively simple, but it appears that many parameters have an influence on the performance of

  8. Raney copper catalysts for the water-gas shift reaction - II. Initial catalyst optimisation

    CSIR Research Space (South Africa)

    Mellor, JR

    1997-12-23

    Full Text Available The initial Raney copper WGS activity based on catalyst volume has been shown to be comparable to industrial and co-precipitated alternatives under varying reaction conditions. The presence of zinc oxide in the Raney copper structure was shown...

  9. Raney copper catalysts for the water-gas shift reaction: I. Preparation, activity and stability

    CSIR Research Space (South Africa)

    Mellor, JR

    1997-12-23

    Full Text Available , T Haltchev, V Kafedjiiski, B. Kunev, M. Kalchev, I. Orizarski, D. Shopov, Proceedings ofthe Sixth International Symposium, Heterogeneous Catalysis, Part 1, Sofia, 1987, p. 235. \\[18\\] W.L. Marsden, M.S. Wainwright, J.B. Friedrich, Ind. Eng. Chem, Prod... and Testing of Catalysts, Academic Press, New York, 1985. \\[33\\] J.M. Thomas, J.W. Thomas, Introduction to the Principles of Heterogeneous Catalysis, Academic Press, New York, 1975, p. 16. \\[34\\] A.D. Tomsett, H.E. Curry-Hyde, M.S. Wainwright. D.J. Young...

  10. Co-Production of Ethanol and 1,2-Propanediol via Glycerol Hydrogenolysis Using Ni/Ce–Mg Catalysts: Effects of Catalyst Preparation and Reaction Conditions

    Directory of Open Access Journals (Sweden)

    Russel N. Menchavez

    2017-09-01

    Full Text Available Crude glycerol from biodiesel production is a biobased material capable of co-producing biofuels and chemicals. This study aimed to develop a line of Ni catalysts supported on cerium–magnesium (Ce–Mg to improve the process efficiency of glycerol hydrogenolysis for ethanol and 1,2-propanediol (1,2-PDO. Results showed that catalytic activity was greatly improved by changing the preparation method from impregnation to deposition precipitation (DP, and by adjusting calcination temperatures. Prepared via DP, the catalysts of 25 wt % Ni supported on Ce–Mg (9:1 mol/mol greatly improved the effectiveness in glycerol conversion while maintaining the selectivities to ethanol and 1,2-PDO. Calcination at 350 °C provided the catalysts better selectivities of 15.61% to ethanol and 67.93% to 1,2-PDO. Increases in reaction temperature and time improved the conversion of glycerol and the selectivity to ethanol, but reduced the selectivity to 1,2-PDO. A lower initial water content led to a higher conversion of glycerol, but lower selectivities to ethanol and 1,2-PDO. Higher hydrogen application affected the glycerol conversion rate positively, but the selectivities to ethanol and 1,2-PDO negatively. A comparison to the commercial Raney® Ni catalyst showed that the Ni/Ce–Mg catalyst developed in this study showed a better potential for the selective co-production of ethanol and 1,2-PDO from glycerol hydrogenolysis.

  11. Reduction of a Ni/Spinel Catalyst for Methane Reforming

    DEFF Research Database (Denmark)

    Kehres, Jan; Andreasen, Jens Wenzel; Fløystad, Jostein Bø

    2015-01-01

    microscopy (HRTEM) was performed on the fresh catalyst sample. The Ni particles in the fresh catalyst sample were observed to exhibit a Ni/NiO core/shell structure. A decrease of the Ni lattice parameter is observed during the reduction in a temperature interval from 413 – 453 K, which can be related...

  12. NOVEL RU-NI-S ELECTRODE CATALYST FOR PEMFC

    Science.gov (United States)

    The expected results from this project include: a new formula and preparation procedures for Ru-Ni-S catalyst; demonstration of CO and S tolerance of the new catalyst; a small size PEMFC with Ru-Ni-S catalyst and good performance; an...

  13. Liquid phase in situ hydrodeoxygenation of biomass-derived phenolic compounds to hydrocarbons over bifunctional catalysts

    Science.gov (United States)

    Junfeng Feng; Chung-yun Hse; Zhongzhi Yang; Kui Wang; Jianchun Jiang; Junming Xu

    2017-01-01

    The objective of this study was to find an effective method for converting renewable biomass-derived phenolic compounds into hydrocarbons bio-fuel via in situ catalytic hydrodeoxygenation. The in situ hydrodeoxygenation of biomass-derived phenolic compounds was carried out in methanol-water solvent over bifunctional catalysts of Raney Ni and HZSM-5 or H-Beta. In the in...

  14. Energetic Mapping of Ni Catalysts by Detailed Kinetic Modeling

    DEFF Research Database (Denmark)

    Bjørgum, Erlend; Chen, De; Bakken, Mari G.

    2005-01-01

    Temperature-programmed desorption (TPD) of CO has been performed on supported and unsupported nickel catalysts. The unsupported Ni catalyst consists of a Ni(14 13 13) single crystal which has been studied under ultrahigh vacuum conditions. The desorption energy for CO at low CO surface coverage...... was found to be 119 kJ/mol, and the binding energy of C to the Ni(111) surface of the crystal was 703 kJ/mol. The supported catalysts consist of nickel supported on hydrotalcite-like compounds with three different Mg2+/Al3+ ratios. The experimental results show that for the supported Ni catalysts TPD of CO...... precursor seems to result in more steplike sites, kinks, and defects for carbon monoxide dissociation. A detailed kinetic modeling of the TPO results based on elementary reaction steps has been conducted to give an energetic map of supported Ni catalysts. Experimental results from the ideal Ni surface fit...

  15. In-situ hydrodeoxygenation of phenol by supported Ni catalyst-explanation for catalyst performance

    DEFF Research Database (Denmark)

    Wang, Ze; Zeng, Ying; Lin, Weigang

    2017-01-01

    In-situ hydrodeoxygenation of phenol with aqueous hydrogen donor over supported Ni catalyst was investigated. The supported Ni catalysts exerted very poor performance, if formic acid was used as the hydrogen donor. Catalyst modification by loading K, Na, Mg or La salt could not make the catalyst...... performance improved. If gaseous hydrogen was used as the hydrogen source the activity of Ni/Al2O3 was pretty high. CO2 was found poisonous to the catalysis, due to the competitive adoption of phenol with CO2. If formic acid was replaced by methanol, the catalyst performance improved remarkably, with major...... products of cyclohexanone and cyclohexanol. The better effect of methanol enlightened the application of the supported Ni catalyst in in-situ hydrodeoxygenation of phenol....

  16. More active and sulfur resistant bimetallic Pd-Ni catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Betti, Carolina; Carrara, Nicolás; Badano, Juan; Lederhos, Cecilia; Vera, Carlos; Quiroga, Mónica, E-mail: mquiroga@fiq.unl.edu.ar [Instituto de Investigaciones en Catálisis y Petroquímica, INCAPE (FIQ-UNL, CONICET), Santa Fe (Argentina)

    2018-02-15

    The influence of the kind of metal precursor and the sequence of impregnation on the properties of Pd-Ni catalysts was evaluated during the test reaction of selective hydrogenation of styrene to ethylbenzene by means of physicochemical characterization. The focus was put on the final hydrogenating activity and the resistance to deactivation by sulfide compounds (thiophene). The used techniques of characterization were ICP, XPS, XDR, TPR, CO chemisorption and TEM. XPS results indicated the presence of different Pd species: Pd{sup δ-}, Pd{sup 0} and Pd{sup δ+}. In the case of the Ni containing catalysts, Ni{sup 0} and NiO species were also detected. These palladium and nickel species would be responsible of the variation of activity and sulfur resistance of the catalysts. NiClPd catalysts had a higher resistance to deactivation by sulfur poisoning. This was associated to a higher concentration of Pd{sup η+}Cl{sub x}O{sub y} species that would prevent the adsorption of thiophene by both steric and electronic effects. It could also be due to the lower concentration of Pd{sup 0} and Ni{sup 0} on these catalysts, as compared to those shown by the PdNiCl catalysts. Both the Pd{sup 0} and Ni{sup 0} species are more prone to poisoning because of their higher electronic availability. (author)

  17. Equilibrium problems for Raney densities

    Science.gov (United States)

    Forrester, Peter J.; Liu, Dang-Zheng; Zinn-Justin, Paul

    2015-07-01

    The Raney numbers are a class of combinatorial numbers generalising the Fuss-Catalan numbers. They are indexed by a pair of positive real numbers (p, r) with p > 1 and 0 0 and similarly use both methods to identify the equilibrium problem for (p, r) = (θ/q + 1, 1/q), θ > 0 and q \\in Z+ . The Wiener-Hopf method is used to extend the latter to parameters (p, r) = (θ/q + 1, m + 1/q) for m a non-negative integer, and also to identify the equilibrium problem for a family of densities with moments given by certain binomial coefficients.

  18. Support effects on hydrotreating activity of NiMo catalysts

    International Nuclear Information System (INIS)

    Dominguez-Crespo, M.A.; Arce-Estrada, E.M.; Torres-Huerta, A.M.; Diaz-Garcia, L.; Cortez de la Paz, M.T.

    2007-01-01

    The effect of the gamma alumina particle size on the catalytic activity of NiMoS x catalysts prepared by precipitation method of aluminum acetate at pH = 10 was studied. The structural characterization of the supports was measured by using XRD, pyridine FTIR-TPD and nitrogen physisorption. NiMo catalysts were characterized during the preparation steps (annealing and sulfidation) using transmission electron microscopy (TEM). Hydrogen TPR studies of the NiMo catalysts were also carried out in order to correlate their hydrogenating properties and their catalytic functionality. Catalytic tests were carried out in a pilot plant at 613, 633 and 653 K temperatures. The results showed that the rate constants of hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodearomatizing (HDA) at 613-653 K decreased in the following order: A > B > C corresponding to the increase of NiMoS particle size associated to these catalysts

  19. The role of Ni in sulfided carbon-supported Ni-Mo hydrodesulfurization catalysts

    NARCIS (Netherlands)

    Bouwens, S.M.A.M.; Barthe-Zahir, N.; Beer, de V.H.J.; Prins, R.

    1991-01-01

    The thiophene hydrodesulfurization activities of Ni and Ni---Mo sulfide catalysts supported on activated carbon were measured at atmospheric pressure and the catalyst structures were studied by means of X-ray photoelectron spectroscopy, dynamic oxygen chemisorption, and chemical sulfur analysis. The

  20. Ni Catalysts Supported on Modified Alumina for Diesel Steam Reforming

    Directory of Open Access Journals (Sweden)

    Antonios Tribalis

    2016-01-01

    Full Text Available Nickel catalysts are the most popular for steam reforming, however, they have a number of drawbacks, such as high propensity toward coke formation and intolerance to sulfur. In an effort to improve their behavior, a series of Ni-catalysts supported on pure and La-, Ba-, (La+Ba- and Ce-doped γ-alumina has been prepared. The doped supports and the catalysts have been extensively characterized. The catalysts performance was evaluated for steam reforming of n-hexadecane pure or doped with dibenzothiophene as surrogate for sulphur-free or commercial diesel, respectively. The undoped catalyst lost its activity after 1.5 h on stream. Doping of the support with La improved the initial catalyst activity. However, this catalyst was completely deactivated after 2 h on stream. Doping with Ba or La+Ba improved the stability of the catalysts. This improvement is attributed to the increase of the dispersion of the nickel phase, the decrease of the support acidity and the increase of Ni-phase reducibility. The best catalyst of the series doped with La+Ba proved to be sulphur tolerant and stable for more than 160 h on stream. Doping of the support with Ce also improved the catalytic performance of the corresponding catalyst, but more work is needed to explain this behavior.

  1. CO methanation over supported bimetallic Ni-Fe catalysts: From computational studies towards catalyst optimization

    DEFF Research Database (Denmark)

    Kustov, Arkadii; Frey, Anne Mette; Larsen, Kasper Emil

    2007-01-01

    with compositions 25Fe75Ni and 50Fe50Ni showed significantly better activity and in some cases also a higher selectivity to methane compared with the traditional monometallic Ni and Fe catalysts. A catalyst with composition 25Fe75Ni was found to be the most active in CO hydrogenation for the MgAl2O4 support at low...... metal loadings. At high metal concentrations, the maximum for the methanation activity was found for catalysts with composition 50Ni50Fe both on the MgAl2O4 and Al2O3 supports. This difference can be attributed to a higher reducibility of the constituting metals with increasing metal concentration......DFT calculations combined with a computational screening method have previously shown that bimetallic Ni-Fe alloys should be more active than the traditional Ni-based catalyst for CO methanation. That was confirmed experimentally for a number of bimetallic Ni-Fe catalysts supported on MgAl2O4. Here...

  2. Influence of RANEY Nickel on the Formation of Intermediates in the Degradation of Lignin

    Directory of Open Access Journals (Sweden)

    Daniel Forchheim

    2012-01-01

    Full Text Available Lignin forms an important part of lignocellulosic biomass and is an abundantly available residue. It is a potential renewable source of phenol. Liquefaction of enzymatic hydrolysis lignin as well as catalytical hydrodeoxygenation of the main intermediates in the degradation of lignin, that is, catechol and guaiacol, was studied. The cleavage of the ether bonds, which are abundant in the molecular structure of lignin, can be realised in near-critical water (573 to 673 K, 20 to 30 MPa. Hydrothermal treatment in this context provides high selectivity in respect to hydroxybenzenes, especially catechol. RANEY Nickel was found to be an adequate catalyst for hydrodeoxygenation. Although it does not influence the cleavage of ether bonds, RANEY Nickel favours the production of phenol from both lignin and catechol. The main product from hydrodeoxygenation of guaiacol with RANEY Nickel was cyclohexanol. Reaction mechanism and kinetics of the degradation of guaiacol were explored.

  3. TEORES DE DIMETIL SULFETO ESTIMADOS PELO MÉTODO NÍQUEL-RANEY E ACEITABILIDADE DE AMOSTRAS DE CACHAÇA Dimethyl sulfide contents estimated by Ni-Raney method and “cachaça” samples acceptability.

    Directory of Open Access Journals (Sweden)

    J. F. A. TOLEDO

    2008-08-01

    Full Text Available

    O defeito sensorial das aguardentes de cana destiladas na ausência de cobre já foi relacionado com a presença do dimetil sulfeto (DMS, o que revela a importância de identificar os teores deste composto eventualmente presente nesta bebida. Considerando-se, porém, o custo relativamente elevado dos métodos de cromatografia de fase gasosa até agora utilizados na determinação do DMS, foi objetivo deste trabalho avaliar a possível utilização do método de Níquel-Raney como forma de controlar o referido defeito. Nesse sentido foi estudada a relação entre os teores de DMS estimados pelo método proposto, com sua influência sensorial avaliada através de testes de aceitação. Os resultados obtidos permitiram concluir que mesmo em concentrações abaixo de 5mg/L, os testes sensoriais revelam haver alta correlação entre os teores de DMS, determinados pelo método de Níquel-Raney com a diminuição da qualidade sensorial das amostras avaliadas. Os resultados obtidos permitem propor o método de Níquel-Raney como uma opção válida no controle da presença de DMS na cachaça e assim, prevenir efeitos negativos na qualidade sensorial do produto final.

    The sensory defect of “cachaça”, when distilled in absence of copper, had been already related to dimethyl sulphide levels, pointing out the importance to control its contents in this beverage. Considering the relatively higher costs of the gas-chromatography techniques, the aim of this work was to evaluate the possible use of the Níquel-Raney method, to control the dimethyl sulphide contents. In this way, the dimethyl sulphide contents (estimated by Níquel-Raney method and its sensory deffect evaluated by acceptability sensory tests, were compared. The results showed that

  4. Effects of preparation method and active metal content on of Ni/kieselguhr catalyst activity

    International Nuclear Information System (INIS)

    Galuh Widiyarti; Wuryaningsih Sri Rahayu

    2010-01-01

    The preparation and the active metal content influence the activity of catalyst. Study has been conducted to see the activity of Ni/kieselguhr based on preparation method and Nickel (Ni) contents in the catalyst in the laboratory scale. The Ni/kieselguhr catalyst were prepared by impregnation and precipitation methods, with Ni active contents of 10, 20, and 30 % by weight. The catalysts characterization was analyzed using X-Ray Diffraction (XRD). Catalysts activities were analyzed based on decreasing of iodine number from hydrogenation of crude palm oil for 2 hours. The activity tests results show that precipitation catalysts are more active than impregnation catalysts. The decreasing in iodine number of fatty acid after 2 hours of hydrogenation process using precipitation catalysts and impregnation catalysts are 51.53 and 21.85 %, respectively. In addition, the catalysts are more active with increasing Ni contents. (author)

  5. Steam Reforming of CH4 Using Ni- Substituted Pyrochlore Catalysts

    Science.gov (United States)

    Haynes, Daniel J.

    The steam reforming of methane (SMR) continues to remain an important industrial reaction for large-scale production of H2 as well as synthesis gas mixtures which can be used for the production of useful chemicals (e.g. methanol). Although SMR is a rather mature technology, traditional nickel based catalysts used industrially are subjected to severe temperatures and reaction conditions, which lead to irreversible activity loss through sintering, support collapse, and carbon formation. Pyrochlore-based mixed oxide have been identified as refractory materials that can be modified through the substitution of catalytic metals and other promoting species into the structure to mitigate these issues causing deactivation. For this study, a lanthanum zirconate pyrochlore catalyst was substituted with Ni to determine whether the oxide structure could effectively stabilize the activity of the catalytic metal during the SMR. The effect of different variables including calcination temperature, a comparison of a substituted versus supported Ni pyrochlore catalyst, Ni weight loading, and Sr promotion have been evaluated to determine the location of the Ni in the structure, and their effect on catalytic behavior. It was revealed that the effect of calcination temperature on a 6wt% Ni substituted pyrochlore produced by the Pechini method demonstrated very little Ni was soluble in the pyrochlore lattice. It was further revealed that by XRD, TEM, and atom probe tomography that, despite the metal loading, Ni exsolves from the structure upon crystallization of the pyrochlore at 700°C, and forms NiO at the surface and grain boundaries. An additional separate La2ZrNiO6 perovskite phase also began to form at higher temperatures (>800°C). Increasing calcination temperature was found to lead to slight sintering of the NiO at the surface, which made the NiO more reducible. Meanwhile decreasing the Ni weight loading was found to produce a lower reduction temperature due to the presence of

  6. MORE ACTIVE AND SULFUR RESISTANT BIMETALLIC Pd-Ni CATALYSTS

    OpenAIRE

    Betti, Carolina; Carrara, Nicolás; Badano, Juan; Lederhos, Cecilia; Vera, Carlos; Quiroga, Mónica

    2018-01-01

    The influence of the kind of metal precursor and the sequence of impregnation on the properties of Pd-Ni catalysts was evaluated during the test reaction of selective hydrogenation of styrene to ethylbenzene by means of physicochemical characterization. The focus was put on the final hydrogenating activity and the resistance to deactivation by sulfided compounds (thiophene). The used techniques of characterization were ICP, XPS, XDR, TPR, CO chemisorption and TEM. XPS results indicated the pr...

  7. The role of promoters for Ni catalysts in low temperature (membrane) steam methane reforming

    NARCIS (Netherlands)

    Ligthart, D.A.J.M.; Pieterse, J.A.Z.; Hensen, E.J.M.

    2011-01-01

    In the search for active and stable Ni-based catalysts for steam methane reforming in membrane reactors, the effect of three different promoters La, B and Rh was compared. Promoted and unpromoted Ni catalysts were characterized by TEM, TPR and X-ray absorption spectroscopy. The average Ni particle

  8. Porous bimetallic PdNi catalyst with high electrocatalytic activity for ethanol electrooxidation.

    Science.gov (United States)

    Feng, Yue; Bin, Duan; Yan, Bo; Du, Yukou; Majima, Tetsuro; Zhou, Weiqiang

    2017-05-01

    Porous bimetallic PdNi catalysts were fabricated by a novel method, namely, reduction of Pd and Ni oxides prepared via calcining the complex chelate of PdNi-dimethylglyoxime (PdNi-dmg). The morphology and composition of the as-prepared PdNi were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Furthermore, the electrochemical properties of PdNi catalysts towards ethanol electrooxidation were also studied by electrochemical impedance spectrometry (EIS), cyclic voltammetry (CV) and chronoamperometry (CA) measurement. In comparison with porous Pd and commercial Pd/C catalysts, porous structural PdNi catalysts showed higher electrocatalytic activity and durability for ethanol electrooxidation, which may be ascribed to Pd and Ni property, large electroactive surface area and high electron transfer property. The Ni exist in the catalyst in the form of the nickel hydroxides (Ni(OH) 2 and NiOOH) which have a high electron and proton conductivity enhances the catalytic activity of the catalysts. All results highlight the great potential application of the calcination-reduction method for synthesizing high active porous PdNi catalysts in direct ethanol fuel cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Raney Distributions and Random Matrix Theory

    Science.gov (United States)

    Forrester, Peter J.; Liu, Dang-Zheng

    2015-03-01

    Recent works have shown that the family of probability distributions with moments given by the Fuss-Catalan numbers permit a simple parameterized form for their density. We extend this result to the Raney distribution which by definition has its moments given by a generalization of the Fuss-Catalan numbers. Such computations begin with an algebraic equation satisfied by the Stieltjes transform, which we show can be derived from the linear differential equation satisfied by the characteristic polynomial of random matrix realizations of the Raney distribution. For the Fuss-Catalan distribution, an equilibrium problem characterizing the density is identified. The Stieltjes transform for the limiting spectral density of the singular values squared of the matrix product formed from inverse standard Gaussian matrices, and standard Gaussian matrices, is shown to satisfy a variant of the algebraic equation relating to the Raney distribution. Supported on , we show that it too permits a simple functional form upon the introduction of an appropriate choice of parameterization. As an application, the leading asymptotic form of the density as the endpoints of the support are approached is computed, and is shown to have some universal features.

  10. Hydrotreatment of bio-oil over Ni-based catalyst.

    Science.gov (United States)

    Zhang, Xinghua; Wang, Tiejun; Ma, Longlong; Zhang, Qi; Jiang, Ting

    2013-01-01

    Inexpensive non-sulfided Ni-based catalysts were evaluated for hydrotreatments using phenol as model compound. HZSM-5, a zeolite with different ratio of Si/Al and γ-Al(2)O(3) were impregnated with Ni(NO(3))(2) · 6H(2)O and calcined at 450 °C. Conversion rates and product distribution for treatment of phenol at 160-240 °C in the presence of catalysts with nickel loads of 6, 10, 14 and 17 wt.% were determined. Phenol conversion was highest (91.8%) at 240 °C in the presence of HZSM-5(Si/Al = 38) loaded with 10% Ni. When hydrotreatment was carried out with bio-oil obtained from pyrolysis of pine sawdust under the optimal conditions determined for phenol, the pH of bio-oil increased from 2.27 to 4.07, and the hydrogen content increased from 6.28 to 7.01 wt.%. The decrease in acidity is desirable for the use of upgraded bio-oil. Copyright © 2012. Published by Elsevier Ltd.

  11. Renewable hydrogen: carbon formation on Ni and Ru catalysts during ethanol steam-reforming

    DEFF Research Database (Denmark)

    Rass-Hansen, Jeppe; Christensen, Christina Hviid; Sehested, J.

    2007-01-01

    for the production of hydrogen is investigated, along with quantitative and qualitative determinations of carbon formation on the catalysts by TPO and TEM experiments. A Ru/ MgAl2O4 catalyst, a Ni/MgAl2O4 catalyst as well as Ag-and K-promoted Ni/ MgAl2O4 catalysts were studied. The operating temperature was between...... addition was a rapid deactivation of the catalyst due to an enhanced gum carbon formation on the Ni crystals. Contrary to this, the effect of K addition was a prolonged resistance against carbon formation and therefore against deactivation. The Ru catalyst operates better than all the Ni catalysts...

  12. Metal oxides modified NiO catalysts for oxidative dehydrogenation of ethane to ethylene

    KAUST Repository

    Zhu, Haibo; Dong, Hailin; Laveille, Paco; Saih, Youssef; Caps, Valerie; Basset, Jean-Marie

    2014-01-01

    in contrast to pure NiO. The introduction of group IV, V and VI transition metals into NiO decreases the catalytic activity in ethane ODH. However, the ethylene selectivity is enhanced with the highest level for the Ni-W-O and Ni-Ti-O catalysts. As a result

  13. Hydrogen production via reforming of biogas over nanostructured Ni/Y catalyst: Effect of ultrasound irradiation and Ni-content on catalyst properties and performance

    Energy Technology Data Exchange (ETDEWEB)

    Sharifi, Mahdi [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Haghighi, Mohammad, E-mail: haghighi@sut.ac.ir [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Abdollahifar, Mozaffar [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of)

    2014-12-15

    Highlights: • Synthesis of nanostructured Ni/Y catalyst by sonochemical and impregnation methods. • Enhancement of size distribution and active phase dispersion by employing sonochemical method. • Evaluation of biogas reforming over Ni/Y catalyst with different Ni-loadings. • Preparation of highly active and stable catalyst with low Ni content for biogas reforming. • Getting H{sub 2}/CO very close to equilibrium ratio by employing sonochemical method. - Abstract: The effect of ultrasound irradiation and various Ni-loadings on dispersion of active phase over zeolite Y were evaluated in biogas reforming for hydrogen production. X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray, Brunauer–Emmett–Teller, Fourier transform infrared analysis and TEM analysis were employed to observe the characteristics of nanostructured catalysts. The characterizations implied that utilization of ultrasound irradiation enhanced catalyst physicochemical properties including high dispersion of Ni on support, smallest particles size and high catalyst surface area. The reforming reactions were carried out at GHSV = 24 l/g.h, P = 1 atm, CH{sub 4}/CO{sub 2} = 1 and temperature range of 550–850 °C. Activity test displayed that ultrasound irradiated Ni(5 wt.%)/Y had the best performance and the activity remained stable during 600 min. Furthermore, the proposed reaction mechanism showed that there are three major reaction channels in biogas reforming.

  14. Metal oxides modified NiO catalysts for oxidative dehydrogenation of ethane to ethylene

    KAUST Repository

    Zhu, Haibo

    2014-06-01

    The sol-gel method was applied to the synthesis of Zr, Ti, Mo, W, and V modified NiO based catalysts for the ethane oxidative dehydrogenation reaction. The synthesized catalysts were characterized by XRD, N2 adsorption, SEM and TPR techniques. The results showed that the doping metals could be highly dispersed into NiO domains without the formation of large amount of other bulk metal oxide. The modified NiO materials have small particle size, larger surface area, and higher reduction temperature in contrast to pure NiO. The introduction of group IV, V and VI transition metals into NiO decreases the catalytic activity in ethane ODH. However, the ethylene selectivity is enhanced with the highest level for the Ni-W-O and Ni-Ti-O catalysts. As a result, these two catalysts show improved efficiency of ethylene production in the ethane ODH reaction. © 2014 Elsevier B.V. All rights reserved.

  15. TiO2 nanotubes supported NiW hydrodesulphurization catalysts: Characterization and activity

    International Nuclear Information System (INIS)

    Palcheva, R.; Dimitrov, L.; Tyuliev, G.; Spojakina, A.; Jiratova, K.

    2013-01-01

    Highlights: ► NiW catalysts supported on TiO 2 nanotubes, titania and alumina. ► The best results are obtained with NiW/TiO 2 nanotubes in hydrodesulfurization (HDS) of thiophene. ► Active phase is Ni-WO x S y . ► Electronic promotion of W by Ti. - Abstract: High surface area TiO 2 nanotubes (Ti-NT) synthesized by alkali hydrothermal method were used as a support for NiW hydrodesulphurization catalyst. Nickel salt of 12-tungstophosphoric acid – Ni 3/2 PW 12 O 40 was applied as oxide precursor of the active components. The catalyst was characterized by S BET , XRD, UV–vis DRS, Raman spectroscopy, XPS, TPR and HRTEM. The results obtained were compared with those for the NiW catalysts prepared over high surface area titania and alumina supports. A polytungstate phase evidenced by Raman spectroscopy was observed indicating the destruction of the initial heteropolyanion. The catalytic experiments revealed two times higher thiophene conversion on NiW catalyst supported on Ti-NT than those of catalysts supported on alumina and titania. Increased HDS activity of the NiW catalyst supported on Ti-NT could be related to a higher amount of W oxysulfide entities interacting with Ni sulfide particles as consequence of the electronic effects of the Ti-NT observed with XPS analysis.

  16. Ni-CeO2/C Catalysts with Enhanced OSC for the WGS Reaction

    Directory of Open Access Journals (Sweden)

    Laura Pastor-Pérez

    2015-03-01

    Full Text Available In this work, the WGS performance of a conventional Ni/CeO2 bulk catalyst is compared to that of a carbon-supported Ni-CeO2 catalyst. The carbon-supported sample resulted to be much more active than the bulk one. The higher activity of the Ni-CeO2/C catalyst is associated to its oxygen storage capacity, a parameter that strongly influences the WGS behavior. The stability of the carbon-supported catalyst under realistic operation conditions is also a subject of this paper. In summary, our study represents an approach towards a new generation of Ni-ceria based catalyst for the pure hydrogen production via WGS. The dispersion of ceria nanoparticles on an activated carbon support drives to improved catalytic skills with a considerable reduction of the amount of ceria in the catalyst formulation.

  17. MOF derived Ni/Co/NC catalysts with enhanced properties for oxygen evolution reaction

    Science.gov (United States)

    Hu, Jiapeng; Chen, Juan; Lin, Hao; Liu, Ruilai; Yang, Xiaobing

    2018-03-01

    Designing efficient electrocatalysts for oxygen evolution reaction (OER) is very important for renewable energy storage and conversion devices. In this paper, we introduced a new strategy to synthesize Ni doped Co/NC catalysts (NC is the abbreviation of nitrogen-doped graphitic carbon), which were derived from ZIF-67. All catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and oxygen evolution reaction (OER). The results show that Ni was well doped in the Ni/Co/NC catalysts and the doping of Ni has great influence on the OER activity of Ni/Co/NC catalysts. Among these catalysts, 0.50Ni/Co/NC exhibits the highest OER activity. The onset potential of 0.50Ni/Co/NC is 1.47 V, which is superior than the onset potential of Co/NC (1.54 V), 0.25Ni/Co/NC (1.48 V), 1.00Ni/Co/NC (1.53 V). The excellent OER activity of 0.50Ni/Co/NC catalyst makes its potential to be used on renewable energy storage.

  18. Energies of Electronic States of Ni (II) Ion in NiO-Al2O3 Catalyst Prepared by Impregnation

    International Nuclear Information System (INIS)

    Obadovic, D. Z.; Kiurski, J.; Marinkovic-Neducin, R. P.

    2007-01-01

    The behavior of NiO-Al2O3 catalysts is strongly dependent on the preparation method, as well as on pretreatment conditions. In the present work we investigated the influences of Ni(II) ion on NiO-Al2O3 catalysts properties due to the preparation by impregnation method. Based on experimental diffuse reflectance spectroscopy (DRS) data of electronic d-d transitions of Ni (II) promoter ion the energies of electronic states in spinel-like structure were calculated, and the most probable scheme of molecular orbital have been proposed

  19. Effect of preparation method on catalytic activity of Ni/ γ-Al2O3 catalysts

    International Nuclear Information System (INIS)

    Miranda Morales, Barbara

    2017-01-01

    The performance of catalysts was shown to be strongly dependent on their methods of preparation. A study to examine the relationship between catalyst preparation procedures and the structure, dispersion, activity, and selectivity of the finished catalyst is reported. 10 wt.%Ni/γ-Al 2 O 3 catalysts were prepared by incipient wetness impregnation and by wet impregnation. The catalysts were used in the conversion of glycerol in gas phase and atmospheric pressure. The selectivity and activity of the catalysts were affected by the preparation method employed. The catalysts were characterized by thermogravimetric analysis (TGA), temperature-programmed reduction (TPR), N 2 -physorption, H 2 -chemisorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR) and temperature-programmed oxidation (TPO). The Ni particle size and dispersion of the catalysts affected the selectivity to hydrogenolysis and dehydration routes, and the formation of carbon deposits was also affected. (author) [es

  20. Evaluation of Pt-Ru-Ni and Pt-Sn-Ni catalysts as anodes in direct ethanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ribadeneira, Esteban; Hoyos, Bibian A. [Escuela de Procesos y Energia, Facultad de Minas, Universidad Nacional de Colombia, Medellin (Colombia)

    2008-05-15

    In this study, the electrooxidation of ethanol on carbon supported Pt-Ru-Ni and Pt-Sn-Ni catalysts is electrochemically studied through cyclic voltammetry at 50 C in direct ethanol fuel cells. All electrocatalysts are prepared using the ethylene glycol-reduction process and are chemically characterized by energy-dispersive X-ray analysis (EDX). For fuel cell evaluation, electrodes are prepared by the transfer-decal method. Nickel addition to the anode improves DEFC performance. When Pt{sub 75}Ru{sub 15}Ni{sub 10}/C is used as an anode catalyst, the current density obtained in the fuel cell is greater than that of all other investigated catalysts. Tri-metallic catalytic mixtures have a higher performance relative to bi-metallic catalysts. These results are in agreement with CV results that display greater activity for PtRuNi at higher potentials. (author)

  1. Preparation and Characterization of NiMo/Al2O3Catalyst for Hydrocracking Processing

    Directory of Open Access Journals (Sweden)

    Widiyadi Aditya

    2018-01-01

    Full Text Available Hydrocracking is a chemical process used in petroleum refineries for converting high boiling hydrocarbons in petroleum crude oils to more valuable lower boiling products such as gasoline, kerosene, and diesel oil that operate at high temperature and pressure. Catalyst was used in hydrocracking to reduce temperature and pressure. Hydrocracking catalyst are composed of active components and support. Alumina is widely used in hydrocracking process as catalyst support due to its high surface area, high thermal stability, and low prices. The objective of this research was preparated NiMo/Al2O3 catalyst that used as hydrocracking catalyst. Catalyst was synthesized by wetness impregnation method and simple heating method with various kind of Al2O3. The physicochemical properties of catalyst were investigated by X-ray diffraction (XRD to determine type of crystal and scanning electron microscopy (SEM to determine morphology of the catalyst. The NiMo/Al2O3 catalyst prepared by aluminium potassium sulfate dodecahydrate exhibited the highest crystallinity of 90.23% and it is clear that MoO3 and NiO crystallites are highly dispersed on the NiMo/Al2O3 catalyst which indicates as the best catalyst. The catalytic activity in hydrocracking process was successfully examined to convert fatty acid into hydrocarbon.

  2. Preparation and Characterization of NiMo/Al2O3Catalyst for Hydrocracking Processing

    Science.gov (United States)

    Widiyadi, Aditya; Guspiani, Gema Adil; Riady, Jeffry; Andreanto, Rikky; Chaiunnisa, Safina Dea; Widayat

    2018-02-01

    Hydrocracking is a chemical process used in petroleum refineries for converting high boiling hydrocarbons in petroleum crude oils to more valuable lower boiling products such as gasoline, kerosene, and diesel oil that operate at high temperature and pressure. Catalyst was used in hydrocracking to reduce temperature and pressure. Hydrocracking catalyst are composed of active components and support. Alumina is widely used in hydrocracking process as catalyst support due to its high surface area, high thermal stability, and low prices. The objective of this research was preparated NiMo/Al2O3 catalyst that used as hydrocracking catalyst. Catalyst was synthesized by wetness impregnation method and simple heating method with various kind of Al2O3. The physicochemical properties of catalyst were investigated by X-ray diffraction (XRD) to determine type of crystal and scanning electron microscopy (SEM) to determine morphology of the catalyst. The NiMo/Al2O3 catalyst prepared by aluminium potassium sulfate dodecahydrate exhibited the highest crystallinity of 90.23% and it is clear that MoO3 and NiO crystallites are highly dispersed on the NiMo/Al2O3 catalyst which indicates as the best catalyst. The catalytic activity in hydrocracking process was successfully examined to convert fatty acid into hydrocarbon.

  3. Ni-Based Catalysts for the Hydrotreatment of Fast Pyrolysis Oil

    NARCIS (Netherlands)

    Ardiyanti, A. R.; Bykova, M. V.; Khromova, S. A.; Yin, W.; Venderbosch, R. H.; Yakovlev, V. A.; Heeres, Hero

    Catalytic hydrotreatment is an attractive technology to convert fast pyrolysis oil to stabilized oil products for co processing in conventional crude oil refinery units. We report here the use of novel bimetallic NiCu- and NiPd-based (Picula) catalysts characterized by a high Ni content (29-58 wt %)

  4. Development of Non-Noble Metal Ni-Based Catalysts for Dehydrogenation of Methylcyclohexane

    KAUST Repository

    Al-ShaikhAli, Anaam H.

    2016-11-30

    Liquid organic chemical hydride is a promising candidate for hydrogen storage and transport. Methylcyclohexane (MCH) to toluene (TOL) cycle has been considered as one of the feasible hydrogen carrier systems, but selective dehydrogenation of MCH to TOL has only been achieved using the noble Pt-based catalysts. The aim of this study is to develop non-noble, cost-effective metal catalysts that can show excellent catalytic performance, mainly maintaining high TOL selectivity achievable by Pt based catalysts. Mono-metallic Ni based catalyst is a well-known dehydrogenation catalyst, but the major drawback with Ni is its hydrogenolysis activity to cleave C-C bonds, which leads to inferior selectivity towards dehydrogenation of MCH to TOL. This study elucidate addition of the second metal to Ni based catalyst to improve the TOL selectivity. Herein, ubiquitous bi-metallic nanoparticles catalysts were investigated including (Ni–M, M: Ag, Zn, Sn or In) based catalysts. Among the catalysts investigated, the high TOL selectivity (> 99%) at low conversions was achieved effectively using the supported NiZn catalyst under flow of excess H2. In this work, a combined study of experimental and computational approaches was conducted to determine the main role of Zn over Ni based catalyst in promoting the TOL selectivity. A kinetic study using mono- and bimetallic Ni based catalysts was conducted to elucidate reaction mechanism and site requirement for MCH dehydrogenation reaction. The impact of different reaction conditions (feed compositions, temperature, space velocity and stability) and catalyst properties were evaluated. This study elucidates a distinctive mechanism of MCH dehydrogenation to TOL reaction over the Ni-based catalysts. Distinctive from Pt catalyst, a nearly positive half order with respect to H2 pressure was obtained for mono- and bi-metallic Ni based catalysts. This kinetic data was consistent with rate determining step as (somewhat paradoxically) hydrogenation

  5. Selective Conversion of Furfural to Cyclopentanone or Cyclopentanol Using Co-Ni Catalyst in Water

    Directory of Open Access Journals (Sweden)

    Yaru Li

    2018-05-01

    Full Text Available Co-Ni catalysts, prepared by a typical wetness impregnation method, can selectively convert furfural (FFA to cyclopentanone (CPO or cyclopentanol (CPL in water, respectively. The catalytic performance depends strongly on the support. It is also strongly influenced by the Co-Ni loadings of the catalyst. The 10%Co-10%Ni/TiO2 catalyst showed the highest selectivity toward CPO (53.3% with almost complete FFA conversion, and the main product was CPL (45.4% over 20%Co/TiO2 at the optimized conditions (150 °C, 4 MPa H2, 4 h. The surface morphology, surface area, composition and reducibility properties of these catalysts were fully characterized by XRD, H2-TPR, ICP-AES and SEM. The factors that influenced the activity of catalysts were also investigated in detail. Additionally, the stability of catalyst for the hydrogenative rearrangement of FFA was studied.

  6. Ni catalysts with different promoters supported on zeolite for dry reforming of methane

    KAUST Repository

    Alotaibi, Raja; Alenazey, Feraih; Alotaibi, Faisal; Wei, Nini; Al-Fatesh, Ahmed; Fakeeha, Anis

    2015-01-01

    Dry reforming of methane (DRM) is considered a high endothermic reaction with operating temperatures between 700 and 1000 °C to achieve high equilibrium conversion of CH4 and CO2 to the syngas (H2 and CO). The conventional catalysts used for DRM are Ni-based catalysts. However, many of these catalysts suffer from the short longevity due to carbon deposition. This study aims to evaluate the effect of La and Ca as promoters for Ni-based catalysts supported on two different zeolite supports, ZL (A) (BET surface area = 925 m2/g, SiO2/Al2O3 mol ratio = 5.1), and ZL (B) (BET surface area = 730 m2/g, SiO2/Al2O3 mol ratio = 12), for DRM. The physicochemical properties of the prepared catalysts were characterized with XRD, BET, TEM and TGA. These catalysts were tested for DRM in a microtubular reactor at reaction conditions of 700 °C. The catalyst activity results show that the catalysts Ni/ZL (B) and Ca-Ni/ZL (B) give the highest methane conversion (60 %) with less time on stream stability compared with promoted Ni on ZL (A). In contrast, La-containing catalysts, La-Ni/ZL (B), show more time on stream stability with minimum carbon content for the spent catalyst indicating the enhancement of the promoters to the Ni/ZL (A) and (B), but with less catalytic activity performance in terms of methane and carbon dioxide conversions due to rapid catalyst deactivation.

  7. Ni catalysts with different promoters supported on zeolite for dry reforming of methane

    KAUST Repository

    Alotaibi, Raja

    2015-07-08

    Dry reforming of methane (DRM) is considered a high endothermic reaction with operating temperatures between 700 and 1000 °C to achieve high equilibrium conversion of CH4 and CO2 to the syngas (H2 and CO). The conventional catalysts used for DRM are Ni-based catalysts. However, many of these catalysts suffer from the short longevity due to carbon deposition. This study aims to evaluate the effect of La and Ca as promoters for Ni-based catalysts supported on two different zeolite supports, ZL (A) (BET surface area = 925 m2/g, SiO2/Al2O3 mol ratio = 5.1), and ZL (B) (BET surface area = 730 m2/g, SiO2/Al2O3 mol ratio = 12), for DRM. The physicochemical properties of the prepared catalysts were characterized with XRD, BET, TEM and TGA. These catalysts were tested for DRM in a microtubular reactor at reaction conditions of 700 °C. The catalyst activity results show that the catalysts Ni/ZL (B) and Ca-Ni/ZL (B) give the highest methane conversion (60 %) with less time on stream stability compared with promoted Ni on ZL (A). In contrast, La-containing catalysts, La-Ni/ZL (B), show more time on stream stability with minimum carbon content for the spent catalyst indicating the enhancement of the promoters to the Ni/ZL (A) and (B), but with less catalytic activity performance in terms of methane and carbon dioxide conversions due to rapid catalyst deactivation.

  8. Pyrolysis of polyethylene terephthalate containing real waste plastics using Ni loaded zeolite catalysts

    Science.gov (United States)

    Al-asadi, M.; Miskolczi, N.

    2018-05-01

    In this work the pyrolysis of polyethylene terephthalate (PET) containing real waste plastic was investigated using different Ni loaded catalysts: Ni/ZSM-5, Ni/y-zeolite, Ni/β-zeolite and Ni/natural zeolite (clinoptilolite). Raw materials were pyrolyzed in a horizontal tubular reactor between 600 and 900°C using 10% of catalysts. It was found, that both temperature increasing and catalysts presence can increase the gas yields, however owing to gasification reactions, the pyrolysis oil yield decreased with increasing temperature. Ni/y-zeolite catalyst had the most benefit in gas yield increasing at low temperature; however Ni/ZSM-5 showed advanced property in gas yield increasing at high temperature. Gases contained hydrogen, carbon oxides and hydrocarbons, which composition was significantly affected by catalysts. Ni loaded zeolites favoured to the formation of hydrogen and branched hydrocarbons; furthermore the concentrations of both CO and CO2 were also increased as function of elevated temperature. That phenomenon was attributed to the further decomposition of PET, especially to the side chain scission reactions. Owing to the Boudouard reaction, the ratio of CO2/CO can increased with temperature. Pyrolysis oils were the mixtures of n-saturated, n-unsaturated, branched, oxygen free aromatics and oxygenated hydrocarbons. Temperature increasing has a significant effect to the aromatization and isomerization reactions, while the catalysts can efficiently decreased the concentration of oxygen containing compounds.

  9. Study of PtNi/C catalyst for direct ethanol fuel cell

    International Nuclear Information System (INIS)

    Moraes, L.P.R. de; Silva, E.L. da; Amico, S.C.; Malfatti, C.F.

    2014-01-01

    In this work, PtNi binary catalyst and pure platin catalyst were synthesized by the impregnation-reduction method, using Vulcan XC72R as support, for direct ethanol fuel cells. The composition and structure of the catalysts were analyzed by X-ray diffraction, the electrochemical behavior was evaluated by cyclic voltammetry and morphology of the catalysts was studied by high-resolution transmission electron microscopy. The results showed that the addition of Ni to Pt led to the contraction of the crystal lattice, increased the catalytic activity compared to pure Pt and initiated the electrooxidation of ethanol at lower potential. (author)

  10. Effects of adding lanthanum to Ni/ZrO2 catalysts on ethanol steam reforming

    International Nuclear Information System (INIS)

    Profeti, Luciene Paula Roberto; Habitzheuter, Filipe; Assaf, Elisabete Moreira

    2012-01-01

    The catalytic performance of Ni/ZrO 2 catalysts loaded with different lanthanum content for steam reforming of ethanol was investigated. Catalysts were characterized by BET surface area, X-ray diffraction, UV-vis spectroscopy, temperature programmed reduction, and X-ray absorption fine structure techniques. Results showed that lanthanum addition led to an increase in the degree of reduction of both NiO and nickel surface species interacting with the support, due to the higher dispersion effect. The best catalytic performance at 450 deg C was found for the Ni/12LZ catalyst, which exhibited an effluent gaseous mixture with the highest H 2 yield. (author)

  11. Ordered Mesoporous NiCeAl Containing Catalysts for Hydrogenolysis of Sorbitol to Glycols

    Science.gov (United States)

    Zhou, Zhiwei; Zhang, Jiaqi; Qin, Juan; Li, Dong; Wu, Wenliang

    2018-03-01

    Cellulose-derived sorbitol is emerging as a feasible and renewable feedstock for the production of value-added chemicals. Highly active and stable catalyst is essential for sorbitol hydrogenolysis. Ordered mesoporous M- xNi yCeAl catalysts with different loadings of nickel and cerium species were successfully synthesized via one-pot evaporation-induced self-assembly strategy (EISA) and their catalytic performance were tested in the hydrogenolysis of sorbitol. The physical chemical properties for the catalysts were characterized by XRD, N2 physisorption, H2-TPR, H2 impulse chemisorption, ICP and TEM techniques. The results showed that the ordered mesopores with uniform pore sizes can be obtained and the Ni nanoparticles around 6 nm in size were homogeneously dispersed in the mesopore channels. A little amount of cerium species introduced would be beneficial to their textural properties resulting in higher Ni dispersion, metal area and smaller size of Ni nanoparticles. The M-10Ni2CeAl catalyst with Ni and Ce loading of 10.9 and 6.3 wt % shows better catalytic performance than other catalysts, and the yield of 1,2-PG and EG can reach 56.9% at 493 K and 6 MPa pressure for 8 h after repeating reactions for 12 times without obvious deterioration of physical and chemical properties. Ordered mesoporous M-NiCeAl catalysts are active and stable in sorbitol hydrogenolysis.

  12. Catalysts characteristics of Ni/YSZ core-shell according to plating conditions using electroless plating

    Science.gov (United States)

    Park, Hyun-Wook; Jang, Jae-Won; Lee, Young-Jin; Kim, Jin-Ho; Jeon, Dae-Woo; Lee, Jong-Heun; Hwang, Hae-jin; Lee, Mi-Jai

    2017-11-01

    This study aims to develop an anode catalyst for a solid oxide fuel cell (SOFC) using electroless nickel plating. We have proposed a new method for electroless plating of Ni metal on yttria-stabilized zirconia (YSZ) particles. We examine the uniformity of the Ni layer on the plated core-shell powder, in addition to the content of Ni and the reproducibility of the plating. We have also evaluated the carbon deposition rate and characteristics of the SOFC anode catalyst. To synthesize Ni-plated YSZ particles, the plated powder is heat-treated at 1200 °C. The resultant particles, which have an average size of 50 μm, were subsequently used in the experiment. The size of the Ni particles and the Ni content both increase with increasing plating temperature and plating time. The X-ray diffraction pattern reveals the growth of Ni particles. After heat-treatment, Ni is oxidized to NiO, leading to the co-existence of Ni and NiO; Ni3P is also observed due to the presence of phosphorous in the plating solution. Following heat treatment for 1 h at 1200 °C, Ni is mostly oxidized to NiO. The carbon deposition rate of the reference YSZ powder is 135%, while that of the Ni-plated YSZ is 1%-6%.

  13. Influence of ni addition to a low-loaded palladium catalyst on the selective hydrogenation of 1-heptyne

    Directory of Open Access Journals (Sweden)

    Cecilia R. Lederhos

    2010-01-01

    Full Text Available Semi-hydrogenation of alkynes has industrial and academic relevance on a large scale. To increase the activity, selectivity and lifetime of monometallic catalysts, the development of bimetallic catalysts has been investigated. 1-Heptyne hydrogenation over low-loaded Pd and Ni monometallic and PdNi bimetallic catalysts was studied in liquid phase at mild conditions. XPS results suggest that nickel addition to Pd modifies the electronic state of palladium as nickel loading is increased. Low-loaded Pd catalysts showed the highest selectivities (> 95%. The most active prepared catalyst, PdNi(1%, was more selective than the Lindlar catalyst.

  14. Enhanced activity of Pt/CNTs anode catalyst for direct methanol fuel cells using Ni2P as co-catalyst

    Science.gov (United States)

    Li, Xiang; Luo, Lanping; Peng, Feng; Wang, Hongjuan; Yu, Hao

    2018-03-01

    The direct methanol fuel cell is a promising energy conversion device because of the utilization of the state-of-the-art platinum (Pt) anode catalyst. In this work, novel Pt/Ni2P/CNTs catalysts were prepared by the H2 reduction method. It was found that the activity and stability of Pt for methanol oxidation reaction (MOR) could be significantly enhanced while using nickel phosphide (Ni2P) nanoparticles as co-catalyst. X-ray photoelectron spectroscopy revealed that the existence of Ni2P affected the particle size and electronic distribution of Pt obviously. Pt/CNTs catalyst, Pt/Ni2P/CNTs catalysts with different Ni2P amount were synthesized, among which Pt/6%Ni2P/CNTs catalyst exhibited the best MOR activity of 1400 mAmg-1Pt, which was almost 2.5 times of the commercial Pt/C-JM catalyst. Moreover, compared to other Pt-based catalysts, this novel Pt/Ni2P/CNTs catalyst also exhibited higher onset current density and better steady current density. The result of this work may provide positive guidance to the research on high efficiency and stability of Pt-based catalyst for direct methanol fuel cells.

  15. Understanding the Performance and Stability of Supported Ni-Co-Based Catalysts in Phenol HDO

    Directory of Open Access Journals (Sweden)

    Thuan M. Huynh

    2016-11-01

    Full Text Available Performances of bimetallic catalysts (Ni-Co supported on different acidic carriers (HZSM-5, HBeta, HY, ZrO2 and corresponding monometallic Ni catalysts in aqueous phase hydrodeoxygenation of phenol were compared in batch and continuous flow modes. The results revealed that the support acidity plays an important role in deoxygenation as it mainly controls the oxygen-removing steps in the reaction network. At the same time, sufficient hydrothermal stability of a solid catalyst is essential. Batch experiments revealed 10Ni10Co/HZSM-5 to be the best-performing catalyst in terms of conversion and cyclohexane yield. Complementary continuous runs provided more insights into the relationship between catalyst structure, efficiency and stability. After 24 h on-stream, the catalyst still reveals 100% conversion and a slight loss (from 100% to 90% in liquid hydrocarbon selectivity. The observed alloy of Co with Ni increased dispersion and stability of Ni-active sites, and combination with HZSM-5 resulted in a well-balanced ratio of metal and acid sites which promoted all necessary steps in preferred pathways. This was proved by studies of fresh and spent catalysts using various characterization techniques (N2 physisorption, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, transmission electron microscopy (TEM and infrared spectroscopy of adsorbed pyridine (pyr-IR.

  16. Recent Scientific Progress on Developing Supported Ni Catalysts for Dry (CO2 Reforming of Methane

    Directory of Open Access Journals (Sweden)

    Hyun Ook Seo

    2018-03-01

    Full Text Available Two major green house gases (CO2 and CH4 can be converted into useful synthetic gas (H2 and CO during dry reforming of methane (DRM reaction, and a lot of scientific efforts has been made to develop efficient catalysts for dry reforming of methane (DRM. Noble metal-based catalysts can effectively assist DRM reaction, however they are not economically viable. Alternatively, non-noble based catalysts have been studied so far, and supported Ni catalysts have been considered as a promising candidate for DRM catalyst. Main drawback of Ni catalysts is its catalytic instability under operating conditions of DRM (>700 °C. Recently, it has been demonstrated that the appropriate choice of metal-oxide supports can address this issue since the chemical and physical of metal-oxide supports can prevent coke formation and stabilize the small Ni nanoparticles under harsh conditions of DRM operation. This mini-review covers the recent scientific findings on the development of supported Ni catalysts for DRM reaction, including the synthetic methods of supported Ni nanoparticles with high sintering resistance.

  17. Alloyed Ni-Fe nanoparticles as catalysts for NH3 decomposition

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Chakraborty, Debasish; Chorkendorff, Ib

    2012-01-01

    A rational design approach was used to develop an alloyed Ni-Fe/Al2O3 catalyst for decomposition of ammonia. The dependence of the catalytic activity is tested as a function of the Ni-to-Fe ratio, the type of Ni-Fe alloy phase, the metal loading and the type of oxide support. In the tests with high...... temperatures and a low NH3-to-H2 ratio, the catalytic activity of the best Ni-Fe/Al2O3 catalyst was found to be comparable or even better to that of a more expensive Ru-based catalyst. Small Ni-Fe nanoparticle sizes are crucial for an optimal overall NH3 conversion because of a structural effect favoring...

  18. Bimetallic Ag–Ni/C particles as cathode catalyst in AFCs (alkaline fuel cells)

    International Nuclear Information System (INIS)

    Song, Xingjuan; Zhang, Dongming

    2014-01-01

    AFCs (alkaline fuel cells) is one of the promising fuel cells, due to their low working temperature and less corrosive environment. However, decreasing the catalyst cost and improving its performance are still the challenges in its application. Transition metal as the catalyst for AFCs not only can reduce its cost, but also has great electro-catalytic efficiency. In this paper, Carbon supported Ag–Ni bimetallic catalysts with differential Ag/Ni atomic ratios were prepared by chemically reducing silver and nickel salts. Ag 3 Ni/C shows the relatively higher ORR (oxygen reduction reaction) activity among the differential Ag/Ni bimetallic particles. In order to improve the activity and stability, the catalysts were heat-treated at the temperature of 500 °C. The results indicate that the limiting current density has been improved greatly for Ag 3 Ni/C-500 °C, which is as high as 2.5× that of Ag/C. The microstructure investigation show that the non-equilibrium state of Ag–Ni alloy by heat treatment is confirmed by HRTEM (high-resolution transmission electron microscopy) images, and Ag(111) surfaces are decreased in XRD pattern, which results in the ORR activity improved and overpotential decreased. Heat treatment also has contributed to Ag–Ni/C electrochemistry stability in some degree. - Highlights: • Ag–Ni/C is applied as cathode catalyst for AFCs (alkaline fuel cells). • Ag 3 Ni/C-500 °C shows the best performance. • Non-equilibrium state of Ag–Ni alloy by heat treatment is observed. • The decreased Ag(111) surfaces are favor to improve the catalyst activity

  19. Synthesis of Ni-Pt catalysts and characterization

    International Nuclear Information System (INIS)

    Santos, Everton R.F. dos; Sousa, Bianca Viana de; Barbosa, Antonielly dos Santos; Leite, Romulo C.N.; Rodrigues, Meiry G.F.

    2009-01-01

    In this work, bifunctionals catalysts using the MCM-22 zeolite as support and the nickel and platinum metal as hydrogenation/dehydrogenation sites were prepared. The method used for metal dispersion on the zeolite was the competitive ion exchange, using the amine complex [Pt(NH 3 ) 4 ]Cl 2 and [Ni(NH 3 ) 6 ]Cl 2 . After the exchange reactions, the samples were calcinated at 500 deg C for 2 hours and reduced at this same temperature under hydrogen flow. The MCM-22 zeolite and samples containing the metal were characterized by the techniques of: EDX, XRD, DTA/TGA. The diffractions of the precursor MCM-22 (P) presented typical peaks of the MWW topology composed by intercalated lamellar layers with organic molecules that are constituents of the template (HMI). According to the XRD pattern of the calcinated sample, no peaks related to the organic material which is responsible to produce the MCM-22 zeolite were detected. By thermogravimetry it was verified that the removal of the template took place between 500 and 650 deg C proving the effectiveness of the removal process. The chemical analysis by X-ray spectrometric was evidenced this the incorporation in the zeolites of platinum and nickel for all the texts in study. Results from XRD confirming the stability and crystal in study of zeolites. (author)

  20. Solvothermal conversion of technical lignins over NiMo catalysts

    DEFF Research Database (Denmark)

    Ghafarnejad Parto, Soheila; Christensen, Jakob Munkholt; Pedersen, Lars Saaby

    Scope: Lignin, cellulose and hemicellulose are the main constituents of plants cell walls. Lignin is an aromatic rich compound, composed of phenolic building blocks. Depending on the method used for isolation of lignin from cellulose and hemicellulose, several types of technical lignin are availa......Scope: Lignin, cellulose and hemicellulose are the main constituents of plants cell walls. Lignin is an aromatic rich compound, composed of phenolic building blocks. Depending on the method used for isolation of lignin from cellulose and hemicellulose, several types of technical lignin...... of the range of available technical lignins. In this work, catalytic conversion of different types of lignin using an alumina supported NiMo catalyst (provided by Haldor Topsøe A/S) is conducted in ethanol at 310 ˚C with initial hydrogen pressure of 25 barg. The reaction time was set to 3 hours. Proton......, attributed as ‘bio-oil’. GC-MS-FID analysis was used for identification and quantification of the bio-oil and ethanol rich light fraction. The molecular weight of the oil fraction was determined by size exclusion chromatography (SEC). Elemental analysis (Eurovector EuroEA3000) was conducted for measuring...

  1. Catalytic reforming of glycerol in supercritical water over bimetallic Pt-Ni catalyst

    NARCIS (Netherlands)

    Chakinala, A.G.; van Swaaij, Willibrordus Petrus Maria; Kersten, Sascha R.A.; de Vlieger, Dennis; Seshan, Kulathuiyer; Brilman, Derk Willem Frederik

    2013-01-01

    Catalytic reforming of pure glycerol for the production of hydrogen at low temperature and short residence times in supercritical water was investigated using a bimetallic Pt–Ni catalyst supported on alumina. Initial tests were carried out to study the reforming activity of bimetallic Pt–Ni

  2. Discovery of a Ni-Ga catalyst for carbon dioxide reduction to methanol

    DEFF Research Database (Denmark)

    Studt, Felix; Sharafutdinov, Irek; Abild-Pedersen, Frank

    2014-01-01

    The use of methanol as a fuel and chemical feedstock could become very important in the development of a more sustainable society if methanol could be efficiently obtained from the direct reduction of CO 2 using solar-generated hydrogen. If hydrogen production is to be decentralized, small-scale CO...... 2 reduction devices are required that operate at low pressures. Here, we report the discovery of a Ni-Ga catalyst that reduces CO 2 to methanol at ambient pressure. The catalyst was identified through a descriptor-based analysis of the process and the use of computational methods to identify Ni......-Ga intermetallic compounds as stable candidates with good activity. We synthesized and tested a series of catalysts and found that Ni 5 Ga 3 is particularly active and selective. Comparison with conventional Cu/ZnO/Al 2 O 3 catalysts revealed the same or better methanol synthesis activity, as well as considerably...

  3. Development of Highly Nano-Dispersed NiO/GDC Catalysts from Ion Exchange Resin Templates

    Directory of Open Access Journals (Sweden)

    Angel Caravaca

    2017-11-01

    Full Text Available Novel NiO/GDC (Gadolinium-doped Ceria cermet catalysts were developed by the Weak Acid Resin (WAR method using an ion exchange resin template. In addition, the specific surface area of these tunable materials was enhanced by NiO partial dissolution in aqueous acid solution. The whole procedure highly improved the micro-structural properties of these materials compared to previous studies. Catalysts with high metal loadings (≥10%, small Ni nanoparticles (<10 nm, and high specific surface areas (>70 m2/g were achieved. These properties are promising for catalytic applications such as methane steam reforming for H2 production.

  4. Hydrogen generation from decomposition of hydrous hydrazine over Ni-Ir/CeO2 catalyst

    Directory of Open Access Journals (Sweden)

    Hongbin Dai

    2017-02-01

    Full Text Available The synthesis of highly active and selective catalysts is the central issue in the development of hydrous hydrazine (N2H4·H2O as a viable hydrogen carrier. Herein, we report the synthesis of bimetallic Ni-Ir nanocatalyts supported on CeO2 using a one-pot coprecipitation method. A combination of XRD, HRTEM and XPS analyses indicate that the Ni-Ir/CeO2 catalyst is composed of tiny Ni-Ir alloy nanoparticles with an average size of around 4 nm and crystalline CeO2 matrix. The Ni-Ir/CeO2 catalyst exhibits high catalytic activity and excellent selectivity towards hydrogen generation from N2H4·H2O at mild temperatures. Furthermore, in contrast to previously reported Ni-Pt catalysts, the Ni-Ir/CeO2 catalyst shows an alleviated requirement on alkali promoter to achieve its optimal catalytic performance.

  5. Catalytic hydrotreatment of fast pyrolysis oil using bimetallic Ni-Cu catalysts on various supports

    NARCIS (Netherlands)

    Ardiyanti, A. R.; Khromova, S. A.; Venderbosch, R. H.; Yakovlev, V. A.; Melian-Cabrera, I. V.; Heeres, H. J.

    2012-01-01

    Bimetallic Ni-Cu catalysts on various Supports (CeO2-ZrO2, ZrO2, SiO2, TiO2, rice husk carbon, and Sibunite) with metal contents ranging from 7.5 to 9.0 (Ni) and 3.1-3.6 wt.% (Cu) for the inorganic supports and 17.1-17.8 (Ni) and 7.1-7.8 (Cu) for the carbon supports were synthesised and screened for

  6. Electrochemical behavior of Ni-Mo electro catalyst for water electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez V, S. M.; Ordonez R, E. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Cabanas M, G. [IPN, Centro de Nanociencias y Micro y Nanotecnologias, A. P. 75-874, 07300 Mexico D. F. (Mexico); Solorza F, O., E-mail: suilma.fernandez@inin.gob.m [IPN, Centro de Investigacion y de Estudios Avanzados, Departamento de Quimica, A. P. 14-740, 07000 Mexico D. F. (Mexico)

    2010-07-01

    Nickel-molybdenum based electrocatalysts were synthesized in organic media for the hydrogen evolution reaction and oxygen evolution reaction in alkaline media. The structure, morphology and chemical composition of the catalysts were evaluated by X-ray diffraction, scanning electron microscopy and Aas. Results revealed nanocrystalline powder materials with Ni{sub 0.006}Mo, Ni{sub 0.1}Mo and Ni Mo compositions. The best performance for hydrogen evolution reaction, was obtained on Ni{sub 0.1}Mo electrode, whereas Ni Mo was for the oxygen evolution reaction. Results suggest that the material with 1:1 stoichiometric ratio could be considered as a promising electro catalyst for oxygen evolution reaction. This nanocrystalline powder is formed by Ni{sub 2}Mo{sub 3}O{sub 8} and a crystalline structure attributed to the possible formation of a Ni Mo cluster, becomes NiMoO{sub 4} after thermal treatment at 1073 K in air. The Ni Mo 1:1 cluster catalyst presented electrochemical stability during the oxygen evolution reaction. (Author)

  7. Electrochemical behavior of Ni-Mo electro catalyst for water electrolysis

    International Nuclear Information System (INIS)

    Fernandez V, S. M.; Ordonez R, E.; Cabanas M, G.; Solorza F, O.

    2010-01-01

    Nickel-molybdenum based electrocatalysts were synthesized in organic media for the hydrogen evolution reaction and oxygen evolution reaction in alkaline media. The structure, morphology and chemical composition of the catalysts were evaluated by X-ray diffraction, scanning electron microscopy and Aas. Results revealed nanocrystalline powder materials with Ni 0.006 Mo, Ni 0.1 Mo and Ni Mo compositions. The best performance for hydrogen evolution reaction, was obtained on Ni 0.1 Mo electrode, whereas Ni Mo was for the oxygen evolution reaction. Results suggest that the material with 1:1 stoichiometric ratio could be considered as a promising electro catalyst for oxygen evolution reaction. This nanocrystalline powder is formed by Ni 2 Mo 3 O 8 and a crystalline structure attributed to the possible formation of a Ni Mo cluster, becomes NiMoO 4 after thermal treatment at 1073 K in air. The Ni Mo 1:1 cluster catalyst presented electrochemical stability during the oxygen evolution reaction. (Author)

  8. ACTIVITY TEST AND REGENERATION OF NiMo/Z CATALYST FOR HYDROCRACKING OF WASTE PLASTIC FRACTION TO GASOLINE FRACTION

    Directory of Open Access Journals (Sweden)

    Rodiansono Rodiansono

    2010-06-01

    Full Text Available Activity test and regeneration of NiMo/active natural zeolite catalyst for hydrocracking of waste plastic fraction of polyprophylene (PP type have been carried out. The catalysts was prepared by loading Mo followed by Ni Metals onto the natural zeolite (Z sample, then calcined at 500oC, oxidized and reduced at 400oC under nitrogen, oxygen and hydrogen stream, respectively. The characterization of catalysts including spesific surface area, average pore radius, and total pore volume were performed by gas sorption analyzer, amount of total acid sites was determined by gas sorption method, and acid site strength was confirmed by IR spectroscopy. The hydrocracking process was carried out in a semi-flow reactor system at 360 oC and catalyst:feed ratio 0.5 under hydrogen stream (150 mL/hour. The feed was vaporized from the pyrolisis reactor into the hydrocracking reactor. A liquid product was collected and analyzed by gas chromatography (GC and gas chromatography-mass spectroscopy (GC-MS. The characterization results showed that spesific surface area, average pore radius, and total pore volume of the Z sample decreased after loading of the Ni and Mo metals. Amount of total acid sites of the NiMo/Z catalyst was higher than that of the Z sample. The activity of NiMo/Z catalyst decreased after several continously runs. Its regeneration produced the NiMo/Z reg catalyst with similar activity and selectivity to the fresh catalyst (NiMo/Z. The activity of catalysts at the optimum condition followed the order of NiMo/Z reg>NiMo/Z>Z (conversion of hydrocarbon C>12 and NiMo/Z reg>NiMo/Z>Z (total yield of gasoline fraction. The selectivity of catalysts for C7-C8 product followed the order of Z>NiMo/Z>NiMo/Z reg. Keywords: activity, polyprophylene, catalyst, gasoline fraction.

  9. An Alumina-Supported Ni-La-Based Catalyst for Producing Synthetic Natural Gas

    Directory of Open Access Journals (Sweden)

    Daniel E. Rivero-Mendoza

    2016-10-01

    Full Text Available LaNi5, known for its hydrogen storage capability, was adapted to the form of a metal oxide-supported (γ-Al2O3 catalyst and its performance for the Sabatier reaction assessed. The 20 wt % La-Ni/γ-Al2O3 particles were prepared via solution combustion synthesis (SCS and exhibited good catalytic activity, achieving a CO2 conversion of 75% with a high CH4 selectivity (98% at 1 atm and 300 °C. Characteristics of the La-Ni/γ-Al2O3 catalyst were identified at various stages of the catalytic process (as-prepared, activated, and post-reaction and in-situ DRIFTS was used to probe the reaction mechanism. The as-prepared catalyst contained amorphous surface La–Ni spinels with particle sizes <6 nm. The reduction process altered the catalyst make-up where, despite the reducing conditions, Ni2+-based particles with diameters between 4 and 20 nm decorated with LaOx moieties were produced. However, the post-reaction catalyst had particle sizes of 4–9 nm and comprised metallic Ni, with the LaOx decoration reverting to a form akin to the as-prepared catalyst. DRIFTS analysis indicated that formates and adsorbed CO species were present on the catalyst surface during the reaction, implying the reaction proceeded via a H2-assisted and sequential CO2 dissociation to C and O. These were then rapidly hydrogenated into CH4 and H2O.

  10. Hydrotreatment of heavy oil from coal liquefaction on Sulfide Ni - W Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zhi-ping Lei; Li-juan Gao; Heng-fu Shui; Shi-biao, Ren; Zhi-cai Wang; Kang-shi Gang, E-mail: shhf@ahut.edu.c [Anhui University of Technology, Maanshan (China). School of Chemistry and Chemical Engineering. Anhui Key Lab. of Coal Clean Conversion and Utilization

    2011-07-01

    Heavy oil (distillation temperature: 320-340 deg C) derived from the direct coal liquefaction process using Shengli coal were hydrotreated using sulfided Ni-Mo/Al{sub 2}O{sub 3}, Ni-W/Al{sub 2}O{sub 3}, and Ni-W/SiO{sub 2} catalysts respectively. The sulfided catalysts were characterized by BET, XRD, H{sub 2}-TPR and NH{sub 3}-TPD respectively. The evaluations of the hydrodenitrogenation (HDN) and hydrodearomatization (HDA) properties of heavy oil on the three catalysts were carried out at 400 deg C and 5.0 MPa initial H2 pressure. The W-based catalysts displayed better performances than Mo-based catalysts for the HDN and HDA reactions. Al{sub 2}O{sub 3} supported catalysts were found to have higher catalytic activities than on SiO{sub 2} supported ones. The activities of sulfided catalysts were associated mainly with the nature of active sites, acidity, metal sulfide crystallite size and the amount of the reducible sulfur species of metal sulfide. (author)

  11. Hydrotreatment of heavy oil from coal liquefaction on Sulfide Ni - W Catalysts

    International Nuclear Information System (INIS)

    Zhi-ping Lei; Li-juan Gao; Heng-fu Shui; Shi-biao, Ren; Zhi-cai Wang; Kang-shi Gang

    2011-01-01

    Heavy oil (distillation temperature: 320-340 deg C) derived from the direct coal liquefaction process using Shengli coal were hydrotreated using sulfided Ni-Mo/Al 2 O 3 , Ni-W/Al 2 O 3 , and Ni-W/SiO 2 catalysts respectively. The sulfided catalysts were characterized by BET, XRD, H 2 -TPR and NH 3 -TPD respectively. The evaluations of the hydrodenitrogenation (HDN) and hydrodearomatization (HDA) properties of heavy oil on the three catalysts were carried out at 400 deg C and 5.0 MPa initial H2 pressure. The W-based catalysts displayed better performances than Mo-based catalysts for the HDN and HDA reactions. Al 2 O 3 supported catalysts were found to have higher catalytic activities than on SiO 2 supported ones. The activities of sulfided catalysts were associated mainly with the nature of active sites, acidity, metal sulfide crystallite size and the amount of the reducible sulfur species of metal sulfide. (author)

  12. Effect of Phosphine Doping and the Surface Metal State of Ni on the Catalytic Performance of Ni/Al2O3 Catalyst

    Directory of Open Access Journals (Sweden)

    Xiaoru Li

    2015-04-01

    Full Text Available Ni-based catalysts as replacement for noble metal catalysts are of particular interest in the catalytic conversion of biomass due to their cheap and satisfactory catalytic activity. The Ni/SiO2 catalyst has been studied for the hydrogenolysis of glycerol, and doping with phosphorus (P found to improve the catalytic performance significantly because of the formation of Ni2P alloys. However, in the present work we disclose a different catalytic phenomenon for the P-doped Ni/Al2O3 catalyst. We found that doping with P has a significant effect on the state of the active Ni species, and thus improves the selectivity to 1,2-propanediol (1,2-PDO significantly in the hydrogenolysis of glycerol, although Ni-P alloys were not observed in our catalytic system. The structure and selectivity correlations were determined from the experimental data, combining the results of X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, hydrogen temperature-programmed reduction (H2-TPR and ammonia temperature-programmed desorption (NH3-TPD. The presence of NiO species, formed from P-doped Ni/Al2O3 catalyst, was shown to benefit the formation of 1,2-PDO. This was supported by the results of the Ni/Al2O3 catalyst containing NiO species with incomplete reduction. Furthermore, the role the NiO species played in the reaction and the potential reaction mechanism over the P-doped Ni/Al2O3 catalyst is discussed. The new findings in the present work open a new vision for Ni catalysis and will benefit researchers in designing Ni-based catalysts.

  13. Ni hollow spheres as catalysts for methanol and ethanol electrooxidation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Changwei [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China); School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Hu, Yonghong; Rong, Jianhua; Liu, Yingliang [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China); Jiang, San Ping [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2007-08-15

    In this paper, we successfully synthesized Ni hollow spheres consisting of needle-like nickel particles by using silica spheres as template with gold nanoparticles seeding method. The Ni hollow spheres are applied to methanol and ethanol electrooxidation in alkaline media. The results show that the Ni hollow spheres give a very high activity for alcohol electrooxidation at a very low nickel loading of 0.10 mg cm{sup -2}. The current on Ni hollow spheres is much higher than that on Ni particles. The onset potential and peak potential on Ni hollow spheres are more negative than that on Ni particles for methanol and ethanol electrooxidation. The Ni hollow spheres may be of great potential in alcohol sensor and direct alcohol fuel cells. (author)

  14. Activity of platinum/carbon and palladium/carbon catalysts promoted by Ni2 P in direct ethanol fuel cells.

    Science.gov (United States)

    Li, Guoqiang; Feng, Ligang; Chang, Jinfa; Wickman, Björn; Grönbeck, Henrik; Liu, Changpeng; Xing, Wei

    2014-12-01

    Ethanol is an alternative fuel for direct alcohol fuel cells, in which the electrode materials are commonly based on Pt or Pd. Owing to the excellent promotion effect of Ni2 P that was found in methanol oxidation, we extended the catalyst system of Pt or Pd modified by Ni2 P in direct ethanol fuel cells. The Ni2 P-promoted catalysts were compared to commercial catalysts as well as to reference catalysts promoted with only Ni or only P. Among the studied catalysts, Pt/C and Pd/C modified by Ni2 P (30 wt %) showed both the highest activity and stability. Upon integration into the anode of a homemade direct ethanol fuel cell, the Pt-Ni2 P/C-30 % catalyst showed a maximum power density of 21 mW cm(-2) , which is approximately two times higher than that of a commercial Pt/C catalyst. The Pd-Ni2 P/C-30 % catalyst exhibited a maximum power density of 90 mW cm(-2) . This is approximately 1.5 times higher than that of a commercial Pd/C catalyst. The discharge stability on both two catalysts was also greatly improved over a 12 h discharge operation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Structured Ni catalysts on porous anodic alumina membranes for methane dry reforming: NiAl 2 O 4 formation and characterization

    KAUST Repository

    Zhou, Lu

    2015-06-29

    This communication presents the successful design of a structured catalyst based on porous anodic alumina membranes for methane dry reforming. The catalyst with a strong Ni-NiAl2O4 interaction shows both excellent activity and stability. This journal is © The Royal Society of Chemistry.

  16. Hydrogenation of naphthalene on NiMo- Ni- and Ru/Al{sub 2}O{sub 3} catalysts. Langmuir-Hinshelwood kinetic modelling

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro-Gezork, Ana Cristina Alves; Winterbottom, John Mike [Department of Chemical Engineering, School of Engineering, The University of Birmingham, Birmingham B15 2TT (United Kingdom); Natividad, Reyna [Department of Chemical Engineering, Faculty of Chemistry, Universidad Autonoma del Estado de Mexico, Paseo Colon Esq. Tollocan, Toluca, Edo. de Mexico, Mexico CP 50120 (Mexico)

    2008-01-30

    The importance of the hydrodearomatisation (HDA) is increasing together with tightening legislation of fuel quality and exhaust emissions. The present study focuses on hydrogenation (HYD) kinetics of the model aromatic compound naphthalene, found in typical diesel fraction, in n-hexadecane over a NiMo (nickel molybdenum), Ni (nickel) and Ru (ruthenium) supported on trilobe alumina (Al{sub 2}O{sub 3}) catalysts. Kinetic reaction expressions based on the mechanistic Langmuir-Hinshelwood (L-H) model were derived and tested by regressing the experimental data that translated the effect of both naphthalene and hydrogen concentration at a constant temperature (523.15 and 573.15 K over the NiMo catalyst and at 373.15 K over the Ni and Ru/Al{sub 2}O{sub 3} catalysts) on the initial reaction rate. The L-H equation, giving an adequate fit to the experimental data with physically meaningful parameters, suggested a competitive adsorption between hydrogen and naphthalene over the presulphided NiMo catalyst and a non-competitive adsorption between these two reactants over the prereduced Ni and Ru/Al{sub 2}O{sub 3} catalysts. In addition, the adsorption constant values indicated that the prereduced Ru catalyst was a much more active catalyst towards naphthalene HYD than the prereduced Ni/Al{sub 2}O{sub 3} or the presulphided NiMo/Al{sub 2}O{sub 3} catalyst. (author)

  17. Structured Ni catalysts on porous anodic alumina membranes for methane dry reforming: NiAl 2 O 4 formation and characterization

    KAUST Repository

    Zhou, Lu; Guo, Y.; Basset, Jean-Marie; Kameyama, H.

    2015-01-01

    This communication presents the successful design of a structured catalyst based on porous anodic alumina membranes for methane dry reforming. The catalyst with a strong Ni-NiAl2O4 interaction shows both excellent activity and stability. This journal is © The Royal Society of Chemistry.

  18. Intermetallic nickel silicide nanocatalyst-A non-noble metal-based general hydrogenation catalyst.

    Science.gov (United States)

    Ryabchuk, Pavel; Agostini, Giovanni; Pohl, Marga-Martina; Lund, Henrik; Agapova, Anastasiya; Junge, Henrik; Junge, Kathrin; Beller, Matthias

    2018-06-01

    Hydrogenation reactions are essential processes in the chemical industry, giving access to a variety of valuable compounds including fine chemicals, agrochemicals, and pharmachemicals. On an industrial scale, hydrogenations are typically performed with precious metal catalysts or with base metal catalysts, such as Raney nickel, which requires special handling due to its pyrophoric nature. We report a stable and highly active intermetallic nickel silicide catalyst that can be used for hydrogenations of a wide range of unsaturated compounds. The catalyst is prepared via a straightforward procedure using SiO 2 as the silicon atom source. The process involves thermal reduction of Si-O bonds in the presence of Ni nanoparticles at temperatures below 1000°C. The presence of silicon as a secondary component in the nickel metal lattice plays the key role in its properties and is of crucial importance for improved catalytic activity. This novel catalyst allows for efficient reduction of nitroarenes, carbonyls, nitriles, N-containing heterocycles, and unsaturated carbon-carbon bonds. Moreover, the reported catalyst can be used for oxidation reactions in the presence of molecular oxygen and is capable of promoting acceptorless dehydrogenation of unsaturated N-containing heterocycles, opening avenues for H 2 storage in organic compounds. The generality of the nickel silicide catalyst is demonstrated in the hydrogenation of over a hundred of structurally diverse unsaturated compounds. The wide application scope and high catalytic activity of this novel catalyst make it a nice alternative to known general hydrogenation catalysts, such as Raney nickel and noble metal-based catalysts.

  19. Microwave-activated Ni/carbon catalysts for highly selective hydrogenation of nitrobenzene to cyclohexylamine.

    Science.gov (United States)

    Lu, Xinhuan; He, Jie; Jing, Run; Tao, Peipei; Nie, Renfeng; Zhou, Dan; Xia, Qinghua

    2017-06-01

    Biocarbon supported Ni catalysts have been prepared by facile impregnation of Ni species by microwave-heating and used for selective hydrogenation of nitrobenzene to cyclohexylamine. These catalysts were characterized by X-ray diffraction, Raman spectra, N2 sorption measurement, X-ray photoelectron spectroscopy, temperature programmed reduction of H2 and H2 temperature-programmed desorption. The morphology and particle size of catalysts were imaged by scanning electron microscope and transmission electron microscope. For the hydrogenation of nitrobenzene to cyclohexylamine, 10%Ni/CSC-II(b) exhibits the best catalytic activity to achieve 100 mol% conversion of nitrobenzene and 96.7% selectivity of cyclohexylamine under reaction conditions of 2.0 MPa H2 and 200 °C, ascribed to high dispersion of Ni species and formation of nanosized Ni particles on the support aided by microwave-heating. Thus-prepared Ni/CSC catalyst is greatly activated, in which the addition of precious metal like Rh is totally avoided.

  20. Fe/Ni-N-CNFs electrochemical catalyst for oxygen reduction reaction/oxygen evolution reaction in alkaline media

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhuang [MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Li, Mian [Faculty of Chemistry, Northeast Normal University, Changchun 130024 (China); Fan, Liquan; Han, Jianan [MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Xiong, Yueping, E-mail: ypxiong@hit.edu.cn [MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2017-04-15

    Highlights: • Novel Fe/Ni-N-CNFs electrocatalysts are prepared by electrospinning technique. • The Fe1Ni1-N-CNFs catalyst exhibits the excellent ORR and OER catalytic activity. • Synergy of Fe/Ni alloy is responsible for the excellent catalytic performance. - Abstract: The novel of iron, nickel and nitrogen doped carbon nanofibers (Fe/Ni-N-CNFs) as bifunctional electrocatalysts are prepared by electrospinning technique. In alkaline media, the Fe/Ni-N-CNFs catalysts (especially for Fe1Ni1-N-CNFs) exhibit remarkable electrocatalytic performances of oxygen reduction reaction (ORR)/oxygen evolution reaction (OER). For ORR catalytic activity, Fe1Ni1-N-CNFs catalyst offers a higher onset potential of 0.903 V, a similar four-electron reaction pathway, and excellent stability. For OER catalytic activity, Fe1Ni1-N-CNFs catalyst possesses a lower onset potential of 1.528 V and a smaller charge transfer resistance of 48.14 Ω. The unparalleled catalytic activity of ORR and OER for the Fe1Ni1-N-CNFs is attributed to the 3D porous cross-linked microstructures of carbon nanofibers with Fe/Ni alloy, N dopant, and abundant M-N{sub x} and NiOOH as catalytic active sites. Thus, Fe1Ni1-N-CNFs catalyst can be acted as one of the efficient and inexpensive catalysts of metal-air batteries.

  1. Synthesis of Ni2B nanoparticles by RF thermal plasma for fuel cell catalyst

    International Nuclear Information System (INIS)

    Cheng, Y; Tanaka, M; Watanabe, T; Choi, S Y; Shin, M S; Lee, K H

    2014-01-01

    The catalyst of Ni 2 B nanoparticles was successfully prepared using nickel and boron as precursors with the quenching gas in radio frequency thermal plasmas. The generating of Ni 2 B needs adequate reaction temperature and boron content in precursors. The quenching gas is beneficial for the synthesis of Ni 2 B in RF thermal plasma. The effect of quenching rate, powder feed rate and boron content in feeding powders on the synthesis of nickel boride nanoparticles was studied in this research. The high mass fraction of 28 % of Ni 2 B nanoparticles can be generated at the fixed initial composition of Ni:B = 2:3. Quenching gas is necessary in the synthesis of Ni 2 B nanoaprticles. In addition, the mass fraction of Ni 2 B increases with the increase of quenching gas flow rate and powder feed rate

  2. Intermetallic compounds of Ni and Ga as catalysts for the synthesis of methanol

    DEFF Research Database (Denmark)

    Sharafutdinov, Irek; Elkjær, Christian Fink; de Carvalho, Hudson Wallace Pereira

    2014-01-01

    In this work, we present a detailed study of the formation of supported intermetallic Ni–Ga catalysts for CO2 hydrogenation to methanol. The bimetallic phase is formed during a temperature-programmed reduction of the metal nitrates. By utilizing a combination of characterization techniques......, in particular in situ and ex situ X-ray diffraction, in situ X-ray absorption spectroscopy, transmission electron microscopy combined with electron energy loss spectroscopy and X-ray fluorescence, we have studied the formation of intermetallic Ni–Ga catalysts of two compositions: NiGa and Ni5Ga3. These methods...... demonstrate that the catalysts with the desired intermetallic phase and composition are formed upon reduction in hydrogen and enable us to propose a mechanism of the Ni–Ga nanoparticles formation. By studying the effect of calcination prior to catalyst reduction, we show that the reactivity depends...

  3. Size and morphology controlled NiSe nanoparticles as efficient catalyst for the reduction reactions

    Energy Technology Data Exchange (ETDEWEB)

    Subbarao, Udumula; Marakatti, Vijaykumar S. [New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064 (India); Amshumali, Mungalimane K. [New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064 (India); Department of Chemistry and Industrial Chemistry, Vijayanagara Sri Krishnadevaraya University, Jnanasagara Campus, Cantonment, Bellary 583105 (India); Loukya, B. [International Center for Materials Science, Jakkur P.O., Bangalore 560064 (India); Singh, Dheeraj Kumar [Chemistry & Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064 (India); Datta, Ranjan [International Center for Materials Science, Jakkur P.O., Bangalore 560064 (India); Peter, Sebastian C., E-mail: sebastiancp@jncasr.ac.in [New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064 (India)

    2016-12-15

    Facile and efficient ball milling and polyol methods were employed for the synthesis of nickel selenide (NiSe) nanoparticle. The particle size of the NiSe nanoparticle has been controlled mechanically by varying the ball size in the milling process. The role of the surfactants in the formation of various morphologies was studied. The compounds were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray energy dispersive spectroscopy (EDS). The efficiency of the NiSe nanoparticle as a catalyst was tested for the reduction of para-nitroaniline (PNA) to para-phenyldiamine (PPD) and para-nitrophenol (PNP) to para-aminophenol (PAP) using NaBH{sub 4} as the reducing agent. Particle size, morphology and the presence of surfactant played a crucial role in the reduction process. - Graphical abstract: NiSe nanoparticles in different size and morphology were synthesized using facile ball milling and polyol methods. Particle size, morphology and the presence of surfactant in these materials played a crucial role in the hydrogenation of PNA and PNP. - Highlights: • NiSe nanoparticles synthesized using ball milling and solution phase methods. • NiSe nanoparticle is an efficient catalyst for the reduction of PNA and PNP. • NiSe is found to be better than the best reported noble metal catalysts.

  4. Size and morphology controlled NiSe nanoparticles as efficient catalyst for the reduction reactions

    International Nuclear Information System (INIS)

    Subbarao, Udumula; Marakatti, Vijaykumar S.; Amshumali, Mungalimane K.; Loukya, B.; Singh, Dheeraj Kumar; Datta, Ranjan; Peter, Sebastian C.

    2016-01-01

    Facile and efficient ball milling and polyol methods were employed for the synthesis of nickel selenide (NiSe) nanoparticle. The particle size of the NiSe nanoparticle has been controlled mechanically by varying the ball size in the milling process. The role of the surfactants in the formation of various morphologies was studied. The compounds were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray energy dispersive spectroscopy (EDS). The efficiency of the NiSe nanoparticle as a catalyst was tested for the reduction of para-nitroaniline (PNA) to para-phenyldiamine (PPD) and para-nitrophenol (PNP) to para-aminophenol (PAP) using NaBH 4 as the reducing agent. Particle size, morphology and the presence of surfactant played a crucial role in the reduction process. - Graphical abstract: NiSe nanoparticles in different size and morphology were synthesized using facile ball milling and polyol methods. Particle size, morphology and the presence of surfactant in these materials played a crucial role in the hydrogenation of PNA and PNP. - Highlights: • NiSe nanoparticles synthesized using ball milling and solution phase methods. • NiSe nanoparticle is an efficient catalyst for the reduction of PNA and PNP. • NiSe is found to be better than the best reported noble metal catalysts.

  5. Rh-Ni and Rh-Co Catalysts for Autothermal Reforming of Gasoline

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yeongyu; Lee, Daehyung; Kim, Yongmin; Lee, Jinhee; Nam, Sukwoo; Choi, Daeki; Yoon, Chang Won [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    2014-01-15

    Rh doped Ni and Co catalysts, Rh-M/CeO{sub 2}(20 wt %)-Al{sub 2}O{sub 3} (0.2 wt % of Rh; M = Ni or Co, 20 wt %) were synthesized to produce hydrogen via autothermal reforming (ATR) of commercial gasoline at 700 .deg. C under the conditions of a S/C ratio of 2.0, an O/C ratio of 0.84, and a gas hourly space velocity (GHSV) of 20,000 h{sup -1}. The Rh-Ni/CeO{sub 2}(20 wt %)-Al{sub 2}O{sub 3} catalyst (1) exhibited excellent activities, with H{sub 2} and (H{sub 2}+CO) yields of 2.04 and 2.58 mol/mol C, respectively. In addition, this catalyst proved to be highly stable over 100 h without catalyst deactivation, as evidenced by energy dispersive spectroscopy (EDX) and elemental analyses. Compared to 1, Rh-Co/CeO{sub 2}(20 wt %)-Al{sub 2}O{sub 3} catalyst (2) exhibited relatively low stability, and its activity decreased after 57 h. In line with this observation, elemental analyses confirmed that nearly no carbon species were formed at 1 while carbon deposits (10 wt %) were found at 2 following the reaction, which suggests that carbon coking is the main process for catalyst deactivation.

  6. Mössbauer emission study on 57Co doped carbon-supported Ni and Ni-Mo sulfide hydrotreating catalysts : the influence of phosphorus on the structure

    NARCIS (Netherlands)

    Crajé, M.W.J.; Beer, de V.H.J.; Kraan, van der A.M.

    1991-01-01

    In the present study it is demonstrated that Mössbauer emission spectroscopy (MES) can generate information on the various Ni phases present in sulfided Ni containing catalysts when a small amount of 57Co is used as a probe for Ni.Application of MES to 57Co:Ni(4.5)Mo(8.0)/C and 57Co:Ni(5.6)/C

  7. The Influence of oxide additives on Ni/Al2O3 catalysts in low temperature methane steam reforming

    International Nuclear Information System (INIS)

    Lazar, Mihaela; Dan, Monica; Mihet, Maria; Almasan, Valer

    2009-01-01

    Hydrogen is industrially produced by methane steam reforming. The process is catalytic and the usual catalyst is based on Ni as the active element. The main problem of this process is its inefficiency. It requires high temperatures at which Ni also favors the formation of graphite, which deactivates the catalysts. Ni has the advantage of being much cheaper than noble metal catalysts, so many researches are done in order to improve the properties of supported Ni catalysts and to decrease the temperature at which the process is energetically efficient. In order to obtain catalysts with high activity and stability, it is essential to maintain the dispersion of the active phase (Ni particles) and the stability of the support. Both properties can be improved by addition of a second oxide to the support. In this paper we present the results obtained in preparation and characterization of Ni/Al 2 O 3 catalysts modified by addition of CeO 2 and La 2 O 3 to alumina support. The following catalysts were prepared by impregnation method: Ni/Al 2 O 3 , Ni/CeO 2 -Al 2 O 3 and Ni/La 2 O 3 -Al 2 O 3 (10 wt.% Ni and 6 wt.% additional oxide). The catalytic surface was characterized by N 2 adsorption - desorption isotherms. The hydrogen - surface bond was characterized by Thermo-Programmed-Desorption (TPD) method. All catalysts were tested in steam reforming reaction of methane in the range of 600 - 700 deg. C, at atmospheric pressure working with CH 4 :H 2 O ratio of 1:3. The modified catalysts showed a better catalytic activity and selectivity for H 2 and CO 2 formation, at lower temperatures than the simple Ni/Al 2 O 3 catalyst. (authors)

  8. Efficient Hydrogenolysis of Guaiacol over Highly Dispersed Ni/MCM-41 Catalyst Combined with HZSM-5

    Directory of Open Access Journals (Sweden)

    Songbai Qiu

    2016-09-01

    Full Text Available A series of MCM-41 supported Ni catalysts with high metal dispersion was successfully synthesized by simple co-impregnation using proper ethylene glycol (EG. The acquired Ni-based catalysts performed the outstanding hydrogenolysis activity of guaiacol. The effects of the synthesis parameters including drying temperature, calcination temperature, and metal loading on the physical properties of NiO nanoparticles were investigated through the use of X-ray diffraction (XRD. The drying temperature was found to significantly influence the particle sizes of NiO supported on MCM-41, but the calcination temperature and metal loading had less influence. Interestingly, the small particle size (≤3.3 nm and the high dispersion of NiO particles were also obtained for co-impregnation on the mixed support (MCM-41:HZSM-5 = 1:1, similar to that on the single MCM-41 support, leading to excellent hydrogenation activity at low temperature. The guaiacol conversion could reach 97.9% at 150 °C, and the catalytic activity was comparative with that of noble metal catalysts. The hydrodeoxygenation (HDO performance was also promoted by the introduction of acidic HZSM-5 zeolite and an 84.1% yield of cyclohexane at 240 °C was achieved. These findings demonstrate potential applications for the future in promoting and improving industrial catalyst performance.

  9. Reductive amination of ethanol to ethylamines over Ni/Al_2O_3 catalysts

    International Nuclear Information System (INIS)

    Park, Jun Hyun; Hong, Eunpyo; An, Sang Hee; Shin, Chae-Ho; Lim, Dong-Hee

    2017-01-01

    Ni(x)/Al_2O_3 (x=wt%) catalysts with Ni loadings of 5-25 wt% were prepared via a wet impregnation method on an γ-Al_2O_3 support and subsequently applied in the reductive amination of ethanol to ethylamines. Among the various catalysts prepared, Ni(10)/Al2O3 exhibited the highest metal dispersion and the smallest Ni particle size, resulting in the highest catalytic performance. To reveal the effects of reaction parameters, a reductive amination process was performed by varying the reaction temperature (T), weight hourly space velocity (WHSV), and NH_3 and H_2 partial pressures in the reactions. In addition, on/off experiments for NH_3 and H_2 were also carried out. In the absence of NH_3 in the reactant stream, the ethanol conversion and selectivities towards the different ethylamine products were significantly reduced, while the selectivity to ethylene was dominant due to the dehydration of ethanol. In contrast, in the absence of H_2, the selectivity to acetonitrile significantly increased due to dehydrogenation of the imine intermediate. Although a small amount of catalyst deactivation was observed in the conversion of ethanol up to 10 h on stream due to the formation of nickel nitride, the Ni(10)/Al_2O_3 catalyst exhibited stable catalytic performance over 90 h under the optimized reaction conditions (i.e., T=190 .deg. C, WHSV=0.9 h"-"1, and EtOH/NH_3/H_2 molar ratio=1/1/6).

  10. Hydrodeoxygenation of bio-oil using different mesoporous supports of NiMo catalysts

    Science.gov (United States)

    Rinaldi, Nino; Simanungkalit, Sabar P.; Kristiani, Anis

    2017-11-01

    Biomass as a renewable and sustainable resources need to utilize in many applications, especially for energy application. One of its energy application is about converting biomass into bio-oil. High oxygen content in bio-oil needs to be upgraded through hydrodeoxygenation process before being used as transportation fuel. The development of heterogenenous catalysts become an important aspect in hydrodeoxygenation process, in particular the upgrading process of bio-oil. Several supporting mesoporous materials, such as TiO2, Al2O3 and MCM-41 have unique properties, both physical and chemical properties that can be utilized in various application, including catalyst. These heterogeneous catalysts were modified their catalytic properties by impregnation with some transition metal. The effect of various supporting material and transition metal impregnated were also studied. Their chemical and physical properties were characterized by X-Ray Diffraction, X-Ray Fluororesence, Fourier Transform Infra-Red, and Surface Area Analyzer. The result of characterizations showed that Ni-Mo/TiO2 is more crystalline than Ni-Mo/MCM-41 and Ni-Mo/Al2O3. In other hand, the specific surface area of Ni-Mo/TiO2 is lower than others. These heterogeneous catalysts were tested their catalytic activity in upgrading bio-oil. The liquid products produced were analyzed by using Elemental Analyzer. The result of catalytic activity tests showed catalysts resulted Ni-Mo/TiO2 exhibits best catalytic activity in hydrodeoxygenation process. The oxygen content decreased significantly from 41.61% to 26.22% by using Ni-Mo/TiO2. Compared with Ni-Mo/TiO2, Ni-Mo/MCM-41 and Ni-Mo/Al2O3 decrease lower to 33.22% % and 28.34%, respectively. Ni-Mo/TiO2 also resulted the highest Deoxygenation Degree (DOD) as of 55% compared with Ni-Mo/MCM-41 and Ni-Mo/Al2O3 as of 31.99 % and 47.99%, respectively.

  11. Catalytic hydrothermal liquefaction (HTL of biomass for bio-crude production using Ni/HZSM-5 catalysts

    Directory of Open Access Journals (Sweden)

    Shouyun Cheng

    2017-04-01

    Full Text Available Hydrothermal liquefaction (HTL is an effective method that can convert biomass into bio-crude, but direct use of bio-crude derived from biomass HTL remains a challenge due to the lower quality. In this study, bifunctional Ni/HZSM-5 catalysts and zinc hydrolysis were combined to produce upgraded bio-crude in an in-situ HTL process. The K2CO3 and HZSM-5 catalysts with different Ni loading ratios were tested. The effects of different catalysts on the yield and quality of bio-crude and gas were investigated. The results indicated that the catalysts improved bio-crude and gas yields, compared to pine sawdust liquefaction without catalyst. The catalysts reduced the contents of undesirable oxygenated compounds such as acids, ketones, phenols, alcohols and esters in bio-crude products while increased desirable hydrocarbons content. K2CO3 produced highest bio-crude yield and lowest solid residue yield among all catalysts. Compared to parent HZSM-5 catalyst, bifunctional Ni/HZSM-5 catalysts exhibited higher catalyst activity to improve quality of upgraded bio-crude due to its integration of cracking and hydrodeoxygenation reactions. 6%Ni/HZSM-5 catalyst produced the bio-crude with the highest hydrocarbons content at 11.02%. This catalyst can be a candidate for bio-crude production from biomass HTL.

  12. Catalytic performance of Ni/MgO catalyst in methane dry reforming

    Science.gov (United States)

    Al-Swai, Basem M.; Osman, N. B.; Abdullah, Bawadi

    2017-10-01

    Methane dry reforming to synthesis gas over nickel catalysts supported on magnesium oxide has been studied. The support was prepared via co-precipitation method using ammonia solution (20 wt% in water) as the precipitating agent. 10 wt% of Ni metal was impregnated to form Ni/MgO catalyst. The prepared catalyst was characterized by different techniques, such as XRD, BET, SEM, and TGA analysis. The effect of reaction conditions on the conversions of CH4 and CO2, selectivity of H2 and CO, and carbon deposition were investigated in a tabular furnace reactor. The catalyst afforded as high as 93% CH4 conversion at 900 °C. The catalyst has also shown excellent stability during reaction at relatively higher space velocity (1.8×104 ml g-1 h-1) and 800 °C reaction temperature. TGA characterization of spent catalyst has shown lesser magnitude of carbon deposition on the surface of the catalyst at 900 °C.

  13. Catalyst Deactivation Simulation Through Carbon Deposition in Carbon Dioxide Reforming over Ni/CaO-Al2O3 Catalyst

    Directory of Open Access Journals (Sweden)

    Istadi Istadi

    2011-11-01

    Full Text Available Major problem in CO2 reforming of methane (CORM process is coke formation which is a carbonaceous residue that can physically cover active sites of a catalyst surface and leads to catalyst deactivation. A key to develop a more coke-resistant catalyst lies in a better understanding of the methane reforming mechanism at a molecular level. Therefore, this paper is aimed to simulate a micro-kinetic approach in order to calculate coking rate in CORM reaction. Rates of encapsulating and filamentous carbon formation are also included. The simulation results show that the studied catalyst has a high activity, and the rate of carbon formation is relatively low. This micro-kinetic modeling approach can be used as a tool to better understand the catalyst deactivation phenomena in reaction via carbon deposition. Copyright © 2011 BCREC UNDIP. All rights reserved.(Received: 10th May 2011; Revised: 16th August 2011; Accepted: 27th August 2011[How to Cite: I. Istadi, D.D. Anggoro, N.A.S. Amin, and D.H.W. Ling. (2011. Catalyst Deactivation Simulation Through Carbon Deposition in Carbon Dioxide Reforming over Ni/CaO-Al2O3 Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 6 (2: 129-136. doi:10.9767/bcrec.6.2.1213.129-136][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.2.1213.129-136 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/1213 ] | View in  |  

  14. Hydrogen Production via Glycerol Dry Reforming over La-Ni/Al2O3 Catalyst

    Directory of Open Access Journals (Sweden)

    Kah Weng Siew

    2013-12-01

    Full Text Available Glycerol (a bio-waste generated from biodiesel production has been touted as a promising bio-syngas precursor via reforming route. Previous studies have indicated that carbon deposition is the major performance-limiting factor for nickel (Ni catalyst during glycerol steam reforming. In the current paper, dry (CO2-reforming of glycerol, a new reforming route was carried out over alumina (Al2O3-supported non-promoted and lanthanum-promoted Ni catalysts. Both sets of catalysts were synthesized via wet co-impregnation procedure. The physicochemical characterization of the catalyst showed that the promoted catalyst possessed smaller metal crystallite size, hence higher metal dispersion compared to the virgin Ni/Al2O3 catalyst. This was also corroborated by the surface images captured by the FESEM analysis. In addition, BET surface area measurement gave 92.05m²/g for non-promoted Ni catalyst whilst promoted catalysts showed an average of 1 to 6% improvement depending on the La loading. Reaction studies at 873 K showed that glycerol dry reforming successfully produced H2 with glycerol conversion and H2 yield that peaked at 9.7% and 25% respectively over 2wt% La content. The optimum catalytic performance by 2%La-Ni/Al2O3 can be attributed to the larger BET surface area and smaller crystallite size that ensured accessibility of active catalytic sites.  © 2013 BCREC UNDIP. All rights reservedReceived: 12nd May 2013; Revised: 7th October 2013; Accepted: 16th October 2013[How to Cite: Siew, K.W., Lee, H.C., Gimbun, J., Cheng, C.K. (2013. Hydrogen Production via Glycerol Dry Reforming over La-Ni/Al2O3 Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (2: 160-166. (doi:10.9767/bcrec.8.2.4874.160-166][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.2.4874.160-166

  15. Steam reforming of different biomass tar model compounds over Ni/Al_2O_3 catalysts

    International Nuclear Information System (INIS)

    Artetxe, Maite; Alvarez, Jon; Nahil, Mohamad A.; Olazar, Martin; Williams, Paul T.

    2017-01-01

    Highlights: • Order of reactivity: anisole > furfural > indene > phenol > toluene > methyl naphthalene. • Higher coke deposition for oxygenates (1.5–2.8%) than for aromatics (0.5–0.8%). • Amorphous coke is deposited for oxygenates and filamentous carbon for aromatics. • Ni content of 20 wt.% shows the higher conversion (90%) and H_2 potential (63%). - Abstract: This work focuses on the removal of the tar derived from biomass gasification by catalytic steam reforming on Ni/Al_2O_3 catalysts. Different tar model compounds (phenol, toluene, methyl naphthalene, indene, anisole and furfural) were individually steam reformed (after dissolving each one in methanol), as well as a mixture of all of them, at 700 °C under a steam/carbon (S/C) ratio of 3 and 60 min on stream. The highest conversions and H_2 potential were attained for anisole and furfural, while methyl naphthalene presented the lowest reactivity. Nevertheless, the higher reactivity of oxygenates compared to aromatic hydrocarbons promoted carbon deposition on the catalyst (in the 1.5–2.8 wt.% range). When the concentration of methanol is decreased in the feedstock and that of toluene or anisole is increased, the selectivity to CO is favoured in the gaseous products, thus increasing coke deposition on the catalyst and decreasing catalyst activity for the steam reforming reaction. Moreover, an increase in Ni loading in the catalyst from 5 to 20% enhances carbon conversion and H_2 formation in the steam reforming of a mixture of all the model compounds studied, but these values decrease for a Ni content of 40%. Coke formation also increased by increasing Ni loading, attaining its maximum value for 40% Ni (6.5 wt.%).

  16. A Study of CO2 Methanation over Ni-Based Catalysts Supported by CNTs with Various Textural Characteristics

    OpenAIRE

    Yanyan Feng; Wen Yang; Wei Chu

    2015-01-01

    This work studied the influence of textural characteristics of CNTs on catalytic performance of Ni/CNTs for CO2 methanation. The CNTs supports were prepared by chemical vapor deposition method using Ni/MgO catalysts, and acetonitrile and ethanol were used as carbon sources, respectively. The Ni/CNTs catalysts were prepared via impregnation method and characterized by X-ray diffraction (XRD), N2 adsorption/desorption, and temperature-programmed reduction (H2-TPR) techniques. The results indica...

  17. Preparation and characterization of NiW-nHA composite catalyst for hydrocracking

    Science.gov (United States)

    Zhou, Gang; Hou, Yongzhao; Liu, Lei; Liu, Hongru; Liu, Can; Liu, Jing; Qiao, Huiting; Liu, Wenyong; Fan, Yubo; Shen, Shituan; Rong, Long

    2012-11-01

    The synthesis, characterization and catalytic capability of the NiW-nano-hydroxyapatite (NiW-nHA) composite were investigated in this paper. The NiW-nHA catalyst was prepared by a co-precipitation method. Then Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDX) were used to analyze this material. In addition, the catalytic capacity of the NiW-nHA composite was also examined by FT-IR and gas chromatography (GC). The results of FT-IR analysis indicated that Ni, W and nHA combined closely. TEM observation revealed that this catalyst was needle shaped and the crystal retained a nanometer size. XRD data also suggested that a new phase of CaWO4 appeared and the lattice parameters of nHA changed in this system. nHA was the carrier of metals. The rates of Ni/W-loading were 73.24% and 65.99% according to the EDX data, respectively. Furthermore, the conversion of 91.88% Jatropha oil was achieved at 360 °C and 3 MPa h-1 over NiW-nHA catalyst. The straight chain alkanes ranging from C15 to C18 were the main components in the production. The yield of C15-C18 alkanes was up to 83.56 wt%. The reaction pathway involved hydrocracking of the C&z.dbd;C bonds of these triglycerides from Jatropha oil. This paper developed a novel non-sulfided catalyst to obtain a ``green biofuel'' from vegetable oil.

  18. TiO2 Nanotubes Supported NiW Hydrodesulphurization Catalysts: Characterization and Activity

    Czech Academy of Sciences Publication Activity Database

    Palcheva, R.; Dimitrov, L.; Tyuliev, G.; Spojakina, A.; Jirátová, Květa

    2013-01-01

    Roč. 265, JAN 15 (2013), s. 309-313 ISSN 0169-4332 Institutional support: RVO:67985858 Keywords : nano-structured TiO2 * NiW catalysts * XPS Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.538, year: 2013

  19. The Deoxygenation Pathways of Palmitic Acid into Hydrocarbons on Silica-Supported Ni12P5 and Ni2P Catalysts

    Directory of Open Access Journals (Sweden)

    Wenjun Zhou

    2018-04-01

    Full Text Available Pure Ni12P5/SiO2 and pure Ni2P/SiO2 catalysts were obtained by adjusting the Ni and P molar ratios, while Ni/SiO2 catalyst was prepared as a reference against which the deoxygenation pathways of palmitic acid were investigated. The catalysts were characterized by N2 adsorption, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, transmission election microscopy (TEM, infrared spectroscopy of pyridine adsorption (Py-IR, H2-adsorption and temperature-programmed desorption of hydrogen (H2-TPD. The crystallographic planes of Ni(111, Ni12P5(400, Ni2P(111 were found mainly exposed on the above three catalysts, respectively. It was found that the deoxygenation pathway of palmitic acid mainly proceeded via direct decarboxylation (DCO2 to form C15 on Ni/SiO2. In contrast, on the Ni12P5/SiO2 catalyst, there were two main competitive pathways producing C15 and C16, one of which mainly proceeded via the decarbonylation (DCO to form C15 accompanying water formation, and the other pathway produced C16 via the dehydration of hexadecanol intermediate, and the yield of C15 was approximately twofold that of C16. Over the Ni2P/SiO2 catalyst, two main deoxygenation pathways formed C15, one of which was mainly the DCO pathway and the other was dehydration accompanying the hexadecanal intermediate and then direct decarbonylation without water formation. The turn over frequency (TOF followed the order: Ni12P5/SiO2 > Ni/SiO2 > Ni2P/SiO2.

  20. Study of PtNi/C catalyst for direct ethanol fuel cell; Estudo do catalisador PtNi/C para celula a combustivel de etanol direto

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, L.P.R. de; Silva, E.L. da; Amico, S.C.; Malfatti, C.F., E-mail: eticiaprm@gmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil)

    2014-07-01

    In this work, PtNi binary catalyst and pure platin catalyst were synthesized by the impregnation-reduction method, using Vulcan XC72R as support, for direct ethanol fuel cells. The composition and structure of the catalysts were analyzed by X-ray diffraction, the electrochemical behavior was evaluated by cyclic voltammetry and morphology of the catalysts was studied by high-resolution transmission electron microscopy. The results showed that the addition of Ni to Pt led to the contraction of the crystal lattice, increased the catalytic activity compared to pure Pt and initiated the electrooxidation of ethanol at lower potential. (author)

  1. Selective Ring Opening of 1-Methylnaphthalene Over NiW-Supported Catalyst Using Dealuminated Beta Zeolite.

    Science.gov (United States)

    Kim, Eun-Sang; Lee, You-Jin; Kim, Jeong-Rang; Kim, Joo-Wan; Kim, Tae-Wan; Chae, Ho-Jeong; Kim, Chul-Ung; Lee, Chang-Ha; Jeong, Soon-Yong

    2016-02-01

    Nanoporous Beta zeolite was dealuminated by weak acid treatment for reducing the acidity. Bi-functional catalysts were prepared using commercial Beta zeolites and the dealuminated zeolites for acidic function, NiW for metallic function. 1-Methylnaphthalene was selected as a model compound for multi-ring aromatics in heavy oil, and its selective ring opening reaction has been investigated using the prepared bi-functional catalysts with different acidity in fixed bed reaction system. The dealuminated Beta zeolites, which crystal structure and nanoporosity were maintained, showed the higher SiO2/Al2O3 ratio and smaller acidity than their original zeolite. NiW-supported catalyst using the dealuminated Beta zeolite with SiO2/Al203 mole ratio of 55 showed the highest performance for the selective ring opening. The acidity of catalyst seemed to play an important role as active sites for the selective ring opening of 1-methylnaphthalene but there should be some optimum catalyst acidity for the reaction. The acidity of Beta zeolite could be controlled by the acid treatment and the catalyst with the optimum acidity for the selective ring opening could be prepared.

  2. Hydrotreating NiMo/sepiolite catalysts: influence of catalyst preparation on activity for HDS, hydrogenation and chain isomerization reactions

    International Nuclear Information System (INIS)

    Melo, F.V.; Sanz, E.; Corma, A.; Mifsud, A.

    1987-01-01

    A series of NiMo catalysts supported on a sepiolite: a) in its natural state, b) modified by acid leaching, and c) modified by cation exchange, have been prepared. The preparation variables studied were: Method of metal deposition, amount of active phase, sepiolite pretreatment, and temperature and time of sulfurization. The catalytic activity for HDS, hydrogenation, and cracking-isomerization has been studied by feeding a thiophene-cyclohexene-cyclohexane mixture and carrying out the reaction in the following conditions: 300 0 and 400 0 C reaction temperature, 20 Kg.cm -2 total pressure, and 3 to 1 molar ratio of H 2 to hydrocarbons. An optimium for HDS and hydrogenation activity was found for a 12% wt MoO 3 , and 5% wt NiO, prepared by simultaneous impregnation by the pore volume method at Ph = 5.0. The optimum conditions with these catalysts are 400 0 C and 3 hours of sulfurization. An increase in the acidity of the support produces a decrease of HDS and hydrogenation and an increase of the cracking-isomerization activities. A good correlation between HDS and the concentration of an XNiO.MoO 3 phase is found. The XNiO.MoO 3 phase is completely sulfurized to a modified MoS 2 , while NiMoO 4 and MoO 3 are only slightly sulfurized. 31 refs.; 7 figs.; 1 table

  3. Transformation of Sodium Bicarbonate and CO2 into Sodium Formate over NiPd Nanoparticle Catalyst

    Directory of Open Access Journals (Sweden)

    Mengnan eWang

    2013-09-01

    Full Text Available The present research systematically investigated, for the first time, the transformation of sodium bicarbonate and CO2 into sodium formate over a series of Ni based metal nanoparticles (NPs. Ni NPs and eight NiM (M stands for a second metal NPs were prepared by a facile wet chemical process and then their catalytic performance were evaluated in sodium bicarbonate hydrogenation. Bimetallic NiPd NPs with a composition of 7:3 were found to be superior for this reaction, which are more active than both pure Ni and Pd NPs. Hot filtration experiment suggested the NPs to be the truly catalytic active species and kinetic analysis indicated the reaction mechanism to be different than most homogeneous catalysts. The enhanced activity of the bimetallic nanoparticles may be attributed to their smaller size and improved stability.

  4. Transformation of Sodium Bicarbonate and CO2 into Sodium Formate over NiPd Nanoparticle Catalyst

    Science.gov (United States)

    Wang, Mengnan; Zhang, Jiaguang; Yan, Ning

    2013-09-01

    The present research systematically investigated, for the first time, the transformation of sodium bicarbonate and CO2 into sodium formate over a series of Ni based metal nanoparticles (NPs). Ni NPs and eight NiM (M stands for a second metal) NPs were prepared by a facile wet chemical process and then their catalytic performance were evaluated in sodium bicarbonate hydrogenation. Bimetallic NiPd NPs with a composition of 7:3 were found to be superior for this reaction, which are more active than both pure Ni and Pd NPs. Hot filtration experiment suggested the NPs to be the truly catalytic active species and kinetic analysis indicated the reaction mechanism to be different than most homogeneous catalysts. The enhanced activity of the bimetallic nanoparticles may be attributed to their smaller size and improved stability.

  5. Origin of low temperature deactivation of Ni5Ga3 nanoparticles as catalyst for methanol synthesis

    DEFF Research Database (Denmark)

    Gardini, Diego; Sharafutdinov, Irek; Damsgaard, Christian Danvad

    that the highest methanol yield is obtained with a Ni5Ga3 alloy exposed to a 25% CO2 – 75% H2 reaction mixture at 210 °C [2]. Under these experimental conditions, the catalyst is found to lose 35% of its activity after 20 hours of continuous testing at both 1 and 5 Bars. Although in situ XRD and EXAFS studies [3......In an effort to find alternative energy sources capable to compete with fossil fuels, methanol synthesis could represent a realistic solution to store “green” hydrogen produced from electrolysis or photo-induced water splitting. Recently, density functional theory (DFT) calculations [1] proposed Ni......-Ga alloys as active catalysts for methanol production from syngas mixtures and Ni-Ga nanoparticles supported on highly porous silica have been prepared using an incipient wetness impregnation technique from a solution of nickel and gallium nitrates [2]. Tests conducted in a fixed-bed reactor showed...

  6. Bio-dissolution of Ni, V and Mo from spent petroleum catalyst using iron oxidizing bacteria.

    Science.gov (United States)

    Pradhan, Debabrata; Kim, Dong J; Roychaudhury, Gautam; Lee, Seoung W

    2010-01-01

    Bioleaching studies of spent petroleum catalyst containing Ni, V and Mo were carried out using iron oxidizing bacteria. Various leaching parameters such as Fe(II) concentration, pulp density, pH, temperature and particle size were studied to evaluate their effects on the leaching efficiency as well as the kinetics of dissolution. The percentage of leaching of Ni and V were higher than Mo. The leaching process followed a diffusion controlled model and the product layer was observed to be impervious due to formation of ammonium jarosite (NH(4))Fe(3)(SO(4))(2)(OH)(6). Apart from this, the lower leaching efficiency of Mo was due to a hydrophobic coating of elemental sulfur over Mo matrix in the spent catalyst. The diffusivities of the attacking species for Ni, V and Mo were also calculated.

  7. Effect of Ce and Zr Addition to Ni/SiO2 Catalysts for Hydrogen Production through Ethanol Steam Reforming

    Directory of Open Access Journals (Sweden)

    Jose Antonio Calles

    2015-01-01

    Full Text Available A series of Ni/Ce\\(_{x}\\Zr\\(_{1-x}\\O\\(_{2}\\/SiO\\(_{2}\\ catalysts with different Zr/Ce mass ratios were prepared by incipient wetness impregnation. Ni/SiO\\(_{2}\\, Ni/CeO\\(_{2}\\ and Ni/ZrO\\(_{2}\\ were also prepared as reference materials to compare. Catalysts' performances were tested in ethanol steam reforming for hydrogen production and characterized by XRD, H\\(_{2}\\-temperature programmed reduction (TPR, NH\\(_{3}\\-temperature programmed desorption (TPD, TEM, ICP-AES and N\\(_{2}\\-sorption measurements. The Ni/SiO\\(_{2}\\ catalyst led to a higher hydrogen selectivity than Ni/CeO\\(_{2}\\ and Ni/ZrO\\(_{2}\\, but it could not maintain complete ethanol conversion due to deactivation. The incorporation of Ce or Zr prior to Ni on the silica support resulted in catalysts with better performance for steam reforming, keeping complete ethanol conversion over time. When both Zr and Ce were incorporated into the catalyst, Ce\\(_{x}\\Zr\\(_{1-x}\\O\\(_{2}\\ solid solution was formed, as confirmed by XRD analyses. TPR results revealed stronger Ni-support interaction in the Ce\\(_{x}\\Zr\\(_{1-x}\\O\\(_{2}\\-modified catalysts than in Ni/SiO\\(_{2}\\ one, which can be attributed to an increase of the dispersion of Ni species. All of the Ni/Ce\\(_{x}\\Zr\\(_{1-x}\\O\\(_{2}\\/SiO\\(_{2}\\ catalysts exhibited good catalytic activity and stability after 8 h of time on stream at 600°. The best catalytic performance in terms of hydrogen selectivity was achieved when the Zr/Ce mass ratio was three.

  8. Sodium borohydride hydrogen generator using Co–P/Ni foam catalysts for 200 W proton exchange membrane fuel cell system

    International Nuclear Information System (INIS)

    Oh, Taek Hyun; Gang, Byeong Gyu; Kim, Hyuntak; Kwon, Sejin

    2015-01-01

    The response characteristics of electroless-deposited Co–P/Ni foam catalysts for sodium borohydride hydrolysis were investigated. The effect of nickel foam geometry on the properties of the catalysts was evaluated. As the PPI (pores per inch) of the nickel foam increased, the hydrogen generation rate per gram of the deposited catalyst increased due to an increase in surface area. The response characteristics of various catalysts were compared under real operating conditions. When a thin nickel foam with high PPI was used, the response characteristics of the catalyst improved due to an increase in the amount of the deposited catalyst and surface area. Finally, a 200 W PEMFC (proton exchange membrane fuel cell) system using electroless-deposited Co–P/Ni foam (110 PPI) catalyst was investigated. The response time to reach a hydrogen generation rate sufficient for a 200 W PEMFC was 71 s, and the energy density of a 200 W fuel cell system for producing 600 Wh was 252.1 Wh/kg. A fuel cell system using Co–P/Ni foam catalysts can be widely used as a power source for mobile applications due to fast response characteristics and high energy density. - Highlights: • Response characteristics of Co–P/Ni foam catalysts are investigated. • Catalytic activity is improved with increase in PPI (pores per inch) of Ni foam. • Co–P/Ni foam (110 PPI) catalyst has improved response characteristics. • The energy density of a 200 W PEMFC system for producing 600 Wh is 252.1 Wh/kg. • Co–P/Ni foam (110 PPI) catalyst is suitable for fuel cell system.

  9. Highly stable and active Ni-doped ordered mesoporous carbon catalyst on the steam reforming of ethanol application

    Directory of Open Access Journals (Sweden)

    Josh Y.Z. Chiou

    2017-02-01

    Full Text Available A novel one-step direct synthesis of nickel embedded in an ordered mesoporous carbon catalyst (NiOMC is done in a basic medium of nonaqueous solution by a solvent evaporation-induced self-assembly process. The NiOMC sample is characterized by a variety of analytical and spectroscopy techniques, e.g., N2 adsorption/desorption isotherm measurement, X-ray diffraction (XRD, transmission electron microscopy (TEM and temperature-programed reduction (TPR. In this study, the NiOMC catalyst is found to exhibit superior catalytic activity for the steam reforming of ethanol (SRE, showing high hydrogen selectivity and durability. Ethanol can be completely converted at 350 °C over the NiOMC catalyst. Also, the durability of the NiOMC catalyst on the SRE reaction exceeds 100 h at 450 °C, with SH2 approaching 65% and SCO of less than 1%.

  10. Pt-Ni and Pt-M-Ni (M = Ru, Sn Anode Catalysts for Low-Temperature Acidic Direct Alcohol Fuel Cells: A Review

    Directory of Open Access Journals (Sweden)

    Ermete Antolini

    2017-01-01

    Full Text Available In view of a possible use as anode materials in acidic direct alcohol fuel cells, the electro-catalytic activity of Pt-Ni and Pt-M-Ni (M = Ru, Sn catalysts for methanol and ethanol oxidation has been widely investigated. An overview of literature data regarding the effect of the addition of Ni to Pt and Pt-M on the methanol and ethanol oxidation activity in acid environment of the resulting binary and ternary Ni-containing Pt-based catalysts is presented, highlighting the effect of alloyed and non-alloyed nickel on the catalytic activity of these materials.

  11. Effects of impregnation methods and drying conditions on quinoline hydrodenitrogenation over Ni-W based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Fang; Qiu, Zegang; Zhao, Liangfu; Xiang, Hongwei [Institute of Coal Chemistry, Chinese Academy of Sciences (China); Guo, Shaoqing [Taiyuan University of Science and Technology (China)

    2014-04-15

    The effects of impregnation methods (co-impregnation and sequential impregnation) and drying conditions (air and vacuum) on the structure and catalytic behavior of MCM-41 supported Ni-W catalysts were investigated. The catalysts were characterized by powder X-ray diffraction (XRD) analysis, Fourier-transform infrared spectroscopy (FT-IR), diffuse reflectance UV-Vis absorbance spectroscopy (DRS), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and pyridine adsorbed infrared spectroscopy (Py-IR) techniques. They were tested for hydrodenitrogenation (HDN) of quinoline at temperatures of 300-400 deg C. The HDN results showed that the catalysts prepared by co-impregnation were more active than the catalysts prepared by sequential impregnation and the catalysts prepared by drying under vacuum were more active than the catalysts dried in air. Characterization revealed that the co-impregnation method and drying under vacuum promoted the dispersion of W, the formation of the active phases, and the formation of acidic sites on the catalysts. (author)

  12. A Comparative Study of Carbon Nanotubes Synthesized from Co/Zn/Al and Fe/Ni/Al Catalyst

    Directory of Open Access Journals (Sweden)

    Ezekiel Dixon Dikio

    2011-01-01

    Full Text Available The catalyst systems Fe/Ni/Al and Co/Zn/Al were synthesized and used in the synthesis of carbon nanotubes. The carbon nanotubes produced were characterized by Field Emission Scanning Electron Microscope (FE-SEM, Energy Dispersive x-ray Spectroscopy (EDS, Raman spectroscopy, Thermogravimetric Analysis (TGA and Transmission Electron Microscope (TEM. A comparison of the morphological profile of the carbon nanotubes produced from these catalysts indicates the catalyst system Fe/Ni/Al to have produced higher quality carbon nanotubes than the catalyst system Co/Zn/Al.

  13. Density functional theory study for the enhanced sulfur tolerance of Ni catalysts by surface alloying

    Science.gov (United States)

    Hwang, Bohyun; Kwon, Hyunguk; Ko, Jeonghyun; Kim, Byung-Kook; Han, Jeong Woo

    2018-01-01

    Sulfur compounds in fuels deactivate the surface of anode materials in solid oxide fuel cells (SOFCs), which adversely affect the long-term durability. To solve this issue, it is important to design new SOFC anode materials with high sulfur tolerance. Unfortunately, it is difficult to completely replace the traditional Ni anode owing to its outstanding reactivity with low cost. As an alternative, alloying Ni with transition metals is a practical strategy to enhance the sulfur resistance while taking advantage of Ni metal. Therefore, in this study, we examined the effects of transition metal (Cu, Rh, Pd, Ag, Pt, and Au) doping into a Ni catalyst on not only the adsorption of H2S, HS, S, and H but also H2S decomposition using density functional theory (DFT) calculations. The dopant metals were selected rationally by considering the stability of the Ni-based binary alloys. The interactions between sulfur atoms produced by H2S dissociation and the surface are weakened by the dopant metals at the topmost layer. In addition, the findings show that H2S dissociation can be suppressed by doping transition metals. It turns out that these effects are maximized in the Au-doped Ni catalyst. Our DFT results will provide useful insights into the design of sulfur-tolerant SOFC anode materials.

  14. Effect of Ni-Co Ternary Molten Salt Catalysts on Coal Catalytic Pyrolysis Process

    Science.gov (United States)

    Cui, Xin; Qi, Cong; Li, Liang; Li, Yimin; Li, Song

    2017-08-01

    In order to facilitate efficient and clean utilization of coal, a series of Ni-Co ternary molten salt crystals are explored and the catalytic pyrolysis mechanism of Datong coal is investigated. The reaction mechanisms of coal are achieved by thermal gravimetric analyzer (TGA), and a reactive kinetic model is constructed. The microcosmic structure and macerals are observed by scanning electron microscope (SEM). The catalytic effects of ternary molten salt crystals at different stages of pyrolysis are analyzed. The experimental results show that Ni-Co ternary molten salt catalysts have the capability to bring down activation energy required by pyrolytic reactions at its initial phase. Also, the catalysts exert a preferable catalytic action on macromolecular structure decomposition and free radical polycondensation reactions. Furthermore, the high-temperature condensation polymerization is driven to decompose further with a faster reaction rate by the additions of Ni-Co ternary molten salt crystal catalysts. According to pyrolysis kinetic research, the addition of catalysts can effectively decrease the activation energy needed in each phase of pyrolysis reaction.

  15. Selective hydrogenation of furfural to cyclopentanone over Cu-Ni-Al hydrotalcite-based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Hongyan; Zhou, Minghao; Zeng, Zuo; Xiao, Guomin; Xiao, Rui [Southeast University, Nanjing (China)

    2014-04-15

    A series of Cu-Ni-Al hydrotalcites derived oxides with a (Cu+Ni)/Al mole ratio of 3 with varied Cu/Ni mole ratio (from 0.017 to 0.5, with a Cu ratio of 0.0125 to 0.25) were prepared by co-precipitation method, then applied to the hydrogenation of furfural in aqueous. Their catalytic performance for liquid phase hydrogenation of furfural to prepare cyclopentanone was described in detail, considering reaction temperature, catalyst composition, reaction time and so on. The yield of cyclopentanone was influenced by the mole ratio of Cu-Ni-Al based heterogeneous catalyst and depended on the reaction conditions. The yield of cyclopentanone was up to 95.8% when the reaction was carried out under 413 K with H{sub 2} pressure of 40 bar for 8 h. The catalysts were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and H{sub 2} temperature-programmed reduction (H{sub 2}-TPR)

  16. Microwave effects on NiMoS and CoMoS single-sheet catalysts.

    Science.gov (United States)

    Borges, I; Silva, Alexander M; Modesto-Costa, Lucas

    2018-05-04

    Single-sheet nanoclusters of MoS 2 , NiMoS or CoMoS are widely used in hydrodesulfurization (HDS) catalysis in the petroleum industry. In HDS reactions under microwave irradiation, experiments indirectly pointed out that for pristine MoS 2 reaction rates are accelerated because hot spots are generated on the catalyst bed. In this work, we investigated NiMoS and CoMoS isolated single-sheet substituted catalysts before and after thiophene adsorption focusing on quantifying the effect of microwave irradiation. For that purpose, density functional theory (DFT) molecular charge densities of each system were decomposed according to the distributed multipole analysis (DMA) of Stone. Site dipole values of each system were directly associated with a larger or smaller interaction with the microwave field according to a proposed general approach. We showed that microwave enhancement of HDS reaction rates can occur more efficiently in the CoMoS and NiMoS promoted clusters compared to pristine MoS 2 in the following order: CoMoS > NiMoS > MoS 2 . The atomic origin of the catalyst hot spots induced by microwaves was clearly established in the promoted clusters.

  17. Pt-Ni/WC Alloy Nanorods Arrays as ORR Catalyst for PEM Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Begum, Mahbuba; Yurukcu, Mesut; Yurtsever, Fatma; Ergul, Busra; Kariuki, Nancy; Myers, Deborah J.; Karabacak, Tansel

    2017-08-24

    Polymer electrolyte membrane fuel cells (PEMFCs) among the other types of fuel cell technology are attractive power sources, especially for electric vehicle applications. While significant progress and plausible prospects of PEMFCs have been achieved, there are still some challenges related to the performance, durability, and cost that need to be overcome to make them economically viable for widespread commercialization. Our strategy is to develop thin films of high-active and stable catalyst coated on vertically aligned nanorod arrays of conductive and stable support. In this work, we fabricated tungsten carbide (WC) nanorods as support and coated them with a platinum-nickel (Pt-Ni) alloy shell denoted as Pt-Ni/WC catalysts. The Pt- Ni/WC nanorods were deposited on glassy carbon disks as well as on silicon substrates for evaluation of their electrocatalytic oxygen reduction reaction (ORR) activity and physical properties. Cyclic voltammetry experiments using rotating disk electrode were performed in perchloric acid (0.1 M HClO4) electrolyte at room temperature to characterize the ORR activity and stability of Pt-Ni/WC nanorods catalysts. Scanning electron microscopy and X-ray diffraction techniques were utilized to study the morphology and crystallographic properties, respectively.

  18. O-Carboxymethyl Chitosan Supported Heterogeneous Palladium and Ni Catalysts for Heck Reaction

    Directory of Open Access Journals (Sweden)

    Dongjun Lv

    2017-01-01

    Full Text Available Two polymer catalysts (Pd-OCMCS and Ni-OCMCS with good reusability were synthesized by coordinating Pd and Ni onto O-carboxymethyl chitosan (OCMCS. The chemical structure and thermal stability of prepared catalysts were determined by Fourier transform infrared (FT-IR spectra, Energy Dispersive Spectrometer (EDSanalysis, X-ray diffraction (XRD, and thermogravimetric analyzer (TG-DTG, and the analysis results showed that the Pd and Ni ions coordinated onto the OCMCS and formed a ligand with the –COOH group, amino groups, and –OH group on the OCMCS, and the EDS and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES analysis results showed that the loading amounts of Pd and Ni were approximately 8.3% and 8.9%, respectively. In the Heck reaction between aryl halides and n-butyl acrylate catalyzed by the prepared catalyst, the test results showed that the product yield followed the order of aryl iodide > aryl bromide > aryl chloride. Additionally, the product yield for the aryl iodide and aryl bromide could reach up to 99% and 96%, respectively. Moreover, the electron-withdrawing and electron-donating property of the group on the aryl also affected the product yield, and the product yield for aryl halides with electron-withdrawing group p-NO2, p-CH3CO, and p-CHO was higher than that with electron-donating group p-CH3.

  19. Preparation, characterization of Mo catalysts supported on Ni- containing calcium deficient hydroxyapatite and reactivity for the thiophene HDS reaction

    Directory of Open Access Journals (Sweden)

    Cherif A.

    2013-09-01

    Full Text Available Ni-containing Calcium Hydroxyapatite (NiCaHAp; 3.31 wt.% Ni was synthesized by coprecipitation and used as catalyst support. Molybdenum was supported on NiCaHAp by impregnation using ammonium heptamolybdate. The prepared catalysts Mo(x/NiCaHAp (x: 2 to 8 wt % in Mo were characterized by elemental analysis, XRD, FT-IR, N2 adsorption-desorption and TEM-EDX. The catalysts were sulfided in-situ at 673 K under flowing H2S/H2 (15 Vol.% H2S and tested in hydrodesulfurization (HDS of thiophene at 673 K. The main XRD peaks of hydroxyapatite CaHAp phase were observed in all samples and a peak due probably to crystalline MoO3 phase was also identified from the results. However, no crystalline phase of NiO was found for the catalysts, which showed its Ni species were highly dispersed. The sulfided catalysts Mo(x/NiCaHAp presented are active in HDS of thiophene, despite the presence of some large MoO3 crystallites and incomplete sulfidation. This activity may be due to interaction of NiO and MoO3 on CaHAp resulting in the formation of Ni-Mo-S phase under flowing H2S/H2. When the molybdenum content increased the HDS activity increasead slightly, which was caused by the agglomeration of MoO3. The Mo(8/NiCaHAp catalyst is about two times less active for thiophene HDS than the commercial NiMoP/Al2O3.

  20. Conversion of furan derivatives for preparation of biofuels over Ni-Cu/C catalyst

    DEFF Research Database (Denmark)

    Fu, Zhaolin; Wang, Z.; Lin, Weigang

    2017-01-01

    Conversions of furfural and 5-hydroxymethylfurfural as model components in bio-oil were investigated over Ni-Cu/C catalyst with formic acid as hydrogen donor in isopropanol solvent to produce biofuels. The effects of reaction temperature, feed ratio, and reaction time were studied. A high yield...... of 2-methylfuran up to 91 mol% was obtained from furfural in 8 h at 200°C, and under same conditions 80 mol% yield of 2,5-dimethylfuran could also be obtained from 5-hydroxymethylfurfural in 6 h. The results verified the catalyst performance and the availability of the reaction conditions for producing...

  1. Mechanochemical synthesis of TiO2/NiFe2O4 magnetic catalysts for operation under RF field

    International Nuclear Information System (INIS)

    Houlding, Thomas K.; Gao, Pengzhao; Degirmenci, Volkan; Tchabanenko, Kirill; Rebrov, Evgeny V.

    2015-01-01

    Highlights: • Novel NiFe 2 O 4 –TiO 2 composite magnetic catalysts have been prepared by mechanochemical synthesis. • The synthesis time of 30 min provides the highest specific absorption rate (SAR) in RF heating. • Formation of NiTiO 3 phase during calcination decreases the SAR of the catalysts. • High stability of the NiFe 2 O 4 –TiO 2 catalyst was observed in a continuous amide bond synthesis under RF heating. - Abstract: Composite NiFe 2 O 4 –TiO 2 magnetic catalysts were prepared by mechanochemical synthesis from a mixture of titania supported nickel ferrite nanoparticles and P25 titania (Evonic). The former provides fast and efficient heating under radiofrequency field, while the latter serves as an active catalyst or catalyst support. The highest heating rate was observed over a catalyst prepared for a milling time of 30 min. The catalytic activity was measured over the sulfated composite catalysts in the condensation of aniline and 3-phenylbutyric acid in a stirred tank reactor and in a continuous RF heated flow reactor in the 140–170 °C range. The product yield of 47% was obtained over the sulfated P25 titania catalyst in the flow reactor

  2. Lanthanum and cerium co-modified Ni/SiO2 catalyst for CO methanation from syngas

    Science.gov (United States)

    Gong, Dandan; Li, Shuangshuang; Guo, Shaoxia; Tang, Honggui; Wang, Hong; Liu, Yuan

    2018-03-01

    Sintering of active metal nanoparticles (NPs) and carbon deposition is critical problems for many metal catalysts, such as nickel based catalysts for generating methane from syngas. To improve the resistance to the sintering and carbon deposition, a new scheme was proposed in this work. Lanthanum and cerium co-modified Ni/SiO2 catalysts were synthesized by using perovskite type oxide of La1-xCexNiO3 loaded on SiO2 as the precursor. In a nanocrystallite of La1-xCexNiO3, ions of nickel, lanthanum and cerium are evenly mixed at atomic level and confined in the nanocrystallite, therefore, Ni NPs and the two promoters of La2O3 and CeO2 should be in close contact and highly dispersed on SiO2 after reduction. The catalysts were characterized by using XRD, TEM, BET, H2-TPD, XPS, TG and Raman techniques. Compared with the mono-promoted catalysts, the bi-promoted La0.75Ce0.25NiO3/SiO2 showed much better resistance to carbon deposition, higher resistance to sintering and higher activity for CO methanation, which are attributed to co-eliminating effect of the two promoters for the deposited carbon, confinement of the interacted two promoters for Ni NPs and the higher dispersion of Ni NPs derived from the smaller size of La0.75Ce0.25NiO3.

  3. NiCo as catalyst for magnetically induced dry reforming of methane

    Science.gov (United States)

    Varsano, F.; Bellusci, M.; Provini, A.; Petrecca, M.

    2018-03-01

    In this paper we report the activation of the dry reforming reaction by induction heating of a NiCo alloy. The catalyst plays a double role, serving both as a promoter for the reforming reaction and producing the heat induced by dissipation of the electromagnetic energy. The elevated temperatures imposed by the reforming reaction suggest the choice of an alloy with a Curie temperature >800°C. In this respect Ni:Co ratio 60:40 was chosen. Alloy active sites for CH4and CO2activation are created by a mechanochemical treatment of the alloy that increases solid-state defects. The catalyst has been successfully tested in a continuous-flow reactor working under atmospheric pressure. Methane conversion and hydrogen production yields have been measured as a function of the applied magnetic field, reactant flow rate and time on stream.

  4. Steam reforming of ethanol over Ni-based catalysts: Effect of feed composition on catalyst stability

    DEFF Research Database (Denmark)

    Trane-Restrup, Rasmus; Dahl, Søren; Jensen, Anker Degn

    2014-01-01

    In this work the effects of steam-to-carbon ratio (S/C), and addition of H2 or O2 to the feed on the product yields and carbon deposition in the steam reforming (SR) of ethanol over Ni/MgAl2O4, Ni/Ce0.6Zr0.4O2, and Ni/CeO2 at 600 °C have been investigated. Increasing the S/C-ratio from 1.6 to 8.3...... showed stable behavior and an average rate of carbon deposition of less than 7 μg C/gCat h. The results indicate that stable operation of ethanol SR is only possible under oxidative conditions....

  5. Synthesis and characterization of Ni-CeO2 catalysts by the hydrothermal method

    International Nuclear Information System (INIS)

    Lazcano O, I.

    2013-01-01

    At the present time the necessity exists to reduce the level of atmospheric pollutants, because these are the main originators of such problems as: the greenhouse effect, acid rain, global heating, among others and that are affecting the human being seriously. In this context, is necessary to look for new solutions that contribute to the improvement of the problems without appealing to limitations in the energy production, because this would imply a non only delay in the economic development, but also in the cultural, technological and of research in our country. An alternative for the energy solution is the use of renewable fuels, because they will decrease the production costs with the time, as well as to diminish the dependence of the fossil fuels, contributing this way to the improvement of the environment quality. The use of the hydrogen as an alternating fuel to the petroleum, is intends as energy solution. The objective of the present work is to develop Ni-CeO 2 catalysts through the hydrothermal method for the hydrogen production starting from the partial oxidation reaction of methanol for the clean fuel generation that does not produce polluting emissions to the environment. As well as, to determine the importance of the metallic load in the catalytic activity for which catalysts to 1 and 2% in weight of Ni were prepared. To achieve these objective different techniques were used to characterize the prepared catalysts, as: Temperature Programmed Reduction to evidence the metal-support interaction, Scanning Electron Microscopy (Sem) to determine the morphology of the catalysts, Surface Area (Bet) with respect to the adsorption-desorption of N 2 and X-Rays Diffraction (XRD) to know the crystalline structure of the catalysts. Also the catalytic properties (activity and selectivity) were studied under the reaction: CH 3 OH + 1/2 O 2 obtaining as products to the CO 2 + 2H 2 , with the help of the multi-tasks equipment Rig-100 that operated to temperatures among

  6. Evaluation as a catalyst in ferrispinel NiFe_2O_4 esterification and transesterification

    International Nuclear Information System (INIS)

    Pereira, Kleberson Ricardo de Oliveira; Dantas, Joelda; Costa, Ana Cristina Figueiredo de Melo; Silva, Adriano Sant'Ana; Kiminami, Ruth Herta Goldschmidt Aliaga

    2014-01-01

    The advancement of nanoscience and nanotechnology, magnetic nanoparticles ferrispinels type, have found numerous applications in biochemistry, molecular biology, biomedicine, diagnosis and heterogeneous catalysis for biodiesel production. Therefore, we propose to synthesize ferrispinel NiFe_2O_4 and evaluate its performance as a catalyst for esterification and transesterification of the methyl soybean oil. The sample was obtained through combustion reaction with production of 10 g / batch and characterized by XRD, SEM and BET. The catalytic reaction was conducted in high-pressure reactor at 180 °C for 1 hour, with a molar ratio of oil:ethanol 1:12 with 2% catalyst. The results showed the formation of ferrispinel phase, morphology composed of aggregates in the form of irregular blocks formed by pre sintered particles and low interparticle porosity. As a catalyst, the conversion values presented ferrispinel 52% and 4% in the esterification and transesterification, respectively, indicating that promising material for use in biodiesel production. (author)

  7. A Study of CO2 Methanation over Ni-Based Catalysts Supported by CNTs with Various Textural Characteristics

    Directory of Open Access Journals (Sweden)

    Yanyan Feng

    2015-01-01

    Full Text Available This work studied the influence of textural characteristics of CNTs on catalytic performance of Ni/CNTs for CO2 methanation. The CNTs supports were prepared by chemical vapor deposition method using Ni/MgO catalysts, and acetonitrile and ethanol were used as carbon sources, respectively. The Ni/CNTs catalysts were prepared via impregnation method and characterized by X-ray diffraction (XRD, N2 adsorption/desorption, and temperature-programmed reduction (H2-TPR techniques. The results indicated that the textural characteristics of CNTs supports significantly impacted on the catalytic performance of Ni/CNTs. The catalyst Ni/CNTs-E (CNTs using ethanol as carbon source had good reducibility, high specific surface area, and moderate defects, resulting in higher CO2 conversion and CH4 yield, followed by Ni/CNTs-C (commercial CNTs and Ni/CNTs-A (CNTs using acetonitrile as carbon source. Based on Arrhenius formula, activation energies of the catalysts were calculated and were found decreased for Ni/CNTs-A and Ni/CNTs-E.

  8. Synergetic effects leading to coke-resistant NiCo bimetallic catalysts for dry reforming of methane

    KAUST Repository

    Li, Lidong

    2015-01-08

    A new dry reforming of methane catalyst comprised of NiCo bimetallic nanoparticles and a Mgx(Al)O support that exhibits high coke resistance and long-term on-stream stability is reported. The structural characterization by XRD, TEM, temperature-programmed reduction, and BET analysis demonstrates that the excellent performance of this catalyst is ascribed to the synergy of various parameters, including metal-nanoparticle size, metal-support interaction, catalyst structure, ensemble size, and alloy effects.

  9. Ni-Based Catalysts for Low Temperature Methane Steam Reforming: Recent Results on Ni-Au and Comparison with Other Bi-Metallic Systems

    Directory of Open Access Journals (Sweden)

    Anna M. Venezia

    2013-06-01

    Full Text Available Steam reforming of light hydrocarbons provides a promising method for hydrogen production. Ni-based catalysts are so far the best and the most commonly used catalysts for steam reforming because of their acceptably high activity and significantly lower cost in comparison with alternative precious metal-based catalysts. However, nickel catalysts are susceptible to deactivation from the deposition of carbon, even when operating at steam-to-carbon ratios predicted to be thermodynamically outside of the carbon-forming regime. Reactivity and deactivation by carbon formation can be tuned by modifying Ni surfaces with a second metal, such as Au through alloy formation. In the present review, we summarize the very recent progress in the design, synthesis, and characterization of supported bimetallic Ni-based catalysts for steam reforming. The progress in the modification of Ni with noble metals (such as Au and Ag is discussed in terms of preparation, characterization and pretreatment methods. Moreover, the comparison with the effects of other metals (such as Sn, Cu, Co, Mo, Fe, Gd and B is addressed. The differences of catalytic activity, thermal stability and carbon species between bimetallic and monometallic Ni-based catalysts are also briefly shown.

  10. Hydrogen generation from deliquescence of ammonia borane using Ni-Co/r-GO catalyst

    Science.gov (United States)

    Chou, Chang-Chen; Chen, Bing-Hung

    2015-10-01

    Hydrogen generation from the catalyzed deliquescence/hydrolysis of ammonia borane (AB) using the Ni-Co catalyst supported on the graphene oxide (Ni-Co/r-GO catalyst) under the conditions of limited water supply was studied with the molar feed ratio of water to ammonia borane (denoted as H2O/AB) at 2.02, 3.97 and 5.93, respectively. The conversion efficiency of ammonia borane to hydrogen was estimated both from the cumulative volume of the hydrogen gas generated and the conversion of boron chemistry in the hydrolysates analyzed by the solid-state 11B NMR. The conversion efficiency of ammonia borane could reach nearly 100% under excess water dosage, that is, H2O/AB = 3.97 and 5.93. Notably, the hydrogen storage capacity could reach as high as 6.5 wt.% in the case with H2O/AB = 2.02. The hydrolysates of ammonia borane in the presence of Ni-Co/r-GO catalyst were mainly the mixture of boric acid and metaborate according to XRD, FT-IR and solid-state 11B NMR analyses.

  11. Hydrocracking of Cerbera manghas Oil with Co-Ni/HZSM-5 as Double Promoted Catalyst

    Directory of Open Access Journals (Sweden)

    Lenny Marlinda

    2017-05-01

    Full Text Available The effect of various reaction temperature on the hydrocracking of Cerbera manghas oil to produce a paraffin-rich mixture of hydrocarbons with Co-Ni/HZSM-5 as doubled promoted catalyst were studied. The Co-Ni/HZSM-5 catalyst with various metal loading and metal ratio was prepared by incipient wetness impregnation. The catalysts were characterized by XRD, AAS, and N2 adsorption-desorption. Surface area, pore diameter, and pore volume of catalysts decreased with the increasing of metals loading. The hydrocracking process was conducted under hydrogen initial pressure in batch reactor equipped with a mechanical stirrer. The reaction was carried out at a temperature of 300-375 oC for 2 h.  Depending on the experimental condition, the reaction pressure changed between 10 bar and 15 bar.   Several parameters were used to evaluate biofuel produced, including oxygen removal, hydrocarbon composition and gasoline/kerosene/diesel yields. Biofuel was analyzed by Fourier Transform Infrared Spectroscopic (FTIR and gas chromatography-mass spectrometry (GC-MS. The composition of hydrocarbon compounds in liquid products was similar to the compounds in the gasoil sold in unit of Pertamina Gas Stations, namely pentadecane, hexadecane, heptadecane, octadecane, and nonadecane with different amounts for each biofuel produced at different reaction temperatures. However, isoparaffin compounds were not formed at all operating conditions. Pentadecane (n-C15 and heptadecane (n-C17 were the most abundant composition in gasoil when Co-Ni/HZSM-5 catalyst was used. Cerbera Manghas oil can be recommended as the source of non-edible vegetable oil to produce gasoil as an environmentally friendly transportation fuel. Copyright © 2017 BCREC Group. All rights reserved Received: 20th May 2016; Revised: 30th January 2017; Accepted: 10th February 2017 How to Cite: Marlinda, L., Al-Muttaqii, M., Gunardi, I., Roesyadi, A., Prajitno, D.H. (2017. Hydrocracking of Cerbera manghas Oil

  12. [In situ diffuse reflectance FTIR spectroscopy study of CO adsorption on Ni2P/mesoporous molecule sieve catalysts].

    Science.gov (United States)

    Liu, Qian-qian; Ji, Sheng-fu; Wu, Ping-yi; Hu, Lin-hua; Huang, Xiao-fan; Zhu, Ji-qin; Li, Cheng-yue

    2009-05-01

    Abstract The supported nickel phosphate precursors were prepared by incipient wetness impregnation using nickel nitrate as nickel source, diammonium hydrogen phosphate as phosphorus source, and MCM-41, MCM-48, SBA-15 and SBA-16 as supports, respectively. Then, the supported Ni2 P catalysts were prepared by temperature-programmed reduction in flowing Hz from their nickel phosphate precursors. The in situ diffuse reflectance FTIR spectroscopy (DRIFTS) analysis with the probe molecule CO was carried out to characterize the surface properties. The results indicated that there were significant differences in the spectral features of the samples. The upsilon(CO) absorbances observed for adsorbed CO on mesoporous molecule sieve was attributed to weak physical adsorption. There are four different kinds of upsilon(CO) absorbances observed for adsorbed CO on Ni2 P/MCM-41 catalyst with the following assignments: (1) the formation of Ni(CO)4 at 2055 cm(-1). (2) CO terminally bonded to cus Ni(delta+) (0Ni+ sites at 2127 cm(-1). (4) CO terminally bonded to P and form P==C==O between 2198 and 2202 cm(-1). There are two different kinds of upsilon(CO) absorbances observed for adsorbed CO on Ni2P/MCM-48, Ni2P/ SBA-15 and Ni2P/SBA-16 catalysts. The absorbance observed at 2051-2055 cm(-1) for CO adsorption on Ni2P/MCM-48, Ni2P/SBA-15 and Ni2P/SBA-16 catalysts is due to the formation of Ni(CO)4 species. The other upsilon absorbances observed at 2093-2096 cm(-1) was attributed to CO terminally bonded to cus Ni(delta+) (0

  13. Effect of Nano-Ni Catalyst on the Growth and Characterization of Diamond Films by HFCVD

    Directory of Open Access Journals (Sweden)

    Chien-Chung Teng

    2010-01-01

    Full Text Available Four different catalysts, nanodiamond seed, nano-Ni, diamond powder, and mixture of nano-Ni/diamond powder, were used to activate Si wafers for diamond film growth by hot-filament CVD (HFCVD. Diamond crystals were shown to grow directly on both large diamond powder and small nanodiamond seed, but a better crystallinity of diamond film was observed on the ultrasonicated nanodiamond seeded Si substrate. On the other hand, nano-Ni nanocatalysts seem to promote the formation of amorphous carbon but suppress transpolyacetylene (t-PA phases at the initial growth of diamond films. The subsequent nucleation and growth of diamond crystals on the amorphous carbon layer leads to generation of the spherical diamond particles and clusters prior to coalescence into continuous diamond films based on the CH3 addition mechanism as characterized by XRD, Raman, ATR/FT-IR, XPS, TEM, SEM, and AFM techniques. Moreover, a 36% reduction in surface roughness of diamond film assisted by nano-Ni catalyst is quite significant.

  14. A possible highly active supported Ni dimer catalyst for O{sub 2} dissociation: A first-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Shan [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Zhang, Yanxing, E-mail: 2016025@htu.edu.cn [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Zhang, Xilin; Mao, Jianjun [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Yang, Zongxian, E-mail: yzx@henannu.edu.cn [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Collaborative Innovation Center of Nano Functional Materials and Applications, Henan Province (China)

    2017-04-30

    Graphical abstract: The minimum energy paths (MEPs) for the dissociation process of O{sub 2} on the surfaces of bare YSZ (111) and Ni{sub n}/YSZ (111) (n = 1, 2 and 3). - Highlights: • The catalytic activity of supported metal catalysts is closely related to the size of metal particles. • The dissociation of O{sub 2} on the YSZ (111) surface is largely enhanced by the supported Ni cluster. • The supported Ni dimer is predicted to be the smallest Ni cluster needed for efficient O{sub 2} dissociation. • The results would provide an important reference to improve the activity and efficiency of the Ni/YSZ(111) nanocomposite catalysts in cost-effective materials. - Abstract: The adsorption and dissociation of O{sub 2} on the supported small nickel clusters with one-, two-, three-Ni atoms on yttria-stabilized zirconia (YSZ) (111) surfaces, as well as those on the bare YSZ(111) and Ni(111) surfaces are comparatively studied using ab initio density functional theory calculations. It is found that the dissociation of O{sub 2} on the YSZ(111) surface is largely enhanced by the supported Ni dimer, which is predicted to be the smallest Ni cluster needed for efficient O{sub 2} dissociation. The results would provide an important reference to improve the activity and efficiency of the Ni/YSZ(111) nanocomposite catalysts in cost-effective materials.

  15. Hydrocracking of α-Cellulose Using Co, Ni, and Pd Supported on Mordenite Catalysts

    Directory of Open Access Journals (Sweden)

    Wega Trisunaryanti

    2018-02-01

    Full Text Available Hydrocracking of α-cellulose has been conducted in a semi-batch reactor at 400, 450, and 500 °C with hydrogen flow (30 mL/min. for 4 h. Mordenite (MOR and Co, Ni and Pd metal supported on the MOR were used as solid catalysts. The catalysts were characterized using X-ray Diffractometer (XRD, Fourier Transform Infrared (FTIR spectroscopy, and Scanning Electron Microscopy (SEM to evaluate the physical-chemical properties. Energy Dispersive X-ray (EDX and Inductively Coupled Plasma (ICP were used to analyze the amount of metal impregnated on the catalysts. The liquid product was analyzed using Gas Chromatograph-Mass Spectroscopy (GC-MS. Thermal hydrocracking was also conducted at 450 °C with the amount of liquid product was 37.86 wt.%. The highest liquid conversion obtained by mordenite catalyst was 94.66 wt.% at 450 °C and the highest liquid conversion (98.08 wt.% was reached by Pd/MOR catalyst at 400 °C.

  16. PREPARATION, CHARACTERIZATIONS AND MODIFICATION OF Ni-Pd/NATURAL ZEOLITE CATALYSTS

    Directory of Open Access Journals (Sweden)

    Wega Trisunaryanti

    2010-06-01

    Full Text Available Preparation, and modification of Ni-Pd/natural zeolite as well as their characterizations had been carried out. The aim of this research for the fututure is to prepare the best characters catalyst for the conversion of waste plastics fraction to gasoline fraction (C5-C12 hydrocarbons. The preparation of catalysts was performed by reacting a natural zeolite with the precursor of Ni(NO32. 9H2O and PdCl2 in an ammonia solution (25%. The modifications were performed by varying the rasio of Ni/Pd loaded to the zeolite, whereas the Pd was previously loaded and total metal content was 1 wt.% based on the zeolite. The characterization of catalysts included determination of acidity gravimetrically by adsorption of ammonia or pyridine vapour  base method, metal content by Atomic Adsorption Spectrophotometer (AAS and X-ray Fluoresence (XRF and crystallinity by X-ray Diffraction (XRD. The treatment of catalysts using Etilene Diamine Tetra Acetic acid  (EDTA was performed to study the metal distribution on the outer or inner surface of the zeolite. The characterization results showed that the loading of metals to the zeolite increased its acidity and decreased its spesific surface area, however, did not defect its crystallnity.  The metals loaded on the zeolite were distributed inside the pore and at outer surface of the zeolite. For all catalyst samples, the acidities determined using ammonia were higher than those of pyridine, and the acidities determined before the EDTA treatment was lower than those after the treatment.  Metal contents of the zeolite before the EDTA treatment were higher than those after the treatment. The EDTA treatment enhanced the crystallinity of the sampel. The relationship between the metal rasio towards the acidity of the catalyst samples were in variation. Catalyst samples produced in this research have good characters, thus promisingly can be used for conversion process of waste plastics to gasoline fraction.    Keywords

  17. Green synthesis of Ni-Nb oxide catalysts for low-temperature oxidative dehydrogenation of ethane

    KAUST Repository

    Zhu, Haibo

    2015-03-05

    The straightforward solid-state grinding of a mixture of Ni nitrate and Nb oxalate crystals led to, after mild calcination (T<400°C), nanostructured Ni-Nb oxide composites. These new materials efficiently catalyzed the oxidative dehydrogenation (ODH) of ethane to ethylene at a relatively low temperature (T<300°C). These catalysts appear to be much more stable than the corresponding composites prepared by other chemical methods; more than 90% of their original intrinsic activity was retained after 50h with time on-stream. Furthermore, the stability was much less affected by the Nb content than in composites prepared by classical "wet" syntheses. These materials, obtained in a solvent-free way, are thus promising green and sustainable alternatives to the current Ni-Nb candidates for the low-temperature ODH of ethane.

  18. CuNi NPs supported on MIL-101 as highly active catalysts for the hydrolysis of ammonia borane

    Science.gov (United States)

    Gao, Doudou; Zhang, Yuhong; Zhou, Liqun; Yang, Kunzhou

    2018-01-01

    The catalysts containing Cu, Ni bi-metallic nanoparticles were successfully synthesized by in-situ reduction of Cu2+ and Ni2+ salts into the highly porous and hydrothermally stable metal-organic framework MIL-101 via a simple liquid impregnation method. When the total amount of loading metal is 3 × 10-4 mol, Cu2Ni1@MIL-101 catalyst shows higher catalytic activity comparing to CuxNiy@MIL-101 with different molar ratio of Cu and Ni (x, y = 0, 0.5, 1.5, 2, 2.5, 3). Cu2Ni1@MIL-101 catalyst has the highest catalytic activity comparing to mono-metallic Cu and Ni counterparts and pure bi-metallic CuNi nanoparticles in hydrolytic dehydrogeneration of ammonia borane (AB) at room temperature. Additionally, in the hydrolysis reaction, the Cu2Ni1@MIL- 101 catalyst possesses excellent catalytic performances, which exhibit highly catalytic activity with turn over frequency (TOF) value of 20.9 mol H2 min-1 Cu mol-1 and a very low activation energy value of 32.2 kJ mol-1. The excellent catalytic activity has been successfully achieved thanks to the strong bi-metallic synergistic effects, uniform distribution of nanoparticles and the bi-functional effects between CuNi nanoparticles and the host of MIL-101. Moreover, the catalyst also displays satisfied durable stability after five cycles for the hydrolytically releasing H2 from AB. The non-noble metal catalysts have broad prospects for commercial applications in the field of hydrogen-stored materials due to the low prices and excellent catalytic activity.

  19. Catalytic upgrading of oleic acid into biofuel using Mo modified zeolite supported Ni oxalate catalyst functionalized with fluoride ion

    International Nuclear Information System (INIS)

    Ayodele, O.B.; Abbas, Hazzim F.; Daud, Wan Mohd Ashri Wan

    2014-01-01

    Highlights: • Modification of zeolite with freshly prepared molybdenum oxalate. • Functionalization of Ni oxalate with HF and incorporation into Mo modified zeolite. • Characterization of synthesized Mo modified zeolite supported Ni oxalate catalyst. • Deoxygenation of oleic acid with the synthesized zeolite supported catalyst. • Reusability study on the synthesized zeolite supported catalyst. - Abstract: In this study, fluoride ion functionalized nickel oxalate supported on molybdenum modified zeolite (NiMoFOx/Zeol) catalyst was synthesized, characterized and tested on the hydrodeoxygenation (HDO) of oleic acid (OA) into paraffinic fuel. The NiMoFOx/Zeol characterization results confirmed the presence of both Ni and Mo as well as the formation of NiMoO 4 which is a highly HDO reactive specie at 2θ value of 43.6° according to the XRD result. NiMoFOx/Zeol also showed loss in crystallinity and reduction in the average particle size leading to increase in the pore volume and specific surface area due to the combined effects of fluoride ion presence, oxalic acid functionalization and calcination. The effect of temperature, pressure and NiMoFOx/Zeol loading studied showed that initial increase in their values increased the yield of the target fractions until some points where reduction was observed. The best observed experimental conditions to hydrodeoxygenate 40 g (∼45 mL) of OA into 75% n-C 18 and 23% i-C 18 were 360 °C, 30 mg NiMoFOx/Zeol loading and 20 bar using 100 mL H 2 /min. The presence of i-C 18 was due to the functionalization of the catalyst with fluoride ion. The catalyst reusability result displayed excellent qualities with marginal loss of only 2% in activity after third reuse due to the improved synthesis protocol that employed organometallic precursor. The results are strongly encouraging for further studies toward industrialization of HDO process

  20. Analysis and removal of heteroatom containing species in coal liquid distillate over NiMo catalysts

    Energy Technology Data Exchange (ETDEWEB)

    S.D. Sumbogo Murtia; Ki-Hyouk Choi; Kinya Sakanishi; Osamu Okuma; Yozo Korai; Isao Mochida [Kyushu University, Fukuoka (Japan). Institute for Materials Chemistry and Engineering

    2005-02-01

    Heteroatom containing molecules in South Banko coal liquid (SBCL) distillate were identified with a gas chromatograph equipped with an atomic emission detector (GC-AED). Thiophenes and benzothiophenes were found to be the major sulfur compounds. Pyridines, anilines, and phenols were the major nitrogen and oxygen compounds, respectively. Reactivities of heteroatom containing species in hydrotreatment over conventional NiMoS/Al{sub 2}O{sub 3}, NiMoS/Al{sub 2}O{sub 3}-SiO{sub 2} catalysts were very different according to their cyclic structure as well as the kind of heteroatom in the species. The sulfur species were completely desulfurized over the catalysts examined in the present study by 60 min at 360{degree}C under initial hydrogen pressure of 5 MPa. However, hydrodenitrogenation was more difficult than hydrodesulfurization even at 450{degree}C. Anilines were found the most refractory ones among the nitrogen species. Hydrodeoxygenation of SBCL was also difficult in the hydrotreatment conditions examined in the present study. Dibenzofuran was the most refractory molecule among the oxygen species. A two-stage reaction configuration at 340 and 360{degree}C improved HDN and HDO reactivities, although the conversions were still insufficient. Increasing the acidity of the support as well as the loading of the metals on the NiMoS/Al{sub 2}O{sub 3} catalysts improved very much the heteroatom reduction to achieve complete removal of nitrogen by two-stage reaction configuration at 340-360{degree}C and oxygen at 360{degree}C, respectively. The addition of H{sub 2}S in the reaction atmosphere inhibited the HDN reaction but increased markedly the HDO conversion. The acidic support increased the activity in hydrotreatment through enhancing the hydrogenation activity, while H{sub 2}S maintained the catalyst in a sufficiently sulfided state. 19 refs., 4 figs., 8 tabs.

  1. Formation of Multiple-Phase Catalysts for the Hydrogen Storage of Mg Nanoparticles by Adding Flowerlike NiS.

    Science.gov (United States)

    Xie, Xiubo; Ma, Xiujuan; Liu, Peng; Shang, Jiaxiang; Li, Xingguo; Liu, Tong

    2017-02-22

    In order to enhance the hydrogen storage properties of Mg, flowerlike NiS particles have been successfully prepared by solvothermal reaction method, and are subsequently ball milled with Mg nanoparticles (NPs) to fabricate Mg-5 wt % NiS nanocomposite. The nanocomposite displays Mg/NiS core/shell structure. The NiS shell decomposes into Ni, MgS and Mg 2 Ni multiple-phases, decorating on the surface of the Mg NPs after the first hydrogen absorption and desorption cycle at 673 K. The Mg-MgS-Mg 2 Ni-Ni nanocomposite shows enhanced hydrogenation and dehydrogenation rates: it can quickly uptake 3.5 wt % H 2 within 10 min at 423 K and release 3.1 wt % H 2 within 10 min at 573 K. The apparent hydrogen absorption and desorption activation energies are decreased to 45.45 and 64.71 kJ mol -1 . The enhanced sorption kinetics of the nanocomposite is attributed to the synergistic catalytic effects of the in situ formed MgS, Ni and Mg 2 Ni multiple-phase catalysts during the hydrogenation/dehydrogenation process, the porthole effects for the volume expansion and microstrain of the phase transformation of Mg 2 Ni and Mg 2 NiH 4 and the reduced hydrogen diffusion distance caused by nanosized Mg. This novel method of in situ producing multiple-phase catalysts gives a new horizon for designing high performance hydrogen storage material.

  2. Hydrogen production from steam reforming of ethanol over Ni/MgO-CeO_2 catalyst at low temperature

    Institute of Scientific and Technical Information of China (English)

    石秋杰; 刘承伟; 谌伟庆

    2009-01-01

    MgO,CeO2 and MgO-CeO2 with different mole ratio of Mg:Ce were prepared by solid-phase burning method.Catalysts Ni/MgO,Ni/CeO2 and Ni/MgO-CeO2 were prepared by impregnation method.The catalytic properties were evaluated in ethanol steam reforming(ESR) reaction.Specific surface areas of the supports were measured by nitrogen adsorption-desorption at 77 K,and the catalysts were characterized with X-ray diffraction(XRD),temperature programmed reduction(TPR) and thermogravimetric(TG).The results showed that well...

  3. Unsupported NiPt alloy metal catalysts prepared by water-in-oil (W/O) microemulsion method for methane cracking

    KAUST Repository

    Zhou, Lu

    2016-05-18

    Unsupported NiPt metal catalyst with Ni/Pt molar ratio of 88/12 is prepared by water-in-oil (W/O) microemulsion method in this study. Compared to monometallic Ni and Pt catalysts, the NiPt catalyst exhibits superior activity and stability for methane cracking. By XRD (X-ray powder diffraction), XPS (X-ray photoelectron spectroscopy) and TEM (Transmission electron microscopy) analyses, the formation of Ni(0)Pt(0) alloy is believed to be the main reason for the reactivity improvement of this catalyst. Carbon nano tube (CNT) with Ni(0)Pt(0) particles anchored on the top of tube are found for the NiPt catalyst. © 2016 Elsevier Ltd.

  4. Heterogeneous hydrogenation of unsaturated compounds with catalyst P-2-Ni with turnover numbers up to 90,000

    Energy Technology Data Exchange (ETDEWEB)

    Strohmeier, W; Pfoehler, M; Steigerwald, H [Wuerzburg Univ. (Germany, F.R.). Inst. fuer Physikalische Chemie

    1977-12-01

    Unsaturated compounds are very rapidly hydrogenated with nickel-boride catalyst P-2-Ni without solvent under mild conditions (70-85/sup 0/C and 10 bar). Turnover numbers UZ up to 90,000 and space-time-yields of 7.440 mmol product per l and 1 mgA Nickel in one hour with a mean catalyst activity a = 124 were observed. This hydrogenation catalyst has a power, which is in the same magnitude of very active noble metal catalysts.

  5. Investigation of ethanol electrooxidation on a Pt-Ru-Ni/C catalyst for a direct ethanol fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhen-Bo; Yin, Ge-Ping; Zhang, Jian; Sun, Ying-Chao; Shi, Peng-Fei [Department of Applied Chemistry, Harbin Institute of Technology, Harbin (China 150001)

    2006-09-29

    This research is aimed to improve the utilization and activity of anodic alloy catalysts and thus to lower the contents of noble metals and the catalyst loading on anodes for ethanol electrooxidation. The DEFC anodic catalysts, Pt-Ru-Ni/C and Pt-Ru/C, were prepared by a chemical reduction method. Their performances were tested by using a glassy carbon working electrode and cyclic voltammetric curves, chronoamperometric curves and half cell measurement in a solution of 0.5molL{sup -1} CH{sub 3}CH{sub 2}OH and 0.5molL{sup -1} H{sub 2}SO{sub 4}. The composition of the Pt-Ru-Ni and Pt-Ru surface particles were determined by EDAX analysis. The particle size and lattice parameter of the catalysts were determined by means of X-ray diffraction (XRD). XRD analysis showed that both of the catalysts exhibited face centered cubic structures and had smaller lattice parameters than a Pt-alone catalyst. Their particle sizes were small, about 4.5nm. No significant differences in the ethanol electrooxidation on both electrodes were found using cyclic voltammetry, especially regarding the onset potential for ethanol electrooxidation. The electrochemically active specific areas of the Pt-Ru-Ni/C and Pt-Ru/C catalysts were almost the same. But, the catalytic activity of the Pt-Ru-Ni/C catalyst was higher for ethanol electrooxidation than that of the Pt-Ru/C catalyst. Their tolerance to CO formed as one of the intermediates of ethanol electrooxidation, was better than that of the Pt-Ru/C catalyst. (author)

  6. Alkali resistant Ni-loaded yolk-shell catalysts for direct internal reforming in molten carbonate fuel cells

    Science.gov (United States)

    Jang, Won-Jun; Hong, Young Jun; Kim, Hak-Min; Shim, Jae-Oh; Roh, Hyun-Seog; Kang, Yun Chan

    2017-06-01

    A facile and scalable spray pyrolysis process is applied to synthesize multi-shelled Ni-loaded yolk-shell catalysts on various supports (Al2O3, CeO2, ZrO2, and La(OH)3). The prepared catalysts are applied to direct internal reforming (DIR) in a molten carbonate fuel cell (MCFC). Even on exposure to alkali hydroxide vapors, the Ni-loaded yolk-shell catalysts remain highly active for DIR-MCFCs. The Ni@Al2O3 microspheres show the highest conversion (92%) of CH4 and the best stability among the prepared Ni-loaded yolk-shell catalysts. Although the initial CH4 conversion of the Ni@ZrO2 microspheres is higher than that of the Ni@CeO2 microspheres, the Ni@CeO2 microspheres are more stable. The catalytic performance is strongly dependent on the surface area and acidity and also partly dependent on the reducibility. The acidic nature of Al2O3 combined with its high surface area and yolk-shell structure enhances the adsorption of CH4 and resistance against alkali poisoning, resulting in efficient DIR-MCFC reactions.

  7. Promotion Effect of CaO Modification on Mesoporous Al2O3-Supported Ni Catalysts for CO2 Methanation

    Directory of Open Access Journals (Sweden)

    Wen Yang

    2016-01-01

    Full Text Available The catalysts Ni/Al2O3 and CaO modified Ni/Al2O3 were prepared by impregnation method and applied for methanation of CO2. The catalysts were characterized by N2 adsorption/desorption, temperature-programmed reduction of H2 (H2-TPR, X-ray diffraction (XRD, and temperature-programmed desorption of CO2 and H2 (CO2-TPD and H2-TPD techniques, respectively. TPR and XRD results indicated that CaO can effectively restrain the growth of NiO nanoparticles, improve the dispersion of NiO, and weaken the interaction between NiO and Al2O3. CO2-TPD and H2-TPD results suggested that CaO can change the environment surrounding of CO2 and H2 adsorption and thus the reactants on the Ni atoms can be activated more easily. The modified Ni/Al2O3 showed better catalytic activity than pure Ni/Al2O3. Ni/CaO-Al2O3 showed high CO2 conversion especially at low temperatures compared to Ni/Al2O3, and the selectivity to CH4 was very close to 1. The high CO2 conversion over Ni/CaO-Al2O3 was mainly caused by the surface coverage by CO2-derived species on CaO-Al2O3 surface.

  8. Strategies for improving the performance and stability of Ni-based catalysts for reforming reactions.

    Science.gov (United States)

    Li, Shuirong; Gong, Jinlong

    2014-11-07

    Owing to the considerable publicity that has been given to petroleum related economic, environmental, and political problems, renewed attention has been focused on the development of highly efficient and stable catalytic materials for the production of chemical/fuel from renewable resources. Supported nickel nanoclusters are widely used for catalytic reforming reactions, which are key processes for generating synthetic gas and/or hydrogen. New challenges were brought out by the extension of feedstock from hydrocarbons to oxygenates derivable from biomass, which could minimize the environmental impact of carbonaceous fuels and allow a smooth transition from fossil fuels to a sustainable energy economy. This tutorial review describes the recent efforts made toward the development of nickel-based catalysts for the production of hydrogen from oxygenated hydrocarbons via steam reforming reactions. In general, three challenges facing the design of Ni catalysts should be addressed. Nickel nanoclusters are apt to sinter under catalytic reforming conditions of high temperatures and in the presence of steam. Severe carbon deposition could also be observed on the catalyst if the surface carbon species adsorbed on metal surface are not removed in time. Additionally, the production of hydrogen rich gas with a low concentration of CO is a challenge using nickel catalysts, which are not so active in the water gas shift reaction. Accordingly, three strategies were presented to address these challenges. First, the methodologies for the preparation of highly dispersed nickel catalysts with strong metal-support interaction were discussed. A second approach-the promotion in the mobility of the surface oxygen-is favored for the yield of desired products while promoting the removal of surface carbon deposition. Finally, the process intensification via the in situ absorption of CO2 could produce a hydrogen rich gas with low CO concentration. These approaches could also guide the design

  9. Influence of Ni Catalyst Layer and TiN Diffusion Barrier on Carbon Nanotube Growth Rate

    Directory of Open Access Journals (Sweden)

    Mérel Philippe

    2010-01-01

    Full Text Available Abstract Dense, vertically aligned multiwall carbon nanotubes were synthesized on TiN electrode layers for infrared sensing applications. Microwave plasma-enhanced chemical vapor deposition and Ni catalyst were used for the nanotubes synthesis. The resultant nanotubes were characterized by SEM, AFM, and TEM. Since the length of the nanotubes influences sensor characteristics, we study in details the effects of changing Ni and TiN thickness on the physical properties of the nanotubes. In this paper, we report the observation of a threshold Ni thickness of about 4 nm, when the average CNT growth rate switches from an increasing to a decreasing function of increasing Ni thickness, for a process temperature of 700°C. This behavior is likely related to a transition in the growth mode from a predominantly “base growth” to that of a “tip growth.” For Ni layer greater than 9 nm the growth rate, as well as the CNT diameter, variations become insignificant. We have also observed that a TiN barrier layer appears to favor the growth of thinner CNTs compared to a SiO2 layer.

  10. Design of ultrathin Pt-Mo-Ni nanowire catalysts for ethanol electrooxidation.

    Science.gov (United States)

    Mao, Junjie; Chen, Wenxing; He, Dongsheng; Wan, Jiawei; Pei, Jiajing; Dong, Juncai; Wang, Yu; An, Pengfei; Jin, Zhao; Xing, Wei; Tang, Haolin; Zhuang, Zhongbin; Liang, Xin; Huang, Yu; Zhou, Gang; Wang, Leyu; Wang, Dingsheng; Li, Yadong

    2017-08-01

    Developing cost-effective, active, and durable electrocatalysts is one of the most important issues for the commercialization of fuel cells. Ultrathin Pt-Mo-Ni nanowires (NWs) with a diameter of ~2.5 nm and lengths of up to several micrometers were synthesized via a H 2 -assisted solution route (HASR). This catalyst was designed on the basis of the following three points: (i) ultrathin NWs with high numbers of surface atoms can increase the atomic efficiency of Pt and thus decrease the catalyst cost; (ii) the incorporation of Ni can isolate Pt atoms on the surface and produce surface defects, leading to high catalytic activity (the unique structure and superior activity were confirmed by spherical aberration-corrected electron microscopy measurements and ethanol oxidation tests, respectively); and (iii) the incorporation of Mo can stabilize both Ni and Pt atoms, leading to high catalytic stability, which was confirmed by experiments and density functional theory calculations. Furthermore, the developed HASR strategy can be extended to synthesize a series of Pt-Mo-M (M = Fe, Co, Mn, Ru, etc.) NWs. These multimetallic NWs would open up new opportunities for practical fuel cell applications.

  11. Hydrodeoxygenation of Methyl Laurate over Ni Catalysts Supported on Hierarchical HZSM-5 Zeolite

    Directory of Open Access Journals (Sweden)

    Nana Li

    2017-12-01

    Full Text Available The hierarchical HZSM-5 zeolite was prepared successfully by a simple NaOH treatment method. The concentration of NaOH solution was carefully tuned to optimal the zeolite acidity and pore structure. Under NaOH treatment conditions, a large number of mesopores, which interconnected with the retained micropores, were created to facilitate mass transfer performance. There are very good correlations between the decline of the relative zeolite crystallinity and the loss of micropores volume. The Ni nanoclusters were uniformly confined in the mesopores of hierarchical HZSM-5 by the excessive impregnation method. The direct deoxygenation in N2 and hydrodeoxygenation in H2 of the methyl laurate were compared respectively over the Ni/HZSM-5 catalysts. In the N2 atmosphere, the deoxygenation rate of the methyl laurate on the Ni/HZSM-5 catalyst is relatively slow. In the presence of H2, the synergistic effect between the hydrogenation function of the metal and the acid function of the zeolite supports can make the deoxygenation level more obvious. The yield of hydrocarbon products gradually reached the maximum with the appropriate treatment concentration of 1M NaOH, which could be attributed to the improved mass transfer in the hierarchical HZSM-5 supports.

  12. Effect of Ca, Ce or K oxide addition on the activity of Ni/SiO{sub 2} catalysts for the methane decomposition reaction

    Energy Technology Data Exchange (ETDEWEB)

    Zapata, Beatriz; Torres-Garcia, Enelio [Instituto Mexicano del Petroleo, Programa de Procesos y Reactores, Eje C. 152, Mexico, D.F., C.P. 07730 (Mexico); Valenzuela, Miguel A.; Palacios, Jorge [Instituto Politecnico Nacional-ESIQIE, Lab. Catalisis y Materiales, Zacatenco, Mexico, D.F., C.P. 07738 (Mexico)

    2010-11-15

    To increase the activity and stability of Ni/SiO{sub 2} catalysts, a series of Ni-Ca, Ni-K and Ni-Ce promoted catalysts were prepared by successive impregnations. The textural properties, reducibility and catalytic performance in the methane decomposition reaction were investigated. The catalyst containing 30 wt.% Ni and 30 wt.% cerium oxide greatly increased the conversion of methane (90% of equilibrium value) and improved the stability, whereas the Ni-K and Ni-Ca were less active and stable than the Ni/SiO{sub 2} catalyst. The results suggest that Ce addition prevents the sintering of nickel particles during reduction process maintaining a random distribution between the silica and cerium oxide improving the distribution and migration of deposited carbon. (author)

  13. Production of liquid alkanes by controlling reactivity of sorbitol hydrogenation with a Ni/HZSM-5 catalyst in water

    International Nuclear Information System (INIS)

    Zhang, Qing; Wang, Tiejun; Xu, Ying; Zhang, Qi; Ma, Longlong

    2014-01-01

    Graphical abstract: MCM-41-modified Ni/HZSM-5 catalyst was developed by impregnation method with high catalytic performance for sorbitol hydrogenation in water. Appropriate amount of MCM-41 addition can distinctly promote the improvement in the surface structure and modulation of acidic sites of the catalyst. The scission of C–O bond in the sorbitol molecule into liquid alkanes was easily carried out on the catalyst containing more Lewis acidic sites. - Highlights: • Ni/HZSM-5 promoted with MCM-41 is active for sorbitol hydrogenation to liquid alkanes. • Lewis acidic sites of Ni/HZSM-5 can be modulated by pure silica MCM-41. • MCM-41 added can distinctly decrease carbon deposition on the catalyst surface. - Abstract: Liquid fuels derived from renewable biomass are of great importance on the potential substitution for diminishing fossil fuels. The conversion of sorbitol (a product of biomass-derived glucose hydrogenation) into liquid alkanes such as pentane and hexane over the Ni/HZSM-5 catalysts with or without MCM-41 addition was investigated in the presence of hydrogen in water medium. The production distribution of sorbitol hydrogenation can be controlled by adjusting the acidity of the catalyst. The scission of C–C bond in the sorbitol molecule into light C 1 –C 4 alkanes was mainly carried out over Ni/HZSM-5 containing strong Brønsted acid sites, while C–O bond scission into heavier alkanes was dominated over the catalysts added by MCM-41 containing weak Lewis acid sites. The sorbitol conversion and total liquid alkanes selectivity were found to be 67.1% and 98.7% over 2%Ni/HZSM-5 modified by 40 wt% of MCM-41, whereas the corresponding value was 40% and 35.6% over 2%Ni/HZSM-5 in the absence of MCM-41. The effect of MCM-41 on the structure, acidity, and reducibility of Ni/HZSM-5 was investigated by using XRD, Py-IR, IR, and H 2 -TPR. Meanwhile, the resistance of carbon deposition over the catalyst modified by MCM-41 was studied by using TG

  14. Towards Highly Performing and Stable PtNi Catalysts in Polymer Electrolyte Fuel Cells for Automotive Application

    Directory of Open Access Journals (Sweden)

    Sabrina C. Zignani

    2017-03-01

    Full Text Available In order to help the introduction on the automotive market of polymer electrolyte fuel cells (PEFCs, it is mandatory to develop highly performing and stable catalysts. The main objective of this work is to investigate PtNi/C catalysts in a PEFC under low relative humidity and pressure conditions, more representative of automotive applications. Carbon supported PtNi nanoparticles were prepared by reduction of metal precursors with formic acid and successive thermal and leaching treatments. The effect of the chemical composition, structure and surface characteristics of the synthesized samples on their electrochemical behavior was investigated. The catalyst characterized by a larger Pt content (Pt3Ni2/C presented the highest catalytic activity (lower potential losses in the activation region among the synthesized bimetallic PtNi catalysts and the commercial Pt/C, used as the reference material, after testing at high temperature (95 °C and low humidification (50% conditions for automotive applications, showing a cell potential (ohmic drop-free of 0.82 V at 500 mA·cm−2. In order to assess the electro-catalysts stability, accelerated degradation tests were carried out by cycling the cell potential between 0.6 V and 1.2 V. By comparing the electrochemical and physico-chemical parameters at the beginning of life (BoL and end of life (EoL, it was demonstrated that the Pt1Ni1/C catalyst was the most stable among the catalyst series, with only a 2% loss of voltage at 200 mA·cm−2 and 12.5% at 950 mA·cm−2. However, further improvements are needed to produce durable catalysts.

  15. Catalytic Chemical Vapor Deposition of Methane to Carbon Nanotubes: Copper Promoted Effect of Ni/MgO Catalysts

    Directory of Open Access Journals (Sweden)

    Wen Yang

    2014-01-01

    Full Text Available The Ni/MgO and Ni-Cu/MgO catalysts were prepared by sol-gel method and used as the catalysts for synthesis of carbon nanotubes by thermal chemical vapor deposition. The effect of Cu on the carbon yield and structure was investigated, and the effects of calcination temperature and reaction temperature were also investigated. The catalysts and synthesized carbon materials were characterized by temperature programmed reduction (TPR, thermogravimetric analysis (TGA, and scanning electron microscopy (SEM. Results showed that the addition of Cu promoted the reduction of nickel species, subsequently improving the growth and yield of CNTs. Meanwhile, CNTs were synthesized by the Ni/MgO and Ni-Cu/MgO catalysts with various calcination temperatures and reaction temperatures, and results suggested that the obtained CNTs on Ni-Cu/MgO catalyst with the calcination temperature of 500°C and the reaction temperature of 650°C were of the greatest yield and quantity of 927%.

  16. Pt Single Atoms Embedded in the Surface of Ni Nanocrystals as Highly Active Catalysts for Selective Hydrogenation of Nitro Compounds.

    Science.gov (United States)

    Peng, Yuhan; Geng, Zhigang; Zhao, Songtao; Wang, Liangbing; Li, Hongliang; Wang, Xu; Zheng, Xusheng; Zhu, Junfa; Li, Zhenyu; Si, Rui; Zeng, Jie

    2018-06-13

    Single-atom catalysts exhibit high selectivity in hydrogenation due to their isolated active sites, which ensure uniform adsorption configurations of substrate molecules. Compared with the achievement in catalytic selectivity, there is still a long way to go in exploiting the catalytic activity of single-atom catalysts. Herein, we developed highly active and selective catalysts in selective hydrogenation by embedding Pt single atoms in the surface of Ni nanocrystals (denoted as Pt 1 /Ni nanocrystals). During the hydrogenation of 3-nitrostyrene, the TOF numbers based on surface Pt atoms of Pt 1 /Ni nanocrystals reached ∼1800 h -1 under 3 atm of H 2 at 40 °C, much higher than that of Pt single atoms supported on active carbon, TiO 2 , SiO 2 , and ZSM-5. Mechanistic studies reveal that the remarkable activity of Pt 1 /Ni nanocrystals derived from sufficient hydrogen supply because of spontaneous dissociation of H 2 on both Pt and Ni atoms as well as facile diffusion of H atoms on Pt 1 /Ni nanocrystals. Moreover, the ensemble composed of the Pt single atom and nearby Ni atoms in Pt 1 /Ni nanocrystals leads to the adsorption configuration of 3-nitrostyrene favorable for the activation of nitro groups, accounting for the high selectivity for 3-vinylaniline.

  17. Pt-Ni and Pt-Co Catalyst Synthesis Route for Fuel Cell Applications

    Science.gov (United States)

    Firdosy, Samad A.; Ravi, Vilupanur A.; Valdez, Thomas I.; Kisor, Adam; Narayan, Sri R.

    2013-01-01

    Oxygen reduction reactions (ORRs) at the cathode are the rate-limiting step in fuel cell performance. The ORR is 100 times slower than the corresponding hydrogen oxidation at the anode. Speeding up the reaction at the cathode will improve fuel cell efficiency. The cathode material is generally Pt powder painted onto a substrate (e.g., graphite paper). Recent efforts in the fuel cell area have focused on replacing Pt with Pt-X alloys (where X = Co, Ni, Zr, etc.) in order to (a) reduce cost, and (b) increase ORR rates. One of these strategies is to increase ORR rates by reducing the powder size, which would result in an increase in the surface area, thereby facilitating faster reaction rates. In this work, a process has been developed that creates Pt-Ni or Pt-Co alloys that are finely divided (on the nano scale) and provide equivalent performance at lower Pt loadings. Lower Pt loadings will translate to lower cost. Precursor salts of the metals are dissolved in water and mixed. Next, the salt mixtures are dried on a hot plate. Finally, the dried salt mixture is heattreated in a furnace under flowing reducing gas. The catalyst powder is then used to fabricate a membrane electrode assembly (MEA) for electrochemical performance testing. The Pt- Co catalyst-based MEA showed comparable performance to an MEA fabri cated using a standard Pt black fuel cell catalyst. The main objective of this program has been to increase the overall efficiencies of fuel cell systems to support power for manned lunar bases. This work may also have an impact on terrestrial programs, possibly to support the effort to develop a carbon-free energy source. This catalyst can be used to fabricate high-efficiency fuel cell units that can be used in space as regenerative fuel cell systems, and terrestrially as primary fuel cells. Terrestrially, this technology will become increasingly important when transition to a hydrogen economy occurs.

  18. Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO.sub.2 reforming of methane

    KAUST Repository

    Biausque, Gregory; Laveille, Paco; Anjum, Dalaver H.; Caps, Valerie; Basset, Jean-Marie

    2015-01-01

    Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO.sub.2 reforming of methane

  19. Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO.sub.2 reforming of methane

    KAUST Repository

    Biausque, Gregory

    2015-04-28

    Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO.sub.2 reforming of methane

  20. High-performance bimetallic alloy catalyst using Ni and N co-doped composite carbon for the oxygen electro-reduction.

    Science.gov (United States)

    Jung, Won Suk

    2018-03-15

    In this study, a novel synthesis method for the bimetallic alloy catalyst is reported, which is subsequently used as an oxygen reduction catalyst in polymer electrolyte membrane fuel cells (PEMFCs). The support prepared from the Ni-chelate complex shows a mesoporous structure with a specific surface area of ca. 400 m 2  g -1 indicating the suitable support for PEMFC applications. Ethylenediamine is converted to the nitrogen and carbon layers to protect the Ni particles which will diffuse into the Pt lattice at 800 °C. The PtNi/NCC catalyst with PtNi cores and Pt-rich shells is successfully formed when acid-treated as evidenced by line scan profiles. The catalyst particles thus synthesized are well-dispersed on the N-doped carbon support, while the average particle size is ca. 3 nm. In the PEMFC test, the maximum power density of the PtNi/NCC catalyst shows approximately 25% higher than that of the commercial Pt/C catalyst. The mass activity of the PtNi/NCC catalyst showed approximately 3-fold higher than that of the commercial Pt/C catalyst. The mass activity strongly depends on the ratio of Pt to Ni since the strain effect can be strong for catalysts due to the mismatch of lattice parameters of the Ni and Pt. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Ni{sub x}Al{sub y} hydrotalcites derived catalysts for methane dry reforming reaction

    Energy Technology Data Exchange (ETDEWEB)

    Touahra, F.; Abdessadek, Z.; Saadi, A.; Cherifi, O.; Halliche, D. [Univ. des Sciences et de la Technologie Houari Boumedienne (USTHB), El-Alia, Alger (Algeria); Bachari, K. [Centre de Recherche Scientifique et Technique en Analyse Physico-Chimique (CRAPC), Alger (Algeria)

    2010-07-01

    CO{sub 2} reforming of methane shows a growing interest from both industrial and environmental viewpoint. Form an environmental perspective, CO{sub 2} and CH{sub 4} are undesirable greenhouse gases and both are consumed by the proposed reaction. The purpose of this paper is to study the effect of varying molar ratio R=Ni{sup 2+}/Al{sup 3+}(R=2, 3, 5, 7 and 9) for CO{sub 2} reforming of methane reaction. The corresponding Ni{sub x}Al{sub y} samples were prepared by coprecipitation at constant basic pH and calcined at 800 C. They were characterized by ICP method, X-Ray powder diffraction patterns, BET method and FTIR. We have studied the reaction of dry reforming of methane by carbon dioxide in presence of the various catalysts at temperatures ranging from 400 to 700 C. A high conversions to natural conversions were obtained when R>5. (orig.)

  2. Synthesis and characterization of NiFe2O4–Pd magnetically recyclable catalyst for hydrogenation reaction

    International Nuclear Information System (INIS)

    Karaoğlu, E.; Özel, U.; Caner, C.; Baykal, A.; Summak, M.M.; Sözeri, H.

    2012-01-01

    Graphical abstract: Display Omitted Highlights: ► Novel superparamagnetic NiFe 2 O 4 –Pd magnetically recyclable catalyst was fabricated through co-precipitation. ► It could be reused several times without significant loss in catalytic activity for hydrogenation reaction. ► No further modification of the NiFe 2 O 4 –Pd magnetically recyclable catalyst is necessary for utilization as catalyst. -- Abstract: Herein we report the fabrication and characterization magnetically recyclable catalysts of NiFe 2 O 4 –Pd nanocomposite as highly effective catalysts for reduction reactions in liquid phase. The reduction Pd 2+ was accomplished with polyethylene glycol 400 (PEG-400) instead of sodium borohydride (NaBH 4 ) and NiFe 2 O 4 nanoparticles was prepared by sonochemically using FeCI 3 ·6H 2 O and NiCl 2 . The chemical characterization of the product was done with X-ray diffractometry, Infrared spectroscopy, transmission electron microscopy, UV–Vis spectroscopy, thermal gravimetry and inductively coupled plasma. Thus formed NiFe 2 O 4 –Pd MRCs showed a very high activity in reduction reactions of 4-nitro aniline and 1,3-dinitrobenzene in liquid phase. It was found out that the catalytic activity of NiFe 2 O 4 –Pd MRCs on the reduction of 4-nitro aniline and 1,3-dinitrobenzene in liquid phase are between 99–93% and 98–93%, respectively. Magnetic character of this system allowed recovery and multiple use without significant loss of its catalytic activity. It is found that NiFe 2 O 4 –Pd MRCs showed very efficient catalytic activity and multiple usability.

  3. Selective hydrogenation of acetylene on SiO{sub 2} supported Ni-In bimetallic catalysts: Promotional effect of In

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yanjun; Chen, Jixiang, E-mail: jxchen@tju.edu.cn

    2016-11-30

    Graphical abstract: A suitable Ni/In ratio remarkably enhanced the acetylene conversion, the selectivity to ethylene and the catalyst stability. Display Omitted - Highlights: • There was a promotional effect of In on the performance of Ni/SiO{sub 2}. • A suitable Ni/In ratio was required for good performance of Ni{sub x}In/SiO{sub 2}. • Both geometrical and electronic effects of In contributed to good performance. • Ni/SiO{sub 2} deactivation is mainly owing to phase change from Ni to nickel carbide. • The carbonaceous deposit was the main reason for Ni{sub x}In/SiO{sub 2} deactivation. - Abstract: Ni/SiO{sub 2} and the bimetallic Ni{sub x}In/SiO{sub 2} catalysts with different Ni/In ratios were tested for the selective hydrogenation of acetylene, and their physicochemical properties before and after the reaction were characterized by means of N{sub 2}-sorption, H{sub 2}-TPR, XRD, TEM, XPS, H{sub 2} chemisorption, C{sub 2}H{sub 4}-TPD, NH{sub 3}-TPD, FT-IR of adsorbed pyridine, and TG/DTA and Raman. A promotional effect of In on the performance of Ni/SiO{sub 2} was found, and Ni{sub x}In/SiO{sub 2} with a suitable Ni/In ratio gave much higher acetylene conversion, ethylene selectivity and catalyst stability than Ni/SiO{sub 2}. This is ascribed to the geometrical isolation of the reactive Ni atoms with the inert In ones and the charge transfer from the In atoms to Ni ones, both of which are favorable for reducing the adsorption strength of ethylene and restraining the C−C hydrogenolysis and the polymerizations of acetylene and the intermediate compounds. On the whole, Ni{sub 6}In/SiO{sub 2} and Ni{sub 10}In/SiO{sub 2} had better performance. Nevertheless, with increasing the In content, the selectivity to the C4+ hydrocarbons tended to increase due to the enhanced catalyst acidity because of the charge transfer from the In atoms to Ni ones. As the Lewis acid ones, the In sites could promote the polymerization. The catalyst deactivation was also analyzed

  4. Highly active Ni/Y-doped ZrO{sub 2} catalysts for CO{sub 2} methanation

    Energy Technology Data Exchange (ETDEWEB)

    Takano, H., E-mail: takano_hi@hitachizosen.co.jp [Hitachi Zosen Corporation, Kashiwa, 277-8515 (Japan); Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, 060-8628 (Japan); Kirihata, Y.; Izumiya, K.; Kumagai, N. [Hitachi Zosen Corporation, Kashiwa, 277-8515 (Japan); Habazaki, H., E-mail: habazaki@eng.hokudai.ac.jp [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, 060-8628 (Japan); Division of Applied Chemistry & Frontier Chemistry Center, Faculty of Engineering, Hokkaido University, Sapporo, 060-8628 (Japan); Hashimoto, K. [Tohoku Institute of Technology, Sendai, 277-8515 (Japan)

    2016-12-01

    Highlights: • The Ni/Y-doped ZrO{sub 2} catalysts show highly catalytic activity for CO{sub 2} methanation. • Bidentate carbonate is a major adsorption spice on the Ni/Y-doped ZrO{sub 2} catalysts. • The oxide support of t-ZrO{sub 2} and/or c-ZrO{sub 2} with oxygen vacancies plays a key role. - Abstract: The catalytic methanation of CO{sub 2} was carried out on Ni catalysts supported on Y-doped ZrO{sub 2} with various Y{sup 3+} concentrations and Ni/(Zr + Y) molar ratio = 1. The catalysts were characterized by X-ray diffraction, scanning transmission electron microscopy, specific surface area, temperature-programmed desorption of CO{sub 2}, and temperature-programmed reaction. In addition, operando diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFT) was used to identify the adsorbed reaction intermediate. Catalysts supported on Y-doped ZrO{sub 2} show higher catalytic activity than the catalyst on Y-free ZrO{sub 2} with a monoclinic ZrO{sub 2} phase. The catalytic activity is also dependent upon the Y{sup 3+} concentration, and the highest activity was obtained for the catalyst with a Y/(Zr + Y) molar ratio of 0.333, which consists mainly of fcc Ni and cubic ZrO{sub 2} phase. Y{sup 3+} doping into ZrO{sub 2} introduces oxygen vacancies, which play an important role in enhancing the catalytic activity. The operando DRIFT study reveals that a CO adsorption intermediate is absent, and bidentate carbonate is an important intermediate for CH{sub 4} formation.

  5. Electro-oxidation of Ethanol on Carbon Supported PtSn and PtSnNi Catalysts

    Directory of Open Access Journals (Sweden)

    Nur Hidayati

    2016-03-01

    Full Text Available Even though platinum is known as an active electro-catalyst for ethanol oxidation at low temperatures (< 100 oC, choosing the electrode material for ethanol electro-oxidation is a crucial issue. It is due to its property which easily poisoned by a strong adsorbed species such as CO. PtSn-based electro-catalysts have been identified as better catalysts for ethanol electro-oxidation. The third material is supposed to improved binary catalysts performance. This work presents a study of the ethanol electro-oxidation on carbon supported Pt-Sn and Pt-Sn-Ni catalysts. These catalysts were prepared by alcohol reduction. Nano-particles with diameters between 2.5-5.0 nm were obtained. The peak of (220 crystalline face centred cubic (fcc Pt phase for PtSn and PtSnNi alloys was repositioned due to the presence of Sn and/or Ni in the alloy. Furthermore, the modification of Pt with Sn and SnNi improved ethanol and CO electro-oxidation. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 1st February 2016; Accepted: 1st February 2016 How to Cite: Hidayati, N., Scott, K. (2016. Electro-oxidation of Ethanol on Carbon Supported PtSn and PtSnNi Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 10-20. (doi:10.9767/bcrec.11.1.394.10-20 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.394.10-20

  6. Enhancing Pt-Ni/CeO2 performances for ethanol reforming by catalyst supporting on high surface silica

    NARCIS (Netherlands)

    Palma, V.; Ruocco, C; Meloni, E.; Gallucci, F.; Ricca, A.

    2018-01-01

    In this paper, bimetallic Pt-Ni/CeO2 catalysts supported over mesoporous silica were employed for ethanol reforming in the low-temperature range. In particular, catalyst behaviour was investigated under a H2O/C2H5OH/N2 as well as H2O/C2H5OH/AIR mixture between 300 and 600 °C at different space

  7. CO2 methanation on the catalyst of Ni/MCM-41 promoted with CeO2.

    Science.gov (United States)

    Wang, Xiaoliu; Zhu, Lingjun; Liu, Yincong; Wang, Shurong

    2018-06-01

    CO 2 as a raw feed combined with renewable hydrogen for the production of useful chemicals and alternative energy products is one of the solutions to environmental and energy problems. In this study, a series of Ni-xCeO 2 /MCM-41 catalysts with a nickel content of 20wt% were prepared through deposition precipitation method for CO 2 methanation. Different characterization methods, including BET, XRD, TEM, SEM, H 2 -TPR and H 2 -TPD were applied to help explore the influence mechanism of CeO 2 on Ni/MCM-41 in CO 2 methanation. It was found that all CeO 2 -promoted catalysts exhibited enhanced catalytic activity when compared to Ni/MCM-41. The catalyst modified with 20wt% CeO 2 showed the best catalytic performance, with CO 2 conversion and CH 4 selectivity of 85.6% and 99.8%, respectively, at the temperature of 380°C under atmospheric pressure. The synergetic effects among Ni 0 active sites, the promoter and the support, including nickel dispersion improvement and increased CO 2 adsorption sites due to the addition of CeO 2 , were considered as important factors for high reactivity of the promoted catalysts. The stability test showed that the promoted catalyst maintained its high reactivity after 30h. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Ni2P Makes Application of the PtRu Catalyst Much Stronger in Direct Methanol Fuel Cells.

    Science.gov (United States)

    Chang, Jinfa; Feng, Ligang; Liu, Changpeng; Xing, Wei

    2015-10-12

    PtRu is regarded as the best catalyst for direct methanol fuel cells, but the performance decay resulting from the loss of Ru seriously hinders commercial applications. Herein, we demonstrated that the presence of Ni2 P largely reduces Ru loss, which thus makes the application of PtRu much stronger in direct methanol fuel cells. Outstanding catalytic activity and stability were observed by cyclic voltammetry. Upon integrating the catalyst material into a practical direct methanol fuel cell, the highest maximum power density was achieved on the PtRu-Ni2P/C catalyst among the reference catalysts at different temperatures. A maximum power density of 69.9 mW cm(-2) at 30 °C was obtained on PtRu-Ni2P/C, which is even higher than the power density of the state-of-the-art commercial PtRu catalyst at 70 °C (63.1 mW cm(-2)). Moreover, decay in the performance resulting from Ru loss was greatly reduced owing to the presence of Ni2 P, which is indicative of very promising applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Hydrogenation of Anthracene in Supercritical Carbon Dioxide Solvent Using Ni Supported on Hβ-Zeolite Catalyst

    Directory of Open Access Journals (Sweden)

    Ashraf Aly Hassan

    2012-01-01

    Full Text Available Catalytic hydrogenation of anthracene was studied over Ni supported on Hβ-zeolite catalyst under supercritical carbon dioxide (sc-CO2 solvent. Hydrogenation of anthracene in sc-CO2 yielded 100% conversion at 100 °C, which is attributed to the reduced mass transfer limitations, and increased solubility of H2 and substrate in the reaction medium. The total pressure of 7 MPa was found to be optimum for high selectivity of octahydroanthracene (OHA. The conversion and selectivity for OHA increased with an increase in H2 partial pressure, which is attributed to higher concentration of hydrogen atoms at higher H2 pressures. The selectivity reduced the pressure below 7 MPa because of enhanced desorption of the tetrahydro-molecules and intermediates from Ni active sites, due to higher solubility of the surface species in sc-CO2. The selectivity of OHA increased with the increase in catalyst weight and reaction time. The rate of hydrogenation of anthracene was compared with that found for napthalene and phenanthrene. The use of acetonitrile as co-solvent or expanded liquid with CO2 decreased the catalytic activity.

  10. Hydrodeoxygenation of prairie cordgrass bio-oil over Ni based activated carbon synergistic catalysts combined with different metals.

    Science.gov (United States)

    Cheng, Shouyun; Wei, Lin; Zhao, Xianhui; Kadis, Ethan; Cao, Yuhe; Julson, James; Gu, Zhengrong

    2016-06-25

    Bio-oil can be upgraded through hydrodeoxygenation (HDO). Low-cost and effective catalysts are crucial for the HDO process. In this study, four inexpensive combinations of Ni based activated carbon synergistic catalysts including Ni/AC, Ni-Fe/AC, Ni-Mo/AC and Ni-Cu/AC were evaluated for HDO of prairie cordgrass (PCG) bio-oil. The tests were carried out in the autoclave under mild operating conditions with 500psig of H2 pressure and 350°C temperature. The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and transmission electron microscope (TEM). The results show that all synergistic catalysts had significant improvements on the physicochemical properties (water content, pH, oxygen content, higher heating value and chemical compositions) of the upgraded PCG bio-oil. The higher heating value of the upgraded bio-oil (ranging from 29.65MJ/kg to 31.61MJ/kg) improved significantly in comparison with the raw bio-oil (11.33MJ/kg), while the oxygen content reduced to only 21.70-25.88% from 68.81% of the raw bio-oil. Compared to raw bio-oil (8.78% hydrocarbons and no alkyl-phenols), the Ni/AC catalysts produced the highest content of gasoline range hydrocarbons (C6-C12) at 32.63% in the upgraded bio-oil, while Ni-Mo/AC generated the upgraded bio-oil with the highest content of gasoline blending alkyl-phenols at 38.41%. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Ni/Ce-MCM-41 mesostructured catalysts for simultaneous production of hydrogen and nanocarbon via methane decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Guevara, J.C.; Wang, J.A.; Chen, L.F.; Valenzuela, M.A. [ESIQIE, Instituto Politecnico Nacional, Col. Zacatenco, Av. Politecnico s/n, 07738 Mexico D. F. (Mexico); Salas, P. [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, Apartado Postal 1-1010, Queretaro 76000 (Mexico); Garcia-Ruiz, A. [UPIICSA, Instituto Politecnico Nacional, Te 950 Col. Granjas-Mexico, 08400 Mexico D.F. (Mexico); Toledo, J.A.; Cortes-Jacome, M.A.; Angeles-Chavez, C. [Programa de Molecular Ingenieria, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, 07730 Mexico D. F. (Mexico); Novaro, O. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, A. P. 20-364, 01000 Mexico D.F. (Mexico)

    2010-04-15

    For the first time, simultaneous production of hydrogen and nanocarbon via catalytic decomposition of methane over Ni-loaded mesoporous Ce-MCM-41 catalysts was investigated. The catalytic performance of the Ni/Ce-MCM-41 catalysts is very stable and the reaction activity remained almost unchanged during 1400 min steam on time at temperatures 540, 560 and 580 C, respectively. The methane conversion level over these catalysts reached 60-75% with a 100% selectivity towards hydrogen. TEM observations revealed that most of the Ni particles located on the tip of the carbon nanofibers/nanotubes in the used catalysts, keeping their exposed surface clean during the test and thus remaining active for continuous reaction without obvious deactivation. Two kinds of carbon materials, graphitic carbon (C{sub g}) as major and amorphous carbon (C{sub A}) as minor were produced in the reaction, as confirmed by XRD analysis and TEM observations. Carbon nanofibers/nanotubes had an average diameter of approximately 30-50 nm and tens micrometers in length, depending on the reaction temperature, reaction time and Ni particle diameter. Four types of carbon nanofibers/nanotubes were detected and their formations greatly depend on the reaction temperature, time on steam and degree of the interaction between the metallic Ni and support. The respective mechanisms of the formation of nanocarbons were postulated and discussed. (author)

  12. Effect of operating conditions on hydrothermal liquefaction of Spirulina over Ni/TiO2 catalyst.

    Science.gov (United States)

    Tian, Wenying; Liu, Renlong; Wang, Wenjia; Yin, Zhaosen; Yi, Xuewen

    2018-05-04

    In this study, the effects of reaction temperature, holding time, algae/water ratio and catalyst dosage on the yield and quality of bio-oil produced via the HTL of Spirulina were investigated. The maximum bio-oil yield (43.05 wt%) and energy recovery (ER) value (64.62%) were obtained at 260 °C for 30 min, with an algae/water ratio of 1/4 and a catalyst dosage of 5 wt%. The bio-oil samples were characterized by elemental analysis, Gas Chromatography-Mass Spectrometry (GC-MS), Fourier Transform Infrared (FI-IR), and Thermo-gravimetric analysis (TGA). Results indicated that higher heating values (HHVs) of bio-oils were in the range of 27.28-36.01 MJ/kg, and main compounds of bio-oil were amides, esters, nitriles, hydroperoxide and alkanes. Adding of the Ni/TiO 2 catalyst can decrease the contents of oxygenated and nitrogenous compounds and promote the formation of desirable components such as esters and alkanes. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Directly observing catalytic intermediates of methane dry reforming (MDR) on model Ni(111) catalyst via in operando surface techniques

    Science.gov (United States)

    Yuan, Kaidi

    In this work, near ambient pressure x-ray photoelectron spectroscopy was used to trace the in operando catalytic intermediates of methane dry reforming on model Ni(111) catalyst. The following reactive carbon intermediates have been characterized from dissociation of CH4: *CH, *C1 (Ni3C), *Cn (n≥2) and clock-reconstructed Ni2C. They can develop into inert graphene, and the conditions for this transition have been explored. One the other hand, the oxygen intermediates from CO2 dissociation were also studied, which play an important role on restraining graphene growth. Their dynamic coverage decreases with increasing temperature, which is suggested the fundamental mechanism of regional carbon overspill and causes irreversible graphene formation. Therefore, solutions based on Ni-O stabilization were proposed in developing coking resisting catalysts.

  14. Formation and Yield of Multi-Walled Carbon Nanotubes Synthesized via Chemical Vapour Deposition Routes Using Different Metal-Based Catalysts of FeCoNiAl, CoNiAl and FeNiAl-LDH

    Directory of Open Access Journals (Sweden)

    Mohd Zobir Hussein

    2014-11-01

    Full Text Available Multi-walled carbon nanotubes (MWCNTs were prepared via chemical vapor deposition (CVD using a series of different catalysts, derived from FeCoNiAl, CoNiAl and FeNiAl layered double hydroxides (LDHs. Catalyst-active particles were obtained by calcination of LDHs at 800 °C for 5 h. Nitrogen and hexane were used as the carrier gas and carbon source respectively, for preparation of MWCNTs using CVD methods at 800 °C. MWCNTs were allowed to grow for 30 min on the catalyst spread on an alumina boat in a quartz tube. The materials were subsequently characterized through X-ray diffraction, Fourier transform infrared spectroscopy, surface area analysis, field emission scanning electron microscopy and transmission electron microscopy. It was determined that size and yield of MWCNTs varied depending on the type of LDH catalyst precursor that is used during synthesis. MWCNTs obtained using CoNiAl-LDH as the catalyst precursor showed smaller diameter and higher yield compared to FeCoNiAl and FeNiAl LDHs.

  15. Glucose- and Cellulose-Derived Ni/C-SO3H Catalysts for Liquid Phase Phenol Hydrodeoxygenation

    Energy Technology Data Exchange (ETDEWEB)

    Kasakov, Stanislav; Zhao, Chen; Barath, Eszter; Chase, Zizwe A.; Fulton, John L.; Camaioni, Donald M.; Vjunov, Aleksei; Shi, Hui; Lercher, Johannes A.

    2015-01-19

    Sulfonated carbons were explored as functionalized supports for Ni nanoparticles to hydrodeoxygenate (HDO) phenol. Both hexadecane and water were used as solvents. The dual-functional Ni catalysts supported on sulfonated carbon (Ni/C-SO3H) showed high rates for phenol hydrodeoxygenation in liquid hexadecane, but not in water. Glucose and cellulose were precursors to the carbon supports. Changes in the carbons resulting from sulfonation of the carbons resulted in variations of carbon sheet structures, morphologies and the surface concentrations of acid sites. While the C-SO3H supports were active for cyclohexanol dehydration in hexadecane and water, Ni/C-SO3H only catalyzed the reduction of phenol to cyclohexanol in water. The state of 3 – 5 nm grafted Ni particles was analyzed by in situ X-ray absorption spectroscopy. The results show that the metallic Ni was rapidly formed in situ without detectable leaching to the aqueous phase, suggesting that just the acid functions on Ni/C-SO3H are inhibited in presence of water. Using in situ IR spectroscopy, it was shown that even in hexadecane, phenol HDO is limited by the dehydration step. Thus, phenol HDO catalysis was further improved by physically admixing C-SO3H with the Ni/C-SO3H catalyst to balance the two catalytic functions. The minimum addition of 7 wt.% C-SO3H to the most active of the Ni/C-SO3H catalysts enabled nearly quantitative conversion of phenol and the highest selectivity (90%) towards cyclohexane in 6 h, at temperatures as low as 473 K, suggesting that the proximity to Ni limits the acid properties of the support.

  16. Glucose- and cellulose-derived Ni/C-SO3H catalysts for liquid phase phenol hydrodeoxygenation.

    Science.gov (United States)

    Kasakov, Stanislav; Zhao, Chen; Baráth, Eszter; Chase, Zizwe A; Fulton, John L; Camaioni, Donald M; Vjunov, Aleksei; Shi, Hui; Lercher, Johannes A

    2015-01-19

    Sulfonated carbons were explored as functionalized supports for Ni nanoparticles to hydrodeoxygenate (HDO) phenol. Both hexadecane and water were used as solvents. The dual-functional Ni catalysts supported on sulfonated carbon (Ni/C-SO3H) showed high rates for phenol hydrodeoxygenation in liquid hexadecane, but not in water. Glucose and cellulose were precursors to the carbon supports. Changes in the carbons resulting from sulfonation of the carbons resulted in variations of carbon sheet structures, morphologies and the surface concentrations of acid sites. While the C-SO3H supports were active for cyclohexanol dehydration in hexadecane and water, Ni/C-SO3H only catalysed the reduction of phenol to cyclohexanol in water. The state of 3-5 nm grafted Ni particles was analysed by in situ X-ray absorption spectroscopy. The results show that the metallic Ni was rapidly formed in situ without detectable leaching to the aqueous phase, suggesting that just the acid functions on Ni/C-SO3H are inhibited in the presence of water. Using in situ IR spectroscopy, it was shown that even in hexadecane, phenol HDO is limited by the dehydration step. Thus, phenol HDO catalysis was further improved by physically admixing C-SO3H with the Ni/C-SO3H catalyst to balance the two catalytic functions. The minimum addition of 7 wt % C-SO3H to the most active of the Ni/C-SO3H catalysts enabled nearly quantitative conversion of phenol and the highest selectivity (90%) towards cyclohexane in 6 h, at temperatures as low as 473 K, suggesting that the proximity to Ni limits the acid properties of the support. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Product of Ginibre matrices: Fuss-Catalan and Raney distributions

    Science.gov (United States)

    Penson, Karol A.; Życzkowski, Karol

    2011-06-01

    Squared singular values of a product of s square random Ginibre matrices are asymptotically characterized by probability distributions Ps(x), such that their moments are equal to the Fuss-Catalan numbers of order s. We find a representation of the Fuss-Catalan distributions Ps(x) in terms of a combination of s hypergeometric functions of the type sFs-1. The explicit formula derived here is exact for an arbitrary positive integer s, and for s=1 it reduces to the Marchenko-Pastur distribution. Using similar techniques, involving the Mellin transform and the Meijer G function, we find exact expressions for the Raney probability distributions, the moments of which are given by a two-parameter generalization of the Fuss-Catalan numbers. These distributions can also be considered as a two-parameter generalization of the Wigner semicircle law.

  18. Deoxygenation of methyl laurate over Ni based catalysts: Influence of supports

    Science.gov (United States)

    Xia, Xiaoqiang; Chen, Hui; Bi, Yadong; Hu, Jianli

    2017-10-01

    The use of a series of nickel based catalysts supported over HZSM-5, Al2O3, C and ZrO2 in the deoxygenation of methyl laurate shows that the deoxygenation activity and deoxygenation pathway of nickel based catalysts can be affected by properties of catalysts. In the absence of H2, β-elimination of methyl laurate is the dominant reaction and a small amount of laurate acid is converted into undecane by direct decarboxylation. At the same time, the highly acidic support HZSM-5 gave higher conversion and C11 alkane selectivity. In the presence of H2, Ni/HZSM-5 catalyst showed a significantly high deoxygenation activity, producing 71% alkanes by methyl laurate conversion at 280 °C and 4MPa H2. While as on mildly acidic (Al2O3) and neutral (C) supports, a restricted hydrodeoxygenation activity was achieved but more oxygenate products were yielded. According to the analysis of intermediate product, the deoxygenation reaction of methyl laurate follows three distinct pathways: in the absence of H2, decarboxylation: C11H23COOCH3→C11H23COOH→C11H24; in the presence of H2, decarbonylation: C11H23COOCH3→C11H23COOH→C11H23CHO→C11H24; and hydrodeoxygenation: C11H23COOCH3 →C11H23COOH→C11H23CHO→C12H25OH→C12H26

  19. Upgrading of the liquid fuel from fast pyrolysis of biomass over MoNi/γ-Al2O3 catalysts

    International Nuclear Information System (INIS)

    Xu, Ying; Wang, Tiejun; Ma, Longlong; Zhang, Qi; Liang, Wei

    2010-01-01

    The hydrotreatment of bio-oil, which obtained from fast pyrolysis of pine sawdust, was investigated over MoNi/γ-Al 2 O 3 catalyst under mild conditions (373 K, 3 MPa hydrogen pressure). Acetic acid was taken as a model compound to investigate the effects of Mo promoter contents and reducing temperatures of catalysts on the catalysts activity under the condition of 473 K and 3 MPa hydrogen pressure. X-ray diffraction and temperature programmed reduction showed that the addition of Mo promoter benefited the uniformity of nickel species and inhibited the formation of NiAl 2 O 4 spinel in the catalysts. The GC spectrum of liquid products showed the mechanism of the model reaction. The maximum conversion of acetic acid (33.20%) was attained over 0.06MoNi/γ-Al 2 O 3 catalysts being reduced at 873 K. This catalyst was chosen for the upgrading of raw bio-oil. After the upgrading process, the pH value of the bio-oil increased from 2.33 to 2.77. The water content increased from 35.52 wt.% to 41.55 wt.% and the gross calorific value increased from 13.96 MJ/kg to 14.17 MJ/kg. The hydrogen content in the bio-oil increased from 6.25 wt.% to 6.95 wt.%. The product properties of the upgraded bio-oil, particularly the hydrogen content and the acidity were considerably improved. The results of gas chromatography-mass spectrometry analysis showed that both hydrotreatment and esterification had happened over 0.06MoNi/γ-Al 2 O 3 (873) catalyst during the upgrading process.

  20. OXIDATIVE-REFORMING OF METHANE AND PARTIAL OXIDATION OF METHANE REACTIONS OVER NiO/PrO2/ZrO2 CATALYSTS: EFFECT OF NICKEL CONTENT

    Directory of Open Access Journals (Sweden)

    Y. J. O. Asencios

    Full Text Available Abstract In this work the behavior of NiO-PrO2-ZrO2 catalysts containing various nickel loadings was evaluated in the partial oxidation of methane and oxidative-reforming reactions of methane. The catalysts were characterized by X-Ray Diffraction Analysis (in situ-XRD, Temperature Programmed Reduction (H2-TPR, Scanning Electron Microscopy (SEM/EDX and Adsorption-Desorption of nitrogen (BET area. The reactions were carried out at 750 °C and 1 atm for 5 hours. The catalysts were studied with different nickel content: 0, 5, 10 and 15% (related to total weight of catalyst, wt%. In both reactions, the catalyst containing the mixture of the three oxides (NiO/PrO2/ZrO2 with 15% nickel (15NiPrZr catalyst showed the best activity for the conversion of the reactants into Syngas and showed high selectivity for H2 and CO. The results suggest that the promoter PrO2 and the Niº centers are in a good proportion in the catalyst with 15% Ni. Our results showed that low nickel concentrations in the catalyst led to high metallic dispersion; however, very low nickel concentrations did not favor the methane transformation into Syngas. The catalyst containing only NiO/ZrO2 in the mixture was not sufficient for the catalysis. The presence of the promoter PrO2 was very important for the catalysis of the POM.

  1. MAu2GeS4-Chalcogel (M = Co, Ni): Heterogeneous Intra- and Intermolecular Hydroamination Catalysts

    KAUST Repository

    Davaasuren, Bambar

    2017-08-08

    High surface area macroporous chalcogenide aerogels (chalcogels) MAu2GeS4 (M = Co, Ni) were prepared from K2Au2GeS4 precursor and Co(OAc)2 or NiCl2 by one-pot sol-gel metathesis reactions in aqueous media. The MAu2GeS4-chalcogels were screened for catalytic intramolecular hydroamination of 4-pentyn-1-amine substrate at different temperatures. 87% and 58% conversion was achieved at 100 °C, using CoAu2GeS4- and NiAu2GeS4-chalcogels respectively, and the reaction kinetics follows the first order. It was established that the catalytic performance of the aerogels is associated with the M(2+) centers present in the structure. Intermolecular hydroamination of aniline with 1-R-4-ethynylbenzene (R = -H, -OCH3, -Br, -F) was carried out at 100 °C using CoAu2GeS4-chalcogel catalyst, due to its promising catalytic performance. The CoAu2GeS4-chalcogel regioselectively converted the pair of substrates to respective Markovnikov products, (E)-1-(4-R-phenyl)-N-phenylethan-1-imine, with 38% to 60% conversion.

  2. MAu2GeS4-Chalcogel (M = Co, Ni): Heterogeneous Intra- and Intermolecular Hydroamination Catalysts

    KAUST Repository

    Davaasuren, Bambar; Emwas, Abdul-Hamid M.; Rothenberger, Alexander

    2017-01-01

    High surface area macroporous chalcogenide aerogels (chalcogels) MAu2GeS4 (M = Co, Ni) were prepared from K2Au2GeS4 precursor and Co(OAc)2 or NiCl2 by one-pot sol-gel metathesis reactions in aqueous media. The MAu2GeS4-chalcogels were screened for catalytic intramolecular hydroamination of 4-pentyn-1-amine substrate at different temperatures. 87% and 58% conversion was achieved at 100 °C, using CoAu2GeS4- and NiAu2GeS4-chalcogels respectively, and the reaction kinetics follows the first order. It was established that the catalytic performance of the aerogels is associated with the M(2+) centers present in the structure. Intermolecular hydroamination of aniline with 1-R-4-ethynylbenzene (R = -H, -OCH3, -Br, -F) was carried out at 100 °C using CoAu2GeS4-chalcogel catalyst, due to its promising catalytic performance. The CoAu2GeS4-chalcogel regioselectively converted the pair of substrates to respective Markovnikov products, (E)-1-(4-R-phenyl)-N-phenylethan-1-imine, with 38% to 60% conversion.

  3. Design of bimetal catalysts Pt-Ni/CeO_2-1D for generation of H_2 by the reforming reaction of methanol

    International Nuclear Information System (INIS)

    Sarmiento F, I.

    2016-01-01

    CeO_2 nano rods were synthesized by hydrothermal method and were used as support for preparing catalysts bimetallic Pt Ni / CeO_2-1D. The catalysts were prepared by classical impregnation by the conventional wet method. The prepared catalysts are Pt (0.5 %) - Ni (5 %) / CeO_2 and Pt (0.5 %) - Ni (15 %) / CeO_2, which were characterized by different physico-chemical techniques: Bet, Sem, TPR and XRD, that were evaluated in the Auto thermal Steam reforming of Methanol for H_2 production. The Bet surface area results, show that the surface area of the catalysts decreases as the nominal load of Ni in the catalyst, increases. Sem shows, that the catalyst support (CeO_2-1D) and the bimetallic catalysts are conformed by nano rods. By XRD were identified the crystalline phases present, in the catalytic material: cerianite distinctive phase of cerium oxide and metallic Ni; however it was not possible to observe diffraction peaks of Platinum using this technique. The temperature-programmed reduction (TPR) analysis allowed to obtain the reduction profiles, of the different species present on the catalysts. The catalytic activity tests carried out, showed that the catalysts total 100% methanol conversion is achieved at 300 degrees Celsius, making them excellent, to be used in reactions at low temperature conditions. Selectivity towards H_2, is very similar in both catalysts, and it reaches a 50% yield per mole of methanol fed stoichiometrically. (Author)

  4. Hydroprocessing of Jatropha Oil for Production of Green Diesel over Non-sulfided Ni-PTA/Al2O3 Catalyst

    Science.gov (United States)

    Liu, Jing; Lei, Jiandu; He, Jing; Deng, Lihong; Wang, Luying; Fan, Kai; Rong, Long

    2015-01-01

    The non-sulfided Ni-PTA/Al2O3 catalyst was developed to produce green diesel from the hydroprocessing of Jatropha oil. The Ni-PTA/Al2O3 catalyst was prepared by one-pot synthesis of Ni/Al2O3 with the co-precipitation method and then impregnanting Ni/Al2O3 with PTA solution. The catalysts were characterized with BET, SEM-EDX, TEM, XRD, XPS, TGA and NH3-TPD. The Ni and W species of the Ni-PTA/Al2O3 catalyst were much more homogeneously distributed on the surface than that of commercial Al2O3. Catalytic performance in the hydroprocessing of Jatropha oil was evaluated by GC. The maximum conversion of Jatropha oil (98.5 wt%) and selectivity of the C15-C18 alkanes fraction (84.5 wt %) occurred at 360 °C, 3.0 MPa, 0.8 h−1. The non-sulfided Ni-PTA/Al2O3 catalyst is more environmentally friendly than the conventional sulfided hydroprocessing catalyst, and it exhibited the highest catalytic activity than the Ni-PTA catalyst supported with commercial Al2O3 grain and Al2O3 powder. PMID:26162092

  5. Synergetic effects leading to coke-resistant NiCo bimetallic catalysts for dry reforming of methane

    KAUST Repository

    Li, Lidong; Anjum, Dalaver; Zhu, Haibo; Saih, Youssef; Laveille, Paco; D'Souza, Lawrence; Basset, Jean-Marie

    2015-01-01

    A new dry reforming of methane catalyst comprised of NiCo bimetallic nanoparticles and a Mgx(Al)O support that exhibits high coke resistance and long-term on-stream stability is reported. The structural characterization by XRD, TEM, temperature

  6. Refurbished dry methane on catalysts Ni / BaTiO 1x In x o 3d

    International Nuclear Information System (INIS)

    Garcia, Veronica; Caldes, Maria T; Joubert Olivier

    2008-01-01

    The effect of the support on the catalytic performance of Ni catalysts in carbon dioxide reforming of methane was studied using perovskite based supports BaTi 1x In x O 3d, known by their ionic and electronic conductivity properties. The results of the investigation showed that there is a close relationship between the catalytic activity and the reducibility of the support.

  7. Hydrodeoxygenation of guaiacol over Ni2P/SiO2–reaction mechanism and catalyst deactivation

    NARCIS (Netherlands)

    Lan, X.; Hensen, E.J.M.; Weber, T.

    2018-01-01

    The catalytic hydrodeoxygenation of guaiacol, a phenolic model compound of biomass lignin pyrolysis products, has been investigated under atmospheric pressure in H2 utilizing a Ni2P/SiO2 catalyst. Reaction networks are proposed based on the product distribution as a function of contact time and the

  8. Preparation and characterization of Ni based on natural zeolite catalyst for citronellol conversion to 3,7-Dimethyl-1-Octanol

    Science.gov (United States)

    Sudiyarmanto, Hidayati, Luthfiana N.; Kristiani, Anis; Ghaisani, Almira; Sukandar, Dede; Adilina, Indri B.; Tursiloadi, Silvester

    2017-11-01

    Citronella oil is a kind of essential oil that contains three main components, namely citronellal, citronellol, and geraniol. The high demand of citronellal and geraniol derivative prompted scientists to develop methods which are stereo-selective synthesis. A hydrogenation reaction using heterogeneous catalyst is one way of synthesis of citronella oil derivatives. In this research, synthesis of citronellol oil derivatives using Ni based on natural zeolite (Ni/ZAB) catalyst which is expected to produce the compound of 3,7-dimethyl-1-octanol. The catalyst was prepared by supporting Ni on natural zeolite by impregnation method. The physical and chemical properties of Ni/ZAB catalyst have been characterized by TGA, BET, XRD and FTIR instrumentations. Variation of pressure and temperature reactions were conducted to determine the optimum conditions for the hydrogenation of citronellol. The products from this reaction were analyzed using GC-MS instrumentation. The yield and selectivity of 3,7-dimethyl-1-octanol compound were achieved with optimum conditions at 200°C and 20 bar during 3 hours which produced around 51.97% and 47.81% respectively.

  9. Coke formation during the hydrotreatment of bio-oil using NiMo and CoMo catalysts

    NARCIS (Netherlands)

    Kadarwati, Sri; Hu, Xun; Gunawan, Richard; Westerhof, Roel; Gholizadeh, Mortaza; Hasan, M. D.Mahmudul; Li, Chun-Zhu

    2017-01-01

    This study aims to investigate the coke formation during the hydrotreatment of bio-oil at low temperature. The catalytic hydrotreatment of bio-oil produced from the pyrolysis of mallee wood was carried out using pre-sulphided NiMo and CoMo catalysts at a temperature range of 150–300 °C. Our results

  10. Hydrodesulfurization of Iraqi Atmospheric Gasoil by Ti-Ni-Mo/γ-Al2O3 Prepared Catalyst

    Directory of Open Access Journals (Sweden)

    Abdul Halim Abdul Karim Mohammed

    2017-11-01

    Full Text Available This study investigates the improvement of Iraqi atmospheric gas oil characteristics which contains 1.402 wt. % sulfur content and 16.88 wt. % aromatic content supplied from Al-Dura Refinery by using hydrodesulfurization (HDS process using Ti-Ni-Mo/γ-Al2O3 prepared catalyst in order to achieve low sulfur and aromatic saturation gas oil. Hydrodearomatization (HDA occurs simultaneously with hydrodesulfurization (HDS process. The effect of titanium on the conventional catalyst Ni-Mo/γ-Al2O3 was investigated by physical adsorption and catalytic activity test.Ti-Ni-Mo/γ-Al2O3 catalyst was prepared under vacuum impregnation condition to ensure efficient precipitation of metals within the carrier γ-Al2O3. The loading percentage of metals as oxide; titanium oxide 3 wt. %, nickel oxide 5 wt. % and molybdenum oxide 12 wt. %. The performance of the synthesized catalyst for removing sulfur and aromatic saturation were tested at various temperatures 275 to 350°C, LHSV 1 to 4h-1, constant pressure 40 bar and H2/HC ratio 500 ml/ml.Results showed that the sulfur and aromatic content were reduced at all operating conditions. Maximum sulfur removal was 75.52 wt. % in gas oil on Ti-Ni-Mo/γ-Al2O3 at temperature 350˚C, LHSV 1h-1, while minimum aromatic content achieved was 15.6 wt. % at the same conditions.

  11. The effect of Ni-Al ratio on the properties of coprecipitated nickel-alumina catalysts with high nickel contents

    NARCIS (Netherlands)

    Lansink Rotgerink, H.G.J.; Bosch, H.; van Ommen, J.G.; Ross, J.R.H.

    1986-01-01

    A series of nickel-alumina catalysts with a Ni/Al ratio between 3 and 20 has been prepared by coprecipitation. The calcination and reduction of these samples have been studied by thermogravimetry and their structures after calcination and reduction at different temperatures has been examined by

  12. Synthesis and characterization of Pt-Sn-Ni alloys to application as catalysts for direct ethanol fuel cells

    International Nuclear Information System (INIS)

    Silva, E.L. da; Correa, P.S.; Oliveira, E.L. de; Takimi, A.S.; Malfatti, C.F.; Radtke, C.

    2010-01-01

    Direct ethanol fuel cells (DEFCs) have been the focus of recent research due its application in mobile energy sources. In order to obtain the maximum efficiency from these systems, it is necessary the total ethanol oxidation, which implies in C-C bond break. Different catalysts described in literature are employed with this intent. This work consists in studying PtSnNi catalysts supported on carbon Vulcan XC72R, to application in DEFCs. Thus, it was used the impregnation/reduction method, varying the atomic proportion among Pt, Sn and Ni. The alloys were characterized by X-Ray Diffraction, Cyclic Voltammetry and Transmission Microscopy. Preliminary results show that predominant structure on the catalysts is the face centered cubic platinum and the densities currents are dependent on the platinum amount. (author)

  13. SHS-produced intermetallides as catalysts for hydrocarbons synthesis from CO and H{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Eliseev, O.L.; Kazantsev, R.V.; Davydov, P.E.; Lapidus, A.L. [Russian Academy of Sciences, Moscow (Russian Federation). N.D. Zelinsky Institute of Organic Chemistry; Borshch, V.N.; Pugacheva, E.V. [Russian Academy of Sciences, Chernogolovka (Russian Federation). Inst. of Structural Macrokinetics and Materials Science

    2012-07-01

    Raney-type polymetallic alloys were prepared by Self-Propagating High-Temperature Synthesis followed by alkaline treating. Surface morphology and composition of were studied using XRD, BET, SEM and EMPA techniques. The samples were tested in Fischer-Tropsch synthesis demonstrated rather high activity and very high selectivity to heavy paraffins. High selectivity to C{sub 5+} hydrocarbons is attributed to high thermal conductivity of alloys which prevents hot spots formation and therefore suppresses formation of methane and light hydrocarbons. Selectivity can be further improved by adding some d-metals in catalyst composition. Promotion with La seems to be particularly suitable for lowering methane formation while doping with Ni enhances methane yield greatly. (orig.)

  14. Water-Gas Shift and CO Methanation Reactions over Ni-CeO2(111) Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    S Senanayake; J Evans; S Agnoli; L Barrio; T Chen; J Hrbek; J Rodriguez

    2011-12-31

    X-ray and ultraviolet photoelectron spectroscopies were used to study the interaction of Ni atoms with CeO{sub 2}(111) surfaces. Upon adsorption on CeO{sub 2}(111) at 300 K, nickel remains in a metallic state. Heating to elevated temperatures (500-800 K) leads to partial reduction of the ceria substrate with the formation of Ni{sup 2+} species that exists as NiO and/or Ce{sub 1-x}Ni{sub x}O{sub 2-y}. Interactions of nickel with the oxide substrate significantly reduce the density of occupied Ni 3d states near the Fermi level. The results of core-level photoemission and near-edge X-ray absorption fine structure point to weakly bound CO species on CeO{sub 2}(111) which are clearly distinguishable from the formation of chemisorbed carbonates. In the presence of Ni, a stronger interaction is observed with chemisorption of CO on the admetal. When the Ni is in contact with Ce{sup +3} cations, CO dissociates on the surface at 300 K forming NiC{sub x} compounds that may be involved in the formation of CH{sub 4} at higher temperatures. At medium and large Ni coverages (>0.3 ML), the Ni/CeO{sub 2}(111) surfaces are able to catalyze the production of methane from CO and H{sub 2}, with an activity slightly higher than that of Ni(100) or Ni(111). On the other hand, at small coverages of Ni (<0.3 ML), the Ni/CeO{sub 2}(111) surfaces exhibit a very low activity for CO methanation but are very good catalysts for the water-gas shift reaction.

  15. Pt/Cr and Pt/Ni catalysts for oxygen reduction reaction: to alloy or not to alloy?

    Science.gov (United States)

    Escaño, Mary Clare; Gyenge, Elod; Nakanishi, Hiroshi; Kasai, Hideaki

    2011-04-01

    Bimetallic systems such as Pt-based alloys or non-alloys have exhibited interesting catalytic properties but pose a major challenge of not knowing a priori how the electronic and chemical properties will be modified relative to the parent metals. In this work, we present the origin of the changes in the reactivity of Pt/Cr and Pt/Ni catalysts, which have been of wide interest in fuel cell research. Using spin-polarized density functional theory calculations, we have shown that the modification of Pt surface reactivity in Pt/Ni is purely of geometric origin (strain). We have also found that the Pt-Ni bonding is very weak, which explains the observed instability of Pt-Ni catalysts under electrochemical measurements. On the other hand, Pt/Cr systems are governed by strong ligand effect (metal-metal interaction), which explains the experimentally observed reactivity dependence on the relative composition of the alloying components. The general characteristics of the potential energy curves for O2 dissociative adsorption on the bimetallic systems and the pure Pt clarify why the d-band center still works for Pt/Cr despite the strong Pt-Cr bonding and high spin polarization of Pt d-states. On the basis of the above clarifications, viable Pt-Cr and Pt-Ni structures, which involve nano-sized alloys and non-alloy bulk catalyst, which may strike higher than the currently observed oxidation reduction reaction activity are proposed.

  16. Processing of spent NiW/Al{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Paulino, Jessica Frontino; Afonso, Julio Carlos, E-mail: julio@iq.ufrj.br [Departamento de Quimica Analitica, Instituto de Quimica, Universidade Federal do Rio de Janeiro, RJ (Brazil); Cunha, Jose Waldemar Silva Dias da [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), RJ (Brazil). Departamento de Quimica e Materiais Nucleares

    2013-09-01

    Spent oxidized (500 deg C, 5 h) commercial NiW/Al{sub 2}O{sub 3} catalysts were processed using two different routes: a) fusion with NaOH (650 deg C, 1 h), the roasted mass was leached in water; b) leaching with HCl or H{sub 2}SO{sub 4} (70 deg C, 1-3 h). HCl was the best leachant. In both routes, soluble tungsten was extracted at pH 1 with Alamine 336 (10 vol.% in kerosene) and stripped with 2 mol L{sup -1} NH{sub 4}OH (25 deg C, one stage, aqueous/organic ratio = 1 v/v). Tungsten was isolated as ammonium paratungstate at very high yield (> 97.5%). The elements were better separated using the acidic route. (author)

  17. Performance of carbon nanofiber supported Pd-Ni catalysts for electro-oxidation of ethanol in alkaline medium

    Science.gov (United States)

    Maiyalagan, T.; Scott, Keith

    Carbon nanofibers (CNF) supported Pd-Ni nanoparticles have been prepared by chemical reduction with NaBH 4 as a reducing agent. The Pd-Ni/CNF catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical voltammetry analysis. TEM showed that the Pd-Ni particles were quite uniformly distributed on the surface of the carbon nanofiber with an average particle size of 4.0 nm. The electro-catalytic activity of the Pd-Ni/CNF for oxidation of ethanol was examined by cyclic voltammetry (CV). The onset potential was 200 mV lower and the peak current density four times higher for ethanol oxidation for Pd-Ni/CNF compared to that for Pd/C. The effect of an increase in temperature from 20 to 60 °C had a great effect on increasing the ethanol oxidation activity.

  18. Performance of carbon nanofiber supported Pd-Ni catalysts for electro-oxidation of ethanol in alkaline medium

    Energy Technology Data Exchange (ETDEWEB)

    Maiyalagan, T.; Scott, Keith [School of Chemical Engineering and Advanced Materials, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2010-08-15

    Carbon nanofibers (CNF) supported Pd-Ni nanoparticles have been prepared by chemical reduction with NaBH{sub 4} as a reducing agent. The Pd-Ni/CNF catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical voltammetry analysis. TEM showed that the Pd-Ni particles were quite uniformly distributed on the surface of the carbon nanofiber with an average particle size of 4.0 nm. The electro-catalytic activity of the Pd-Ni/CNF for oxidation of ethanol was examined by cyclic voltammetry (CV). The onset potential was 200 mV lower and the peak current density four times higher for ethanol oxidation for Pd-Ni/CNF compared to that for Pd/C. The effect of an increase in temperature from 20 to 60 C had a great effect on increasing the ethanol oxidation activity. (author)

  19. Reactivity of hydrogen contained in Raney nickel for ethylene hydrogenation studied by means of a tritium tracer

    International Nuclear Information System (INIS)

    Miyatani, Daisaku; Takeuchi, Toyosaburo.

    1979-01-01

    Reactivity of hydrogen contained in Raney nickel with ethylene was studied by using a tritium tracer. Hydrogen in Raney nickel was previously labeled with tritium and distinguished from hydrogen introduced during the hydrogenation reaction. The reactivity of the contained hydrogen was determined by measurement of the radioactivity of ethane produced in the hydrogenation. Ethylene reacted with hydrogen in Raney nickel for no supply of hydrogen during the hydrogenation. However, when ethylene was hydrogenated by both hydrogen in Raney nickel and introduced hydrogen, over 99% of the ethylene reacted with the introduced hydrogen and hardly reacted with the contained hydrogen. (author)

  20. Carbon Dioxide Dry Reforming of Glycerol for Hydrogen Production using Ni/ZrO2 and Ni/CaO as Catalysts

    Directory of Open Access Journals (Sweden)

    Nur Nabillah Mohd Arif

    2016-08-01

    Full Text Available Glycerol, byproduct from the biodiesel production can be effectively utilized as the promising source of synthesis gas (syngas through a dry reforming reaction. Combination of these waste materials with greenhouse gases which is carbon dioxide (CO2 will help to reduce environmental problem such as global warming. This dry reforming reaction has been carried out in a fixed bed batch reactor at 700 °C under the atmospheric pressure for 3 hours. In this experiment, reforming reaction was carried out using Nickel (Ni as based catalyst and supported with zirconium (ZrO2 and calcium (CaO oxides. The catalysts were prepared by wet impregnation method and characterized using Bruanaer-Emmett-Teller (BET surface area, Scanning Electron Microscopy (SEM, X-ray Diffraction (XRD, Thermo Gravimetric (TGA, and Temperature Programmed Reduction (TPR analysis. Reaction studies show that 15% Ni/CaO give the highest hydrogen yield and glycerol conversion that peaked at 24.59% and 30.32%, respectively. This result is verified by XRD analysis where this catalyst shows low crystallinity and fine dispersion of Ni species resulted in high specific surface area which gives 44.93 m2/g that is validated by BET.  Copyright © 2016 BCREC GROUP. All rights reserved Received: 21st January 2016; Revised: 24th February 2016; Accepted: 29th February 2016 How to Cite: Arif, N.M.M., Vo, D.V.N., Azizan,M.T., Abidin S.Z. (2016. Carbon Dioxide Dry Reforming of Glycerol for Hydrogen Production using Ni/ZrO2 and Ni/CaO as Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (2: 200-209 (doi:10.9767/bcrec.11.2.551.200-209 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.2.551.200-209

  1. The atomistic origin of the extraordinary oxygen reduction activity of Pt3Ni7 fuel cell catalysts.

    Science.gov (United States)

    Fortunelli, Alessandro; Goddard Iii, William A; Sementa, Luca; Barcaro, Giovanni; Negreiros, Fabio R; Jaramillo-Botero, Andrés

    2015-07-01

    Recently Debe et al. reported that Pt 3 Ni 7 leads to extraordinary Oxygen Reduction Reaction (ORR) activity. However, several reports show that hardly any Ni remains in the layers of the catalysts close to the surface ("Pt-skin effect"). This paradox that Ni is essential to the high catalytic activity with the peak ORR activity at Pt 3 Ni 7 while little or no Ni remains close to the surface is explained here using large-scale first-principles-based simulations. We make the radical assumption that processing Pt-Ni catalysts under ORR conditions would leach out all Ni accessible to the solvent. To simulate this process we use the ReaxFF reactive force field, starting with random alloy particles ranging from 50% Ni to 90% Ni and containing up to ∼300 000 atoms, deleting the Ni atoms, and equilibrating the resulting structures. We find that the Pt 3 Ni 7 case and a final particle radius around 7.5 nm lead to internal voids in communication with the exterior, doubling the external surface footprint, in fair agreement with experiment. Then we examine the surface character of these nanoporous systems and find that a prominent feature in the surface of the de-alloyed particles is a rhombic structure involving 4 surface atoms which is crystalline-like but under-coordinated. Using density-functional theory, we calculate the energy barriers of ORR steps on Pt nanoporous catalysts, focusing on the O ad -hydration reaction (O ad + H 2 O ad → OH ad + OH ad ) but including the barriers of O 2 dissociation (O 2ad → O ad + O ad ) and water formation (OH ad + H ad → H 2 O ad ). We find that the reaction barrier for the O ad -hydration rate-determining-step is reduced significantly on the de-alloyed surface sites compared to Pt(111). Moreover we find that these active sites are prevalent on the surface of particles de-alloyed from a Pt-Ni 30 : 70 initial composition. These simulations explain the peak in surface reactivity at Pt 3 Ni 7 , and provide a rational guide to

  2. Role of CeO2 promoter in NiO/α-Al2O3 catalyst for dry reforming of methane

    Science.gov (United States)

    Loc, Luu Cam; Phuong, Phan Hong; Tri, Nguyen

    2017-09-01

    A series of Ni/α-Al2O3 (NiAl) catalysts promoted by CeO2 was prepared by co-impregnation methods with content of (NiO+CeO2) being in the range of 10-30 wt%. The NiO:CeO2 weight ratio was fluctuated at 1:1, 1:2 and 1:3. Several techniques, including X-ray powder diffraction (XRD), Hydrogen temperature-programmed reduction (H2-TPR), and transmission electron microscopy (TEM) were used to investigate catalysts' physico-chemical properties. The activity of these catalysts in dry reforming of CH4 was investigated at temperature range of 550-800 °C. The results revealed that the most suitable CeO2 promoted Ni catalyst contained 20 wt% of (NiO+CeO2) and NiO:CeO2 weight ratio of 1:2. The best catalytic performance of catalyst [20(1Ni2Ce)Al] due to a better reducibility resulted in a higher amount of free small particle NiO. At 700 °C and CH4:CO2 molar ratio of 1:1, the conversion of CH4 and CO2 on the most suitable CeO2 promoted Ni catalyst reached 86% and 67%, respectively; H2 and CO selectivity of 90% and H2:CO molar ratio of 1.15 were obtained. Being similar to MgO [1], promoter CeO2 could improve catalytic activity of Ni/α-Al2O3 catalyst at a lower range of temperature. Besides, both MgO and CeO2 had a great impact on improving coke resistance of Ni catalysts. At higher temperature, the role of CeO2 as well as MgO in preventing coke formation on catalyst was clarified by temperature-programmed oxidation (TPO) technique. Coke amount formed after 30-h TOS on 20(1Ni2Ce) catalyst was found to be 22.18 mgC/gcat, being less than on non-promoted catalyst (36.75 mgC/gcat), but more than on 20(1Ni2Mg)Al one (5.25 mgC/gcat).

  3. Syngas Production from CO2 Reforming and CO2-steam Reforming of Methane over Ni/Ce-SBA-15 Catalyst

    Science.gov (United States)

    Tan, J. S.; Danh, H. T.; Singh, S.; Truong, Q. D.; Setiabudi, H. D.; Vo, D.-V. N.

    2017-06-01

    This study compares the catalytic performance of mesoporous 10 Ni/Ce-SBA-15 catalyst for CO2 reforming and CO2-steam reforming of methane reactions in syngas production. The catalytic performance of 10 Ni/Ce-SBA-15 catalyst for CO2 reforming and CO2-steam reforming of methane was evaluated in a temperature-controlled tubular fixed-bed reactor at stoichiometric feed composition, 1023 K and atmospheric pressure for 12 h on-stream with gas hourly space velocity (GHSV) of 36 L gcat -1 h-1. The 10 Ni/Ce-SBA-15 catalyst possessed a high specific BET surface area and average pore volume of 595.04 m2 g-1. The XRD measurement revealed the presence of NiO phase with crystallite dimension of about 13.60 nm whilst H2-TPR result indicates that NiO phase was completely reduced to metallic Ni0 phase at temperature beyond 800 K and the reduction temperature relied on different degrees of metal-support interaction associated with the location and size of NiO particles. The catalytic reactivity was significantly enhanced with increasing H2O/CO2 feed ratio. Interestingly, the H2/CO ratio for CO2-steam reforming of methane varied between 1 and 3 indicated the occurrence of parallel reactions, i.e., CH4 steam reforming giving a H2/CO of 3 whilst reverse water-gas shift (RWGS) reaction consuming H2 to produce CO gaseous product.

  4. A New Approach to Deep Desulfurization of Light Cycle Oil over Ni2P Catalysts: Combined Selective Oxidation and Hydrotreating

    Directory of Open Access Journals (Sweden)

    Gwang-Nam Yun

    2018-03-01

    Full Text Available Amphiphilic phosphotungstic acid (A-PTA and Ni2P/SBA-15 catalysts were prepared to apply for selective oxidation of refractory sulfur compounds in light cycle oils and hydrotreating of the oxidized S compounds, respectively. Physical properties of the catalyst samples were analyzed by BET, CO uptake chemisorption, and TEM. Structural properties for the supported Ni2P catalysts were analyzed by X-ray diffraction (XRD and extended X-ray absorption fine structure (XAFS spectroscopy. The selective oxidation of S compounds in the LCO feed was conducted in a batch reactor at H2O2/S ratio of 10, atmospheric pressure and 353 K and then the products were fed to a continuous flow fixed-bed reactor for hydrotreating at 623 K, 3.0 MPa, and LHSV’s of 0.5–2.0 h−1. A-PTA catalyst showed a high oxidation conversion of 95% for a real LCO feed. The following hydrotreating led to a hydrodesulfurization (HDS conversion of 99.6% and a hydrodenitrogenation (HDN conversion of 94.7% over Ni2P/SBA-15, which were much higher than those of direct hydrotreating results which gave an HDS conversion of 63.5% and an HDN conversion of 17.5% based on the same LHSV of 2.0 h−1. It was revealed that the reduction in refractory nitrogen compounds after oxidative treatment contributed to the increase of the following HDS activity.

  5. Oxidation of CO and Methanol on Pd-Ni Catalysts Supported on Different Chemically-Treated Carbon Nanofibers

    Directory of Open Access Journals (Sweden)

    Juan Carlos Calderón

    2016-10-01

    Full Text Available In this work, palladium-nickel nanoparticles supported on carbon nanofibers were synthesized, with metal contents close to 25 wt % and Pd:Ni atomic ratios near to 1:2. These catalysts were previously studied in order to determine their activity toward the oxygen reduction reaction. Before the deposition of metals, the carbon nanofibers were chemically treated in order to generate oxygen and nitrogen groups on their surface. Transmission electron microscopy analysis (TEM images revealed particle diameters between 3 and 4 nm, overcoming the sizes observed for the nanoparticles supported on carbon black (catalyst Pd-Ni CB 1:2. From the CO oxidation at different temperatures, the activation energy Eact for this reaction was determined. These values indicated a high tolerance of the catalysts toward the CO poisoning, especially in the case of the catalysts supported on the non-chemically treated carbon nanofibers. On the other hand, apparent activation energy Eap for the methanol oxidation was also determined finding—as a rate determining step—the COads diffusion to the OHads for the catalysts supported on carbon nanofibers. The results here presented showed that the surface functional groups only play a role in the obtaining of lower particle sizes, which is an important factor in the obtaining of low CO oxidation activation energies.

  6. MECHANISTIC KINETIC MODELS FOR STEAM REFORMING OF CONCENTRATED CRUDE ETHANOL ON NI/AL2O3 CATALYST

    Directory of Open Access Journals (Sweden)

    O. A. OLAFADEHAN

    2015-05-01

    Full Text Available Mechanistic kinetic models were postulated for the catalytic steam reforming of concentrated crude ethanol on a Ni-based commercial catalyst at atmosphere pressure in the temperature range of 673-863 K, and at different catalyst weight to the crude ethanol molar flow rate ratio (in the range 0.9645-9.6451 kg catalyst h/kg mole crude ethanol in a stainless steel packed bed tubular microreactor. The models were based on Langmuir-Hinshelwood-Hougen-Watson (LHHW and Eley-Rideal (ER mechanisms. The optimization routine of Nelder-Mead simplex algorithm was used to estimate the inherent kinetic parameters in the proposed models. The selection of the best kinetic model amongst the rival kinetic models was based on physicochemical, statistical and thermodynamic scrutinies. The rate determining step for the steam reforming of concentrated crude ethanol on Ni/Al2O3 catalyst was found to be surface reaction between chemisorbed CH3O and O when hydrogen and oxygen were adsorbed as monomolecular species on the catalyst surface. Excellent agreement was obtained between the experimental rate of reaction and conversion of crude ethanol, and the simulated results, with ADD% being ±0.46.

  7. Nitrogen–doped graphitized carbon shell encapsulated NiFe nanoparticles: A highly durable oxygen evolution catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Du, Lei; Luo, Langli; Feng, Zhenxing; Engelhard, Mark; Xie, Xiaohong; Han, Binghong; Sun, Junming; Zhang, Jianghao; Yin, Geping; Wang, Chongmin; Wang, Yong; Shao, Yuyan

    2017-09-01

    Oxygen evolution reaction (OER) plays a crucial role in various energy conversion devices such as water electrolyzers and metal–air batteries. Precious metal catalysts such as Ir, Ru and their oxides are usually used for enhanced reaction kinetics but are limited by their scarce resource. The challenges associated with alternative non–precious metal catalysts such as transition metal oxides and (oxy)hydroxides etc. are their low electronic conductivity and poor durability. Here, we report OER catalysts of NiFe nanoparticles encapsulated by nitrogen–doped graphitized carbon shells derived from bimetallic metal–organic frameworks (MOFs) precursors. The optimal OER catalyst shows excellent activity (360 mV overpotential at 10 mA cm–2GEO) and durability (no obvious degradation after 20 000 cycles). The electron-donation from Fe and tuned electronic structure of metal cores by Ni are revealed to be primary contributors to the enhanced OER activity. We further demonstrated that the structure and morphology of encapsulating carbon shells, which are the key factors influencing the durability, are facilely controlled by chemical state of precursors. Severe metal particle growth probably caused by oxidation of carbon shells and encapsulated nanoparticles is believed to the main mechanism for activity degradation in these catalysts.

  8. Reductive amination of ethanol to ethylamines over Ni/Al{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jun Hyun [Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of); Hong, Eunpyo; An, Sang Hee; Shin, Chae-Ho; Lim, Dong-Hee [Chungbuk National University, Chungju (Korea, Republic of)

    2017-10-15

    Ni(x)/Al{sub 2}O{sub 3} (x=wt%) catalysts with Ni loadings of 5-25 wt% were prepared via a wet impregnation method on an γ-Al{sub 2}O{sub 3} support and subsequently applied in the reductive amination of ethanol to ethylamines. Among the various catalysts prepared, Ni(10)/Al2O3 exhibited the highest metal dispersion and the smallest Ni particle size, resulting in the highest catalytic performance. To reveal the effects of reaction parameters, a reductive amination process was performed by varying the reaction temperature (T), weight hourly space velocity (WHSV), and NH{sub 3} and H{sub 2} partial pressures in the reactions. In addition, on/off experiments for NH{sub 3} and H{sub 2} were also carried out. In the absence of NH{sub 3} in the reactant stream, the ethanol conversion and selectivities towards the different ethylamine products were significantly reduced, while the selectivity to ethylene was dominant due to the dehydration of ethanol. In contrast, in the absence of H{sub 2}, the selectivity to acetonitrile significantly increased due to dehydrogenation of the imine intermediate. Although a small amount of catalyst deactivation was observed in the conversion of ethanol up to 10 h on stream due to the formation of nickel nitride, the Ni(10)/Al{sub 2}O{sub 3} catalyst exhibited stable catalytic performance over 90 h under the optimized reaction conditions (i.e., T=190 .deg. C, WHSV=0.9 h{sup -1}, and EtOH/NH{sub 3}/H{sub 2} molar ratio=1/1/6).

  9. Simple synthesis of mesoporous FeNi/graphitic carbon nanocomposite catalysts and study on their activities in catalytic cracking of toluene

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yangang, E-mail: ygwang8136@gmail.com [Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); Chen, Yuting; Yao, Mingcui [Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); Qin, Hengfei; Kang, Shifei; Li, Xi [Department of Environmental Science and Engineering, Fudan University, Shanghai 200433 (China); Zuo, Yuanhui; Zhang, Xiaodong [Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); Cui, Li-Feng, E-mail: lifeng.cui@gmail.com [Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China)

    2015-11-01

    Mesoporous FeNi alloy/graphitic carbon nanocomposite catalysts with different Fe/Ni molar ratios have been synthesized through a simple solid–liquid grinding/templating method using mesoporous silica SBA-15 as the template. Metal nitrates and natural soybean oil were respectively used as the magnetic particle precursors and carbon source, which can be infiltrated into the silica template after simple impregnation, grinding and subsequent heat treatment. X-ray diffraction, nitrogen adsorption–desorption, transmission electron microscopy and thermogravimetric analysis techniques were used to characterize the samples. It is observed that high contents of FeNi alloy nanoparticles with the sizes of 3–6 nm are well dispersed into the walls of graphitic mesoporous carbon matrix, and the resulting nanocomposites have a uniform mesostructure with a high specific surface area and large pore volume. Because of these properties, the obtained FeNi/graphitic carbon nanocomposites can be used as novel catalysts for the catalytic cracking of toluene and exhibit a higher activity and stability than FeNi/commercial activated carbon (AC) catalyst. After a period of 810 min reaction at 700 °C, the toluene conversion on the FeNi/graphitic carbon nanocomposites can be maintained at a level of more than 75% and this value is 2.5 times as high as that of the FeNi/AC catalyst. - Highlights: • Mesoporous FeNi alloy/graphitic carbon nanocomposites (FeNi/GCN) were synthesized. • High contents of FeNi alloy nanoparticles are well embedded into the graphitic carbon walls. • The obtained FeNi/GCN catalysts have a high surface area and uniform mesostructure. • The FeNi/GCN catalysts exhibited excellent catalytic performance in the cracking of toluene.

  10. Production of Renewable Hydrogen from Glycerol Steam Reforming over Bimetallic Ni-(Cu,Co,Cr Catalysts Supported on SBA-15 Silica

    Directory of Open Access Journals (Sweden)

    Alicia Carrero

    2017-02-01

    Full Text Available Glycerol steam reforming (GSR is a promising alternative to obtain renewable hydrogen and help the economics of the biodiesel industry. Nickel-based catalysts are typically used in reforming reactions. However, the choice of the catalyst greatly influences the process, so the development of bimetallic catalysts is a research topic of relevant interest. In this work, the effect of adding Cu, Co, and Cr to the formulation of Ni/SBA-15 catalysts for hydrogen production by GSR has been studied, looking for an enhancement of its catalytic performance. Bimetallic Ni-M/SBA-15 (M: Co, Cu, Cr samples were prepared by incipient wetness co-impregnation to reach 15 wt % of Ni and 4 wt % of the second metal. Catalysts were characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES, N2-physisorption, X-ray powder diffraction (XRD, hydrogen temperature programmed reduction (H2-TPR, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and thermogravimetric analyses (TGA, and tested in GSR at 600 °C and atmospheric pressure. The addition of Cu, Co, and Cr to the Ni/SBA-15 catalyst helped to form smaller crystallites of the Ni phase, this effect being more pronounced in the case of the Ni-Cr/SBA-15 sample. This catalyst also showed a reduction profile shifted towards higher temperatures, indicating stronger metal-support interaction. As a consequence, the Ni-Cr/SBA-15 catalyst exhibited the best performance in GSR in terms of glycerol conversion and hydrogen production. Additionally, Ni-Cr/SBA-15 achieved a drastic reduction in coke formation compared to the Ni/SBA-15 material.

  11. Speciation of Raney Copper Oxide during High-Temperature Desulfurization

    International Nuclear Information System (INIS)

    Wang, T. C.; Chen, C. Y.; Huang, H.-L.; Wang, H. Paul; Wei Yuling

    2007-01-01

    Speciation of copper in the Raney copper oxides (R-CuO) during high-temperature desulfurization has been studied by X-ray absorption spectroscopy. The preedge XANES spectra (8975-8979 eV) of R-CuO exhibit a very weak 1s-to-3d transition forbidden by the selection rule in the case of the perfect octahedral symmetry. A shoulder at 8985-8988 eV and an intense band at 8994-9002 eV can be attributed to the 1s-to-4p transition that indicates the existence of the Cu(II) species. The preedge band at 8981-8984 eV can be attributed to the dipole-allowed 1s-to-4p transition of Cu(I), suggesting an existence of Cu2S during sulfurization. An enhanced absorbance at 9003 eV shows that Cu(0) species may be formed in the sulfurized R-CuO. The main copper species in regenerated R-CuO are CuO (96%) and Cu2S (4%)

  12. Ultrasound assisted dispersion of different amount of Ni over ZSM-5 used as nanostructured catalyst for hydrogen production via CO2 reforming of methane

    International Nuclear Information System (INIS)

    Vafaeian, Yaser; Haghighi, Mohammad; Aghamohammadi, Sogand

    2013-01-01

    Graphical abstract: A series of Ni/ZSM-5 nanocatalysts with different amount of Ni were prepared via ultrasound assisted method and characterized with XRD, FESEM, TEM, BET and FTIR techniques. The research deals with catalyst development for dry reforming of methane with the aim of reaching the most stable catalyst specifically over nano-sized catalysts. About more than 99% of Ni particles size is less than 100 nm for the sample prepared with 8% Ni, which is essential to the relative suppression of the carbon formation on catalysts. Catalyst prepared with 8% Ni content showed superior activity in process expected due to its better catalytic properties. - Highlights: • Using ZSM-5 zeolite in dry reforming of methane. • Employing ultrasound energy in synthesis of Ni/ZSM-5 nanocatalyst. • Enhancement of Ni particles size to meet desired catalyst at lower amount of Ni loading. • Dry reforming of methane over Ni/ZSM-5 nanocatalyst with different Ni-loading. • Superior activity of Ni/ZSM-5 nanocatalyst synthesized with 8% Ni content. - Abstract: Carbon dioxide reforming of methane is an interesting route for synthesis gas production especially over nanostructured catalysts. The present research deals with nanocatalyst development by sonochemical method for dry reforming of methane with the aim of reaching the most efficient nanocatalyst. Effect of Ni metal content, one of the most significant variables, on the properties of the ZSM-5 supported nanocatalysts was taken into account. The Ni/ZSM-5 nanocatalysts were prepared via assisted traditional impregnation method via ultrasound irradiation and characterized with XRD, FESEM, TEM, BET and FTIR techniques. Comparison of XRD patterns implies that the peaks related to NiO become sharper by increasing metal content over the support. In the case of nanocatalysts with lower metal content (3% and 8%), the beneficial influence of ultrasound assisted procedure become more pronounced and the observed reduction in

  13. Synthesis of a carbon-coated NiO/MgO core/shell nanocomposite as a Pd electro-catalyst support for ethanol oxidation

    International Nuclear Information System (INIS)

    Mahendiran, C.; Maiyalagan, T.; Scott, K.; Gedanken, A.

    2011-01-01

    Highlights: → Carbon coated on NiO/MgO in a core/shell nanostructure is synthesized by RAPET. → The carbon-coated NiO/MgO is supported by Pd. → The electrocatalytic properties of the Pd/(NiO/MgO-C) catalyst for ethanol oxidation studied. - Abstract: Carbon coated on NiO/MgO in a core/shell nanostructure was synthesized by the single-step RAPET (reaction under autogenic pressure at elevated temperatures) technique, and the obtained formation mechanism of the core/shell nanocomposite was presented. The carbon-coated NiO/MgO and its supported Pd catalyst, Pd/(NiO/MgO-C), were characterized by SEM, HR-TEM, XRD and cyclic voltammetry. The X-ray diffraction patterns confirmed the face-centered cubic crystal structure of NiO/MgO. Raman spectroscopy measurements provided structural evidence for the formation of a NiO/MgO composite and the nature of the coated carbon shell. The high-resolution transmission electron microscopy images showed the core and shell morphologies individually. The electrocatalytic properties of the Pd/(NiO/MgO-C) catalyst for ethanol oxidation were investigated in an alkaline solution. The results indicated that the prepared Pd-NiO/MgO-C catalyst has excellent electrocatalytic activity and stability.

  14. Electrocatalytic glucose oxidation via hybrid nanomaterial catalyst of multi-wall TiO2 nanotubes supported Ni(OH)2 nanoparticles: Optimization of the loading level

    International Nuclear Information System (INIS)

    Gu, Yingying; Liu, Yicheng; Yang, Haihong; Li, Benqiang; An, Yarui

    2015-01-01

    Highlights: • Multi-wall TiO 2 nanotube supported Ni(OH) 2 nanoparticles, Ni(OH) 2 /TNTs, was prepared and investigated as anode electro-catalysts for glucose oxidation. • Ni(OH) 2 -24.2%/TNTs obtains the best catalytic activity. • Compared with Ni(OH) 2, the current density of Ni(OH) 2 -24.2%/TNTs increased 5.9 times in 0.1 M NaOH solution. - Abstract: The novel hybrid nanomaterial catalyst of multi-wall TiO 2 nanotube supported Ni(OH) 2 nanoparticles (Ni(OH) 2 /TNTs) was prepared through hydrothermal method and investigated as anode electro-catalysts for glucose oxidation. The nanostructure was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), thermogravimetry-differential thermal analysis (TGA) and nitrogen adsorption-desorption (BET-BJH). The electrochemical performance was measured by a range of electrochemical measurements. Compared with Ni(OH) 2 , the current density of Ni(OH) 2 /TNTs modified GC electrode increased 5.9 times in 0.1 M NaOH solution. The results indicated that the synthesized nanoparticles exhibited good electro-catalytic activity and stability for glucose oxidation. Meanwhile, the hybrid nanomaterial of Ni(OH) 2 /TNTs may be a potential candidate catalyst for direct glucose fuel cell

  15. Study of polyoxide catalysts of methane combustion on Mn, Cu, Ni, rare earth elements, alkaline earth elements base by the X-ray fluorescence analysis method

    International Nuclear Information System (INIS)

    Grigor'eva, V.P.; Popova, N.M.; Zheksenbaeva, Z.T.; Sass, A.S.; Salakhova, R.Kh.; Dosumov, K.D.

    2002-01-01

    The results of X-ray fluorescence analysis of polyoxide catalysts on of Mn, Cu, Ni, rare earth elements, alkaline earth elements base supported on 2 % Ce/θ-Al 2 O 3 are presented. This polyoxide catalysts are using for deep methane oxidation. DRON-4-7 X-ray diffractometers was applied for the analysis. It was found, that oxides in Ni-Cu-Cr catalysts after long time heating up to 1200 deg. C have been interacted with catalyst supports with Ni(Cu)Al 2 O 3 aluminates formation and due to its decomposition transformation degree of CH 4 to CO 2 are reduced. Activity of MnBaSrCeLa catalysts after heating up to 1200 deg. C does not changed

  16. An anodic alumina supported Ni-Pt bimetallic plate-type catalysts for multi-reforming of methane, kerosene and ethanol

    KAUST Repository

    Zhou, Lu

    2014-05-01

    An anodic alumina supported Ni-Pt bimetallic plate-type catalyst was prepared by a two-step impregnation method. The trace amount 0.08 wt% of Pt doping efficiently suppressed the nickel particle sintering and improved the nickel oxides reducibility. The prepared Ni-Pt catalyst showed excellent performance during steam reforming of methane, kerosene and ethanol under both 3000 h stationary and 500-time daily start-up and shut-down operation modes. Self-activation ability of this catalyst was evidenced, which was considered to be resulted from the hydrogen spillover effect over Ni-Pt alloy. In addition, an integrated combustion-reforming reactor was proposed in this study. However, the sintering of the alumina support is still a critical issue for the industrialization of Ni-Pt catalyst. Copyright © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  17. Direct production of carbon nanofibers decorated with Cu2O by thermal chemical vapor deposition on Ni catalyst electroplated on a copper substrate

    Directory of Open Access Journals (Sweden)

    MA Vesaghi

    2012-12-01

    Full Text Available  Carbon nanofibers (CNFs decorated with Cu2O particles were grown on a Ni catalyst layer deposited on a Cu substrate by thermal. chemical vapor deposition from liquid petroleum gas. Ni catalyst nanoparticles with different sizes were produced in an electroplating system at 35˚C. These nanoparticles provide the nucleation sites for CNF growth, removing the need for a buffer layer. High temperature surface segregation of the Cu substrate into the Ni catalyst layer and its exposition to O2 at atmospheric environment, during the CNFs growth, lead to the production of CNFs decorated with Cu2O particles. The surface morphology of the Ni catalyst films and grown CNFs over it was studied by scanning electron microscopy. Transmission electron microscopy and Raman spectroscopy revealed the formation of CNFs. The selected area electron diffraction pattern and electron diffraction studies show that these CNFs were decorated with Cu2O nanoparticles.

  18. Structural and textural study of Ni and/or Co in a common molybdate lattice as catalysts

    Directory of Open Access Journals (Sweden)

    Boukhlouf H.

    2013-09-01

    Full Text Available This work deals with the search for new molybdate catalyst formulations, which are known to be active in light alkane oxidative dehydrogenation, a process which could be replace in the near future the common steam cracking and pure dehydrogenation processes currently used for the production of alkenes. Co, Ni and mixed Ni-Co molybdates of various compositions are prepared by a modified coprecipitation procedure from metal nitrates and ammonium heptamolybdate. Their structural and textural properties were studied by XRD, Raman, B.E.T and XPS. Textural and structural properties of the materials are correlated to the composition.

  19. Hydroconversion of methyl laurate on bifunctional Ni2P/AlMCM-41 catalyst prepared via in situ phosphorization using triphenylphosphine

    Science.gov (United States)

    Zhao, Sha; Zhang, Zhena; Zhu, Kongying; Chen, Jixiang

    2017-05-01

    A series of Ni2P/AlMCM-41-x bifunctional catalysts with different Si/Al ratios (x) were synthesized by in situ phosphorization of Ni/AlMCM-41-x with triphenylphosphine (nominal Ni/P ratio of 0.75) at 300 °C on a fixed-bed reactor. For comparison, NiP/AlMCM-41-5-TPR was also prepared by the TPR method from the supported nickel phosphate with the Ni/P ratio of 1.0, during which metallic Ni rather than Ni2P formed. TEM images show that Ni and Ni2P particles uniformly distributed in Ni2P/AlMCM-41-x and NiP/AlMCM-41-5-TPR. The Ni2P/AlMCM-41-x acidity increased with decreasing the Si/Al ratio. In the hydroconversion of methyl laurate, the conversions were close to 100% on all catalysts at 360 °C, 3.0 MPa, methyl laurate WHSV of 2 h-1 and H2/methyl laurate ratio of 25. As to Ni2P/AlMCM-41-x, with decreasing the Si/Al ratio, the total selectivity to C11 and C12 hydrocarbons decreased, while the total selectivity to isoundecane and isododecane (Si-C11+i-C12) firstly increased and then decreased. Ni2P/AlMCM-41-5 gave the largest Si-C11+i-C12 of 43.2%. While NiP/AlMCM-41-5-TPR gave higher Si-C11+i-C12 than Ni2P/AlMCM-41-5, it was more active for the undesired Csbnd C bond cleavage and methanation. We propose that the in-situ phosphorization adopted here is a promising approach to preparing Ni2P-based bifunctional catalysts.

  20. Pyrolysis and gasification of landfilled plastic wastes with Ni-Mg-La/Al2O3 catalyst.

    Science.gov (United States)

    Kaewpengkrow, Prangtip; Atong, Duangduen; Sricharoenchaikul, Viboon

    2012-12-01

    Pyrolysis and gasification processes were utilized to study the feasibility of producing fuels from landfilled plastic wastes. These wastes were converted in a gasifier at 700-900 degrees C. The equivalence ratio (ER) was varied from 0.4-0.6 with or without addition ofa Ni-Mg-La/Al2O3 catalyst. The pyrolysis and gasification of plastic wastes without catalyst resulted in relatively low H2, CO and other fuel gas products with methane as the major gaseous species. The highest lower heating value (LHV) was obtained at 800 degrees C and for an ER of 0.4, while the maximum cold gas efficiency occurred at 700 degrees C and for an ER of 0.4. The presence of the Ni-Mg-La/Al2O3 catalyst significantly enhanced H2 and CO production as well as increasing the gas energy content to 15.76-19.26 MJ/m3, which is suitable for further usage as quality fuel gas. A higher temperature resulted in more H2 and CO and other product gas yields, while char and liquid (tars) decreased. The maximum gas yield, gas calorific value and cold gas efficiency were achieved when the Ni-Mg-La/Al2O3 catalyst was used at 900 degrees C. In general, addition of prepared catalyst resulted in greater H2, CO and other light hydrocarbon yields from superior conversion of wastes to these gases. Thus, thermochemical treatment of these problematic wastes using pyrolysis and gasification processes is a very attractive alternative for sustainable waste management.

  1. A Non-sulfided flower-like Ni-PTA Catalyst that Enhances the Hydrotreatment Efficiency of Plant Oil to Produce Green Diesel

    Science.gov (United States)

    Liu, Jing; Chen, Pan; Deng, Lihong; He, Jing; Wang, Luying; Rong, Long; Lei, Jiandu

    2015-01-01

    The development of a novel non-sulfided catalyst with high activity for the hydrotreatment processing of plant oils, is of high interest as a way to improve the efficient production of renewable diesel. To attempt to develop such a catalyst, we first synthesized a high activity flower-like Ni-PTA catalyst used in the hydrotreatment processes of plant oils. The obtained catalyst was characterized with SEM, EDX, HRTEM, BET, XRD, H2-TPR, XPS and TGA. A probable formation mechanism of flower-like Ni(OH)2 is proposed on the basis of a range of contrasting experiments. The results of GC showed that the conversion yield of Jatropha oil was 98.95%, and the selectivity of C11-C18 alkanes was 70.93% at 360 °C, 3 MPa, and 15 h−1. The activity of this flower-like Ni-PTA catalyst was more than 15 times higher than those of the conventional Ni-PTA/Al2O3 catalysts. Additionally, the flower-like Ni-PTA catalyst exhibited good stability during the process of plant oil hydrotreatment. PMID:26503896

  2. Development of Fe-Ni/YSZ-GDC electro-catalysts for application as SOFC anodes. XRD and TPR characterization, and evaluation in ethanol steam reforming reaction

    Energy Technology Data Exchange (ETDEWEB)

    Paz Fiuza, Raigenis da; Silva, Marcos Aurelio da; Boaventura, Jaime Soares [UFBA, Salvador, Bahia (Brazil). Energy and Materials Science Group

    2010-07-01

    Electro-catalysts based on Fe-Ni alloys were prepared using physical mixture and modified Pechini methods; they were supported on a composite of Yttria Stabilized Zirconia (YSZ) and Gadolinia Doped Ceria (GDC). The composites had compositions of 35% metal load and 65% support (70% wt. YSZ and 30% wt. GDC mixture) (cermets). The samples were characterized by Temperature-Programmed Reduction (TPR) and X-Ray Diffraction (XRD) and evaluated in ethanol steam reforming at 650 C for six hours and in the temperature range 300 - 900 C. The XRD results showed that the bimetallic sample calcined at 800 C formed a mixed oxide (NiFe{sub 2}O{sub 4}) in spinel structure; after reducing the sample in hydrogen, Ni-Fe alloys were formed. The presence of Ni decreased the final reduction temperature of the NiFe{sub 2}O{sub 4} species. The addition of Fe to Ni anchored to YSZ-GDC increased the hydrogen production and inhibits the carbon deposition. The bimetallic 30Fe5Ni samples reached an ethanol conversion of about 95%, and a hydrogen yield up to 48% at 750 C. In general, the ethanol conversion and hydrogen production were independent of the metal content in the electro-catalyst. However, the substitution of Ni for Fe significantly reduced the carbon deposition on the electro-catalyst: 74, 31 and 9 wt. % in the 35Ni, 20Fe15Ni, and 30Fe5Ni samples, respectively. (orig.)

  3. Synergistically Enhanced Electrochemical Performance of Ni3S4-PtX (X = Fe, Ni) Heteronanorods as Heterogeneous Catalysts in Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Huang, Shoushuang; Ma, Dui; Hu, ZhangJun; He, Qingquan; Zai, Jiantao; Chen, Dayong; Sun, Huai; Chen, Zhiwen; Qiao, Qiquan; Wu, Minghong; Qian, Xuefeng

    2017-08-23

    Platinum (Pt)-based alloys are considerably promising electrocatalysts for the reduction of I - /I 3 - and Co 2+ /Co 3+ redox couples in dye-sensitized solar cells (DSSCs). However, it is still challenging to minimize the dosage of Pt to achieve comparable or even higher catalytic efficiency. Here, by taking full advantages of the Mott-Schottky (M-S) effect at the metal-semiconductor interface, we successfully strategize a low-Pt-based M-S catalyst with enhanced electrocatalytic performance and stability for the large-scale application of DSSCs. The optimized M-S electrocatalyst of Ni 3 S 4 -Pt 2 X 1 (X = Fe, Ni) heteronanorods is constructed by rationally controlling the ratio of Pt to transition metal in the hybrids. It was found that the electrons transferred from Ni 3 S 4 to Pt 2 X 1 at their interface under the Mott-Schottky effect result in the concentration of electrons onto Pt 2 X 1 domains, which subsequently accelerates the regeneration of both I - /I 3 - and Co 2+ /Co 3+ redox shuttles in DSSCs. As a result, the DSSC with Ni 3 S 4 -Pt 2 Fe 1 manifests an impressive power conversion efficiency (PCE) of 8.79% and 5.56% for iodine and cobalt-based electrolyte under AM1.5G illumination, respectively. These PCEs are obviously superior over those with Ni 3 S 4 -Pt, PtFe, Ni 3 S 4 , and pristine Pt electrodes. The strategy reported here is able to be further expanded to fabricate other low-Pt-alloyed M-S catalysts for wider applications in the fields of photocatalysis, water splitting, and heterojunction solar cells.

  4. An anodic alumina supported Ni-Pt bimetallic plate-type catalysts for multi-reforming of methane, kerosene and ethanol

    KAUST Repository

    Zhou, Lu; Guo, Yu; Kameyama, Hideo; Basset, Jean-Marie

    2014-01-01

    . The prepared Ni-Pt catalyst showed excellent performance during steam reforming of methane, kerosene and ethanol under both 3000 h stationary and 500-time daily start-up and shut-down operation modes. Self-activation ability of this catalyst was evidenced

  5. Use of Hydrogen Chemisorption and Ethylene Hydrogenation as Predictors for Aqueous Phase Reforming of Lactose over Ni@Pt and Co@Pt Bimetallic Overlayer Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Qinghua; Skoglund, Michael D.; Zhang, Chen; Morris, Allen R.; Holles, Joseph H.

    2016-10-20

    Overlayer Pt on Ni (Ni@Pt) or Co (Co@Pt) were synthesized and tested for H2 generation from APR of lactose. H2 chemisorption descriptor showed that Ni@Pt and Co@Pt overlayer catalysts had reduced H2 adsorption strength compared to a Pt only catalyst, which agree with computational predictions. The overlayer catalysts also demonstrated lower activity for ethylene hydrogenation than the Pt only catalyst, which likely resulted from decreased H2 binding strength decreasing the surface coverage of H2. XAS results showed that overlayer catalysts exhibited higher white line intensity than the Pt catalyst, which indicates a negative d-band shift for the Pt overlayer, further providing evidence for overlayer formation. Lactose APR studies showed that lactose can be used as feedstock to produce H2 and CO under desirable reaction conditions. The Pt active sites of Ni@Pt and Co@Pt overlayer catalysts showed significantly enhanced H2 production selectivity and activity when compared with that of a Pt only catalyst. The single deposition overlayer with the largest d-band shift showed the highest H2 activity. The results suggest that overlayer formation using directed deposition technique could modify the behavior of the surface metal and ultimately modify the APR activity.

  6. A comparative study of alumina-supported Ni catalysts prepared by photodeposition and impregnation methods on the catalytic ozonation of 2,4-dichlorophenoxyacetic acid

    International Nuclear Information System (INIS)

    Rodríguez, Julia L.; Valenzuela, Miguel A.; Tiznado, Hugo; Poznyak, Tatiana; Chairez, Isaac; Magallanes, Diana

    2017-01-01

    The heterogeneous catalytic ozonation on unsupported and supported oxides has been successfully tested for the removal of several refractory compounds in aqueous solution. In this work, alumina-supported nickel catalysts prepared by photodeposition and impregnation methods were compared in the catalytic ozonation of 2,4-dichlorophenoxyacetic acid (2,4-D). The catalysts were characterized by high-resolution electron microscopy and X-ray photoelectron spectroscopy. The photochemical decomposition of Ni acetylacetonate to produce Ni(OH) 2 , NiO, and traces of Ni° deposited on alumina was achieved in the presence of benzophenone as a sensitizer. A similar surface composition was found with the impregnated catalyst after its reduction with hydrogen at 500 °C and exposed to ambient air. Results indicated a higher initial activity and maleic acid (byproduct) concentration with the photodeposited catalyst (1 wt% Ni) compared to the impregnated catalyst (3 wt% Ni). These findings suggest the use of the photodeposition method as a simple and reliable procedure for the preparation of supported metal oxide/metal catalysts under mild operating conditions.

  7. Nickel oxide and carbon nanotube composite (NiO/CNT) as a novel cathode non-precious metal catalyst in microbial fuel cells.

    Science.gov (United States)

    Huang, Jianjian; Zhu, Nengwu; Yang, Tingting; Zhang, Taiping; Wu, Pingxiao; Dang, Zhi

    2015-10-15

    Comparing with the precious metal catalysts, non-precious metal catalysts were preferred to use in microbial fuel cells (MFCs) due to the low cost and high oxygen reduction reaction (ORR) efficiency. In this study, the transmission electron microscope and X-ray diffraction as well as Raman investigation revealed that the prepared nanoscale NiO was attached on the surface of CNT. Cyclic voltammogram and rotating ring-disk electrode tests showed that the NiO/CNT composite catalyst had an apparent oxygen reduction peak and 3.5 electron transfer pathway was acquired under oxygen atmosphere. The catalyst performance was highly dependent on the percentage of NiO in the CNT nanocomposites. When 77% NiO/CNT nano-sized composite was applied as cathode catalyst in membrane free single-chamber air cathode MFC, a maximum power density of 670 mW/m(2) and 0.772 V of OCV was obtained. Moreover, the MFC with pure NiO (control) could not achieve more than 0.1 V. All findings suggested that NiO/CNT could be a potential cathode catalyst for ORR in MFCs. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. UV Light-Assisted Synthesis of Highly Efficient Pd-Based Catalyst over NiO for Hydrogenation of o-Chloronitrobenzene.

    Science.gov (United States)

    Jiang, Weidong; Xu, Bin; Fan, Guangyin; Zhang, Kaiming; Xiang, Zhen; Liu, Xiaoqiang

    2018-04-14

    Supported Pd-based catalyst over active nickel oxide (NiO) was repared using the impregnation method companying with UV-light irradiation. Moreover, the catalytic performance of the obtained Pd-based catalysts was evaluated towards the hydrogenation of o -chloronitrobenzene ( o -CNB). Observations indicate that the as-prepared UV-irradiated Pd/NiO catalyst with a mole fraction 0.2% (0.2%Pd/NiO) has higher activity and selectivity in the o -CNB hydrogenation. Especially, UV-light irradiation played a positive role in the improvement of catalytic activity of 0.2%Pd/NiO catalyst, exhibiting an excess 11-fold activity superiority in contrast with non-UV-irradiated 0.2%Pd/NiO catalyst. In addition, it was investigated that effects of varied factors (i.e., reaction time, temperature, o -CNB/Pd ratio, Pd loading, hydrogen pressure) on the selective hydrogenation of ο -CNB catalyzed by UV-irradiated 0.2%Pd/NiO catalyst. Under the reaction conditions of 60 °C, 0.5 h, 1 MPa H₂ pressure, 100% conversion of o -CNB, and 81.1% o -CAN selectivity were obtained, even at high molar ratio (8000:1) of o -CNB to Pd.

  9. Steam Reforming of Ethylene Glycol over Ni/Al2O3 Catalysts: Effect of the Preparation Method and Reduction Temperature

    International Nuclear Information System (INIS)

    Choi, Dong Hyuck; Park, Jung Eun; Park, Eun Duck

    2015-01-01

    The effect of preparation method on the catalytic activities of the Ni/Al 2 O 3 catalysts on steam reforming of ethylene glycol was investigated. The catalysts were prepared with various preparation methods such as an incipient wetness impregnation, wet impregnation, and coprecipitation method. In the case of coprecipitation method, various precipitants such as KOH, K 2 CO 3 , and NH 4 OH were compared. The prepared catalysts were characterized by using N 2 physisorption, inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction, temperature programmed reduction, pulsed H 2 chemisorption, temperature-programmed oxidation, scanning electron microscopy, and thermogravimetric analysis. Among the catalysts reduced at 773 K, the Ni/Al 2 O 3 catalyst prepared by a coprecipitation with KOH or K 2 CO 3 as precipitants showed the best catalytic performance. The preparation method affected the particle size of Ni, reducibility of nickel oxides, catalytic performance (activity and stability), and types of coke formed during the reaction. The Ni/Al 2 O 3 catalyst prepared by a coprecipitation with KOH showed the increasing catalytic activity with an increase in the reduction temperature from 773 to 1173 K because of an increase in the reduction degree of Ni oxide species even though the particle size of Ni increased with increasing reduction temperature

  10. A comparative study of alumina-supported Ni catalysts prepared by photodeposition and impregnation methods on the catalytic ozonation of 2,4-dichlorophenoxyacetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez, Julia L., E-mail: ozliliana@yahoo.com.mx [Lab. Ing. Química Ambiental. ESIQIE–Instituto Politécnico Nacional (Mexico); Valenzuela, Miguel A. [Lab.Catálisis y Materiales. ESIQIE–Instituto Politécnico Nacional. Zacatenco (Mexico); Tiznado, Hugo [Centro de Nanociencias y Nanotecnología. CNyN Universidad Nacional Autónoma de México (Mexico); Poznyak, Tatiana [Lab. Ing. Química Ambiental. ESIQIE–Instituto Politécnico Nacional (Mexico); Chairez, Isaac [Departamento de Bioprocesos, UPIBI- Instituto Politécnico Nacional (Mexico); Magallanes, Diana [Lab. Ing. Química Ambiental. ESIQIE–Instituto Politécnico Nacional (Mexico)

    2017-02-15

    The heterogeneous catalytic ozonation on unsupported and supported oxides has been successfully tested for the removal of several refractory compounds in aqueous solution. In this work, alumina-supported nickel catalysts prepared by photodeposition and impregnation methods were compared in the catalytic ozonation of 2,4-dichlorophenoxyacetic acid (2,4-D). The catalysts were characterized by high-resolution electron microscopy and X-ray photoelectron spectroscopy. The photochemical decomposition of Ni acetylacetonate to produce Ni(OH){sub 2}, NiO, and traces of Ni° deposited on alumina was achieved in the presence of benzophenone as a sensitizer. A similar surface composition was found with the impregnated catalyst after its reduction with hydrogen at 500 °C and exposed to ambient air. Results indicated a higher initial activity and maleic acid (byproduct) concentration with the photodeposited catalyst (1 wt% Ni) compared to the impregnated catalyst (3 wt% Ni). These findings suggest the use of the photodeposition method as a simple and reliable procedure for the preparation of supported metal oxide/metal catalysts under mild operating conditions.

  11. Catalytic reforming of toluene as tar model compound: effect of Ce and Ce-Mg promoter using Ni/olivine catalyst.

    Science.gov (United States)

    Zhang, Ruiqin; Wang, Huajian; Hou, Xiaoxue

    2014-02-01

    Tar produced by biomass gasification as a route of renewable energy must be removed before the gas can be used. This study was undertaken using toluene as a model tar compound for evaluating its steam reforming conversion with three Ni-based catalysts, Ni/olivine, Ni-Ce/olivine and Ni-Ce-Mg/olivine. Effects of Ce and Mg promoters on the reaction activity and coke deposition were studied. Overall the performance of Ce and Mg promoted Ni/olivine catalysts is better than that of only Ce promoter and Ni/olivine alone. The experimental results indicate that Ni-Ce-Mg/olivine catalysts could improve the resistance to carbon deposition, enhance energy gases yield and resist 10ppm H2S poison at 100mLmin(-1) for up to 400min. Furthermore, the activity of catalysts was related to the steam/carbon (S/C) ratios; at S/C ratio=5, T=790°C, space velocity=782h(-1) and t=2h, the Ni-Ce-Mg/olivine system yielded 89% toluene conversion, 5.6Lh(-1) product gas rate, 62.6mol% H2 content and 10% (mol useful gas mol(-1) toluene) energy yield. Moreover, at low S/C ratio, it had higher reaction activity and better ability to prevent coking. There is a small amount of carbon deposition in the form of amorphous carbon after 7h. Various characterization techniques such as XRD, FTIR and thermogravimetric were performed to investigate the coke deposition of Ni/olivine, Ni-Ce/olivine and Ni-Ce-Mg/olivine. It is suggested that 3% Ni-1% Ce-1% Mg/olivine was the most promising catalyst due to its minimum coke amount and the lower activation energy of coke burning. Copyright © 2014. Published by Elsevier Ltd.

  12. Nitrogen–doped graphitized carbon shell encapsulated NiFe nanoparticles: A highly durable oxygen evolution catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Du, Lei; Luo, Langli; Feng, Zhenxing; Engelhard, Mark; Xie, Xiaohong; Han, Binghong; Sun, Junming; Zhang, Jianghao; Yin, Geping; Wang, Chongmin; Wang, Yong; Shao, Yuyan

    2017-09-01

    Oxygen evolution reaction (OER) plays a crucial role in various energy conversion devices such as water electrolyzers and metal–air batteries. Precious metal catalysts such as Ir, Ru and their oxides are usually used for enhancing reaction kinetics but are limited by their scarce resource. The challenges associated with alternative non–precious metal catalysts such as transition metal oxides and (oxy)hydroxides etc. are their low electronic conductivity and durability. Herein, we report a highly active (360 mV overpotential at 10 mA cm–2GEO) and durable (no degradation after 20000 cycles) OER catalyst derived from bimetallic metal–organic frameworks (MOFs) precursors. This catalyst consists of NiFe nanoparticles encapsulated by nitrogen–doped graphitized carbon shells. The electron-donation/deviation from Fe and tuned electronic structure of metal cores by Ni are revealed to be primary contributors to the enhanced OER activity, whereas N concentration contributes negligibly. We further demonstrated that the structure and morphology of encapsulating carbon shells, which are the key factors influencing the durability, are facilely controlled by the chemical state of precursors.

  13. The effect of noble metals on catalytic methanation reaction over supported Mn/Ni oxide based catalysts

    Directory of Open Access Journals (Sweden)

    Wan Azelee Wan Abu Bakar

    2015-09-01

    Full Text Available Carbon dioxide (CO2 in sour natural gas can be removed using green technology via catalytic methanation reaction by converting CO2 to methane (CH4 gas. Using waste to wealth concept, production of CH4 would increase as well as creating environmental friendly approach for the purification of natural gas. In this research, a series of alumina supported manganese–nickel oxide based catalysts doped with noble metals such as ruthenium and palladium were prepared by wetness impregnation method. The prepared catalysts were run catalytic screening process using in-house built micro reactor coupled with Fourier Transform Infra Red (FTIR spectroscopy to study the percentage CO2 conversion and CH4 formation analyzed by GC. Ru/Mn/Ni(5:35:60/Al2O3 calcined at 1000 °C was found to be the potential catalyst which gave 99.74% of CO2 conversion and 72.36% of CH4 formation at 400 °C reaction temperature. XRD diffractogram illustrated that the supported catalyst was in polycrystalline with some amorphous state at 1000 °C calcination temperature with the presence of NiO as active site. According to FESEM micrographs, both fresh and used catalysts displayed spherical shape with small particle sizes in agglomerated and aggregated mixture. Nitrogen Adsorption analysis revealed that both catalysts were in mesoporous structures with BET surface area in the range of 46–60 m2/g. All the impurities have been removed at 1000 °C calcination temperature as presented by FTIR, TGA–DTA and EDX data.

  14. One-Step Condensation and Hydrogenation of Furfural-Acetone Using Mixed and Single Catalyst Based on Ni/M-Oxide [M=Al; Mg

    Science.gov (United States)

    Ulfa, S. M.; Pramesti, I. N.; Mustafidah, H.

    2018-01-01

    Modification of furfural by condensation and hydrogenation reaction is a promising approach to produce higher alkane derivatives (C8-C13) as diesel fraction. This research investigated the catalytic activity of Ni/MgO as bifunctional catalyst compared with MgO-Ni/Al2O3 mixed catalyst for condensation-hydrogenation reaction. The Ni/MgO and Ni/Al2O3 with 20% Ni loading were prepared by wet impregnation methods using Ni(NO3)2.6H2O salt, calcined and reduced at 500°C. The catalyst performance was tested for one-step condensation-hydrogenation reaction using autoclave oil batch reactor. The reaction was conducted by reacting furfural and acetone in 1:1 ratio using water as solvent. Condensation reaction was performed at 100°C for 8 hours, followed by hydrogenation at 120°C during 7 hours. Analysis by gas chromatography showed that C=C double bond of furfurylidene acetone were successfully hydrogenated. Using Ni/MgO catalyst at 120°C, the products were identified as 1,5-bis-(2-furanyl)-1,4-penta-1-ene-3-one (2.68%) and 1,5-bis-(2-furanyl)-1,4-pentan-3-one (trace amount). On the other hand, reaction using mixed catalyst, MgO-Ni/Al2O3 showed better activity over bifunctional Ni/MgO at the same reaction temperature. The products were identified as 4-(2-furanyl)-3-butan-2-one (27.30%); 1,5-bis-(2-furanyl)-1,4-penta-1-ene-3-one (3.82%) and 1,5-bis-(2-furanyl)-1,4-pentan-3-one (1.11%). The impregnation of Ni on MgO decrease the physical properties of catalyst, confirmed by surface area analysis (SAA).

  15. Hydrotreatment of 8-hydroxyquinoline on a NiMo/Al sub 2 O sub 3 catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C.M.; Satterfield, C.N. (Massachusetts Institute of Technology, Cambridge, MA (USA). Dept. of Chemical Engineering)

    The hydrotreatment of 8-hydroxyquinoline was studied on a sulfided NiMo/Al{sub 2}O{sub 3} catalyst at 360{degree}C and 6.9 MPa total pressure of H{sub 2} in a vapour-phase tubular reactor. Some minor studies were performed at 385{degree}C. 8-Hydroxyquinoline undergoes hydrodeoxygenation via three routes to enter the hydrodenitrogenation network of quinoline. Route 1 is hydrogenation of the heterocyclic ring to 8-hydroxy-1,2,3,4-tetrahydroquinoline (8HTHQ) followed by hydrogenation of the aromatic ring to 8-hydroxydecahydroquinoline which undergoes C-O hydrogenolysis to decahydroquinoline. Route 2 is direct C-O hydrogenolysis of 8HTHQ to form 1,2,3,4-tetrahydroquinoline (PyTHQ). Route 3 is hydrogenation of the benzene ring in 8-hydroxyquinoline to form 8-hydroxy-5,6,7,8-tetrahydroquinoline followed by removal of the oxygen to form 5,6,7,8-tetrahydroquinoline. After oxygen removal, subsequent reactions follow the hydrodenitrogenation network of quinoline. The hydroconversion of 8-hydroxyquinoline is governed by the N center rather than the OH center. 14 refs., 9 figs.

  16. Deoxygenation of Plant Fatty Acid using NiSnK/ SiO2 as Catalyst

    International Nuclear Information System (INIS)

    Chiam, L.T.; Tye, C.T.

    2013-01-01

    Environmental friendly bio-oil which offers supply reliability as a potential alternative fuel, has spurred to rapid development of bio fuels technology. Palm oil is a potential renewable energy source for bio fuels production in the future and Malaysia is one of the world largest palm oil producers. However, undesired oxygen content in the plant fatty acid that contributes to low energy density, high viscosity, and low stability, makes the palm oil not effective to be used as bio fuels directly. In the present study, the performance of silica supported trimetal catalyst, NiSnK/ SiO 2 , on deoxygenation of used palm oil was evaluated. In addition, the effects of operating parameters, such as reaction temperature and weight hourly space velocity were investigated. Conversion of palmitic acid as high as 90 % was achieved in deoxygenation of used palm oil at reaction temperature 350 degree Celsius. In order to have a better understanding on the deoxygenation reaction, model compound system using the major saturated fatty acid in the used palm oil, palmitic acid was also carried out. Palmitic acid was found mainly decarboxylated into n-pentadecane with some decarboxylation and isomerization products. (author)

  17. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts

    Directory of Open Access Journals (Sweden)

    Rodiansono Rodiansono

    2015-07-01

    Full Text Available A bulk structure of inexpensive intermetallic nickel-tin (Ni-Sn alloys catalysts demonstrated highly selective in the hydrogenation of levulinic acid in water into g-valerolactone. The intermetallic Ni-Sn catalysts were synthesized via a very simple thermochemical method from non-organometallic precursor at low temperature followed by hydrogen treatment at 673 K for 90 min. The molar ratio of nickel salt and tin salt was varied to obtain the corresponding Ni/Sn ratio of 4.0, 3.0, 2.0, 1.5, and 0.75. The formation of Ni-Sn alloy species was mainly depended on the composition and temperature of H2 treatment. Intermetallics Ni-Sn that contain Ni3Sn, Ni3Sn2, and Ni3Sn4 alloy phases are known to be effective heterogeneous catalysts for levulinic acid hydrogenation giving very excellence g-valerolactone yield of >99% at 433 K, initial H2 pressure of 4.0 MPa within 6 h. The effective hydrogenation was obtained in H2O without the formation of by-product. Intermetallic Ni-Sn(1.5 that contains Ni3Sn2 alloy species demonstrated very stable and reusable catalyst without any significant loss of its selectivity. © 2015 BCREC UNDIP. All rights reserved. Received: 26th February 2015; Revised: 16th April 2015; Accepted: 22nd April 2015  How to Cite: Rodiansono, R., Astuti, M.D., Ghofur, A., Sembiring, K.C. (2015. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (2: 192-200. (doi:10.9767/bcrec.10.2.8284.192-200Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.2.8284.192-200  

  18. Simultaneous oxidative conversion and co/sub 2/ reforming of methane to syngas over modified Ni/Al/sub 2/O/sub 3/ catalysts

    International Nuclear Information System (INIS)

    Eli, W.

    2013-01-01

    A series of Ni/Al/sub 2/O/sub 3/ and modified Ni-M/Al/sub 2/O/sub 3/ (MLa, Na, K, Ca and Ba) catalysts have been prepared and characterized by XRD, BET, XPS, TGA, TEM and SEM. The performance of these catalysts for simultaneous oxidative conversion and CO/sub 2/ reforming of methane to syngas was evaluated using a fixed-bed reactor. The results indicated that the catalytic activity of Ni/Al/sub 2/O/sub 3/ increased with Ni loading, and reached maximum at 12% Ni loading. The La-modified Ni/Al/sub 2/O/sub 3/ exhibited an excellent catalytic activity and stability within 20 h as compared with unmodified and Na-modified ones. It was found that the addition of La decreased the particle size of nickel, thus increased the Ni dispersion accordingly as indicated by the characterization data. The catalytic activity of Na-modified Ni/Al/sub 2/O/sub 3/ decreased obviously only after 6 h of reaction due to aggregation of metallic Ni particles. Hence, it was suggested that the sintering of Ni particles dominated the catalyst deactivation during the catalytic reaction process. (author)

  19. Hydrogenation of toluene on Ni-Co-Mo supported zeolite catalysts ...

    African Journals Online (AJOL)

    -a, HY-b and Mordenite were prepared and characterized using many techniques for use as hydrotreating catalysts. In a preliminary investigation, toluene was employed as model compound to test the catalysts in hydrogenation, as a major ...

  20. Oxidative-reforming of model biogas over NiO/Al{sub 2}O{sub 3} catalysts: The influence of the variation of support synthesis conditions

    Energy Technology Data Exchange (ETDEWEB)

    Asencios, Yvan J.O., E-mail: yvan.jesus@unifesp.br [Departamento de Ciências do Mar, Universidade Federal de São Paulo, Av. Alm. Saldanha da Gama, 89, Ponta da Praia, CEP: 11030-400, Santos-SP (Brazil); Elias, Kariny F.M. [Instituto de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador Sãocarlense, 400, 13560-970, São Carlos-SP (Brazil); Assaf, Elisabete M., E-mail: eassaf@iqsc.usp.br [Instituto de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador Sãocarlense, 400, 13560-970, São Carlos-SP (Brazil)

    2014-10-30

    Graphical abstract: - Highlights: • Precipitation pH and ageing T °C of Al{sub 2}O{sub 3} influenced the performance of Ni/Al{sub 2}O{sub 3}. • Ni catalysts supported on Al{sub 2}O{sub 3} obtained at pH 7 recorded high conversion values. • Catalysts supported on Al{sub 2}O{sub 3} obtained at pH 7 and 80 °C are promissory for reforming of biogas. • Catalysts supported on Al{sub 2}O{sub 3} obtained at pH 6 deactivated readily during reaction. - Abstract: In this study, nickel catalysts (20 wt%) supported on γ-Al{sub 2}O{sub 3} were prepared by the impregnation method. The γ-Al{sub 2}O{sub 3}, was synthesized by precipitation of bayerite gel obtained from aluminum scrap. The synthetic conditions of the bayerite gel varied as follows: precipitation pH ranging from 6 to 7; ageing temperature ranging from 25 to 80 °C, the calcination temperature for all samples was 500 °C. The catalysts and the supports were analyzed by temperature programmed reduction (H{sub 2}-TPR), X-ray diffraction (XRD), physisorption of N{sub 2} (BET), X-ray absorption near-edge structure (XANES) and scanning electron microscopy (SEM). Isopropanol decomposition reactions over the catalysts were carried out to evaluate their acidity. SEM images of the spent catalysts showed that the morphology of the carbon formed during the reaction is of the filamentous type. The TPR analysis of the catalysts showed the presence of NiO species weakly interacted with the support as well as stoichiometric and non-stoichiometric nickel aluminate, the reduction of these species was also observed by XANES analysis. XRD analysis of the fresh catalyst showed peaks assigned to NiO, NiAl{sub 2}O{sub 4} and γ-Al{sub 2}O{sub 3}. The best catalysts (samples NiAl7-25 and NiAl7-80) synthesized in this report showed high stability and high conversion values (CH{sub 4} (70%) and CO{sub 2} (78%)). These catalysts showed better performance than the catalyst supported on commercial γ-Al{sub 2}O{sub 3}, which showed a

  1. Physico-chemical characterisations and catalytic performance of Ni-based catalyst systems for dry reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Vlach, K.; Hoang, D.L.; Schneider, M.; Pohl, M.M.; Armbruster, U.; Martin, A. [Rostock Univ. (Germany). Leibniz-Institut fuer Katalyse e.V.

    2012-07-01

    In this study, ternary perovskite type oxides LaNi{sub x}Cu{sub 1-x}O{sub 3} (x = 0, 0.2, 0.5, 0.8, 1) were synthesized using NaOH and diethylenetriaminepentaacetic acid (H{sub 5}DTPA). The catalysts resulting from perovskite precursors exhibit catalytic activities for CO{sub 2} reforming of CH{sub 4} at 700 C that increase with a higher Ni content. Characterization methods showed that the activation led to formation of small metallic Ni/Cu particles. Methane and carbon dioxide conversions varied from 20 to 65% for CH{sub 4} and 3 to 58% for CO{sub 2}. Selectivities from 46 to 93% for CO and from 4 to 64% for H{sub 2} were obtained. (orig.)

  2. Cuboid Ni2 P as a Bifunctional Catalyst for Efficient Hydrogen Generation from Hydrolysis of Ammonia Borane and Electrocatalytic Hydrogen Evolution.

    Science.gov (United States)

    Du, Yeshuang; Liu, Chao; Cheng, Gongzhen; Luo, Wei

    2017-11-16

    The design of high-performance catalysts for hydrogen generation is highly desirable for the upcoming hydrogen economy. Herein, we report the colloidal synthesis of nanocuboid Ni 2 P by the thermal decomposition of nickel chloride hexahydrate (NiCl 2 ⋅6 H 2 O) and trioctylphosphine. The obtained nanocuboid Ni 2 P was characterized by using powder X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma atomic emission spectroscopy. For the first time, the as-synthesized nanocuboid Ni 2 P is used as a bifunctional catalyst for hydrogen generation from the hydrolysis of ammonia borane and electrocatalytic hydrogen evolution. Owing to the strong synergistic electronic effect between Ni and P, the as-synthesized Ni 2 P exhibits catalytic performance that is superior to its counterpart without P doping. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Synthesis and characterization of Fe–Ni/ɣ-Al2O3 egg-shell catalyst for H2 generation by ammonia decomposition

    DEFF Research Database (Denmark)

    Silva, Hugo José Lopes; Nielsen, Morten Godtfred; Fiordaliso, Elisabetta Maria

    2015-01-01

    The Fe–Ni alloyed nanoparticles are a promising alternative to expensive ruthenium-based catalysts for a real-scale application of hydrogen generation by ammonia decomposition. In practical applications, millimeter-sized extrudates are used as catalyst supports, where the spatial distribution...... of the active phase should match with the type of reaction. In this work, a novel synthesis route was developed for the preparation of a Fe–Ni/ɣ-Al2O3 egg-shell catalyst. Egg-shell is a preferred profile considering the highly endothermic nature of ammonia decomposition reaction. The high viscosity of glycerol...... using focused ion bean (FIB) milling allowed to acquire high resolution images of the Ni and Fe nanoparticles on ɣ-Al2O3, which is particularly challenging due to the crystalline nature of this support. Distinct regions of the egg-shell catalyst were analyzed through scanning TEM (STEM) and TEM...

  4. Study to improve the quality of a Mexican straight run gasoil over NiMo/γ-Al2O3 catalysts

    International Nuclear Information System (INIS)

    Dominguez-Crespo, M.A.; Diaz-Garcia, L.; Arce-Estrada, E.M.; Torres-Huerta, A.M.; Cortez de la Paz, M.T.

    2006-01-01

    Four NiMo catalyst supported on Al 2 O 3 with different textural properties have been studied in the hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodearomatization (HDA) of a Mexican straight run gasoil (SRGO). All reactions were carried out at three different temperatures 613, 633, and 653 K. Alumina supports were analysed by pyridine FTIR-TPD and nitrogen physisorption in order to determine their surface acidity and textural properties, respectively. TPR studies of the NiMo catalysts were analysed to correlate their hydrogenating properties. Metallic particles were characterized (after sulfidation) using transmission electron microscopy (TEM). Catalytic activities are discussed in relation to the physicochemical properties of NiMo catalysts. The importance of textural properties on coke deposition has been emphasized. The results of catalytic activity of these materials varied depending on dispersed MoS particles and pore distribution in final catalysts. The optimum pore diameter was found around 80 A for HDS and HDN

  5. Study to improve the quality of a Mexican straight run gasoil over NiMo/γ-Al 2O 3 catalysts

    Science.gov (United States)

    Domínguez-Crespo, M. A.; Díaz-García, L.; Arce-Estrada, E. M.; Torres-Huerta, A. M.; Cortéz-De la Paz, M. T.

    2006-11-01

    Four NiMo catalyst supported on Al 2O 3 with different textural properties have been studied in the hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodearomatization (HDA) of a Mexican straight run gasoil (SRGO). All reactions were carried out at three different temperatures 613, 633, and 653 K. Alumina supports were analysed by pyridine FTIR-TPD and nitrogen physisorption in order to determine their surface acidity and textural properties, respectively. TPR studies of the NiMo catalysts were analysed to correlate their hydrogenating properties. Metallic particles were characterized (after sulfidation) using transmission electron microscopy (TEM). Catalytic activities are discussed in relation to the physicochemical properties of NiMo catalysts. The importance of textural properties on coke deposition has been emphasized. The results of catalytic activity of these materials varied depending on dispersed MoS particles and pore distribution in final catalysts. The optimum pore diameter was found around 80 Å for HDS and HDN.

  6. Influence of excess sodium ions on the specific surface area formation in a NiO-Al2O3 catalyst prepared by different methods

    Directory of Open Access Journals (Sweden)

    Lazić M.M.

    2008-01-01

    Full Text Available The influence of sodium ions on the specific surface area of a NiO-Al2O3 catalyst in dependence of nickel loading (5, 10, and 20 wt% Ni, temperature of heat treatment (400, 700 and 1100oC and the method of sample preparation was investigated. Low temperature nitrogen adsorption (LTNA, X-ray diffraction (XRD and scanning electron microscopy (SEM were applied for sample characterization. Dramatic differences in the specific surface area were registered between non-rinsed and rinsed Al2O3 and NiO-Al2O3 samples. The lagged sodium ions promote sintering of non-rinsed catalyst samples.

  7. Use of Ni-Zn ferrites doped with Cu as catalyst in the transesterification of soybean oil to methyl esters

    International Nuclear Information System (INIS)

    Dantas, Joelda; Santos, Jakeline Raiane D.; Cunha, Rodrigo Bruno L.; Costa, Ana Cristina F.M.; Kiminami, Ruth Herta G.A.

    2013-01-01

    The purpose of this work is to evaluate the performance of Ni 0.5 Zn 0.5 Fe 2 O 4 ferrite doped with 0.1 and 0.4 mol of Cu as a catalyst for the transesterification of soybean oil to biodiesel, using methanol. The samples were characterized by X-ray diffraction, nitrogen adsorption and scanning electron microscopy. The reaction was performed for 2 hours at a temperature of 160 °C, using 10 g of soybean oil, a molar ratio of oil: alcohol of 1:20, and 4% (w/w) of catalyst. The product of the reaction was characterized by gas chromatography, which confirmed conversion to methyl esters. The diffraction patterns showed the presence only of Ni 0.5 Zn 0.5 Fe 2 O 4 ferrite phase with a crystallite size of 29 nm. The samples doped with 0.1 and 0.4 mol of Cu showed a surface area and particle size of 22.17 m2 g -1 and 50.47 nm; and 23.49 m 2 g -1 and 47.64 nm, respectively. The morphology of both samples consisted of brittle block-shaped agglomerates with a wide particle size distribution. A comparative analysis of the two catalysts indicated that the catalyst doped with 0.4 mol of Cu showed the better performance, with a conversion rate of 50.25%, while the catalyst doped with 0.1 mol of Cu showed 42.71% conversion. (author)

  8. Use of Ni-Zn ferrites doped with Cu as catalyst in the transesterification of soybean oil to methyl esters

    Energy Technology Data Exchange (ETDEWEB)

    Dantas, Joelda; Santos, Jakeline Raiane D.; Cunha, Rodrigo Bruno L.; Costa, Ana Cristina F.M., E-mail: joeldadantas@yahoo.com.br [Universidade Federal de Campina Grande (LabSMaC/UFCG), PB (Brazil). Dept. de Engenharia de Materiais. Lab. de Sintese de Materiais Ceramicos; Kiminami, Ruth Herta G.A. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Dept. de Engenhria de Materiais

    2013-11-01

    The purpose of this work is to evaluate the performance of Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} ferrite doped with 0.1 and 0.4 mol of Cu as a catalyst for the transesterification of soybean oil to biodiesel, using methanol. The samples were characterized by X-ray diffraction, nitrogen adsorption and scanning electron microscopy. The reaction was performed for 2 hours at a temperature of 160 Degree-Sign C, using 10 g of soybean oil, a molar ratio of oil: alcohol of 1:20, and 4% (w/w) of catalyst. The product of the reaction was characterized by gas chromatography, which confirmed conversion to methyl esters. The diffraction patterns showed the presence only of Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} ferrite phase with a crystallite size of 29 nm. The samples doped with 0.1 and 0.4 mol of Cu showed a surface area and particle size of 22.17 {sup m2}g{sup -1} and 50.47 nm; and 23.49 m{sup 2}g{sup -1} and 47.64 nm, respectively. The morphology of both samples consisted of brittle block-shaped agglomerates with a wide particle size distribution. A comparative analysis of the two catalysts indicated that the catalyst doped with 0.4 mol of Cu showed the better performance, with a conversion rate of 50.25%, while the catalyst doped with 0.1 mol of Cu showed 42.71% conversion. (author)

  9. Use of Ni-Zn ferrites doped with Cu as catalyst in the transesterification of soybean oil to methyl esters

    Directory of Open Access Journals (Sweden)

    Joelda Dantas

    2013-06-01

    Full Text Available The purpose of this work is to evaluate the performance of Ni0.5Zn0.5Fe2O4 ferrite doped with 0.1 and 0.4 mol of Cu as a catalyst for the transesterification of soybean oil to biodiesel, using methanol. The samples were characterized by X-ray diffraction, nitrogen adsorption and scanning electron microscopy. The reaction was performed for 2 hours at a temperature of 160 °C, using 10 g of soybean oil, a molar ratio of oil: alcohol of 1:20, and 4% (w/w of catalyst. The product of the reaction was characterized by gas chromatography, which confirmed conversion to methyl esters. The diffraction patterns showed the presence only of Ni0.5Zn0.5Fe2O4 ferrite phase with a crystallite size of 29 nm. The samples doped with 0.1 and 0.4 mol of Cu showed a surface area and particle size of 22.17 m²g- 1 and 50.47 nm; and 23.49 m²g- 1 and 47.64 nm, respectively. The morphology of both samples consisted of brittle block-shaped agglomerates with a wide particle size distribution. A comparative analysis of the two catalysts indicated that the catalyst doped with 0.4 mol of Cu showed the better performance, with a conversion rate of 50.25%, while the catalyst doped with 0.1 mol of Cu showed 42.71% conversion.

  10. Effect of phosphorus addition on the hydrotreating activity of NiMo/Al{sub 2}O{sub 3} carbide catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Sundaramurthy, V.; Dalai, A.K. [Catalysis and Chemical Reaction Engineering Laboratories, Department of Chemical Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9 (Canada); Adjaye, J. [Syncrude Edmonton Research Centre, Edmonton, AB T6N 1H4 (Canada)

    2007-07-30

    A series of phosphorus promoted {gamma}-Al{sub 2}O{sub 3} supported NiMo carbide catalysts with 0-4.5 wt.% P, 13 wt.% Mo and 2.5 wt.% Ni were synthesized and characterized by elemental analysis, pulsed CO chemisorption, BET surface area measurement, X-ray diffraction, near-edge X-ray absorption fine structure, DRIFT spectroscopy of CO adsorption and H{sub 2} temperature programmed reduction. X-ray diffraction patterns and CO uptake showed the P addition to NiMo/{gamma}-Al{sub 2}O{sub 3} carbide, increased the dispersion of {beta}-Mo{sub 2}C particles. DRIFT spectra of adsorbed CO revealed that P addition to NiMo/{gamma}-Al{sub 2}O{sub 3} carbide catalyst not only increases the dispersion of Ni-Mo carbide phase, but also changes the nature of surface active sites. The hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) activities of these P promoted NiMo/{gamma}-Al{sub 2}O{sub 3} carbide catalysts were performed in trickle bed reactor using light gas oil (LGO) derived from Athabasca bitumen and model feed containing quinoline and dibenzothiophene at industrial conditions. The P added NiMo/{gamma}-Al{sub 2}O{sub 3} carbide catalysts showed enhanced HDN activity compared to the NiMo/{gamma}-Al{sub 2}O{sub 3} catalysts with both the feed stocks. The P had almost no influence on the HDS activity of NiMo/{gamma}-Al{sub 2}O{sub 3} carbide with LGO and dibenzothiophene. P addition to NiMo/{gamma}-Al{sub 2}O{sub 3} carbide accelerated C-N bond breaking and thus increased the HDN activity. (author)

  11. Room temperature hydrogen generation from hydrolysis of ammonia-borane over an efficient NiAgPd/C catalyst

    KAUST Repository

    Hu, Lei

    2014-12-01

    NiAgPd nanoparticles are successfully synthesized by in-situ reduction of Ni, Ag and Pd salts on the surface of carbon. Their catalytic activity was examined in ammonia borane (NH3BH3) hydrolysis to generate hydrogen gas. This nanomaterial exhibits a higher catalytic activity than those of monometallic and bimetallic counterparts and a stoichiometric amount of hydrogen was produced at a high generation rate. Hydrogen production rates were investigated in different concentrations of NH3BH3 solutions, including in the borates saturated solution, showing little influence of the concentrations on the reaction rates. The hydrogen production rate can reach 3.6-3.8 mol H2 molcat -1 min-1 at room temperature (21 °C). The activation energy and TOF value are 38.36 kJ/mol and 93.8 mol H2 molcat -1 min-1, respectively, comparable to those of Pt based catalysts. This nanomaterial catalyst also exhibits excellent chemical stability, and no significant morphology change was observed from TEM after the reaction. Using this catalyst for continuously hydrogen generation, the hydrogen production rate can be kept after generating 6.2 L hydrogen with over 10,000 turnovers and a TOF value of 90.3 mol H2 molcat -1 min-1.

  12. Hydrogenation of the Exocyclic Olefinic Bond at C-16/C-17 Position of ent-Kaurane Diterpene Glycosides of Stevia rebaudiana Using Various Catalysts

    Science.gov (United States)

    Chaturvedula, Venkata Sai Prakash; Prakash, Indra

    2013-01-01

    Catalytic hydrogenation of the exocyclic double bond present between C16 and C17 carbons of the four ent-kaurane diterpene glycosides namely rebaudioside A, rebaudioside B, rebaudioside C, and rebaudioside D isolated from Stevia rebaudiana has been carried out using Pt/C, Pd(OH)2, Rh/C, Raney Ni, PtO2, and 5% Pd/BaCO3 to their corresponding dihydro derivatives with 17α and 17β methyl group isomers. Reactions were performed using the above-mentioned catalysts with the solvents methanol, water, and ethanol/water (8:2) under various conditions. Synthesis of reduced steviol glycosides was performed using straightforward chemistry and their structures were characterized on the basis of 1D and 2D NMR spectral data, including a comparison with reported spectral data. PMID:23896597

  13. Hydrogenation of the Exocyclic Olefinic Bond at C-16/C-17 Position of ent-Kaurane Diterpene Glycosides of Stevia rebaudiana Using Various Catalysts

    Directory of Open Access Journals (Sweden)

    Indra Prakash

    2013-07-01

    Full Text Available Catalytic hydrogenation of the exocyclic double bond present between C16 and C17 carbons of the four ent-kaurane diterpene glycosides namely rebaudioside A, rebaudioside B, rebaudioside C, and rebaudioside D isolated from Stevia rebaudiana has been carried out using Pt/C, Pd(OH2, Rh/C, Raney Ni, PtO2, and 5% Pd/BaCO3 to their corresponding dihydro derivatives with 17α and 17β methyl group isomers. Reactions were performed using the above-mentioned catalysts with the solvents methanol, water, and ethanol/water (8:2 under various conditions. Synthesis of reduced steviol glycosides was performed using straightforward chemistry and their structures were characterized on the basis of 1D and 2D NMR spectral data, including a comparison with reported spectral data.

  14. Catalisadores Ni/Al2O3 promovidos com molibdênio para a reação de reforma a vapor de metano Mo-Ni/AL2O3 catalysts for the methane steam reforming reaction

    Directory of Open Access Journals (Sweden)

    Silvia Sálua Maluf

    2003-03-01

    Full Text Available Mo-promoted Ni/Al2O3 catalysts for the methane steam reforming reaction were studied in this work. The Ni/Al2O3 catalysts were prepared by precipitation and molibdenum was added by impregnation up to 2%wt. The solids were tested using a micro-reactor under two H2Ov/C conditions and were characterized by ICP-OES, XRD, N2 adsoption, H2 chemisorption and TPR. NiO and NiAl2O4 phases were observed and the metallic area decreased with the increase of the Mo content. From the catalytic tests high stability was verified for H2Ov/C=4.0. On the other hand, only the catalyst containing 0,05% Mo stayed stable during 30 hours of the test at H2Ov/C=2.0.

  15. Hydrotreating and hydrocracking of Athabasca bitumen derived heavy gas oils using NiMo catalyst supported on titania modified alumina

    Energy Technology Data Exchange (ETDEWEB)

    Ferdous, D.; Bakhshi, N.N.; Dalai, A.K.; Adjaye, J. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Chemical Engineering, Catalysis and Chemical Reaction Engineering Laboratories]|[Syncrude Canada Ltd., Edmonton, AB (Canada)

    2006-07-01

    Different NiMo catalysts supported on titania modified Al{sub 2}O{sub 3} were synthesized and characterized in an effort to study the hydrodenitrigenation (HDN) and hydrodesulfurization (HDS) of different gas oils derived from Athabasca bitumen. The Al{sub x}O{sub 3} supports were modified by incorporating up to 9 wt per cent titanium (Ti). All modified supports as well as fresh and spent catalysts were characterized by BET surface area, pore volume and pore diameter, XRD, TPR, TPD and SEM. A trickle-bed reactor using 3 different gas oils from the Athabasca bitumen was used to test the initial activity of these catalysts. The 3 oils were light gas oil (LGO), heavy gas oil (HGO) and blended gas oil having 50 per cent LGO and 50 per cent HGO. The study showed that nitrogen conversion increased for all the gas oils when Ti was incorporated into the alumina. With an increase in Ti concentrations from 0 to 6 wt per cent, nitrogen conversion increased from 57-69.5 wt per cent, 75-80.2 wt per cent, 83-91.5 wt per cent and for LGO, HGO and blended, respectively. Nearly 86 wt per cent sulphur conversion was obtained for all Ti concentrations for LGO, while HGO and blended sulphur conversions were in the range of 96-97 wt per cent. Detailed hydrotreating and hydrocracking of HGO was then performed using the 6 wt per cent Ti modified catalyst because it achieved the maximum nitrogen conversion. This paper also presented the temperature, pressure and liquid hourly space velocity for this catalyst along with the maximum nitrogen and sulphur conversions. Results were compared with those of commercial catalysts. tabs., figs.

  16. Design of heterogeneous catalysts

    DEFF Research Database (Denmark)

    Frey, Anne Mette

    was inspired by a computational screening, suggesting that alloys such as Ni-Fe, Co-Ni, and Co-Fe should show superior activity to the industrially used nickel catalyst. Especially the Ni-Fe system was considered to be interesting, since such alloy catalysts should be both more active and cheaper than the Ni...... catalyst. The results from the screening were experimentally verified for CO hydrogenation, CO2 hydrogenation, and simultaneous CO and CO2 hydrogenation by bimetallic Ni-Fe catalysts. These catalysts were found to be highly active and selective. The Co-Ni and Co-Fe systems were investigated for CO...... well, and the best catalyst prepared had a C5+ yield almost a factor of two higher than a standard air calcined Co catalyst. In the NH3-SCR reaction it is desirable to develop an active and stable catalyst for NOx removal in automotive applications, since the traditionally used vanadium-based catalyst...

  17. Probing the electronic structure of M-graphene oxide (M = Ni, Co, NiCo) catalysts for hydrolytic dehydrogenation of ammonia borane

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Binhua; Liu, Jinyin; Zhou, Litao [Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Material (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, Suzhou 215123 (China); Long, Dan, E-mail: legend_long@aliyun.com [Department of Radiology, Zhejiang Cancer Hospital, Hangzhou 310022 (China); Feng, Kun; Sun, Xuhui [Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Material (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, Suzhou 215123 (China); Zhong, Jun, E-mail: jzhong@suda.edu.cn [Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Material (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, Suzhou 215123 (China)

    2016-01-30

    Graphical abstract: An interaction between metal and graphene oxide was probed to enhance the hydrolysis efficiency of ammonia borane. - Highlights: • Various metal elements (M = Ni, Co, NiCo) were dispersed on graphene oxide (GO) for the hydrolysis of ammonia borane (AB). • The electronic structure of the hybrids has been probed by scanning transmission X-ray microscopy (STXM). • An interfacial interaction between metal and GO was observed which could be related to the hydrolysis performance. • The results provide new insight into the enhanced performance of the M-GO hybrids. - Abstract: Various metal elements (M = Ni, Co, NiCo) were dispersed on graphene oxide (GO) to form the M-GO hybrids by a facile way. The hybrids showed good catalytic activities in the hydrolytic dehydrogenation of ammonia borane (AB, NH{sub 3}BH{sub 3}), which were significantly enhanced when compared to the metal nanoparticles or GO alone. The electronic structure of the hybrids has been probed by scanning transmission X-ray microscopy (STXM). The distribution of metal elements was clearly imaged with identical electronic structure. Moreover, an interfacial interaction between metal and GO was observed with the peak intensity proportional to the catalytic performance in the hydrolysis of AB. The results provide new insight into the enhanced performance of the M-GO hybrids and may help for the design of advanced catalysts.

  18. Catalytic activity and effect of modifiers on Ni-based catalysts for the dry reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Barroso-Quiroga, Maria Martha; Castro-Luna, Adolfo Eduardo [Facultad de Ingenieria y Ciencias Economico-Sociales INTEQUI-CONICET-UNSL, Av. 25 de Mayo 384 (5730) Villa Mercedes (S.L.) (Argentina)

    2010-06-15

    Ni catalysts supported on different ceramic oxides (Al{sub 2}O{sub 3}, CeO{sub 2}, La{sub 2}O{sub 3}, ZrO{sub 2}) were prepared by wet impregnation. The catalytic behavior toward hydrogen production through the dry reforming of methane using a fixed-bed reactor was evaluated under certain experimental conditions, and the catalyst supported on ZrO{sub 2} showed the highest stable activity during the period of time studied. The catalyst supported on CeO{sub 2} has a relatively good activity, but shows signs of deactivation after a certain time during the reaction. This catalyst was chosen to be studied after the addition of 0.5 wt% Li and K as activity modifiers. The introduction of the alkaline metals produces a reduction of the catalytic activity but a better stability over the reactant conversion time. The reverse water-gas shift reaction influences the global system of reactions, and as the results indicate, should be considered near equilibrium. (author)

  19. HDO of guaiacol over NiMo catalyst supported on activated carbon derived from castor de-oiled cake

    Directory of Open Access Journals (Sweden)

    Viviana Ospina

    2015-05-01

    Full Text Available Physical and chemical activation methods were used to prepare two different activated carbons (ACs from castor de-oiled cake. H2O/CO2 mixture was used as the physical activating agent, and for chemical activation potassium carbonate (K2CO3 was used. For both materials, textural and chemical properties were characterized by N2 adsorption–desorption isotherms, thermogravimetric analysis (TGA, Fourier Transform Infrared Spectroscopy (FTIR, thermal programmed reduction (TPR, X-ray fluorescence (XRF, and scanning electron microscopy (SEM. The ACs were used as supports for NiMo sulfide catalysts, which were prepared by wetness impregnation and in-situ sulfided for the hydrodeoxygenation (HDO of guaiacol (GUA as a model compound of bio-oil. The HDO reaction was carried out in a typical batch reactor at 5 MPa of H2 and 350 °C. Under the same test conditions, commercial catalysts were also tested in the reaction. Although the commercial catalysts displayed higher GUA conversion, the prepared catalysts showed higher activity and non-oxygenated and saturated products yield.

  20. Catalytic Steam Reforming of Toluene as a Model Compound of Biomass Gasification Tar Using Ni-CeO2/SBA-15 Catalysts

    Directory of Open Access Journals (Sweden)

    Erik Dahlquist

    2013-07-01

    Full Text Available Nickel supported on SBA-15 doped with CeO2 catalysts (Ni-CeO2/SBA-15 was prepared, and used for steam reforming of toluene which was selected as a model compound of biomass gasification tar. A fixed-bed lab-scale set was designed and employed to evaluate the catalytic performances of the Ni-CeO2/SBA-15 catalysts. Experiments were performed to reveal the effects of several factors on the toluene conversion and product gas composition, including the reaction temperature, steam/carbon (S/C ratio, and CeO2 loading content. Moreover, the catalysts were subjected to analysis of their carbon contents after the steam reforming experiments, as well as to test the catalytic stability over a long experimental period. The results indicated that the Ni-CeO2/SBA-15 catalysts exhibited promising capabilities on the toluene conversion, anti-coke deposition and catalytic stability. The toluene conversion reached as high as 98.9% at steam reforming temperature of 850 °C and S/C ratio of 3 using the Ni-CeO2(3wt%/SBA-15 catalyst. Negligible coke formation was detected on the used catalyst. The gaseous products mainly consisted of H2 and CO, together with a little CO2 and CH4.

  1. Ni-Pd-Al2O3 catalyst supported on reticulated ceramic foam for dry methane reforming

    Directory of Open Access Journals (Sweden)

    Vesna Nikolić

    2015-03-01

    Full Text Available In the present study, Ni-Pd/Al2O3 catalyst supported on α-Al2O3 based foam was prepared and evaluated in the dry methane reforming process. Corresponding metal chlorides were deposited to the foam surface by impregnation of the foam with ultrasonically aerosolized salt solutions at 473 K and drying at that temperature. Calcination step was excluded and the catalyst was reduced at very low temperature – 533 K. The reforming experiment lasted for 3 h, with standing time of 1 h at the following temperatures: 873, 973 and 1023 K. Conclusions on selectivity, catalytic activity and stability were reached on the basis of CO and H2 yields.

  2. Gram-Scale Synthesis of Highly Active and Durable Octahedral PtNi Nanoparticle Catalysts for Proton Exchange Membrane Fuel Cell

    DEFF Research Database (Denmark)

    Choi, Juhyuk; Jang, Jue-Hyuk; Roh, Chi-Woo

    2018-01-01

    for the commercialization of PEMFCs. In this study, we focus on gram-scale synthesis of octahedral PtNi nanoparticles with Pt overlayers (PtNi@Pt) supported on the carbon, resulting in enhanced catalytic activity and durability. Such PtNi@Pt catalysts show high mass activity (1.24 A mgPt−1) at 0.9 V (vs RHE) for the ORR......Proton exchange membrane fuel cells (PEMFC) are regarded as a promising renewable energy source for a future hydrogen energy society. However, highly active and durable catalysts are required for the PEMFCs because of their intrinsic high overpotential at the cathode and operation under the acidic...... condition for oxygen reduction reaction (ORR). Since the discovery of the exceptionally high surface activity of Pt3Ni(111), the octahedral PtNi nanoparticles have been synthesized and tested. Nonetheless, their milligram-scale synthesis method and poor durability make them unsuitable...

  3. High efficient conversion of furfural to 2-methylfuran over Ni-Cu/Al2O3 catalyst with formic acid as a hydrogen donor

    DEFF Research Database (Denmark)

    Fu, Zhaolin; Wang, Ze; Lin, Weigang

    2017-01-01

    Conversion of furfural to 2-methylfuran over Cu/Al2O3, Ni/Al2O3 and Ni-Cu/Al2O3 catalysts were investigated with formic acid as a hydrogen donor. Ni/Al2O3 showed a high catalytic activity but a moderate selectivity to 2-methylfuran. Contrarily, Cu/Al2O3 showed a low catalytic activity but a high...... selectivity for carbonyl reduction. Over the bimetallic catalysts Ni-10%Cu/Al2O3, by increasing Ni content, more furfural was converted with the reduction of carbonyl primarily. The effect of reaction solvent and the fraction of formic acid were also studied. The result showed that isopropanol solvent could...

  4. Hydroconversion of Waste Cooking Oil into Green Biofuel over Hierarchical USY-Supported NiMo Catalyst: A Comparative Study of Desilication and Dealumination

    Directory of Open Access Journals (Sweden)

    Zongwei Zhang

    2017-09-01

    Full Text Available The hydroconversion of waste cooking oil into hydrocarbon fuel was investigated over the hierarchical USY zeolite-supported NiMo catalysts which were prepared by dealumination ((NH42SiF6/desilication (NaOH. The physical and acidity properties of the hierarchical catalysts were characterized by X-ray diffraction (XRD, the Brunauer-Emmett-Teller (BET infrared spectroscopy of adsorbed pyridine (Py-IR, ammonia temperature-programmed desorption (NH3-TPD, and H2 temperature-programmed reduction (H2-TPR. The Brønsted/Lewis (B/L acid distribution was little affected by dealumination and the acid density decreased significantly. However, the highly-desilicated catalysts decreased the B/L ratio obviously. Therefore, many more Mo species in the NiMoO4− and MoO3 phases were produced in the AHFS-treated catalysts, while more high-valence-state Mo species in the NiMoO4− phase were formed in the NaOH-treated catalysts. The AHFS-treated catalysts showed higher catalytic activity and better DCO2 selectivity and selective cracking for jet fuel. The 42.3% selectivity of jet fuel and 13.5% selectivity of jet-range aromatics was achieved over the 8 wt % (NH42SiF6-treated catalyst with 67% DCO2 selectivity.

  5. Co-catalytic effect of Ni in the methanol electro-oxidation on Pt-Ru/C catalyst for direct methanol fuel cell

    International Nuclear Information System (INIS)

    Wang, Z.B.; Yin, G.P.; Zhang, J.; Sun, Y.C.; Shi, P.F.

    2006-01-01

    This research is aimed to improve the utilization and activity of anodic catalysts, thus to lower the contents of noble metals loading in anodes for methanol electro-oxidation. The direct methanol fuel cell anodic catalysts, Pt-Ru-Ni/C and Pt-Ru/C, were prepared by chemical reduction method. Their performances were tested by using a glassy carbon working electrode through cyclic voltammetric curves, chronoamperometric curves and half-cell measurement in a solution of 0.5 mol/L CH 3 OH and 0.5 mol/L H 2 SO 4 . The composition of the Pt-Ru-Ni and Pt-Ru surface particles were determined by EDAX analysis. The particle size and lattice parameter of the catalysts were determined by means of X-ray diffraction (XRD). XRD analysis showed that both of the catalysts exhibited face-centered cubic structures and had smaller lattice parameters than Pt-alone catalyst. Their sizes are small, about 4.5 nm. No significant differences in the methanol electro-oxidation on both electrodes were found by using cyclic voltammetry, especially regarding the onset potential for methanol electro-oxidation. The electrochemically active-specific areas of the Pt-Ru-Ni/C and Pt-Ru/C catalysts are almost the same. But, the catalytic activity of the Pt-Ru-Ni/C catalyst is higher for methanol electro-oxidation than that of the Pt-Ru/C catalyst. Its tolerance performance to CO formed as one of the intermediates of methanol electro-oxidation is better than that of the Pt-Ru/C catalyst

  6. Concentration of ions Co(II), Ni(II) at the Tokem-250 carboxylic cation exchange for catalysts development

    Science.gov (United States)

    Zharkova, Valentina; Bobkova, Ludmila; Brichkov, Anton; Kozik, Vladimir

    2017-11-01

    Sorption and catalytic properties of the cation exchanger are investigated. It was found that the Tokem-250 has a wide operating range of pH. The value of the effective ionization constant of the functional groups of the cation exchanger (pKa) is 6.59. The Tokem-250 cation exchanger exhibits selectivity to Ni2+ ions to Co2+ (D˜103). This is probably due to the stability of ion-exchange complexes detected by the method of diffuse reflectance electron spectroscopy (ESDD). According to these data, for Co2+ ions, in contrast to Ni2+, tetragonal distortion of octahedral coordination is characteristic, which has a positive effect on the stability of complexes with Co2+. To obtain spherical catalysts on the basis of Tokem-250, cobalt-containing samples of cation exchanger were used. The developed spherical materials have catalytic activity in the reactions of deep and partial oxidation of n-heptane.

  7. Ni-M-O (M=Sn, Ti and W) catalysts prepared from dry mixing method for oxidative dehydrogenation of ethane

    KAUST Repository

    Zhu, Haibo; Rosenfeld, Devon C.; Harb, Moussab; Anjum, Dalaver H.; Hedhili, Mohamed N.; Ould-Chikh, Samy; Basset, Jean-Marie

    2016-01-01

    A new generation of Ni-Sn-O, Ni-Ti-O, and Ni-W-O catalysts has been prepared by a solid state grinding method. In each case the doping metal varied from 2.5% to 20%. These catalysts exhibited higher activity and selectivity for ethane oxidative dehydrogenation (ODH) than conventionally prepared mixed oxides. Detailed characterisation was achieved using XRD, N2 adsorption, H2-TPR, SEM, TEM, and HAADF-STEM in order to study the detailed atomic structure and textural properties of the synthesized catalysts. Two kinds of typical structures are found in these mixed oxides, which are (major) “NixMyO” (M = Sn, Ti or W) solid solution phases (NiO crystalline structure with doping atom incorporated in the lattice) and (minor) secondary phases (SnO2, TiO2 or WO3). The secondary phase exists as a thin layer around small “NixMyO” particles, lowering the aggregation of nanoparticles during the synthesis. DFT calculations on the formation energies of M-doped NiO structures (M = Sn, Ti, W) clearly confirm the thermodynamic feasibility of incorporating these doping metals into NiO struture. The incorporation of doping metals into the NiO lattice decreases the number of holes (h+) localized on lattice oxygen (O2- + h+ ➔ O●-), which is the main reason for the improved catalytic performance (O●- is known to favor complete ethane oxidation to CO2). The high efficiency of ethylene production achieved in these particularly prepared mixed oxide catalysts indicates that the solid grinding method could serve as a general and practical approach for the preparation of doped NiO based catalysts.

  8. Ni-M-O (M=Sn, Ti and W) catalysts prepared from dry mixing method for oxidative dehydrogenation of ethane

    KAUST Repository

    Zhu, Haibo

    2016-03-25

    A new generation of Ni-Sn-O, Ni-Ti-O, and Ni-W-O catalysts has been prepared by a solid state grinding method. In each case the doping metal varied from 2.5% to 20%. These catalysts exhibited higher activity and selectivity for ethane oxidative dehydrogenation (ODH) than conventionally prepared mixed oxides. Detailed characterisation was achieved using XRD, N2 adsorption, H2-TPR, SEM, TEM, and HAADF-STEM in order to study the detailed atomic structure and textural properties of the synthesized catalysts. Two kinds of typical structures are found in these mixed oxides, which are (major) “NixMyO” (M = Sn, Ti or W) solid solution phases (NiO crystalline structure with doping atom incorporated in the lattice) and (minor) secondary phases (SnO2, TiO2 or WO3). The secondary phase exists as a thin layer around small “NixMyO” particles, lowering the aggregation of nanoparticles during the synthesis. DFT calculations on the formation energies of M-doped NiO structures (M = Sn, Ti, W) clearly confirm the thermodynamic feasibility of incorporating these doping metals into NiO struture. The incorporation of doping metals into the NiO lattice decreases the number of holes (h+) localized on lattice oxygen (O2- + h+ ➔ O●-), which is the main reason for the improved catalytic performance (O●- is known to favor complete ethane oxidation to CO2). The high efficiency of ethylene production achieved in these particularly prepared mixed oxide catalysts indicates that the solid grinding method could serve as a general and practical approach for the preparation of doped NiO based catalysts.

  9. Synthesis and characterization of NiFe{sub 2}O{sub 4}–Pd magnetically recyclable catalyst for hydrogenation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Karaoğlu, E., E-mail: ekaraoglu@fatih.edu.tr [Department of Chemistry, Faculty of Arts and Sciences, Fatih University, 34500 B. Cekmece, Istanbul (Turkey); Özel, U.; Caner, C.; Baykal, A.; Summak, M.M. [Department of Chemistry, Faculty of Arts and Sciences, Fatih University, 34500 B. Cekmece, Istanbul (Turkey); Sözeri, H. [TUBITAK-UME, National Metrology Institute, PO Box 54, 41470 Gebze-Kocaeli (Turkey)

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► Novel superparamagnetic NiFe{sub 2}O{sub 4}–Pd magnetically recyclable catalyst was fabricated through co-precipitation. ► It could be reused several times without significant loss in catalytic activity for hydrogenation reaction. ► No further modification of the NiFe{sub 2}O{sub 4}–Pd magnetically recyclable catalyst is necessary for utilization as catalyst. -- Abstract: Herein we report the fabrication and characterization magnetically recyclable catalysts of NiFe{sub 2}O{sub 4}–Pd nanocomposite as highly effective catalysts for reduction reactions in liquid phase. The reduction Pd{sup 2+} was accomplished with polyethylene glycol 400 (PEG-400) instead of sodium borohydride (NaBH{sub 4}) and NiFe{sub 2}O{sub 4} nanoparticles was prepared by sonochemically using FeCI{sub 3}·6H{sub 2}O and NiCl{sub 2}. The chemical characterization of the product was done with X-ray diffractometry, Infrared spectroscopy, transmission electron microscopy, UV–Vis spectroscopy, thermal gravimetry and inductively coupled plasma. Thus formed NiFe{sub 2}O{sub 4}–Pd MRCs showed a very high activity in reduction reactions of 4-nitro aniline and 1,3-dinitrobenzene in liquid phase. It was found out that the catalytic activity of NiFe{sub 2}O{sub 4}–Pd MRCs on the reduction of 4-nitro aniline and 1,3-dinitrobenzene in liquid phase are between 99–93% and 98–93%, respectively. Magnetic character of this system allowed recovery and multiple use without significant loss of its catalytic activity. It is found that NiFe{sub 2}O{sub 4}–Pd MRCs showed very efficient catalytic activity and multiple usability.

  10. The Comparison of Co, Ni, Mo, CoMo and NiMo Sulfided Catalysts in Rapeseed Oil Hydrodeoxygenation.

    Czech Academy of Sciences Publication Activity Database

    Kaluža, Luděk; Kubička, D.

    2017-01-01

    Roč. 122, č. 1 (2017), s. 333-341 ISSN 1878-5190 R&D Projects: GA ČR(CZ) GA17-22490S Institutional support: RVO:67985858 Keywords : triolein hydrodeoxygenation scheme * rapeseed oil * sulfide catalysts Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.264, year: 2016

  11. Development of Non-Noble Metal Ni-Based Catalysts for Dehydrogenation of Methylcyclohexane

    KAUST Repository

    Shaikh Ali, Anaam

    2016-01-01

    to TOL has only been achieved using the noble Pt-based catalysts. The aim of this study is to develop non-noble, cost-effective metal catalysts that can show excellent catalytic performance, mainly maintaining high TOL selectivity achievable by Pt based

  12. Catalytic hydroprocessing of simulated coal tars. 2. Effect of acid catalysts on the hydroconversion of model compounds on a sulphided Ni-Mo/Al/sub 2/O/sub 3/ catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Lemberton, J.L.; Touzeyidio, M.; Guisnet, M. (Laboratoire de Catalyse en Chimie Organique CNRS, Poitiers (France))

    1989-09-15

    Acid catalysts were added to sulphided Ni-Mo/Al/sub 2/O/sub 3/ catalyst in order to obtain a higher hydrocracking activity. The hydroconversion of phenanthrene, alone or in the presence of carbazole and/or 1-naphthol, was chosen as a model reaction. The presence of acid catalysts greatly increases the conversion of phenanthrene and allows significant amounts of light products to be obtained. In the presence of carbazole or of 1-naphthol, acid catalysts create a small increase in phenanthrene conversion, but light products are no longer obtained as the acid sites are poisoned either by adsorption of ammonia from carbazole decomposition, or by extensive coke deposition generated from 1-naphthol. In the presence of carbazole and 1-naphthol, there is no longer any effect of the acid catalysts on the hydroconversion of phenanthrene, owing to complete inhibition of the acid sites. 12 refs., 5 tabs.

  13. Enhancement of Glycerol Steam Reforming Activity and Thermal Stability by Incorporating CeO2 and TiO2 in Ni- and Co-MCM-41 Catalysts

    Science.gov (United States)

    Dade, William N.

    Hydrogen (H2) has many applications in industry with current focus shifted to production of hydrocarbon fuels and valuable oxygenates using the Fischer-Tropsch technology and direct use in proton exchange membrane fuel cell (PEMFC). Hydrogen is generally produced via steam reforming of natural gas or alcohols like methanol and ethanol. Glycerol, a by-product of biodiesel production process, is currently considered to be one of the most attractive sources of sustainable H2 due to its high H/C ratio and bio-based origin. Ni and Co based catalysts have been reported to be active in glycerol steam reforming (GSR); however, deactivation of the catalysts by carbon deposition and sintering under GSR operating conditions is a major challenge. In this study, a series of catalysts containing Ni and Co nanoparticles incorporated in CeO2 and TiO2 modified high surface area MCM-41 have been synthesized using one-pot method. The catalysts are tested for GSR (at H2O/Glycerol mole ratio of 12 and GHSV of 2200 h-1) to study the effect of support modification and reaction temperature (450 - 700 °C) on the product selectivity and long term stability. GSR results revealed that all the catalysts performed significantly well exhibiting over 85% glycerol conversion at 650 °C except Ni catalysts that showed better low temperature activities. Deactivation studies of the catalysts conducted at 650 °C indicated that the Ni-TiO2-MCM-41 and Ni-CeO 2-MCM-41 were resistant to deactivation with ˜100% glycerol conversion for 40 h. In contrast, Co-TiO2-MCM-41 perform poorly as the catalyst rapidly deactivated after 12 h to yield ˜20% glycerol conversion after 40 h. The WAXRD and TGA-DSC analyses of spent catalysts showed a significant amount of coke deposition that might explain catalysts deactivation. The flattening shape of the original BET type IV isotherm with drastic reduction of catalyst surface area can also be responsible for observed drop in catalysts activities.

  14. Microstructural study of Ni/γ-Al2O3 catalyst: addition effects of CeO2 on carbon dioxide reforming of methane

    International Nuclear Information System (INIS)

    Valentini, Antoninho; Probst, Luiz Fernando Dias; Carreno, Neftali L. V.; Leite, Edson R.; Pontes, Fenelon M.; Longo, Elson; Schreiner, Wido H.; Lisboa-Filho, Paulo N.

    2003-01-01

    The carbon dioxide reforming of methane was carried out over nickel catalysts supported on the γ-Al 2 O 3 /CeO 2 system prepared by wet impregnation. With the increase of the Co2 weight in the catalyst, a higher stability was observed in the catalytic activity, together with an excellent resistance to carbon deposition and a better Ni dispersion. The catalysts were characterized by means of surface area measurements, TPR, H 2 chemisorption, XRD, SEM, EDX, XPS and TEM. An interaction between Ni and CeO 2 was observed to the Ni/CeO 2 sample after activation in a H 2 atmosphere above 300 deg C. Such behavior has a significantly influence on the catalytic activity. (author)

  15. Methane dry reforming over Ni catalysts supported on Ce–Zr oxides prepared by a route involving supercritical fluids

    Directory of Open Access Journals (Sweden)

    Smirnova Marina Yu.

    2017-12-01

    Full Text Available Ce0.5Zr0.5O2 mixed oxides were prepared in a flow reactor in supercritical isopropanol with acetylacetone as a complexing agent. Variation of the nature of the Zr salt and the temperature of synthesis affected the phase composition, morphology and specific surface area of oxides. X-ray diffraction and Raman spectroscopy studies revealed formation of metastable t” and t’ phases. Oxides are comprised of agglomerates with sizes depending on the synthesis parameters. Loading NiO decreases the specific surface area without affecting X-ray particle sizes of supports. Such sintering was the most pronounced for a support with the highest specific surface area, which resulted in the lowest surface content of Ni as estimated by X-ray photoelectron spectroscopy and in the formation of flattened NiO particles partially embedded into the support. The catalytic activity and stability of these samples in the dry reforming of methane were determined by the surface concentration of Ni and the morphology of its particle controlled by the metal-support interaction, which also depends on the type of catalyst pretreatment. Samples based on ceria-zirconia oxides prepared under these conditions provide a higher specific catalytic activity as compared with the traditional Pechini route, which makes them promising for the practical application.

  16. Development of Ni-Based Catalysts Derived from Hydrotalcite-Like Compounds Precursors for Synthesis Gas Production via Methane or Ethanol Reforming

    OpenAIRE

    Ya-Li Du; Xu Wu; Qiang Cheng; Yan-Li Huang; Wei Huang

    2017-01-01

    As a favorably clean fuel, syngas (synthesis gas) production has been the focus of concern in past decades. Substantial literatures reported the syngas production by various catalytic reforming reactions particularly in methane or ethanol reforming. Among the developed catalysts in these reforming processes, Ni-based catalysts from hydrotalcite-like compounds (HTLcs) precursors have drawn considerable attention for their preferable structural traits. This review covers the recent literature r...

  17. Development of low light-off catalyst; Teion kassei ni sugureta shokubai no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Takemoto, T; Ichikawa, S; Koda, Y; Yamamoto, E; Sumida, H; Yamada, H; Shigetsu, M; Komatsu, K [Mazda Motor Corp., Tokyo (Japan)

    1997-10-01

    A new type of three way catalyst was developed in order to reduce HC, CO and NOx in cold exhaust gas. This catalyst consists of double layer, and has a base support material of alumina and oxygen storage components (OSC) loaded with active metals including platinum. palladium and rhodium. It has good light-off performance and high catalytic activity. This catalyst includes two types of OSC. One is CeO2, and the other is CePrO2 that makes possible to improve NOx conversion at high exhaust gas temperature. 8 refs., 13 figs., 2 tabs.

  18. Development of Ni-Based Catalysts Derived from Hydrotalcite-Like Compounds Precursors for Synthesis Gas Production via Methane or Ethanol Reforming

    Directory of Open Access Journals (Sweden)

    Ya-Li Du

    2017-02-01

    Full Text Available As a favorably clean fuel, syngas (synthesis gas production has been the focus of concern in past decades. Substantial literatures reported the syngas production by various catalytic reforming reactions particularly in methane or ethanol reforming. Among the developed catalysts in these reforming processes, Ni-based catalysts from hydrotalcite-like compounds (HTLcs precursors have drawn considerable attention for their preferable structural traits. This review covers the recent literature reporting syngas production with Ni-based catalysts from HTLc precursors via methane or ethanol reforming. The discussion was initiated with catalyst preparation (including conventional and novel means, followed by subsequent thermal treatment processes, then composition design and the addition of promoters in these catalysts. As Ni-based catalysts have thermodynamic potential to deactivate because of carbon deposition or metal sintering, measures for dealing with these problems were finally summarized. To obtain optimal catalytic performances and resultantly better syngas production, based on analyzing the achievements of the references, some perspectives were finally proposed.

  19. Optimization of Charcoal Production Process from Woody Biomass Waste: Effect of Ni-Containing Catalysts on Pyrolysis Vapors

    Directory of Open Access Journals (Sweden)

    Jon Solar

    2018-05-01

    Full Text Available Woody biomass waste (Pinus radiata coming from forestry activities has been pyrolyzed with the aim of obtaining charcoal and, at the same time, a hydrogen-rich gas fraction. The pyrolysis has been carried out in a laboratory scale continuous screw reactor, where carbonization takes place, connected to a vapor treatment reactor, at which the carbonization vapors are thermo-catalytically treated. Different peak temperatures have been studied in the carbonization process (500–900 °C, while the presence of different Ni-containing catalysts in the vapor treatment has been analyzed. Low temperature pyrolysis produces high liquid and solid yields, however, increasing the temperature progressively up to 900 °C drastically increases gas yield. The amount of nickel affects the vapors treatment phase, enhancing even further the production of interesting products such as hydrogen and reducing the generated liquids to very low yields. The gases obtained at very high temperatures (700–900 °C in the presence of Ni-containing catalysts are rich in H2 and CO, which makes them valuable for energy production, as hydrogen source, producer gas or reducing agent.

  20. Extended X-ray absorption fine structure and X-ray diffraction studies on supported Ni catalysts

    International Nuclear Information System (INIS)

    Aldea, N.; Marginean, P.; Yaning, Xie; Tiandou, Hu; Tao, Liu; Wu, Zhongua; ZhenYa, Dai

    1999-01-01

    In the first part of this paper, we present a study based on EXAFS spectroscopy. This method can yield structural information about the local environment around a specific atomic constituent in the amorphous materials, the location and chemical state of any catalytic atom on any support or point defect structures, in alloys and composites. EXAFS is a specific technique of the scattering of X-ray on materials. The present study is aimed toward elucidation of the local structure of Ni atoms and their interaction with oxide support. The second goal of the paper consists in X-ray diffraction on the same samples. X-ray diffraction method that is capable to determine average particle size, microstrains, probability of faults as well as particle size distribution function of supported Ni catalysts is presented. The method is based on the Fourier analysis of a single X-Ray diffraction profile. The results obtained on supported nickel catalysts, which are used in H/D isotopic exchange reactions are reported. The global structure is obtained with a new fitting method based on the Generalised Fermi Function facilities for approximation and Fourier transform of the experimental X-Ray line profiles. Both types of measurements were performed on Beijing Synchrotron Radiation Facilities (BSRF). (authors)

  1. Electrode kinetics of ethanol oxidation on novel CuNi alloy supported catalysts synthesized from PTFE suspension

    Science.gov (United States)

    Sen Gupta, S.; Datta, J.

    An understanding of the kinetics and mechanism of the electrochemical oxidation of ethanol is of considerable interest for the optimization of the direct ethanol fuel cell. In this paper, the electro-oxidation of ethanol in sodium hydroxide solution has been studied over 70:30 CuNi alloy supported binary platinum electrocatalysts. These comprised mixed deposits of Pt with Ru or Mo. The electrodepositions were carried out under galvanostatic condition from a dilute suspension of polytetrafluoroethylene (PTFE) containing the respective metal salts. Characterization of the catalyst layers by scanning electron microscope (SEM)-energy dispersive X-ray (EDX) indicated that this preparation technique yields well-dispersed catalyst particles on the CuNi alloy substrate. Cyclic voltammetry, polarization study and electrochemical impedance spectroscopy were used to investigate the kinetics and mechanism of ethanol electro-oxidation over a range of NaOH and ethanol concentrations. The relevant parameters such as Tafel slope, charge transfer resistance and the reaction orders in respect of OH - ions and ethanol were determined.

  2. Syngas Production from Catalytic CO2 Reforming of CH4 over CaFe2O4 Supported Ni and Co Catalysts: Full Factorial Design Screening

    Directory of Open Access Journals (Sweden)

    M. Anwar Hossain

    2018-01-01

    Full Text Available In this study, the potential of dry reforming reaction over CaFe2O4 supported Ni and Co catalysts were investigated. The Co/CaFe2O4 and Ni/CaFe2O4 catalysts were synthesized using wet impregnation method by varying the metal loading from 5-15 %. The synthesized catalysts were tested in methane dry reforming reaction at atmospheric pressure and reaction temperature ranged 700-800 oC. The catalytic performance of the catalysts based on the initial screening is ranked as 5%Co/CaFe2O4 < 10%Co/CaFe2O4 < 5%Ni/CaFe2O4 < 10%Ni/CaFe2O4 according to their performance. The Ni/CaFe2O4 catalyst was selected for further investigation using full factorial design of experiment. The interaction effects of three factors namely metal loading (5-15 %, feed ratio (0.4-1.0, and reaction temperature (700-800 oC were evaluated on the catalytic activity in terms of CH4 and CO2 conversion as well as H2 and CO yield. The interaction between the factors showed significant effects on the catalyst performance at metal loading, feed ratio and reaction temperature of 15 %, 1.0, and 800 oC. respectively. The 15 wt% Ni/CaFe2O4 was subsequently characterized by Thermogravimetric (TGA, X-ray Diffraction (XRD, Field Emission Scanning Electron Microscopy (FESEM, Energy Dispersive X-ray Spectroscopy (EDX, X-ray Photoelectron Spectroscopy (XPS, N2-physisorption, Temperature Programmed Desorption (TPD-NH3, TPD-CO2, and Fourier Transform Infra Red (FTIR to ascertain its physiochemical properties.  This study demonstrated that the CaFe2O4 supported Ni catalyst has a good potential to be used for syngas production via methane dry reforming. Copyright © 2018 BCREC Group. All rights reserved Received: 5th May 2017; Revised: 8th August 2017; Accepted: 9th August 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018 How to Cite: Hossain, M.A., Ayodele, B.V., Cheng, C.K., Khan, M.R. (2018. Syngas Production from Catalytic CO2 Reforming of CH4 over CaFe2O4 Supported

  3. Low-Temperature Catalytic Performance of Ni-Cu/Al2O3 Catalysts for Gasoline Reforming to Produce Hydrogen Applied in Spark Ignition Engines

    Directory of Open Access Journals (Sweden)

    Le Anh Tuan

    2016-03-01

    Full Text Available The performance of Ni-Cu/Al2O3 catalysts for steam reforming (SR of gasoline to produce a hydrogen-rich gas mixture applied in a spark ignition (SI engine was investigated at relatively low temperature. The structural and morphological features and catalysis activity were observed by X-ray diffractometry (XRD, scanning electron microscopy (SEM, and temperature programmed reduction (TPR. The results showed that the addition of copper improved the dispersion of nickel and therefore facilitated the reduction of Ni at low temperature. The highest hydrogen selectivity of 70.6% is observed over the Ni-Cu/Al2O3 catalysts at a steam/carbon ratio of 0.9. With Cu promotion, a gasoline conversion of 42.6% can be achieved at 550 °C, while with both Mo and Ce promotion, the gasoline conversions were 31.7% and 28.3%, respectively, higher than with the conventional Ni catalyst. On the other hand, initial durability testing showed that the conversion of gasoline over Ni-Cu/Al2O3 catalysts slightly decreased after 30 h reaction time.

  4. Processing of spent NiMo and CoMo/Al2O3 catalysts via fusion with KHSO4

    International Nuclear Information System (INIS)

    Busnardo, Roberto Giovanini; Busnardo, Natalia Giovanini; Salvato, Gustavo Nascimento; Afonso, Julio Carlos

    2007-01-01

    This work describes a route for processing spent commercial hydrorefining (HDR) catalysts (CoMo and NiMo/Al 2 O 3 ), containing support additives, for recovering active phase and support components. Samples were used as catalysts in diesel hydrotreaters. They had neither been submitted to mechanical stresses nor overheating while under operation. The route is based on fusion of samples with KHSO 4 . Four experimental parameters were optimized: reaction time, sample/flux mass ratio, temperature, and sample physical characteristics (ground/non-ground). After fusion, the solid was dissolved in water (90-100 deg. C); the insoluble matter presented low crystallization. Several phases were identified: silicates, spinel-like compounds and aluminosilicates. Cobalt, nickel, molybdenum and aluminum were recovered by conventional precipitation techniques or selective solvent-extraction procedures, with at least 85 wt.% yield. Final liquid colorless effluents are obtained as neutral solutions of alkali sulfates or chlorides and a water insoluble solid after fusion, which can be either sent to industrial dumps or co-processed. Fusion with KHSO 4 was shown to be applicable to the catalysts of the present study, and the optimized experimental parameters are much less drastic than the conventional pyrometallurgical routes proposed in the literature

  5. Synergism between Ni and W in the NiW/gama-Al2O3 Hydrotreating Catalysts

    Czech Academy of Sciences Publication Activity Database

    Spojakina, A.A.; Palcheva, R.; Jirátová, Květa; Tyuliev, G.; Petrov, L.

    2005-01-01

    Roč. 104, 1-2 (2005), s. 45-52 ISSN 1011-372X Institutional research plan: CEZ:AV0Z40720504 Keywords : NiW/gama-Al2O3 * Thiophene hydrodesulfurization * TPR, XPS Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.088, year: 2005

  6. Characterization of catalysts Rh and Ni/CexZr1-xO2 for hydrogen production by ethanol steam reforming

    International Nuclear Information System (INIS)

    Birot, A.

    2005-01-01

    This work concerned a study on catalytic behaviour of metallic catalysts (Rh or Ni) supported on earth rare oxides Ce x Zr 1-x O 2 in ethanol steam reforming in order to produce hydrogen. Catalyst 1%Rh/Ce0,50Zr0,50O 2 showed a good activity with a good hydrogen yield. We turned a study onto understanding inter-conversion reaction between H 2 , CO and CO 2 which lead to CH 4 formation. We also studied intrinsic properties of catalysts. We confirmed basic character of catalysts and a good hydrogenation activity. A good activity in CO hydrogenation allowed to evidence a necessity to use a catalyst which is less active in hydrogenation reaction and with a basic character in order to improve hydrogen yield. (author)

  7. Characterization of the various catalyst for solvent hydrogenation at 1t/d PSU; 1t/d PSU ni okeru kakushu yozai suisoka shokubai no seino hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Kakebayashi, H.; Nogami, Y.; Inokuchi, K. [Mitsui SRC Development Co. Ltd., Tokyo (Japan); Aihara, Y.; Imada, K. [Nippon Steel Corp., Tokyo (Japan)

    1996-10-28

    Performance of various catalysts for hydrogenation of recycle solvent was evaluated for the operation of NEDOL process 1 t/d process supporting unit (PSU). Distillate between 220 and 538{degree}C derived from the liquefaction of Tanito Harum coal was used as recycle solvent. Deactivation behaviors of catalysts were compared using a prediction equation of catalyst life, by which aromatic carbon index (fa) after hydrogenation can be determined from the fa of recycle oil before hydrogenation, reaction temperature, and total hydrogenation time. Total hydrogenation time satisfying the {Delta}fa, 0.05 before and after hydrogenation were 8,000, 4,000, and 2,000 hours for NiMo-based catalysts C, A, and B, respectively. Catalyst C showed the longest life. Used catalysts were also characterized. The catalyst C showed larger mean pore size than those of the others, which resulted in the longer life due to the delay of pore blockage. From measurements by XPS and EPMA, relative atomic concentration of carbon increased remarkably after the use for all of catalysts, which was considered to be due to the adhesion of hydrocarbons. Increase of metal atoms, such as Fe and Cr, was also observed due to the contamination of entrainment residues. Deactivation of catalysts was caused by the adhesion of hydrocarbons, and metallic compounds, such as Fe and Cr. 3 refs., 1 fig., 5 tabs.

  8. A real support effect on the hydrodeoxygenation of methyl oleate by sulfided NiMo catalysts

    NARCIS (Netherlands)

    Coumans, A.E.; Hensen, E.J.M.

    2017-01-01

    The effect of the support on the catalytic performance of sulfided NiMo in the hydrodeoxygenation of methyl oleate as a model compound for triglyceride upgrading to green diesel was investigated. NiMo sulfides were prepared by impregnation and sulfidation on activated carbon, silica, γ-alumina and

  9. Green synthesis of Ni-Nb oxide catalysts for low-temperature oxidative dehydrogenation of ethane

    KAUST Repository

    Zhu, Haibo; Rosenfeld, Devon C.; Anjum, Dalaver H.; Caps, Valerie; Basset, Jean-Marie

    2015-01-01

    The straightforward solid-state grinding of a mixture of Ni nitrate and Nb oxalate crystals led to, after mild calcination (T<400°C), nanostructured Ni-Nb oxide composites. These new materials efficiently catalyzed the oxidative dehydrogenation (ODH

  10. Upgrading of the liquid fuel from fast pyrolysis of biomass over MoNi/{gamma}-Al{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ying; Liang, Wei [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, Guangdong (China); Graduate School of the Chinese Academy of Sciences, Beijing (China); Wang, Tiejun; Ma, Longlong; Zhang, Qi [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, Guangdong (China); Key Laboratory of Renewable Energy and Gas Hydrate, Chinese Academy of Sciences, Guangzhou, Guangdong (China)

    2010-09-15

    The hydrotreatment of bio-oil, which obtained from fast pyrolysis of pine sawdust, was investigated over MoNi/{gamma}-Al{sub 2}O{sub 3} catalyst under mild conditions (373 K, 3 MPa hydrogen pressure). Acetic acid was taken as a model compound to investigate the effects of Mo promoter contents and reducing temperatures of catalysts on the catalysts activity under the condition of 473 K and 3 MPa hydrogen pressure. X-ray diffraction and temperature programmed reduction showed that the addition of Mo promoter benefited the uniformity of nickel species and inhibited the formation of NiAl{sub 2}O{sub 4} spinel in the catalysts. The GC spectrum of liquid products showed the mechanism of the model reaction. The maximum conversion of acetic acid (33.20%) was attained over 0.06MoNi/{gamma}-Al{sub 2}O{sub 3} catalysts being reduced at 873 K. This catalyst was chosen for the upgrading of raw bio-oil. After the upgrading process, the pH value of the bio-oil increased from 2.33 to 2.77. The water content increased from 35.52 wt.% to 41.55 wt.% and the gross calorific value increased from 13.96 MJ/kg to 14.17 MJ/kg. The hydrogen content in the bio-oil increased from 6.25 wt.% to 6.95 wt.%. The product properties of the upgraded bio-oil, particularly the hydrogen content and the acidity were considerably improved. The results of gas chromatography-mass spectrometry analysis showed that both hydrotreatment and esterification had happened over 0.06MoNi/{gamma}-Al{sub 2}O{sub 3} (873) catalyst during the upgrading process. (author)

  11. Synergy in Lignin Upgrading by a Combination of Cu-Based Mixed Oxide and Ni-Phosphide Catalysts in Supercritical Ethanol.

    Science.gov (United States)

    Korányi, Tamás I; Huang, Xiaoming; Coumans, Alessandro E; Hensen, Emiel J M

    2017-04-03

    The depolymerization of lignin to bioaromatics usually requires a hydrodeoxygenation (HDO) step to lower the oxygen content. A mixed Cu-Mg-Al oxide (CuMgAlO x ) is an effective catalyst for the depolymerization of lignin in supercritical ethanol. We explored the use of Ni-based cocatalysts, i.e. Ni/SiO 2 , Ni 2 P/SiO 2 , and Ni/ASA (ASA = amorphous silica alumina), with the aim of combining lignin depolymerization and HDO in a single reaction step. While the silica-supported catalysts were themselves hardly active in lignin upgrading, Ni/ASA displayed comparable lignin monomer yield as CuMgAlO x . A drawback of using an acidic support is extensive dehydration of the ethanol solvent. Instead, combining CuMgAlO x with Ni/SiO 2 and especially Ni 2 P/SiO 2 proved to be effective in increasing the lignin monomer yield, while at the same time reducing the oxygen content of the products. With Ni 2 P/SiO 2 , the lignin monomer yield was 53 wt %, leading to nearly complete deoxygenation of the aromatic products.

  12. The effect of Sodium hydroxide catalyst in formation of Ni nanoparticles at room temperature

    International Nuclear Information System (INIS)

    Shahbahrami, N.; Reyhani, A.; Afshari, N.; Mortazavi, Z.; Norouzian, Sh.; Hojabri, A.; Novinrooz, A. J.

    2007-01-01

    In this paper, Ni nanoparticles growth is studies by spontaneous auto catalytic reduction in an alcohol- water solution in present NaOH catalysis with various ratio at room temperature. The scanning electron microscopy and XRD analyses have been used for investigation diameter and structure of Ni nanoparticles. Investigation of the analyses show that have not formed Ni Nanoparticles in Ph values 8, 9, 10 and 13, but in Ph values 11 and 12 have formed Ni Nanoparticles with average diameter of about 65 and 90 nm, respectively. The XRD patterns show that samples have face-centered cubic structure with (111),(200).(222) planes. The results show that sodium hydroxide value is very effect on the Ni nanoparticles growth.

  13. Synthesis and characterization of bimetallic Pd-Ni catalysts in a CeO_2 matrix for the generation of H_2 by the reforming reaction of methanol

    International Nuclear Information System (INIS)

    Contreras C, R.

    2016-01-01

    The hydrothermal method was used for the synthesis of CeO_2 nano rods using Ce(NO_3)_3·6H_2O and NH_4OH. The catalytic support was calcined at 700 degrees Celsius. The synthesis of CeO_2 nano rods were impregnated with an aqueous solution of Ni(NO_3)_2·6H_2O by an incipient wetness impregnation method at an appropriate concentration to yield 5 and 15% of Ni in the catalysts. Then 0.5% of Pd was impregnated using PdCl_2. The samples obtained were calcined at 400 and reduced at 450 degrees Celsius. The catalytic materials were characterized by: temperature programmed reduction (TPR), Scanning Electron Microscopy (Sem) , surface area and X-ray diffraction (XRD) . Sem results showed that the CeO_2 is formed by nano rods and in lesser proportion semi spherical particles. Bet surface area of the catalysts decreases with Ni loading onto the CeO_2 nano rods. Pd O and Ni O were reduced at low and high temperature as was observed by TPR. The CeO_2 one-dimensional nano rods showed a highly crystalline structure with sharp diffraction peaks, with a typical fluorite structure (cubic structure of the CeO_2) and characteristic peaks corresponding to metallic Ni. No diffraction peaks of Pd were found. This is due to the low concentration of this metal in the catalyst. These catalysts showed high activity and selectivity to H_2 at maximum reaction temperature. According to the results of activity and selectivity, the catalysts with Pd-Ni are an alternative for the H_2 production in auto thermal reforming reaction of methanol. (Author)

  14. Development of Cu and Ni catalysts supported on ZrO2 for the generation of H2 by means of the reaction of reformed methanol in atmosphere oxidizer

    International Nuclear Information System (INIS)

    Lopez C, P.

    2012-01-01

    ZrO 2 was prepared by the sol-gel method and calcined at 450 C. The prepared zirconia was impregnated with an aqueous solution of Cu(CH 3 CO 2 ) 2 ·H 2 O or NiNO 3 ·6H 2 O at an appropriate concentration to yield 3 wt % of copper or nickel, respectively, in the mono metallic catalysts. Three bimetallic samples were prepared at 80% Cu and 20% Ni respectively to obtain 3 wt % of total metallic phase. Surface area of the Cu-Ni base catalysts supported on ZrO 2 oxide showed differences as a function of the metal addition. Between them, the Cu/ZrO 2 catalyst had the lowest surface area than other catalysts. X-ray diffraction patterns of the bimetallic catalysts did not show diffraction peaks of the Cu, Ni or bimetallic Cu-Ni alloys. In addition, TPR profiles of the bimetallic catalysts had the lowest reduction temperature compared with the mono metallic samples. The reactivity of the catalysts in the range of 250-350 C showed that the samples prepared by successive impregnation had the highest catalytic activity than the other catalysts studied. Also the selectivity for H 2 production was higher for these catalysts. This finding was associated to the presence of the bimetallic Cu-Ni nanoparticles, as was evidenced by Tem-EDX analysis. (Author)

  15. Hydrodeoxygenation of lignin-derived phenolic compounds to hydrocarbons over Ni/SiO2-ZrO2 catalysts.

    Science.gov (United States)

    Zhang, Xinghua; Zhang, Qi; Wang, Tiejun; Ma, Longlong; Yu, Yuxiao; Chen, Lungang

    2013-04-01

    Inexpensive non-sulfided Ni-based catalysts were evaluated for hydrodeoxygenation (HDO) using guaiacol as model compound. SiO2-ZrO2 (SZ), a complex oxide synthesized by precipitation method with different ratio of Si/Zr, was impregnated with Ni(NO3)2·6H2O and calcined at 500°C. Conversion rates and product distribution for guaiacol HDO at 200-340°C were determined. Guaiacol conversion reached the maximum at 300°C in the presence of Ni/SZ-3. When HDO reaction was carried out with real lignin-derived phenolic compounds under the optimal conditions determined for guaiacol, the total yield of hydrocarbons was 62.81%. These hydrocarbons were comprised of cyclohexane, alkyl-substituted cyclohexane and alkyl-substituted benzene. They have high octane number, would be the most desirable components for fungible liquid transportation fuel. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Co, Fe and Ni catalysts supported on coke for direct coal liquefaction

    International Nuclear Information System (INIS)

    Jimenez, Jose A; Villalba, Oscar A; Rodriguez, Luis I; Hernandez, Orlando; Agamez, Yasmin Y; Dias Jose de Jesus

    2008-01-01

    Transition metal catalysts supported on coke were prepared by impregnation with a solution of complex of metal-thiourea, that is produced from salt precursors of cobalt chloride, Nickel chloride or iron sulfate and ammonium. sulphide formation on the support surface was generated by decomposition of the metal complex. The catalysts obtained were used in direct coal liquefaction of a medium volatile bituminous coal (Yerbabuena N 1) from Cundinamarca using a 250 Ml, Parr reactor at 723 K and a hydrogen-donor solvent. The catalytic results show, for all samples, both a good coal conversion and an enhancement of the yield of oils, this indicates that the proposed preparation method of catalyst is effective and that eventually the H 2 S sulphidation conventional process could be replaced

  17. Ni/SiO2 Catalyst Prepared with Nickel Nitrate Precursor for Combination of CO2 Reforming and Partial Oxidation of Methane: Characterization and Deactivation Mechanism Investigation

    Directory of Open Access Journals (Sweden)

    Sufang He

    2015-01-01

    Full Text Available The performance of Ni/SiO2 catalyst in the process of combination of CO2 reforming and partial oxidation of methane to produce syngas was studied. The Ni/SiO2 catalysts were prepared by using incipient wetness impregnation method with nickel nitrate as a precursor and characterized by FT-IR, TG-DTA, UV-Raman, XRD, TEM, and H2-TPR. The metal nickel particles with the average size of 37.5 nm were highly dispersed over the catalyst, while the interaction between nickel particles and SiO2 support is relatively weak. The weak NiO-SiO2 interaction disappeared after repeating oxidation-reduction-oxidation in the fluidized bed reactor at 700°C, which resulted in the sintering of metal nickel particles. As a result, a rapid deactivation of the Ni/SiO2 catalysts was observed in 2.5 h reaction on stream.

  18. Synergy in lignin upgrading by a combination of Cu-based mixed oxide and Ni-phosphide catalysts in supercritical ethanol

    NARCIS (Netherlands)

    Koranyi, T.I.; Huang, X.; Coumans, A.E.; Hensen, E.J.M.

    2017-01-01

    The depolymerization of lignin to bioaromatics usually requires a hydrodeoxygenation (HDO) step to lower the oxygen content. A mixed Cu–Mg–Al oxide (CuMgAlOx) is an effective catalyst for the depolymerization of lignin in supercritical ethanol. We explored the use of Ni-based cocatalysts, i.e.

  19. Influence of Ce-precursor and fuel on structure and catalytic activity of combustion synthesized Ni/CeO{sub 2} catalysts for biogas oxidative steam reforming

    Energy Technology Data Exchange (ETDEWEB)

    Vita, Antonio, E-mail: antonio.vita@itae.cnr.it; Italiano, Cristina; Fabiano, Concetto; Laganà, Massimo; Pino, Lidia

    2015-08-01

    A series of nanosized Ni/CeO{sub 2} catalysts were prepared by Solution Combustion Synthesis (SCS) varying the fuel (oxalyldihydrazide, urea, carbohydrazide and glycerol), the cerium precursor (cerium nitrate and cerium ammonium nitrate) and the nickel loading (ranging between 3.1 and 15.6 wt%). The obtained powders were characterized by X-ray Diffraction (XRD), N{sub 2}-physisorption, CO-chemisorption, Temperature Programmed Reduction (H{sub 2}-TPR) and Scanning Electron Microscopy (SEM). The catalytic activity towards the Oxy Steam Reforming (OSR) of biogas was assessed. The selected operating variables have a strong influence on the nature of combustion and, in turn, on the morphological and structural properties of the synthesized catalysts. Particularly, the use of urea allows to improve nickel dispersion, surface area, particle size and reducibility of the catalysts, affecting positively the biogas OSR performances. - Highlights: • Synthesis of Ni/CeO{sub 2} nanopowders by quick and easy solution combustion synthesis. • The fuel and precursor drive the structural and morphological properties of the catalysts. • The use of urea as fuel allows to improve nickel dispersion, surface area and particle size. • Ni/CeO{sub 2} (7.8 wt% of Ni loading) powders synthesized by urea route exhibits high performances for the biogas OSR process.

  20. Influence of Ce-precursor and fuel on structure and catalytic activity of combustion synthesized Ni/CeO2 catalysts for biogas oxidative steam reforming

    International Nuclear Information System (INIS)

    Vita, Antonio; Italiano, Cristina; Fabiano, Concetto; Laganà, Massimo; Pino, Lidia

    2015-01-01

    A series of nanosized Ni/CeO 2 catalysts were prepared by Solution Combustion Synthesis (SCS) varying the fuel (oxalyldihydrazide, urea, carbohydrazide and glycerol), the cerium precursor (cerium nitrate and cerium ammonium nitrate) and the nickel loading (ranging between 3.1 and 15.6 wt%). The obtained powders were characterized by X-ray Diffraction (XRD), N 2 -physisorption, CO-chemisorption, Temperature Programmed Reduction (H 2 -TPR) and Scanning Electron Microscopy (SEM). The catalytic activity towards the Oxy Steam Reforming (OSR) of biogas was assessed. The selected operating variables have a strong influence on the nature of combustion and, in turn, on the morphological and structural properties of the synthesized catalysts. Particularly, the use of urea allows to improve nickel dispersion, surface area, particle size and reducibility of the catalysts, affecting positively the biogas OSR performances. - Highlights: • Synthesis of Ni/CeO 2 nanopowders by quick and easy solution combustion synthesis. • The fuel and precursor drive the structural and morphological properties of the catalysts. • The use of urea as fuel allows to improve nickel dispersion, surface area and particle size. • Ni/CeO 2 (7.8 wt% of Ni loading) powders synthesized by urea route exhibits high performances for the biogas OSR process

  1. Effect of radiation-thermal treatment on the physicochemical properties of the Ni-Mo/Al2O3 hydrotreatment catalyst

    International Nuclear Information System (INIS)

    Solovetskij, Yu.I.; Lunin, V.V.; Miroshnichenko, I.I.

    1993-01-01

    A study was made on reasons of radiation-thermal damage by 2.0 MeV accelerated electron beams of surface and active metal phases of Al, Ni, Mo base hydrodesulfurization catalysts. Data of diffusion reflection electron spectra for coked industrial and model systems after radiation-thermal treatment are presented. 14 refs., 2 figs

  2. Effect of ceria and zirconia promotors on Ni/SBA-15 catalysts for coking and sintering resistant steam reforming of propylene glycol in microreactors

    NARCIS (Netherlands)

    Shanmugam, V.; Zapf, R.; Neuberg, S.; Hessel, V.; Kolb, G.

    2017-01-01

    Highly dispersed and size controlled Ni nanoparticles in CeO2, ZrO2 and CeO2-ZrO2 promoted mesoporous SBA-15 silica were achieved with the aid of treatment by ultrasound. The catalysts were characterized systematically to investigate their morphological structure and surface properties. It was found

  3. Synthesis, characterization and performance of NiMo catalysts supported on titania modified alumina for the hydroprocessing of different gas oils derived from Athabasca bitumen

    Energy Technology Data Exchange (ETDEWEB)

    Ferdous, D.; Bakhshi, N.N.; Dalai, A.K. [Catalysis and Chemical Reactor Engineering Laboratories, Department of Chemical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, Sask. (Canada); Adjaye, J. [Syncrude Canada Ltd., Edmonton Research Center, No. 9421, 17th Avenue, Edmonton, Alta. (Canada)

    2007-03-08

    In this work, a series of NiMo/Al{sub 2}O{sub 3} catalyst was prepared using different Al{sub 2}O{sub 3} supports modified by titania (0-9 wt%). All modified supports and fresh catalysts were characterized by BET surface area, pore volume and pore diameter measurement, TPR, TPD, XRD, FTIR and Raman spectroscopy analyses. The initial activity of these catalysts were tested in a trickle-bed reactor using three different gas oils such as light gas oil (LGO), blended gas oil (blended: 50% LGO and 50% HGO) and heavy gas oil (HGO), all derived from Athabasca bitumen. Little structural change in alumina was observed with the incorporation of titania. XRD analysis showed the well dispersion of Ni and Mo on the support. Titania in alumina increased the formation of polymolybdenum oxide on the catalyst as evident from TPR and Raman analyses. Weak-intermediate-strong acid sites on the catalyst were observed at all titania concentrations. The Lewis and Bronsted acidity on the catalyst surface increased with the increase in titania concentration from 0 to 9 wt%. Nitrogen conversion increased from 57 to 71 wt%, from 83 to 93 wt% and from 75 to 80 wt% for LGO, blended and HGO, respectively and also sulfur conversion of LGO increased from 86 to 92 wt% when titania concentration was increased from 0 to 9 wt%. For blended and HGO, sulfur conversion was in the range 96-99 wt% at all titania concentrations. (author)

  4. Catalytic technology in the energy/environment field. Utilization of catalyst in coal pyrolysis and gasification processes; Energy kankyo bun`ya ni okeru shokubai gijutsu. Sekitan no netsubunkai oyobi gas ka ni okeru shokubai no riyo

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Y. [Tohoku University, Institute for Chemical Reaction Science (Japan)

    1998-05-20

    This review article focuses on the utilization of several catalysts during coal pyrolysis and gasification. In situ or off line catalytic upgrading of volatile matters during pyrolysis of low rank coals is carried out in pressurized H2 with different reactors to produce BTX (benzene, toluene and xylene). When NiSO4 and Ni(OH)2 are used in the hydropyrolysis of Australian brown coal using an entrained bed reactor with two separated reaction zones, BTX yield reaches 18-23%. MS-13X zeolite and USY zeolite mixed with Al2O3 are effective for producing BTX with powder-particle fluidized bed and two-stage reactors, respectively. Catalytic gasification is described from a standpoint of direct production of SNG(CH4) from coal and steam. When K2CO3 and Ni are compared for this purpose, Ni catalyst is more suitable at low temperatures of 500-600degC, where CH4 formation is thermodynamically favorable. Fe and Ca catalysts can successfully be prepared from inexpensive raw materials and are rather active for steam gasification at {>=}700degC. The use of upgrading and gasification catalysts is discussed in terms of preparation, performance, life and recovery. 27 refs., 6 figs., 2 tabs.

  5. Hydroconversion of methyl laurate on bifunctional Ni{sub 2}P/AlMCM-41 catalyst prepared via in situ phosphorization using triphenylphosphine

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Sha; Zhang, Zhena [Tianjin Key Laboratory of Applied Catalysis Science and Technology, Department of Catalysis Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Zhu, Kongying, E-mail: ausky@tju.edu.cn [Analysis and Measurement Center, Tianjin University, Tianjin 300072 (China); Chen, Jixiang, E-mail: jxchen@tju.edu.cn [Tianjin Key Laboratory of Applied Catalysis Science and Technology, Department of Catalysis Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

    2017-05-15

    Highlights: • Bifunctional Ni{sub 2}P/AlMCM-41 was prepared by in situ phosphorization at 300 °C. • There were similar Ni{sub 2}P particle sizes in Ni{sub 2}P/AlMCM-41 with different Si/Al ratios. • The acid amount of Ni{sub 2}P/AlMCM-41 increased with decreasing the Si/Al ratio. • Ni{sub 2}P/AlMCM-41 with the Si/Al ratio of 5 had the highest activity for isomerization. • Ni{sub 2}P/AlMCM-41 had very low activity for methanation and C−C bond hydrogenolysis. - Abstract: A series of Ni{sub 2}P/AlMCM-41-x bifunctional catalysts with different Si/Al ratios (x) were synthesized by in situ phosphorization of Ni/AlMCM-41-x with triphenylphosphine (nominal Ni/P ratio of 0.75) at 300 °C on a fixed-bed reactor. For comparison, NiP/AlMCM-41-5-TPR was also prepared by the TPR method from the supported nickel phosphate with the Ni/P ratio of 1.0, during which metallic Ni rather than Ni{sub 2}P formed. TEM images show that Ni and Ni{sub 2}P particles uniformly distributed in Ni{sub 2}P/AlMCM-41-x and NiP/AlMCM-41-5-TPR. The Ni{sub 2}P/AlMCM-41-x acidity increased with decreasing the Si/Al ratio. In the hydroconversion of methyl laurate, the conversions were close to 100% on all catalysts at 360 °C, 3.0 MPa, methyl laurate WHSV of 2 h{sup −1} and H{sub 2}/methyl laurate ratio of 25. As to Ni{sub 2}P/AlMCM-41-x, with decreasing the Si/Al ratio, the total selectivity to C11 and C12 hydrocarbons decreased, while the total selectivity to isoundecane and isododecane (S{sub i-C11+i-C12}) firstly increased and then decreased. Ni{sub 2}P/AlMCM-41-5 gave the largest S{sub i-C11+i-C12} of 43.2%. While NiP/AlMCM-41-5-TPR gave higher S{sub i-C11+i-C12} than Ni{sub 2}P/AlMCM-41-5, it was more active for the undesired C−C bond cleavage and methanation. We propose that the in-situ phosphorization adopted here is a promising approach to preparing Ni{sub 2}P-based bifunctional catalysts.

  6. Hierarchical hybrid of Ni{sub 3}N/N-doped reduced graphene oxide nanocomposite as a noble metal free catalyst for oxygen reduction reaction

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Qi; Li, Yingjun; Li, Yetong [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Huang, Keke [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China); Wang, Qin, E-mail: qinwang@imu.edu.cn [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Inner Mongolia Key Lab. of Nanoscience and Nanotechnology, Inner Mongolia University, Hohhot 010021 (China); Zhang, Jun, E-mail: cejzhang@imu.edu.cn [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Inner Mongolia Key Lab. of Nanoscience and Nanotechnology, Inner Mongolia University, Hohhot 010021 (China)

    2017-04-01

    Highlights: • Hybrid of Ni{sub 3}N/N-RGO catalysts are synthesized by using a two-step method. • The catalysts manifest superior catalytic activity towards the ORR. • High activities are attributed to enhanced electron density and synergistic effects. - Abstract: Novel nickel nitride (Ni{sub 3}N) nanoparticles supported on nitrogen-doped reduced graphene oxide nanosheets (N-RGOs) are synthesized via a facile strategy including hydrothermal and subsequent calcination methods, in which the reduced graphene oxide nanosheets (RGOs) are simultaneously doped with nitrogen species. By varying the content of the RGOs, a series of Ni{sub 3}N/N-RGO nanocomposites are obtained. The Ni{sub 3}N/N-RGO-30% hybrid nanocomposite exhibits superior catalytic activity towards oxygen reduction reaction (ORR) under alkaline condition (0.1 M KOH). Furthermore, this hybrid catalyst also demonstrates high tolerance to methanol poisoning. The RGO containing rich N confers the nanocomposite with large specific surface area and high electronic conduction ability, which can enhance the catalytic efficiency of Ni{sub 3}N nanoparticles. The enhanced catalytic activity can be attributed to the synergistic effect between Ni{sub 3}N and nitrogen doped reduced graphene oxide. In addition, the sufficient contact between Ni{sub 3}N nanoparticles and the N-RGO nanosheets simultaneously promotes good nanoparticle dispersion and provides a consecutive activity sites to accelerate electron transport continuously, which further enhance the ORR performance. The Ni{sub 3}N/N-RGO may be further an ideal candidate as efficient and inexpensive noble metal-free ORR electrocatalyst in fuel cells.

  7. Deoxygenation of palm kernel oil to jet fuel-like hydrocarbons using Ni-MoS_2/γ-Al_2O_3 catalysts

    International Nuclear Information System (INIS)

    Itthibenchapong, Vorranutch; Srifa, Atthapon; Kaewmeesri, Rungnapa; Kidkhunthod, Pinit; Faungnawakij, Kajornsak

    2017-01-01

    Highlights: • The Ni-MoS_2/γ-Al_2O_3 catalysts synthesized using thiourea solution processing. • The Ni-MoS_2 showed semi-amorphous crystallinity with crystallite size of 5–10 nm. • The Ni K-edge XANES and EXAFS indicated the Ni substitution in MoS_2 structure. • A high yield of jet fuel-like hydrocarbon (>90%) from the palm kernel oil feedstock. • The HDO pathway was highly selective, while the DCO_2 and DCO pathways were minor. - Abstract: In the current study, palm kernel oil was used as a renewable feedstock for production of jet fuel-like hydrocarbons via the deoxygenation over the Ni-MoS_2/γ-Al_2O_3 catalyst. The dominant C12 fatty acid content in palm kernel oil makes it promising for jet fuel application. Synthesized by a liquid processing method with thiourea organosulfur agent, the catalyst revealed MoS_2 structure with low stacking, while Ni substitution in the MoS_2 structure and interaction with the Al_2O_3 support were determined based on the Ni K-edge XANES and EXAFS results. A high hydrodeoxygenation (HDO) activity, which as the major pathway in the deoxygenation, was observed upon application of a H_2 pressure of 30–50 bar over Ni-MoS_2/γ-Al_2O_3. The optimum product yield of approximately 92% was obtained mainly from the HDO pathway (∼60%) with 58% selectivity to C10–C12 jet fuel hydrocarbons. The flow property of the jet fuel-like hydrocarbons was more desirable than those obtained from palm olein oil-derived fuel.

  8. Synthesis and characterization of Pt-Sn-Ni alloys to application as catalysts for direct ethanol fuel cells; Sintese e caracterizacao de ligas de Pt-Sn-Ni para aplicacao como caztalisadores em celulas a combustivel do tipo DEFC

    Energy Technology Data Exchange (ETDEWEB)

    Silva, E.L. da; Correa, P.S.; Oliveira, E.L. de; Takimi, A.S.; Malfatti, C.F., E-mail: celia.malfatti@ufrgs.b [Universidade Federal do Rio Grande do Sul (LAPEC/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica. Lab. de Pesquisa em Corrosao; Radtke, C. [Universidade Federal do Rio Grande do Sul (IQ/UFRGS), Porto Alegre, RS (Brazil). Inst. de Quimica

    2010-07-01

    Direct ethanol fuel cells (DEFCs) have been the focus of recent research due its application in mobile energy sources. In order to obtain the maximum efficiency from these systems, it is necessary the total ethanol oxidation, which implies in C-C bond break. Different catalysts described in literature are employed with this intent. This work consists in studying PtSnNi catalysts supported on carbon Vulcan XC72R, to application in DEFCs. Thus, it was used the impregnation/reduction method, varying the atomic proportion among Pt, Sn and Ni. The alloys were characterized by X-Ray Diffraction, Cyclic Voltammetry and Transmission Microscopy. Preliminary results show that predominant structure on the catalysts is the face centered cubic platinum and the densities currents are dependent on the platinum amount. (author)

  9. Synthesis of renewable diesel through hydrodeoxygenation reaction from nyamplung oil (Calophyllum Inophyllum oil) using NiMo/Z and NiMo/C catalysts with rapid heating and cooling method

    Science.gov (United States)

    Susanto, B. H.; Prakasa, M. B.; Shahab, M. H.

    2016-11-01

    The synthesis of metal nanocrystal was conducted by modification preparation from simple heating method which heating and cooling process run rapidly. The result of NiMo/Z 575 °C characterizations are 33.73 m2/gram surface area and 31.80 nm crystal size. By used NiMo/C 700 °C catalyst for 30 minutes which had surface area of 263.21 m2/gram, had 31.77 nm crystal size, and good morphology, obtained catalyst with high activity, selectivity, and stability. After catalyst activated, synthesis of renewable diesel performed in hydrogenation reactor at 375 °C, 12 bar, and 800 rpm. The result of conversion was 81.99%, yield was 68.08%, and selectivity was 84.54%.

  10. Jet-Fuel Range Hydrocarbons from Biomass-Derived Sorbitol over Ni-HZSM-5/SBA-15 Catalyst

    Directory of Open Access Journals (Sweden)

    Yujing Weng

    2015-12-01

    Full Text Available Aromatics and cyclic-hydrocarbons are the significant components of jet fuel with high energy-density. However, conventional technologies for bio-fuel production cannot produce these products without further aromatization and isomerization. In this work, renewable liquid fuel with high content of aromatics and cyclic-hydrocarbons was obtained through aqueous catalytic conversion of biomass sorbitol over Ni-HZSM-5/SBA-15 catalyst. Texture characteristics of the catalyst were determined by physisorption of N2, which indicated its bimodal pore structures were microporous (HZSM-5, pore width: 0.56 nm and mesoporous (SBA-15, pore width: 8 nm. The surface acidity included weak and strong acid sites, predominantly Lewis type, and was further confirmed by the NH3-TPD and Py-IR analysis. The catalytic performances were tested in a fixed-bed reactor under the conditions of 593 K, WHSV of 0.75 h−1, GHSV of 2500 h−1 and 4.0 MPa of hydrogen pressure, whereby oil yield of 40.4 wt. % with aromatics and cyclic-hydrocarbons content of 80.0% was obtained.

  11. Iron alloy Fischer-tropsch catalysts--1. Oxidation-reduction studies of the Fe-Ni system

    Energy Technology Data Exchange (ETDEWEB)

    Unmuth, E.E.; Schwartz, L.H.; Butt, J.B.

    1980-01-01

    Catalysts containing 5% iron, nickel, or 4:1 iron-nickel on silica were hydrogen-reduced at 425/sup 0/C for 12 or 24 hr, reoxidized in air for 2 or 4 hr, reduced again in hydrogen for 12 hr, and studied at each treatment step by Moessbauer spectroscopy, X-ray diffraction, and temperature-programed desorption. The nickel was reduced directly to the metal, redispersed during the oxidation, and gave 20% smaller particles in the second reduction than in the first reduction. The ..cap alpha..-Fe/sub 2/O/sub 3/ reduced via an Fe/sub 3/O/sub 4/ intermediate and yielded approx. 70% metallic iron and the second reduction produced about the same particle size as the first reduction. The alloy catalyst reduced into a mixture of two phases, a face-centered cubic phase containing approx. 37.5% Ni, i.e., the bulk equilibrium value, and a body-centered cubic phase, and the particle sizes obtained in the first and second reductions were similar. The activation energies for the reduction were determined.

  12. Thermal conductivity of partially graphitized biocarbon obtained by carbonization of medium-density fiberboard in the presence of a Ni-based catalyst

    Science.gov (United States)

    Orlova, T. S.; Parfen'eva, L. S.; Smirnov, B. I.; Gutierrez-Pardo, A.; Ramirez-Rico, J.

    2016-01-01

    The thermal conductivity k and resistivity ρ of biocarbon matrices, prepared by carbonizing medium-density fiberboard at T carb = 850 and 1500°C in the presence of a Ni-based catalyst (samples MDF-C( Ni)) and without a catalyst (samples MDF-C), have been measured for the first time in the temperature range of 5-300 K. X-ray diffraction analysis has revealed that the bulk graphite phase arises only at T carb = 1500°C. It has been shown that the temperature dependences of the thermal conductivity of samples MDFC- 850 and MDF-C-850(Ni) in the range of 80-300 K are to each other and follow the law of k( T) ˜ T 1.65, but the use of the Ni-catalyst leads to an increase in the thermal conductivity by a factor of approximately 1.5, due to the formation of a greater fraction of the nanocrystalline phase in the presence of the Ni-catalyst at T carb = 850°C. In biocarbon MDF-C-1500 prepared without a catalyst, the dependence is k( T) ˜ T 1.65, and it is controlled by the nanocrystalline phase. In MDF-C-1500(Ni), the bulk graphite phase formed increases the thermal conductivity by a factor of 1.5-2 compared to the thermal conductivity of MDF-C-1500 in the entire temperature range of 5-300 K; k( T = 300 K) reaches the values of ˜10 W m-1 K-1, characteristic of biocarbon obtained without a catalyst only at high temperatures of T carb = 2400°C. It has been shown that MDF-C-1500(Ni) in the temperature range of 40‒300 K is characterized by the dependence, k( T) ˜ T 1.3, which can be described in terms of the model of partially graphitized biocarbon as a composite of an amorphous matrix with spherical inclusions of the graphite phase.

  13. Electrodeposition and Characterization of Nanocrystalline Ni-Mo Catalysts for Hydrogen Production

    OpenAIRE

    Halim, J.; Abdel-Karim, R.; El-Raghy, S.; Nabil, M.; Waheed, A.

    2012-01-01

    Ni-Mo nanocrystalline deposits (7–43 nm) with a nodular morphology were prepared by electrodeposition using direct current from citrate-ammonia solutions. They exhibited a single Ni-Mo solid solution phase. The size of the nodules increased as electroplating current density increased. The molybdenum content—estimated using EDX analysis—in the deposits decreased from about 31 to 11 wt% as the current density increased from 5 to 80 mA·cm−2. The highest microhardness value (285 Hv) corresponded ...

  14. Catalytic decomposition of trichloroethylene over Pt-/Ni-catalyst under microwave heating

    Energy Technology Data Exchange (ETDEWEB)

    Takashima, Hideaki; Karches, Martin [Chemiace Laboratory, 36-13 Hon-cho, Hachioji 192-0066 (Japan); Kanno, Yoshinori [Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4-3-11 Takeda, Kofu 400-8511 (Japan)], E-mail: kanno@yamanashi.ac.jp

    2008-01-30

    Microwave (MW)-activated catalytic reactor system was studied and the results were compared with that of a conventional system based on the thermal activation method. Trichloroethylene (TCE) was decomposed under various MW-powers supply. Results showed that there is an optimum film thickness that was loaded on supports in MW heating system. The threshold may be within 1-3 {mu}m. Lower temperature cannot activate the catalyst, while higher temperature results in carbon deposition and catalyst deactivation. This means that the dechlorination reaction needs to fix an optimum film MW-power supply in order to avoid the deposition of carbon on the surface of the active phase. MW-activated system is also worth compensating the conventional system in VOCs decomposition reaction.

  15. Oxidative regeneration of Ni-Mo-gamma-Al/sub 2/O/sub 3/ catalysts used for hydrotreatment of coal-derived oil

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Yuji; Furimsky, Edward; Sato, Toshio; Shimada, Hiromichi; Matsubayashi, Nobuyuki; Nishijima, Akio

    1986-10-23

    In order to easily find the oxidative reaction characteristics of carbonaceous materials and sulfur deposited on the catalysts used for hydrogenation, oxidative regeneration behavior as studied with a fixed bed reactor, and the surfaces of the spent catalysts were analyzed by XPS to find the changes in form of active metals and sulfur on the catalysts. Ni-Mo-gamma-Al/sub 2/O/sub 3/ catalysts were used for hydrotreatment of primary coal-derived oil from Morwell coal. The spent catalysts were extracted by THF, dried and crushed into 100-200 mesh powder. The relation between catalyst regeneration temperature and CO/sub 2/ or SO/sub 2/, the relation between generated gas compositions and temperature in regeneration, and the activation energy of carbon and sulfur in the catalysts for oxidative reaction were indicated with data. As a result, it was found that a part of the active metals turned to sulfates by hydrotreatment and the residual sulfur existed in form of sulfate. ( 6 figs, 2 tabs, 4 refs )

  16. Performance of a palladium membrane reactor using a Ni catalyst for fusion fuel impurities processing

    International Nuclear Information System (INIS)

    Willms, R.S.; Wilhelm, R.; Okuno, K.

    1994-01-01

    The palladium membrane reactor (PNM) provides a means to recover hydrogen isotopes from impurities expected to be present in fusion reactor exhaust. This recovery is based on reactions such as water-gas shift and steam reforming for which conversion is equilibrium limited. By including a selectively permeable membrane such as Pd/Ag in the catalyst bed, hydrogen isotopes can be removed from the reacting environment, thus promoting the reaction to complete conversion. Such a device has been built and operated at the Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory (LANL). For the reactions listed above, earlier study with this unit has shown that hydrogen single-pass recoveries approaching 100% can be achieved. It was also determined that a nickel catalyst is a feasible choice for use with a PMR appropriate for fusion fuel impurities processing. The purpose of this study was to systematically assess the performance of the PMR using a nickel catalyst over a range of temperatures, feed compositions and flowrates. Reactions which were studied are the water-gas shift reaction and steam reforming

  17. Synthesis and electrochemical performances of LiNiCuZn oxides as anode and cathode catalyst for low temperature solid oxide fuel cell.

    Science.gov (United States)

    Jing, Y; Qin, H; Liu, Q; Singh, M; Zhu, B

    2012-06-01

    Low temperature solid oxide fuel cell (LTSOFC, 300-600 degrees C) is developed with advantages compared to conventional SOFC (800-1000 degrees C). The electrodes with good catalytic activity, high electronic and ionic conductivity are required to achieve high power output. In this work, a LiNiCuZn oxides as anode and cathode catalyst is prepared by slurry method. The structure and morphology of the prepared LiNiCuZn oxides are characterized by X-ray diffraction and field emission scanning electron microscopy. The LiNiCuZn oxides prepared by slurry method are nano Li0.28Ni0.72O, ZnO and CuO compound. The nano-crystallites are congregated to form ball-shape particles with diameter of 800-1000 nm. The LiNiCuZn oxides electrodes exhibits high ion conductivity and low polarization resistance to hydrogen oxidation reaction and oxygen reduction reaction at low temperature. The LTSOFC using the LiNiCuZn oxides electrodes demonstrates good cell performance of 1000 mW cm(-2) when it operates at 470 degrees C. It is considered that nano-composite would be an effective way to develop catalyst for LTSOFC.

  18. Two 3D structured Co-Ni bimetallic oxides as cathode catalysts for high-performance alkaline direct methanol fuel cells

    Science.gov (United States)

    Liu, Yan; Shu, Chengyong; Fang, Yuan; Chen, Yuanzhen; Liu, Yongning

    2017-09-01

    Two NiCo2O4 bimetallic oxides were synthesized via a facile hydrothermal method. SEM and TEM observations show that these materials have three-dimensional (3D) dandelion-like (DL) and flower-like (FL) morphologies. Their large specific surface areas (90.68 and 19.8 m2·g-1) and porous structures provide many active sites and effective transport pathways for the oxygen reduction reaction (ORR). Electrochemical measurements with a rotating ring-disc electrode (RRDE) indicate that the electron transfer numbers of the NiCo2O4-DL and NiCo2O4-FL catalysts for ORR in an alkaline solution are 3.97 and 3.91, respectively. Fuel cells were assembled with the bimetallic oxides, PtRu/C and a polymer fiber membrane (PFM) as cathode catalysts, anode catalyst and electrolyte film, respectively. For NiCo2O4-DL, the peak power density reaches up to 73.5 mW·cm-2 at 26 °C, which is the highest room-temperature value reported to date. The high catalytic activity of NiCo2O4 is mainly attributed to the presence of many Co3+ cations that directly donate electrons to O2 to reduce it via a more efficient and effective route. Furthermore, the catalytic performance of NiCo2O4-DL is superior to that of NiCo2O4-FL because it has a higher specific surface area and is less crystalline.

  19. Various characteristics of Ni and Pt-Al2O3 nano catalysts prepared by microwave method to be applied in some petrochemical processes

    International Nuclear Information System (INIS)

    Gobara, H.M.; Mohamed, A.R.S.; Khalil, F.H.; El-Shall, M.S.; Hassan, S.A.

    2014-01-01

    Alumina-supported metal nano catalysts were prepared via the microwave method, by loading nano Ni particles (at 1, 3 and 5 wt %) or nano Pt particles (at 0.3, 0.6 and 0.9 wt %). Structural and adsorption features of the nano catalysts were revealed through XRD, DSC- DTA, TEM, H 2 -chemisorption and N 2 -physisorption. N 2 -adsorption-desorption isotherms of type IV were related typically to meso porous materials with H 2 class of hysteresis loops characterizing ink bottle type of pores. The well dispersed nano-sized metal particles were evidenced in the studied catalytic systems, exhibiting marked thermal stability up to 800 degree C. The catalytic performances of different catalyst samples were assessed during cyclohexane, normal hexane and ethanol conversions, using the micro-catalytic pulse technique at different operating conditions. The 5% Ni-γAl 2 O 3 sample was found to be the most active in dehydration of ethanol to produce ethylene, as well as in n -hexane cracking. However, the 1% Ni-Al 2 O 3 sample showed the highest dehydrogenation activity for selective production of benzene from cyclohexane. On the other hand, the 0.9% Pt-γAl 2 O 3 sample exhibited the highest activity in the dehydration of ethanol and in the dehydrogenation of cyclohexane. The 0.3% Pt-γAl 2 O 3 sample was the most active in the dehydrocyclization of normal hexane, as compared to the other catalyst samples under study

  20. Phase purity of NiCo2O4, a catalyst candidate for electrolysis of water

    Science.gov (United States)

    Singer, J.; Fielder, W. L.; Garlick, R. G.; Negas, T.

    1987-01-01

    NiCo2O4 is shown to be difficult to obtain as a pure phase, and may never have been so obtained. High resolution x-ray diffractometry is required for its precise characterization. Film XRD is not likely to show the asymmetry in the spinel diffraction lines, caused by poorly crystallized NiO, as seen in diffractometer traces. The Co3O4 which is expected to accompany NiO as an impurity in NiCo2O4 syntheses has the same diffraction pattern as the binary oxide. Firings of the co-precipitated hydroxides at 300, 350, and 400 C, including one in pure O2, failed to produce single phase cobaltate. Scanning electron microscopy showed all the sintered products to range over several orders of magnitude in agglomerate/particle size. Surface areas by BET were all in the range 40 to 110 m sq/g, equivalent to particles of 200 to 100 Angstrom diameter. The spinel diffraction line breadths were compatible with those approximate dimensions.

  1. Green synthesis of Ni-Nb oxide catalysts for low-temperature oxidative dehydrogenation of ethane.

    Science.gov (United States)

    Zhu, Haibo; Rosenfeld, Devon C; Anjum, Dalaver H; Caps, Valérie; Basset, Jean-Marie

    2015-04-13

    The straightforward solid-state grinding of a mixture of Ni nitrate and Nb oxalate crystals led to, after mild calcination (Tethane to ethylene at a relatively low temperature (Tethane. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Development of Cu and Ni catalysts supported on ZrO{sub 2} for the generation of H{sub 2} by means of the reaction of reformed methanol in atmosphere oxidizer; Desarrollo de catalizadores de Cu y Ni soportados en ZrO{sub 2} para la generacion de H{sub 2} mediante la reaccion de reformado de metanol en atmosfera oxidante

    Energy Technology Data Exchange (ETDEWEB)

    Lopez C, P.

    2012-07-01

    ZrO{sub 2} was prepared by the sol-gel method and calcined at 450 C. The prepared zirconia was impregnated with an aqueous solution of Cu(CH{sub 3}CO{sub 2}){sub 2}{center_dot}H{sub 2}O or NiNO{sub 3}{center_dot}6H{sub 2}O at an appropriate concentration to yield 3 wt % of copper or nickel, respectively, in the mono metallic catalysts. Three bimetallic samples were prepared at 80% Cu and 20% Ni respectively to obtain 3 wt % of total metallic phase. Surface area of the Cu-Ni base catalysts supported on ZrO{sub 2} oxide showed differences as a function of the metal addition. Between them, the Cu/ZrO{sub 2} catalyst had the lowest surface area than other catalysts. X-ray diffraction patterns of the bimetallic catalysts did not show diffraction peaks of the Cu, Ni or bimetallic Cu-Ni alloys. In addition, TPR profiles of the bimetallic catalysts had the lowest reduction temperature compared with the mono metallic samples. The reactivity of the catalysts in the range of 250-350 C showed that the samples prepared by successive impregnation had the highest catalytic activity than the other catalysts studied. Also the selectivity for H{sub 2} production was higher for these catalysts. This finding was associated to the presence of the bimetallic Cu-Ni nanoparticles, as was evidenced by Tem-EDX analysis. (Author)

  3. Hydrogen Production by Ethanol Steam Reforming (ESR over CeO2 Supported Transition Metal (Fe, Co, Ni, Cu Catalysts: Insight into the Structure-Activity Relationship

    Directory of Open Access Journals (Sweden)

    Michalis Konsolakis

    2016-03-01

    Full Text Available The aim of the present work was to investigate steam reforming of ethanol with regard to H2 production over transition metal catalysts supported on CeO2. Various parameters concerning the effect of temperature (400–800 °C, steam-to-carbon (S/C feed ratio (0.5, 1.5, 3, 6, metal entity (Fe, Co, Ni, Cu and metal loading (15–30 wt.% on the catalytic performance, were thoroughly studied. The optimal performance was obtained for the 20 wt.% Co/CeO2 catalyst, achieving a H2 yield of up to 66% at 400 °C. In addition, the Co/CeO2 catalyst demonstrated excellent stability performance in the whole examined temperature range of 400–800 °C. In contrast, a notable stability degradation, especially at low temperatures, was observed for Ni-, Cu-, and Fe-based catalysts, ascribed mainly to carbon deposition. An extensive characterization study, involving N2 adsorption-desorption (BET, X-ray diffraction (XRD, Scanning Electron Microscopy (SEM/EDS, X-ray Photoelectron Spectroscopy (XPS, and Temperature Programmed Reduction (H2-TPR was undertaken to gain insight into the structure-activity correlation. The excellent reforming performance of Co/CeO2 catalysts could be attributed to their intrinsic reactivity towards ethanol reforming in combination to their high surface oxygen concentration, which hinders the deposition of carbonaceous species.

  4. Influence of Solvent on Liquid Phase Hydrodeoxygenation of Furfural-Acetone Condensation Adduct using Ni/Al2O3-ZrO2 Catalysts

    Science.gov (United States)

    Ulfa, S. M.; Mahfud, A.; Nabilah, S.; Rahman, M. F.

    2017-02-01

    Influence of water and acidic protic solvent on hydrodeoxygenation (HDO) of the furfural-acetone adduct (FAA) over Ni/Al2O3-ZrO2 (NiAZ) catalysts were investigated. The HDO of FAA was carried out in a batch reactor at 150°C for 8 hours. The NiAZ catalysts were home-made catalysts which were prepared by wet impregnation method with 10 and 20% nickel loading. The HDO reaction of FAA using 10NiAZ in water at 150°C gave alkane and oxygenated hydrocarbons at 31.41% with selectivity over tridecane (C13) in 6.67%. On the other hand, a reaction using acetic acid:water (1:19 v/v) in similar reaction condition gave only oxygenated compounds and hydrocracking product (C8-C10). The formation of tridecane (C13) was proposed by hydrogenation of C=O and C=C followed by decarboxylation without hydrocracking process. The presence of water facilitated decarboxylation mechanism by stabilized dehydrogenated derivatives of FAA.

  5. Hydrogenation/Deoxygenation (H/D Reaction of Furfural-Acetone Condensation Product using Ni/Al2O3-ZrO2 Catalyst

    Directory of Open Access Journals (Sweden)

    Adam Mahfud

    2016-08-01

    Full Text Available The catalytic hydrogenation/deoxygenation (H/D reaction was carried out using Ni/Al2O3-ZrO2 catalyst. The 10% (wt/wt of Ni were impregnated on Al2O3-ZrO2 (10NiAZ by wet impregnation method followed by calcination and reduction. X-Ray diffraction analysis showed that Nideposited on the surface, with specific surface areas (SBET was 48.616 m2/g. Catalyst performance were evaluated for H/D reaction over furfural-acetone condensation products, mixture of 2-(4-furyl-3-buten-2-on and 1,5-bis-(furan-2-yl-pentan-3-one. The reaction was carried out in a batch, performed at 150°C for 8 hours. The H/D reaction gave alkane derivatives C8 and C10 by hydrogenation process followed by ring opening of furan in 15.2% yield. While, oxygenated product C10-C13 were also detected in 17.2% yield. The increasing of pore volume of 10NiAZ might enhance catalyst activity over H/D reaction. The alkene C=C bond was easy to hydrogenated under this condition by the lower bond energy gap.

  6. Co-Processing of Jatropha-Derived Bio-Oil with Petroleum Distillates over Mesoporous CoMo and NiMo Sulfide Catalysts

    Directory of Open Access Journals (Sweden)

    Shih-Yuan Chen

    2018-02-01

    Full Text Available The co-processing of an unconventional type of Jatropha bio-oil with petroleum distillates over mesoporous alumina-supported CoMo and NiMo sulfide catalysts (denoted CoMo/γ-Al2O3 and NiMo/γ-Al2O3 was studied. Either a stainless-steel high-pressure batch-type reactor or an up-flow fixed-bed reaction system was used under severe reaction conditions (330–350 °C and 5–7 MPa, similar to the conditions of the conventional diesel hydrodesulfurization (HDS process. To understand the catalytic performance of the mesoporous sulfide catalysts for co-processing, we prepared two series of oil feedstocks. First, model diesel oils, consisting of hydrocarbons and model molecules with various heteroatoms (sulfur, oxygen, and nitrogen were used for the study of the reaction mechanisms. Secondly, low-grade oil feedstocks, which were prepared by dissolving of an unconventional type of Jatropha bio-oil (ca. 10 wt % in the petroleum distillates, were used to study the practical application of the catalysts. Surface characterization by gas sorption, spectroscopy, and electron microscopy indicated that the CoMo/γ-Al2O3 sulfide catalyst, which has a larger number of acidic sites and coordinatively unsaturated sites (CUS on the mesoporous alumina framework, was associated with small Co-incorporated MoS2-like slabs with high stacking numbers and many active sites at the edges and corners. In contrast, the NiMo/γ-Al2O3 sulfide catalyst, which had a lower number of acidic sites and CUS on mesoporous alumina framework, was associated with large Ni-incorporated MoS2-like slabs with smaller stacking numbers, yielding more active sites at the brims and corresponding to high hydrogenation (HYD activity. Concerning the catalytic performance, the mesoporous CoMo/γ-Al2O3 sulfide catalyst with large CUS number was highly active for the conventional diesel HDS process; unfortunately, it was deactivated when oxygen- and nitrogen-containing model molecules or Jatropha bio

  7. From 3D to 2D Co and Ni Oxyhydroxide Catalysts: Elucidation of the Active Site and Influence of Doping on the Oxygen Evolution Activity

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Hansen, Heine Anton; Vegge, Tejs

    2017-01-01

    Layered oxyhydroxides (ox-hys) of Ni and Co are among the most active catalysts for oxygen evolution in alkaline media. Their activities can be further tuned by delamination into single-layer oxide sheets or by means of doping. The active site for the reaction and how doping and delamination...... investigate the role of terrace and edge sites and use stability, catalytic activity, and electronic conductivity as evaluation criteria to pinpoint the best catalysts. We arrive at several important conclusions: the ox-hy surface is fully oxidized under oxygen evolution conditions, bulk terraces...

  8. Electrodeposition and Characterization of Nanocrystalline Ni-Mo Catalysts for Hydrogen Production

    Directory of Open Access Journals (Sweden)

    J. Halim

    2012-01-01

    Full Text Available Ni-Mo nanocrystalline deposits (7–43 nm with a nodular morphology were prepared by electrodeposition using direct current from citrate-ammonia solutions. They exhibited a single Ni-Mo solid solution phase. The size of the nodules increased as electroplating current density increased. The molybdenum content—estimated using EDX analysis—in the deposits decreased from about 31 to 11 wt% as the current density increased from 5 to 80 mA·cm−2. The highest microhardness value (285 Hv corresponded to nanodeposits with 23% Mo. The highest corrosion resistance accompanied by relatively high hardness was detected for electrodeposits containing 15% Mo. Mo content values between 11 and 15% are recommended for obtaining better electrocatalytic activity for HER.

  9. Preparation of Au/Y2O3 and Au/NiO catalysts by co-precipitation and their oxidation activities

    International Nuclear Information System (INIS)

    Sreethawong, Thammanoon; Sitthiwechvijit, Norsit; Rattanachatchai, Apiwat; Ouraipryvan, Piya; Schwank, Johannes W.; Chavadej, Sumaeth

    2011-01-01

    Research highlights: → The catalytic activity of Au catalysts supported on Y 2 O 3 and NiO prepared by co-precipitation was investigated for CO and methanol oxidation. → The phase transformation of yttrium support greatly affected the CO oxidation activity. → The Au/Y 2 O 3 exhibited the same activity as Au/NiO for the methanol oxidation while the Au/NiO gave higher activity for CO oxidation. - Abstract: The objective of this work was to investigate the catalytic activity of gold catalysts supported on two metal oxides, yttrium oxide and nickel oxide, prepared by co-precipitation for CO and methanol oxidation reactions. The TGA and XRD results confirmed that yttrium hydroxide (Y(OH) 3 ) was formed at calcination temperature below 300 deg. C. When it was calcined at 400 deg. C, the Y(OH) 3 was transformed to yttrium oxide hydroxide (YOOH). Finally, when calcination temperature was raised to 600 deg. C, the YOOH was completely transformed to yttrium oxide (Y 2 O 3 ). Interestingly, the gold loaded on YOOH calcined at 400 deg. C and gold loaded on Y 2 O 3 calcined at 500 deg. C comparatively showed the highest catalytic activity for complete CO oxidation at a reaction temperature of 300 deg. C. The 0.12% Au/Y 2 O 3 catalyst calcined at 500 deg. C was employed for both CO and methanol oxidation studies. For complete CO oxidation, the reaction temperatures of Au/Y 2 O 3 and Au/NiO catalysts were 325 deg. C and 250 deg. C, respectively. The light-off temperatures of Au/Y 2 O 3 and Au/NiO catalysts for methanol oxidation were 210 deg. C and 205 deg. C, respectively. Conclusively, the Au/Y 2 O 3 clearly exhibited the same activity as that of Au/NiO for methanol oxidation while the Au/NiO gave higher activity for CO oxidation.

  10. Solid state synthesis, characterization, surface and catalytic properties of Pr2CoO4 and Pr2NiO4 catalyst

    International Nuclear Information System (INIS)

    Sinha, K.K.; Indu, N.K.; Sinha, S.K.; Pankaj, A.K.

    2008-01-01

    Full text: The most interesting non-stoichiometric oxides are found in transition metal and rare earth oxides at higher temperatures. The role of Solid State properties in the catalysis using mixed metal oxide as catalyst have wide applications in fertilizer, Petro-chemical, Pharmaceutical, cosmetic, paint detergents, plastics and food-stuff industries and these are also resistive towards acids and alkalies. The use of catalyst has opened up new process routes or revolutioned the existing process in terms of economics and efficiency and has radically changed the industrial scenario. The use of catalyst is so pervasive today that nearly 70 % of modern chemical processes are based on it at some stage or other and 90% new processes developed are catalytic nature. A series of non-stoichiometric spinel type of oxide catalyst of Praseodymium with cobalt and nickel were synthesized by their oxalates through Solid State reaction technique at different activation temperatures i.e. 600, 700, 800 and 900 deg C. The characterization of catalyst was done by XRD, FTIR and ESR methods. X-ray powder diffraction study shows that catalysts are made up of well grown crystallinities mostly in single phase crystal and system is of orthorhombic structure. FTIR is related to inadequate decomposition of oxalate ion from the Catalyst. The kinetic decomposition of Urea was employed as a model reaction to study the catalytic potentiality of different catalysts. Surface and Catalytic Properties of catalysts were measured. A relation between activation temperature and surface properties like excess surface oxygen (E.S.O.), surface acidity and surface area was observed. A linear relationship between the surface area of the catalyst and the amount of ammonia gas evolved per gm of the sample was observed also. Nickel containing catalysts were found a bit more catalytic active in comparison to cobalt oxide catalysts. Transition metal ions (i.e. Ni 2+ and Co 2+ ions) are mainly responsible for

  11. Influences of doping Cr/Fe/Ta on the performance of Ni/CeO{sub 2} catalyst under microwave irradiation in dry reforming of CH{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Odedairo, Taiwo [School of Chemical Engineering, The University of Queensland, St Lucia, Brisbane (Australia); Ma, Jun [School of Engineering, University of South Australia, Mawson Lakes, SA (Australia); Chen, Jiuling, E-mail: cjlchen@yahoo.com [School of Chemical Engineering, The University of Queensland, St Lucia, Brisbane (Australia); Wang, Shaobin [Department of Chemical Engineering, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia); Zhu, Zhonghua, E-mail: z.zhu@uq.edu.au [School of Chemical Engineering, The University of Queensland, St Lucia, Brisbane (Australia)

    2016-01-15

    The structure of Ni/CeO{sub 2} catalyst with doping of Cr, Fe and Ta was investigated with XRD, N{sub 2} physisorption, XPS and HRTEM and the catalytic activity of the catalysts under microwave irradiation in dry reforming of methane was tested in a microwave reactor. The results show that the introduction of Cr and Ta to Ni/CeO{sub 2} can enhance the interaction between Ni and the support/promoter and inhibit the enlargement of NiO particles during the synthesis. The CH{sub 4} conversions in dry reforming on the catalysts follow the order: Ni/CeO{sub 2}<2Fe–Ni<2Ta–Ni<2Cr–Ni. The superior performance of 2Ta–Ni and 2Cr–Ni may be attributed to the locally-heated Ni particles caused by the strong microwave absorption of the in-situ grown graphene attached on them under microwave irradiation. - Highlights: • The influences of doping Cr, Fe and Ta on Ni/CeO{sub 2} were investigated. • The catalytic performances before and after doping were investigated. • The in-situ grown graphene can promote the conversion of reactants.

  12. Synthesis of Highly Branched Polyolefins Using Phenyl Substituted α-Diimine Ni(II Catalysts

    Directory of Open Access Journals (Sweden)

    Fuzhou Wang

    2016-04-01

    Full Text Available A series of α-diimine Ni(II complexes containing bulky phenyl groups, [ArN = C(NaphthC = NAr]NiBr2 (Naphth: 1,8-naphthdiyl, Ar = 2,6-Me2-4-PhC6H2 (C1; Ar = 2,4-Me2-6-PhC6H2 (C2; Ar = 2-Me-4,6-Ph2C6H2 (C3; Ar = 4-Me-2,6-Ph2C6H2 (C4; Ar = 4-Me-2-PhC6H3 (C5; Ar = 2,4,6-Ph3C6H2 (C6, were synthesized and characterized. Upon activation with either diethylaluminum chloride (Et2AlCl or modified methylaluminoxane (MMAO, all Ni(II complexes showed high activities in ethylene polymerization and produced highly branched amorphous polyethylene (up to 145 branches/1000 carbons. Interestingly, the sec-butyl branches were observed in polyethylene depending on polymerization temperature. Polymerization of 1-alkene (1-hexene, 1-octene, 1-decene and 1-hexadecene with C1-MMAO at room temperature resulted in branched polyolefins with narrow Mw/Mn values (ca. 1.2, which suggested a living polymerization. The polymerization results indicated the possibility of precise microstructure control, depending on the polymerization temperature and types of monomers.

  13. The Role of Neodymium in the Optimization of a Ni/CeO2 and Ni/CeZrO2 Methane Dry Reforming Catalyst

    Directory of Open Access Journals (Sweden)

    Alfonsina Pappacena

    2018-04-01

    Full Text Available The development of a sustainable economy based on the use of renewable resources and the reduction of greenhouse gases emissions is an important mandate in modern societies to minimize the global warming. The CO2-reforming of methane through a conversion of CO2 and CH4 to syngas is a suitable process for this purpose and there is growing interest in the development of new catalysts for this process’ application at an industrial scale. This study is the first to investigate methane dry reforming activity of nickel supported on CeO2 and CeO2–ZrO2 solid solutions doped with neodymium. The supports were synthesized using a surfactant-assisted co-precipitation method and characterized through several analytical techniques to understand the role of synthesis parameters in the distribution of the dopant as well as in the properties of the supports. Co-doping with Zr and Nd resulted in an enhancement of dry reforming activity of ceria due to a higher dispersion of Ni and changes in the strength of basic sites. It was also shown that the addition of Nd helped to mitigate coking issues by increasing the mobility of surface oxygen in ceria and ceria–zirconia oxides and, accordingly, the rate of oxidation of carbonaceous deposits.

  14. Recovery of Ni Metal from Spent Catalyst with Emulsion Liquid Membrane Using Cyanex 272 as Extractant

    Science.gov (United States)

    Yuliusman; Huda, M.; Ramadhan, I. T.; Farry, A. R.; Wulandari, P. T.; Alfia, R.

    2018-03-01

    In this study was conducted to recover nickel metal from spent nickel catalyst resulting from hydrotreating process in petroleum industry. The nickel extraction study with the emulsion liquid membrane using Cyanex 272 as an extractant to extract and separate nickel from the feed phase solution. Feed phase solution was preapred from spent catalyst using sulphuric acid. Liquid membrane consists of a kerosene as diluent, a Span 80 as surfactant, a Cyanex 272 as carrier and sulphuric acid solutions have been used as the stripping solution. The important parameters governing the permeation of nickel and their effect on the separation process have been studied. These parameters are surfactant concentration, extractant concentration feed phase pH. The optimum conditions of the emulsion membrane making process is using 0.06 M Cyanex 272, 8% w/v SPAN 80, 0.05 M H2SO4, internal phase extractant / phase volume ratio: 1/1, and stirring speed 1150 rpm for 60 Minute that can produce emulsion membrane with stability level above 90% after 4 hours. In the extraction process with optimum condition pH 6 for feed phase, ratio of phase emulsion/phase of feed: 1/2, and stirring speed 175 rpm for 15 minutes with result 81.51% nickel was extracted.

  15. Catalyst surface characterized by high magnetic field NMR; Kojiba NMR ni yoru shokubai hyomen no kansatsu

    Energy Technology Data Exchange (ETDEWEB)

    Sato, S. [Chiba University, Chiba (Japan). Faculty of Engineering

    1997-08-01

    This paper introduces studies performed by the authors on observation of surface of solid catalysts by means of solid NMR measurement using the high-speed MAS technology which uses a high magnetic field device. In the studies, a device with 14.1T (resonant frequency of proton at 600 MHz) was used to conduct CP-MAS NMR measurement on {sup 29}Si to identify bonding of silica carrier in a fixed aluminum chloride catalyst. As a result, it was verified that the surface structure of aluminum chloride species deposited on the silica carrier turns to a structure in which AlCl2 species of a monomeric substance is bonded with a surface hydroxyl group and fixed in four- or five-orientation. When adjusted at low temperatures, an Al2Cl5 structure is formed, which is fixed as a dimeric substance with AlCl3 oriented in the AlCl2 species. It is conceived that the Al2Cl5 species has higher electrophilicity than the AlCl2 species as a result of AlCl3 oriented in AlCl2, whereas the hydroxyl group on the silica surface oriented with the Al2Cl5 species dissociates, discharging protons, thus showing strong acidity. 18 refs., 8 figs., 2 tabs.

  16. Three-gamma annihilation of ortho-positronium in NiO/γ-Al2O3 catalysts detected by positron lifetime and coincidence Doppler broadening measurements

    International Nuclear Information System (INIS)

    Huang, S.H.; Chen, Z.Q.; Zhang, H.J.

    2012-01-01

    The pore structure of NiO/γ-Al 2 O 3 catalysts is characterized by positron lifetime and Doppler broadening measurements. A very long lifetime τ 4 of 92 ns is resolved from the positron lifetime spectrum measured for pure Al 2 O 3 , which could be attributed to the ortho-positronium (o-Ps) lifetime in large pores. It was also found that the fitted lifetime τ 4 and its corresponding intensity I 4 obtained from the lifetime spectra both decrease with narrowing energy window of the stop channel in the fast–fast coincidence lifetime measurement system. This suggests that the ultra long lifetime is primarily due to the self annihilation of o-Ps which emits three gamma-rays. Such 3γ annihilation is further evidenced by measuring the Doppler broadening of annihilation gamma rays in coincidence with the prompt gamma rays (1.28 MeV) emitted from the 22 Na positron source. In NiO/γ-Al 2 O 3 catalysts both the lifetime τ 4 and its intensity I 4 decreases with increasing NiO content (from 3 wt% to 40 wt%), which indicates decreasing of the number of 3γ events. The 3γ annihilation parameter analyzed from the coincidence Doppler broadening spectrum shows consistent decrease with increasing NiO content. - Highlights: ► Above paper reported study of the 3-gamma annihilation of o-Ps. ► 3γ annihilation was verified by varying the energy window of the lifetime system. ► A new coincidence Doppler broadening technique is also used to record 3γ events. ► 3γ parameter decreases with NiO content in NiO/γ-Al 2 O 3 catalysts.

  17. Biodiesel production in methyl esterification in the frying oil using catalyst Ni_0_,_5Zn_0_,_5Fe_2O_4 to produce biodiesel

    International Nuclear Information System (INIS)

    Vasconcelos, E.V.; Dantas, J.; Pereira, K.B.O.; Barros, A.B.; Moura, T.F.B.; Costa, A.C.F.M.

    2016-01-01

    The use of magnetic catalysts for biodiesel production has gaining prominence because of possibility about its recovery and its reuse, as well as, the reuse of materials that would be discarded in the environment. Thus, we propose to evaluate the efficiency of the catalyst Ni_0_,_5Zn_0_,_5Fe_2O_4 in methyl esterification in the frying oil to produce biodiesel. The catalyst was produced by combustion reaction using containers with different production capacity and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and infrared spectrometry with Fourier transform (FTIR). The catalytic tests were conducted in a stainless steel reactor at 180°C/1h, 2% of catalyst, oil/ethanol ratio of 1:12. Regardless of the container production capacity it was verified the catalyst obtaining with the major phase formation of the inverse spinel and traces of segregated phases with an average crystallite size of 42.13, 32.07 and 36.93 nm. All catalysts showed satisfactory results with conversions of 74%, 77% and 71%. (author)

  18. A new Ni(II complex as a novel and efficient recyclable catalyst for the synthesis of pyrano[2,3-d]pyrimidines

    Directory of Open Access Journals (Sweden)

    M. Habibi Kheirabadi

    2016-12-01

    Full Text Available A simple and highly efficient one-pot three-component synthesis of a series of pyrido[2,3-d]pyrimidines from the condensation of barbituric acid, malononitrile and aromatic aldehydes using catalytic amount of a new Ni(II complex based on 5-nitro-N1-((pyridin-2-ylmethylene benzene-1,2-diamine (NiL is reported. This new heterogeneous catalyst has the advantages of being environmentally friendly, simple work-up and high yields character.

  19. Kinetics on NiZn Bimetallic Catalysts for Hydrogen Evolution via Selective Dehydrogenation of Methylcyclohexane to Toluene

    KAUST Repository

    Shaikh Ali, Anaam

    2017-01-18

    Liquid organic chemical hydrides are effective hydrogen storage media for easy and safe transport. The chemical couple of methylcyclohexane (MCH) and toluene (TOL) has been considered one of the feasible cycles for a hydrogen carrier, but the selective dehydrogenation of MCH to TOL has been reported using only Pt-based noble metal catalysts. This study reports MCH dehydrogenation to TOL using supported NiZn as a selective, non-noble-metal catalyst. A combined experimental and computational study was conducted to provide insight into the site requirements and reaction mechanism for MCH dehydrogenation to TOL, which were compared with those for cyclohexane (CH) dehydrogenation to benzene (BZ). The kinetic measurements carried out at 300-360°C showed an almost zero order with respect to MCH pressure in the high-pressure region (≥10 kPa) and nearly a positive half order with respective to H pressure (≤40 kPa). These kinetic data for the dehydrogenation reaction paradoxically indicate that hydrogenation of a strongly chemisorbed intermediate originating from TOL is the rate-determining step. Density functional theory (DFT) calculation confirms that the dehydrogenated TOL species at the aliphatic (methyl) position group (CHCH) were strongly adsorbed on the surface, which must be hydrogenated to desorb as TOL. This hydrogen-assisted desorption mechanism explains the essential role of excess H present in the feed in maintaining the activity of the metallic surface for hydrogenation. The rate of the CH to BZ reaction was less sensitive to H pressure than that of MCH to TOL, which can be explained by the absence of a methyl group in the structure, which in turn reduces the binding energy of the adsorbed species. DFT suggests that the improved TOL selectivity by adding Zn to Ni was due to Zn atoms preferentially occupying low-coordination sites on the surface (the corner and edge sites), which are likely the unselective sites responsible for the C-C dissociation of the

  20. Kinetics on NiZn Bimetallic Catalysts for Hydrogen Evolution via Selective Dehydrogenation of Methylcyclohexane to Toluene

    KAUST Repository

    Shaikh Ali, Anaam; Jedidi, Abdesslem; Anjum, Dalaver H.; Cavallo, Luigi; Takanabe, Kazuhiro

    2017-01-01

    Liquid organic chemical hydrides are effective hydrogen storage media for easy and safe transport. The chemical couple of methylcyclohexane (MCH) and toluene (TOL) has been considered one of the feasible cycles for a hydrogen carrier, but the selective dehydrogenation of MCH to TOL has been reported using only Pt-based noble metal catalysts. This study reports MCH dehydrogenation to TOL using supported NiZn as a selective, non-noble-metal catalyst. A combined experimental and computational study was conducted to provide insight into the site requirements and reaction mechanism for MCH dehydrogenation to TOL, which were compared with those for cyclohexane (CH) dehydrogenation to benzene (BZ). The kinetic measurements carried out at 300-360°C showed an almost zero order with respect to MCH pressure in the high-pressure region (≥10 kPa) and nearly a positive half order with respective to H pressure (≤40 kPa). These kinetic data for the dehydrogenation reaction paradoxically indicate that hydrogenation of a strongly chemisorbed intermediate originating from TOL is the rate-determining step. Density functional theory (DFT) calculation confirms that the dehydrogenated TOL species at the aliphatic (methyl) position group (CHCH) were strongly adsorbed on the surface, which must be hydrogenated to desorb as TOL. This hydrogen-assisted desorption mechanism explains the essential role of excess H present in the feed in maintaining the activity of the metallic surface for hydrogenation. The rate of the CH to BZ reaction was less sensitive to H pressure than that of MCH to TOL, which can be explained by the absence of a methyl group in the structure, which in turn reduces the binding energy of the adsorbed species. DFT suggests that the improved TOL selectivity by adding Zn to Ni was due to Zn atoms preferentially occupying low-coordination sites on the surface (the corner and edge sites), which are likely the unselective sites responsible for the C-C dissociation of the

  1. Synthesis NiAl1,0Fe1,0O4 catalyst by the combustion reaction to their use in the shift reaction (WGSR)

    International Nuclear Information System (INIS)

    Santos, P.T.A.; Costa, A.C.F.M.; Neiva, L.S.; Gama, L.; Argolo, F.; Andrade, H.M.C.

    2009-01-01

    This work aims at the synthesis of catalyst NiAl 1,0 Fe 1,0 O 4 by combustion reaction using urea as fuel, to evaluate its performance in the production of hydrogen by the reaction of displacement of water vapor (WGSR). The initial composition of the solution was based on valencia total oxidizing and reducing reagents based on the concepts of the chemistry of propellants, using container as a crucible of glassy silica. The resulting powder was characterized by X-ray diffraction, infrared spectroscopy, nitrogen adsorption isotherms (BET), scanning electronic microscope and catalytic tests. The DRX results reveal the presents majoritary phase NiAl 1,0 Fe 1,0 O 4 spinel, the catalyst presents surface area 28 m 2 /g and isotherms type III. Higher conversion CO/CO 2 of 75% CO conversion observed at 500 deg C and catalytic activity of 43 mmolg -1 .h -1 at 450 deg C. (author)

  2. Comparison of P-containing {gamma}-Al{sub 2}O{sub 3} supported Ni-Mo bimetallic carbide, nitride and sulfide catalysts for HDN and HDS of gas oils derived from Athabasca bitumen

    Energy Technology Data Exchange (ETDEWEB)

    Sundaramurthy, V.; Dalai, A.K. [Catalysis and Chemical Reaction Engineering Laboratories, Department of Chemical Engineering, University of Saskatchewan, Saskatoon, SK (Canada); Adjaye, J. [Syncrude Edmonton Research Centre, Edmonton, AB (Canada)

    2006-09-01

    Phosphorus containing {gamma}-Al{sub 2}O{sub 3} supported bimetallic Ni-Mo carbide, nitride and sulfide catalysts have been synthesized from an oxide precursor containing 12.73wt.% Mo, 2.54wt.% Ni and 2.38wt.% P and characterized by elemental analysis, pulsed CO chemisorption, surface area measurements, X-ray diffraction, temperature-programmed reduction and DRIFT spectroscopy of CO adsorption. DRIFT spectroscopy of adsorbed CO on activated catalysts showed that carbide and nitride catalysts have surface exposed sites of Mo{sup o+} (0Ni-Mo carbide, nitride and sulfide catalysts were compared against commercial Ni-Mo/Al{sub 2}O{sub 3} catalyst in a trickle bed reactor using light gas oil and heavy gas oil derived from Athabasca bitumen in the temperature range 340-370 and 375-400{sup o}C respectively at 8.8MPa. The gradual transformation of Ni-Mo carbide and nitride phases into Ni-Mo sulfide phases was observed during precoking period, and the formed Ni-Mo sulfide phases enhanced the HDN and HDS activities of carbide and nitride catalysts. The {gamma}-Al{sub 2}O{sub 3} supported Ni-Mo bimetallic sulfide catalyst was found to be more active for HDN and HDS of light gas oil and heavy gas oil than the corresponding carbide and nitride catalysts on the basis of unit weight. (author)

  3. Experimental and theoretical study about sulfur deactivation of Ni/ CeO{sub 2} and Rh/CeO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ocsachoque, Marco A., E-mail: ocmarco@quimica.unlp.edu.ar [Centro de Investigación y Desarrollo en Ciencias Aplicadas “Dr Jorge J. Ronco”, (CONICET, CCT La Plata), Departamento de Química, Facultad de Cs Exactas (UNLP), Calle 48 N° 257, 1900 La Plata (Argentina); Eugenio Russman, Juan I.; Irigoyen, Beatriz [Instituto de Tecnologías del Hidrógeno y Energías Sostenibles (ITHES), Departamento de Ingeniería Química, Facultad de Ingeniería (UBA), Buenos Aires (Argentina); Gazzoli, Delia [Dipartimento di Chimia, Universitá di Roma “La Sapienza”, Roma (Italy); González, María G. [Centro de Investigación y Desarrollo en Ciencias Aplicadas “Dr Jorge J. Ronco”, (CONICET, CCT La Plata), Departamento de Química, Facultad de Cs Exactas (UNLP), Calle 48 N° 257, 1900 La Plata (Argentina)

    2016-04-01

    Sulfur deactivation of Ni/CeO{sub 2} and Rh/CeO{sub 2} catalysts were examined through an experimental and theoretical study. These catalysts were characterized by N{sub 2} adsorption, X-ray diffraction, temperature programmed reaction, thermogravimetric analysis, Uv–visible spectroscopy and Raman spectroscopy, and tested under the methane dry reforming reaction in the presence of H{sub 2}S. On the other hand, different possible interactions of sulfur with Rh, Ni or surface sites of the CeO{sub 2} support were evaluated by performing energy calculations with the density functional theory (DFT). Overall, the results indicate that tolerance to sulfur of Rh/CeO{sub 2} catalyst is higher than that of Ni/CeO{sub 2} one. In this sense, TPR measurements show that reduction of CeO{sub 2} is promoted by the presence of Rh. This effect, probably caused by hydrogen spillover to CeO{sub 2} support during the reduction of RhO{sub x} species, could be linked to a high oxygen donation capacity of Rh/CeO{sub 2} catalysts. Accordingly, the O{sup 2−} species existing on Rh/CeO{sub 2} catalysts, revealed by Raman spectra of these samples, could favor sulfur oxidation and prevent Rh–S interactions. Likewise, the theoretical calculations show that desorption of S–O species from Rh/CeO{sub 2} system is more favorable than that from Ni/CeO{sub 2} one. Therefore, our experimental and theoretical study about sulfur deactivation of Ni and Rh supported on CeO{sub 2} allow us to postulate that Rh can help to desorb SO{sub x} species formed on the support, retarding sulfur poisoning of the Rh/CeO{sub 2} catalysts. - Highlights: • CeO{sub 2} support can act as a sacrifice trap decreasing sulfur poisoning. • Theoretical calculations indicate an important nickel affinity with sulfur. • Rh would favor desorption of S–O species formed on the support. • The O{sup 2−} species present on the Rh–CeO{sub 2} sample favor sulfur removal.

  4. [NiFe] hydrogenase structural and functional models: new bio-inspired catalysts for hydrogen evolution

    International Nuclear Information System (INIS)

    Oudart, Y.

    2006-09-01

    Hydrogenase enzymes reversibly catalyze the oxidation and production of hydrogen in a range close to the thermodynamic potential. The [NiFe] hydrogenase active site contains an iron-cyano-carbonyl moiety linked to a nickel atom which is in an all sulphur environment. Both the active site originality and the potential development of an hydrogen economy make the synthesis of functional and structural models worthy. To take up this challenge, we have synthesised mononuclear ruthenium models and more importantly, nickel-ruthenium complexes, mimicking some structural features of the [NiFe] hydrogenase active site. Ruthenium is indeed isoelectronic to iron and some of its complexes are well-known to bear hydrides. The compounds described in this study have been well characterised and their activity in proton reduction has been successfully tested. Most of them are able to catalyze this reaction though their electrocatalytic potentials remain much more negative compared to which of platinum. The studied parameters point out the importance of the complexes electron richness, especially of the nickel environment. Furthermore, the proton reduction activity is stable for several hours at good rates. The ruthenium environment seems important for this stability. Altogether, these compounds represent the very first catalytically active [NiFe] hydrogenase models. Important additional results of this study are the synergetic behaviour of the two metals in protons reduction and the evidence of a protonation step as the limiting step of the catalytic cycle. We have also shown that a basic site close to ruthenium improves the electrocatalytic potential of the complexes. (author)

  5. Promoting effect of oxygen for hydrogenation of butadiene over Ni/sub 2/P catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Nozaki, F.; Kitoh, T.; Sodesawa, T.

    1980-04-01

    When 0-10 mm Hg of oxygen were added to the reaction of 75 mm Hg butadiene and 225 mm Hg hydrogen over dinickel phosphide in a closed circulation system at 40/sup 0/C, increasing amounts of oxygen caused increasing lengths of induction periods followed by hydrogenation at reaction rates which had a maximum at 3 mm Hg oxygen. This maximum rate was about six times higher than the rate without oxygen addition. Adsorption, temperature-programed desorption, IR spectroscopy, and the product distribution of butadiene deuteration showed that two types of oxygen adsorbed on the dinickel phosphide catalyst; molecular oxygen on nickel, which desorbed on evacuation below 50/sup 0/C and which could be displaced by butadiene, was responsible for the induction period; molecular oxygen on phosphorus atoms, which promoted hydrogen adsorption, was responsible for the increased hydrogenation rate.

  6. Sequential Condensation and Hydrodeoxygenation Reaction of Furfural-Acetone Adduct over Mix Catalysts Ni/SiO2 and Cu/SiO2 in Water

    Directory of Open Access Journals (Sweden)

    Siti Mariyah Ulfa

    2018-05-01

    Full Text Available Sequential condensation and hydrodeoxygenation reaction were perform using autoclave batch reactor in the presence of water as a solvent. The condensation of furfural and acetone was performed using MgO catalyst followed by hydrodeoxygenation using mix catalyst Ni/SiO2 and Cu/SiO2. The catalyst was prepared by wet-impregnation method and analyzed by XRD, SEM-EDX as well as BET surface. Condensation of furfural and acetone in 1:2 mol ratio was carried out by reflux gave 4-(2-furyl-3-buten-2-one and 1,5-bis-(2-furanyl-1,4-pentadien-3-one. The condensation product was then subjected for hydrodeoxygenation using batch reactor, catalyzed by mixed Ni/SiO2 and Cu/SiO2 at 150 and 180 °C for 2 h. The product identified as alkane derivatives with the conversion at 38.83 and 50.35%, respectively. The selectivity of hydrocarbon is 61.39% at 150 °C and 16.55% at 180 °C. Increasing the reaction temperature to 200 °C did not give any products except the recovery of the precursor. It showed that higher temperature enhanced the catalyst activity but the selectivity is controlled by low reaction temperature.

  7. Synthesis of Green Diesel From Waste Cooking Oil Through Hydrodeoxygenation Technology With NiMo/γ-Al2O3 Catalysts

    Directory of Open Access Journals (Sweden)

    Heriyanto Heri

    2018-01-01

    Full Text Available Hydrodeoxygenation (HDO of waste cooking oil (WCO and trapped grease over sulfide catalysts was examined to produce high quality transportation fuel from low-grade resources. The hydrodeoxygenation of waste cooking oils was carried out in a high pressure of 30 and 60 bar and high temperature of 300 – 400 °C in a batch reactor autoclave. NiMo/γ-Al2O3 catalyst was prepared and for the first time tested in hydroprocessing of waste cooking oil. The content of NiMo/γ-Al2O3 in each catalyst was about wCo 5 wt.%. A maximum of 77,97 % green diesel yield was achieved at nearly complete conversion of waste cooking oil using NiMo/γ-Al2O3 at temperature of 400°C, pressure 60 bar and 4 hours of reaction time. The oxygen content was decreased from 14,25 wt.% to 13,35 wt.%, at temperature of 400°C, pressure of 30 bar and 1 hour of reaction time. The Hydrodeoxygenation process was much influenced by temperature, pressure, and time.

  8. Influence of silica-alumina support ratio on H2 production and catalyst carbon deposition from the Ni-catalytic pyrolysis/reforming of waste tyres.

    Science.gov (United States)

    Zhang, Yeshui; Tao, Yongwen; Huang, Jun; Williams, Paul

    2017-10-01

    The influence of catalyst support alumina-silica in terms of different Al 2 O 3 to SiO 2 mole ratios containing 20 wt.% Ni on the production of hydrogen and catalyst coke formation from the pyrolysis-catalysis of waste tyres is reported. A two-stage reactor system was used with pyrolysis of the tyres followed by catalytic reaction. There was only a small difference in the total gas yield and hydrogen yield by changing the Al 2 O 3 to SiO 2 mole ratios in the Ni-Al 2 O 3 /SiO 2 catalyst. The 1:1 ratio of Al 2 O 3 :SiO 2 ratio produced the highest gas yield of 27.3 wt.% and a hydrogen production of 14.0 mmol g -1 tyre . Catalyst coke formation decreased from 19.0 to 13.0 wt.% as the Al 2 O 3 :SiO 2 ratio was changed from 1:1 to 2:1, with more than 95% of the coke being filamentous-type carbon, a large proportion of which was multi-walled carbon nanotubes. Further experiments introduced steam to the second-stage reactor to investigate hydrogen production for the pyrolysis-catalytic steam reforming of the waste tyres using the 1:1 Al 2 O 3 /SiO 2 nickel catalyst. The introduction of steam produced a marked increase in total gas yield from ~27 wt. % to ~58 wt.%; in addition, hydrogen production was increased to 34.5 mmol g -1 and there was a reduction in catalyst coke formation to 4.6 wt.%.

  9. Influence of silica–alumina support ratio on H2 production and catalyst carbon deposition from the Ni-catalytic pyrolysis/reforming of waste tyres

    Science.gov (United States)

    Zhang, Yeshui; Tao, Yongwen; Huang, Jun; Williams, Paul

    2017-01-01

    The influence of catalyst support alumina–silica in terms of different Al2O3 to SiO2 mole ratios containing 20 wt.% Ni on the production of hydrogen and catalyst coke formation from the pyrolysis-catalysis of waste tyres is reported. A two-stage reactor system was used with pyrolysis of the tyres followed by catalytic reaction. There was only a small difference in the total gas yield and hydrogen yield by changing the Al2O3 to SiO2 mole ratios in the Ni-Al2O3/SiO2 catalyst. The 1:1 ratio of Al2O3:SiO2 ratio produced the highest gas yield of 27.3 wt.% and a hydrogen production of 14.0 mmol g-1tyre. Catalyst coke formation decreased from 19.0 to 13.0 wt.% as the Al2O3:SiO2 ratio was changed from 1:1 to 2:1, with more than 95% of the coke being filamentous-type carbon, a large proportion of which was multi-walled carbon nanotubes. Further experiments introduced steam to the second-stage reactor to investigate hydrogen production for the pyrolysis-catalytic steam reforming of the waste tyres using the 1:1 Al2O3/SiO2 nickel catalyst. The introduction of steam produced a marked increase in total gas yield from ~27 wt. % to ~58 wt.%; in addition, hydrogen production was increased to 34.5 mmol g-1 and there was a reduction in catalyst coke formation to 4.6 wt.%. PMID:28789599

  10. Comparative study between traditional and modified Pechini synthesis methods in the preparation of LaNiO_3 and LaNi_0_,_8Co_0_,_2O_3 catalysts

    International Nuclear Information System (INIS)

    Silva, F.E.F.; Aquino, F.M.; Silva, M.C.M.F.

    2016-01-01

    One of the ways of obtaining hydrogen is from the methane reforming reaction, which is an endothermic and non-spontaneous reaction. In order to minimize this energy, nickel catalysts are used. This work aims to synthesize and characterize the catalysts LaNiO_3 and LaNi_0_,_8Co_0_,_2O_3 using the Pechini method, making use of citric acid and ethylene glycol and modified Pechini, using the edible gelatin as a chelating and polymerizing agent. The obtained materials were characterized by X-Ray Diffraction (XRD), where the formation of peaks characteristic of perovskite and monophasic structures was observed. Scanning Electron Microscopy (SEM) showed that porosity and powders with few agglomerates were observed by both methods. In the analysis of determination of the specific surface area (BET) the materials were shown with areas that are according to the literature

  11. Synthesis and characterization of Ni-CeO{sub 2} catalysts by the hydrothermal method; Sintesis y caracterizacion de catalizadores de Ni-CeO{sub 2} por el metodo hidrotermal

    Energy Technology Data Exchange (ETDEWEB)

    Lazcano O, I.

    2013-07-01

    At the present time the necessity exists to reduce the level of atmospheric pollutants, because these are the main originators of such problems as: the greenhouse effect, acid rain, global heating, among others and that are affecting the human being seriously. In this context, is necessary to look for new solutions that contribute to the improvement of the problems without appealing to limitations in the energy production, because this would imply a non only delay in the economic development, but also in the cultural, technological and of research in our country. An alternative for the energy solution is the use of renewable fuels, because they will decrease the production costs with the time, as well as to diminish the dependence of the fossil fuels, contributing this way to the improvement of the environment quality. The use of the hydrogen as an alternating fuel to the petroleum, is intends as energy solution. The objective of the present work is to develop Ni-CeO{sub 2} catalysts through the hydrothermal method for the hydrogen production starting from the partial oxidation reaction of methanol for the clean fuel generation that does not produce polluting emissions to the environment. As well as, to determine the importance of the metallic load in the catalytic activity for which catalysts to 1 and 2% in weight of Ni were prepared. To achieve these objective different techniques were used to characterize the prepared catalysts, as: Temperature Programmed Reduction to evidence the metal-support interaction, Scanning Electron Microscopy (Sem) to determine the morphology of the catalysts, Surface Area (Bet) with respect to the adsorption-desorption of N{sub 2} and X-Rays Diffraction (XRD) to know the crystalline structure of the catalysts. Also the catalytic properties (activity and selectivity) were studied under the reaction: CH{sub 3}OH + 1/2 O{sub 2} obtaining as products to the CO{sub 2} + 2H{sub 2}, with the help of the multi-tasks equipment Rig-100 that

  12. Production of hydrogen with methane decomposition using Ni-Mn/Ce-ZrO{sub 2} catalysts; Produccion de hidrogeno via descomposicion de metano mediante catalizadores de Ni-Mn/Ce-ZrO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, C; Hernandez-Pichardo, M L; Valenzuela, M A [Instituto Politecnico Nacional-ESIQIE, Mexico, D.F. (Mexico); Del Angel, P; Montoya de la Fuente, J.A. [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico)

    2009-09-15

    The catalytic decomposition of methane makes it possible to obtain CO and CO{sub 2} free hydrogen, which is a desirable characteristic for fuel cell applications. In addition, this method simultaneously obtains diverse carbon nanostructures with a large variety of applications. This work prepared catalysts with different Ni contents supported by Ce-Zr mixed oxides and doped with manganese to promote activity. The supports were synthesized with surfactant-assisted coprecipitation. The Ni and Mn deposits were performed using conventional impregnation for evaluation in the methane decomposition catalyst at 500 degrees Celsius. It was observed that with the incorporation of 1% of Mn into the Ni0 active phase, the conversion of methane into hydrogen and carbon nanostructures increased. The results of reduction at the programmed temperature indicate that the addition of Mn enables the formation of different NiO{sub x} species, increasing dispersion and the degree of reduction to Ni0. Analyses with electron and transmission microscopy show the formation of distinct species of carbon, including nanotubes, nanofibers and concentric onion-like structures, as well as a significant formation of encapsulated Ni0 particles. [Spanish] La descomposicion catalitica de metano permite la obtencion de hidrogeno libre de CO y CO{sub 2}, lo cual es una caracteristica deseable para su aplicacion en celdas de combustible. Ademas, por esta ruta, simultaneamente se obtienen diversas nanoestructuras de carbono con una gran variedad de aplicaciones. En este trabajo se prepararon catalizadores con diferentes contenidos de Ni soportados en oxidos mixtos Ce-Zr y se doparon con manganeso como promotor de actividad. Los soportes se sintetizaron por coprecipitacion asistida por surfactante y el deposito del Ni y del Mn se efectuo por impregnacion convencional para su evaluacion en la descomposicion catalitica de metano a 500 grados centigrados. Se observo que mediante la incorporacion de 1% de Mn a

  13. Evaluation as a catalyst in ferrispinel NiFe{sub 2}O{sub 4} esterification and transesterification; Avaliacao do ferroespinelio NiFe{sub 2}O{sub 4} como catalisador em reacao de esterificacao e transesterificacao

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Kleberson Ricardo de Oliveira; Dantas, Joelda; Costa, Ana Cristina Figueiredo de Melo; Silva, Adriano Sant' Ana, E-mail: klebersonric@usp.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Kiminami, Ruth Herta Goldschmidt Aliaga [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Engenharia de Materiais

    2014-07-01

    The advancement of nanoscience and nanotechnology, magnetic nanoparticles ferrispinels type, have found numerous applications in biochemistry, molecular biology, biomedicine, diagnosis and heterogeneous catalysis for biodiesel production. Therefore, we propose to synthesize ferrispinel NiFe{sub 2}O{sub 4} and evaluate its performance as a catalyst for esterification and transesterification of the methyl soybean oil. The sample was obtained through combustion reaction with production of 10 g / batch and characterized by XRD, SEM and BET. The catalytic reaction was conducted in high-pressure reactor at 180 °C for 1 hour, with a molar ratio of oil:ethanol 1:12 with 2% catalyst. The results showed the formation of ferrispinel phase, morphology composed of aggregates in the form of irregular blocks formed by pre sintered particles and low interparticle porosity. As a catalyst, the conversion values presented ferrispinel 52% and 4% in the esterification and transesterification, respectively, indicating that promising material for use in biodiesel production. (author)

  14. Performance of NiWP/Al2O3 catalyst for hydroprocessing of light gas oils derived from Athabasca bitumen

    Energy Technology Data Exchange (ETDEWEB)

    Owusu-Boakye, A.; Ferdous, D.; Dalai, A.K. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Chemistry and Chemical Engineering; Adjaye, J. [Syncrude Canada Ltd., Edmonton, AB (Canada). Edmonton Research Centre

    2004-07-01

    The quality of diesel fuel in terms of cetane number and coloring is diminished if it has a high content of aromatics which cause the formation of undesirable emissions in exhaust gases. These compounds typically occur as mono, di, tri and polyaromatics. In response to strict environmental regulations, middle distillates now have fewer aromatics. Sulphur and nitrogen compounds in diesel fuels also cause the formation of SOx and NOx in the atmosphere, but the aromatic hydrogenation of diesel fuels is more complex than any of the hydrodesulphurization (HDS) or hydrodenitrogenation (HDN) processes. The NiWP/Al{sub 2}O{sub 3} catalyst in a trickle-bed reactor was used under a range of temperature and pressure conditions to study the reactivity of vacuum, atmospheric and hydrocracked light gas oils produced from Athabasca bitumen. The hydrogen feed ratio was kept constant and product samples from different feedstocks were analyzed with respect to sulfur, nitrogen and aromatic content. The study also included a comparison of gasoline selectivity and kinetic parameters for HDS and HDN reactions for the feed materials.

  15. Support acidity influence in NiMoS (Nickel and Molybdenum) catalyst for Marlim diesel; Influencia da acidez do suport de catalisadores NiMoS (Niquel e Molibidenio) no hidrotratamento de diesel Marlim

    Energy Technology Data Exchange (ETDEWEB)

    Ferraz, Sheila Guimaraes de Almeida; Zotin, Jose Luiz; Jesus, Anderson Gomes de; Santos, Bruno Martins; Medeiros, Marcus Vinicius Costa [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2008-07-01

    The specification of diesel points to the reduction of the sulfur content, of the final boiling point, of the density range and increase of the cetane number. These two last properties are directly related with the ability of the hydrotreating catalytic system in promoting the hydrogenation of aromatic structures and ring opening of the naphthenic compounds, which are both associated to low cetane number. In such way, more acidic catalysts, able to promote the cracking of naphthenic structures, should be evaluated for the diesel HDT. Three bifunctional NiMo catalysts with the same metal content, different acidity and similar active phase dispersion were prepared using alumina, silica-alumina and alumina-Y zeolite as supports. These catalysts were evaluated in a micro-reactor unit for diesel HDT aiming to correlate their activity with the support acidity. The alumina and alumina-zeolite supported catalysts presented better performance than the one supported on silica-alumina. NiMo/alumina-zeolite showed higher cetane and density improvement, associated with a slight decrease in the initial boiling point. (author)

  16. Catalytic hydroprocessing of simulated coal tars. 1. Activity of a sulphided Ni-Mo/Al/sub 2/O/sub 3/ catalyst for the hydroconversion of model compounds

    Energy Technology Data Exchange (ETDEWEB)

    Lemberton, J.L.; Touzeyidio, M.; Guisnet, M. (Laboratoire de Catalyse en Chimie Organique CNRS, Poitiers (France))

    1989-09-15

    The conversion of tars from coal pyrolysis into light aromatics, such as BTX (benzene-toluene-xylenes) and naphthalene, requires the hydrocracking of heavy polyaromatics in the presence of nitrogen- and oxygen-containing compounds. The hydroconversion of phenanthrene, which occurs through bifunctional catalysis, was chosen as a model reaction. It was carried out over a sulphided Ni-Mo/Al/sub 2/O/sub 3/ catalyst (Ketjen 153) in the presence of carbazole and 1-naphthol. Carbazole poisons slightly through coking both the hydrogenating and the acid sites of the catalyst. 1-Naphthol has a more significant deactivating effect: the hydrogenating sites of the catalyst are poisoned by the water eliminated from 1-naphthol and the acid sites by coke generated by 1-naphthol. Lastly, the hydrogenating activity of the catalyst is not substantially affected in the presence of carbazole and 1-naphthol, but its cracking activity is much reduced, making it impossible for the catalyst to achieve the hydrocracking of phenanthrene into into light aromatics. 5 figs, 21 refs., 1 tab.

  17. Conversion of hot coke oven gas into light fuel gas over Ni/Al{sub 2}O{sub 3} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Li, L.Y.; Morishita, K.; Takarada, T. [Gunma University, Gunma (Japan). Dept. of Biology & Chemical Engineering

    2006-04-15

    Conversion of hot coke oven gas (COG, containing tarry material) into light fuel gas over a Ni/Al{sub 2}O{sub 3} catalyst was studied. Laboratory scale tests were carried out in a two-stage fixed-bed reactor at ambient pressure. The nickel catalyst promoted the hydropyrolysis reaction of tarry materials. High yields of total product gas and methane were obtained at high hydrogen concentrations. If the hydrogen supply was adequate for hydropyrolysis of the tarry material, conversion of coal volatiles was high, at more than 95% on carbon balance, even with a gas residence time as short as 0.15 s in the catalyst bed. The product gas yield depended on catalytic temperature. At 923 K, the maximum conversion of coal volatiles into the light gas was achieved at 95.0% on carbon balance, with methane 86.7 vol% of the carbonaceous gas product. Although carbon deposits deactivated the catalyst after a long period of use, the catalyst could be regenerated by treatment with oxygen at 800 K, providing high activity in subsequent decomposition of tarry material. The influence of sulphide on the tarry material decomposition reaction was small even in a 2000 ppm H{sub 2}S atmosphere.

  18. An investigation of thin-film Ni-Fe oxide catalysts for the electrochemical evolution of oxygen.

    Science.gov (United States)

    Louie, Mary W; Bell, Alexis T

    2013-08-21

    A detailed investigation has been carried out of the structure and electrochemical activity of electrodeposited Ni-Fe films for the oxygen evolution reaction (OER) in alkaline electrolytes. Ni-Fe films with a bulk and surface composition of 40% Fe exhibit OER activities that are roughly 2 orders of magnitude higher than that of a freshly deposited Ni film and about 3 orders of magnitude higher than that of an Fe film. The freshly deposited Ni film increases in activity by as much as 20-fold during exposure to the electrolyte (KOH); however, all films containing Fe are stable as deposited. The oxidation of Ni(OH)2 to NiOOH in Ni films occurs at potentials below the onset of the OER. Incorporation of Fe into the film increases the potential at which Ni(OH)2/NiOOH redox occurs and decreases the average oxidation state of Ni in NiOOH. The Tafel slope (40 mV dec(-1)) and reaction order in OH(-) (1) for the mixed Ni-Fe films (containing up to 95% Fe) are the same as those for aged Ni films. In situ Raman spectra acquired in 0.1 M KOH at OER potentials show two bands characteristic of NiOOH. The relative intensities of these bands vary with Fe content, indicating a change in the local environment of Ni-O. Similar changes in the relative intensities of the bands and an increase in OER activity are observed when pure Ni films are aged. These observations suggest that the OER is catalyzed by Ni in Ni-Fe films and that the presence of Fe alters the redox properties of Ni, causing a positive shift in the potential at which Ni(OH)2/NiOOH redox occurs, a decrease in the average oxidation state of the Ni sites, and a concurrent increase in the activity of Ni cations for the OER.

  19. Influences of species of metals and supports on the hydrogenation activity of carbon-supported metal sulfides catalysts; Tanso biryushi tanji shokubai no suisoka kassei ni taisuru kassei kinzoku oyobi tantaishu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Sakanishi, K.; Hasuo, H.; Taniguchi, H.; Nagamatsu, T.; Mochida, I. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study

    1996-10-28

    In order to design catalysts suitable for primary liquefaction stage and secondary upgrading stage respectively in the multi-stage liquefaction process, various carbon-supported catalysts were prepared. Catalytic activities of them were investigated for the hydrogenation of 1-methylnaphthalene, to discuss the influences of metals and carbon species on the catalytic activity. Various water soluble and oil soluble Mo and Ni salts were used for NiMo supported catalysts. Among various carbon supports, Ketjen Black (KB) was effective for preparing the catalyst showing the most excellent hydrogenation activity. The KB and Black Pearl 2000 (BP2000) showing high hydrogenation activity were fine particles having high specific surface area more than 1000 m{sup 2}/g and primary particle diameter around 30 nm. This was inferred to contribute to the high dispersion support of active metals. Since such fine particles of carbon exhibited hydrophobic surface, they were suitable for preparing catalysts from the methanol-soluble metals. Although Ni and Mo added iron-based catalysts provided lower aromatic hydrogenation activity, they exhibited liquefaction activity competing with the NiMo/KB catalyst. 3 refs., 1 fig., 3 tabs.

  20. A series of NiMo/Al{sub 2}O{sub 3} catalysts containing boron and phosphorus. Part 2. Hydrodenitrogenation and hydrodesulfurization using heavy gas oil derived from Athabasca bitumen

    Energy Technology Data Exchange (ETDEWEB)

    Ferdous, D.; Dalai, A.K. [Catalysis and Chemical Reactor Engineering Laboratories, Department of Chemical Engineering, University of Saskatchewan, Saskatoon (Canada) SK S7N 5C9; Adjaye, J. [Syncrude Canada Ltd., Edmonton Research Center (Canada)

    2004-04-08

    The hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) activity of a series of NiMo/Al{sub 2}O{sub 3} catalyst containing boron (B) and phosphorus (P) were tested in a trickle bed reactor using heavy gas oil derived from Athabasca bitumen. Detailed characterization of these catalysts is given in Part I of this paper. Addition of B and P caused the formation of extremely strong acid sites on the catalyst and enhanced its HDN activity. The total (TN), basic (BN) and non-basic nitrogen (NBN) conversions increased from 61.9 to 78.0wt.%, from 78.9 to 93.0wt.% and from 52.8 to 70.0wt.%, respectively, with the increase in B concentration from 0 to 1.7wt.% to NiMo/Al{sub 2}O{sub 3} catalyst. Similarly, TN, BN and NBN conversions increased from 61.9 to 78.4wt.%, from 78.9 to 91.0wt.%, and from 52.8 to 71.6wt.% with the addition of 2.7wt.% P. Though the addition of B and P to NiMo/Al{sub 2}O{sub 3} catalyst did not show any significant effect on S conversion, the HDN and HDS activities of the catalyst containing 1.7wt.% B and the one containing 2.7wt.% P are comparable to those of a commercial catalyst. The activity over extended period indicated that catalysts L and K were more stable (lower deactivation rate) in terms of nitrogen removal activity than catalyst B (reference catalyst). On the other hand, the stability for sulfur removal was comparable with catalyst B. Selected catalysts after use were characterized using BET surface area, TPR, TPD and SEM techniques which were correlated further with their activities.

  1. Hydrotreatment of solvolytically liquefied lignocellulosic biomass over NiMo/Al2O3 catalyst: Reaction mechanism, hydrodeoxygenation kinetics and mass transfer model based on FTIR

    International Nuclear Information System (INIS)

    Grilc, M.; Likozar, B.; Levec, J.

    2014-01-01

    Raw residual wood biomass, containing cellulose, hemicellulose and lignin, was liquefied at low temperature by ultrasound-assisted solvolysis and acidolysis by glycerol, diethylene glycol and p-toluenesulfonic acid. Liquefied biomass was consequently upgraded by hydrotreatment utilizing heterogeneous catalysis over NiMo/Al 2 O 3 bifunctional catalyst. Effects of temperature (200−350 °C), heating rate (2.5–10.0 K min −1 ), hydrogen/nitrogen pressure (2−8 MPa), mixing (250−1000 min −1 ), hydrogen donor solvent (tetralin) and catalyst contents on deoxygenation were established. Reactions of liquefaction products, such as levulinic acid, were quantified based on their functional groups by Fourier transform infrared spectroscopy, whereas catalyst was examined by scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction analysis (XRD). Chemical kinetics of hydrodeoxygenation (HDO), decarbonylation and decarboxylation were determined by originally developed lumped model, based on reaction mechanisms and pathways, while the external mass transfer resistance proved to be negligible under the applied hydrodynamic conditions. The presence of hydrocracking reactions was confirmed by a decrease in product viscosity, and the upgrade for energetic or fuel applications by measurements of calorific value. - Highlights: • Liquefaction of waste lignocellulosic biomass with glycerol at low temperature. • Hydrotreatment, hydrocracking and hydrodeoxygenation of liquefied waste biomass. • Deoxygenation using heterogeneous catalysis over NiMo/Al 2 O 3 bifunctional catalyst. • Proposal of reaction mechanism; chemical kinetics and mass transfer considerations. • Effect of temperature, heating rate, pressure, mixing, solvent and catalyst content

  2. Preparation of a Ni-MgO-Al2O3 catalyst with high activity and resistance to potassium poisoning during direct internal reforming of methane in molten carbonate fuel cells

    Science.gov (United States)

    Jang, Won-Jun; Jung, You-Shick; Shim, Jae-Oh; Roh, Hyun-Seog; Yoon, Wang Lai

    2018-02-01

    Steam reforming of methane (SRM) is conducted using a series of Ni-MgO-Al2O3 catalysts for direct internal reforming (DIR) in molten carbonate fuel cells (MCFCs). Ni-MgO-Al2O3 catalysts are prepared by the homogeneous precipitation method with a variety of MgO loading amounts ranging from 3 to 15 wt%. In addition, each precursor concentrations are systemically changed (Ni: 1.2-4.8 mol L-1; Mg: 0.3-1.2 mol L-1; Al: 0.4-1.6 mol L-1) at the optimized composition (10 wt% MgO). The effects of MgO loading and precursor concentration on the catalytic performance and resistance against poisoning of the catalyst by potassium (K) are investigated. The Ni-MgO-Al2O3 catalyst with 10 wt% MgO and the original precursor concentration (Ni: 1.2 mol L-1; Mg: 0.3 mol L-1; Al: 0.4 mol L-1) exhibits the highest CH4 conversion and resistance against K poisoning even at the extremely high gas space velocity (GHSV) of 1,512,000 h-1. Excellent SRM performance of the Ni-MgO-Al2O3 catalyst is attributed to strong metal (Ni) to alumina support interaction (SMSI) when magnesium oxide (MgO) is co-precipitated with the Ni-Al2O3. The enhanced interaction of the Ni with MgO-Al2O3 support is found to protect the active Ni species against K poisoning.

  3. Synthesis of Supported NiPt Bimetallic Nanoparticles, Methods for Controlling the Surface Coverage of Ni Nanoparticles With Pt, Methods Of Making NiPt Multilayer Core-Shell Structures and Application of the Supported Catalysts for CO2 Reforming

    KAUST Repository

    Li, Lidong; Anjum, Dalaver H.; Zhou, Lu; Laveille, Paco; Basset, Jean-Marie

    2015-01-01

    Embodiments of the present disclosure provide for supported Ni/Pt bimetallic nanoparticles, compositions including supported NiPt nanoparticles, methods of making supported NiPt nanoparticles, methods of using supported NiPt nanoparticles

  4. Synthesis of Supported NiPt Bimetallic Nanoparticles, Methods for Controlling the Surface Coverage of Ni Nanoparticles With Pt, Methods Of Making NiPt Multilayer Core-Shell Structures and Application of the Supported Catalysts for CO2 Reforming

    KAUST Repository

    Li, Lidong

    2015-06-25

    Embodiments of the present disclosure provide for supported Ni/Pt bimetallic nanoparticles, compositions including supported NiPt nanoparticles, methods of making supported NiPt nanoparticles, methods of using supported NiPt nanoparticles, and the like.

  5. Steam reforming of bio-ethanol over Ni on Ce-ZrO2 support: Influence of redox properties on the catalyst reactivity

    Directory of Open Access Journals (Sweden)

    Sumittra Charojrochkul

    2006-11-01

    Full Text Available The steam reforming of ethanol over Ni on Ce-ZrO2 support, (Ni/ Ce-ZrO2 were studied. The catalyst provides significantly higher reforming reactivity and excellent resistance toward carbon deposition compared to Ni/Al2O3 under the same conditions. At the temperature above 800ºC, the main products from the reforming processes over Ni/Ce-ZrO2 were H2, CO, and CO2 with small amount of CH4 depending on the inlet ethanol/steam and oxygen/ethanol ratios, whereas high hydrocarbon compounds i.e., C2H4 and C2H6 were also observed from the reforming of ethanol over Ni/Al2O3 in the range of conditions studied (700- 1000ºC.These excellent ethanol reforming performances of Ni/Ce-ZrO2 in terms of stability, reactivity and product selectivities are due to the high redox property of Ce-ZrO2. During the ethanol reforming process, in addition to the reactions on Ni surface, the gas-solid reactions between the gaseous components presented in the system (C2H5OH, C2H6, C2H4, CH4, CO2, CO, H2O, and H2 and the lattice oxygen (Ox on Ce-ZrO2 surface also take place. Among these redox reactions, the reactions of adsorbed surface hydrocarbons with the lattice oxygen (Ox (CnHm + Ox → nCO + m/2(H2 + Ox-n can eliminate the formation of high hydrocarbons (C2H6 and C2H4, which easily decompose and form carbon species on Ni surface (CnHm→ nC + m/2H2.

  6. Comparison of product selectivity during hydroprocessing of bitumen derived gas oil in the presence of NiMo/Al{sub 2}O{sub 3} catalyst containing boron and phosphorus

    Energy Technology Data Exchange (ETDEWEB)

    D. Ferdous; A.K. Dalai; J. Adjaye [University of Saskatchewan, SK (Canada). Catalysis and Chemical Reactor Engineering Laboratories, Department of Chemical Engineering

    2006-06-15

    A detailed experimental study was performed in a trickle-bed reactor using bitumen derived gas oil. The objective of this work was to compare the activity of NiMo/Al{sub 2}O{sub 3} catalyst containing boron or phosphorus for the hydrotreating and mild hydrocracking of bitumen derived gas oil. Experiments were performed at the temperature and LHSV of 340-420{sup o}C and 0.5-2 h{sup -1}, respectively, using NiMo/Al{sub 2}O{sub 3} catalysts containing 1.7 wt% boron or 2.7 wt% phosphorus. In the temperature range of 340-390{sup o}C, higher nitrogen conversion was observed from boron containing catalyst than that from phosphorus containing catalyst whereas in the same temperature range, phosphorus containing catalyst gave higher relative removal of sulfur than boron containing catalyst. Phosphorus containing catalyst showed excellent hydrocracking and mild hydrocracking activities at all operating conditions. Higher naphtha yield and selectivity were obtained using phosphorus containing catalyst at all operating conditions. Maximum gasoline selectivity of {approximately}45 wt% was obtained at the temperature, pressure, and LHSV of 400{sup o}C, 9.4 MPa and 0.5 h{sup -1}, respectively, using catalyst containing 2.7 wt% phosphorus. 40 refs., 13 figs., 1 tab.

  7. Cracking vegetable oil from Callophylluminnophyllum L. seeds to bio-gasoline by Ni-Mo/Al2O3 and Ni-Mo/Zeolite as micro-porous catalysts

    Science.gov (United States)

    Savitri, Effendi, R.; Tursiloadi, S.

    2016-02-01

    Natural minerals such as zeolite are local natural resources in the various regions in Indonesia. Studies on the application of natural mineral currently carried out by national research institutions, among others, as a filler, bleaching agent, or dehydration agent. However, not many studies that utilize these natural minerals as green catalysts material which has high performance for biomass conversion processes and ready to be applied directly by the bio-fuel industry. The trend movement of green and sustainable chemistry research that designing environmentally friendly chemical processes from renewable raw materials to produce innovative products derived biomass for bio-fuel. Callophylluminnophyllum L. seeds can be used as raw material for bio-energy because of its high oil content. Fatty acid and triglyceride compounds from this oil can be cracked into bio-gasoline, which does not contain oxygen in the hydrocarbon structure. Bio-gasoline commonly is referred to as drop-in biofuel because it can be directly used as a substitute fuel. This paper focused on the preparation and formulation of the catalyst NiMo/H-Zeolite and Ni-Mo/Al2O3 which were used in hydro-cracking process of oil from Callophylluminnophyllum L. seeds to produce bio-gasoline. The catalysts were analyzed using XRD, BET and IR-adsorbed pyridine method. The results of hydro-cracking products mostly were paraffin (C10-C19) straight chain, with 59.5 % peak area based on GC-MS analysis.

  8. Hydrogen-Rich Gas Production by Sorption Enhanced Steam Reforming of Woodgas Containing TAR over a Commercial Ni Catalyst and Calcined Dolomite as CO2 Sorbent

    Directory of Open Access Journals (Sweden)

    Vincenzo Naso

    2013-07-01

    Full Text Available The aim of this work was the evaluation of the catalytic steam reforming of a gaseous fuel obtained by steam biomass gasification to convert topping atmosphere residue (TAR and CH4 and to produce pure H2 by means of a CO2 sorbent. This experimental work deals with the demonstration of the practical feasibility of such concepts, using a real woodgas obtained from fluidized bed steam gasification of hazelnut shells. This study evaluates the use of a commercial Ni catalyst and calcined dolomite (CaO/MgO. The bed material simultaneously acts as reforming catalyst and CO2 sorbent. The experimental investigations have been carried out in a fixed bed micro-reactor rig using a slipstream from the gasifier to evaluate gas cleaning and upgrading options. The reforming/sorption tests were carried out at 650 °C while regeneration of the sorbent was carried out at 850 °C in a nitrogen environment. Both combinations of catalyst and sorbent are very effective in TAR and CH4 removal, with conversions near 100%, while the simultaneous CO2 sorption effectively enhances the water gas shift reaction producing a gas with a hydrogen volume fraction of over 90%. Multicycle tests of reforming/CO2 capture and regeneration were performed to verify the stability of the catalysts and sorbents to remove TAR and capture CO2 during the duty cycle.

  9. Kinetics of methane decomposition to CO{sub x}-free hydrogen and carbon nanofiber over Ni-Cu/MgO catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Borghei, Maryam; Karimzadeh, Ramin [Chemical Engineering Department, Tarbiat Modares University, Tehran (Iran); Rashidi, Alimorad; Izadi, Nosrat [Research Center of Nanotechnology, Research Institute of Petroleum Industry, Tehran (Iran)

    2010-09-15

    Kinetic modeling of methane decomposition to CO{sub x}-free hydrogen and carbon nanofiber has been carried out in the temperature range 550-650 C over Ni-Cu/MgO catalyst from CH{sub 4}-H{sub 2} mixtures at atmospheric pressure. Assuming the different mechanisms of the reaction, several kinetic models were derived based on Langmuir-Hinshelwood type. The optimum value of kinetic parameters has been obtained by Genetic Algorithm and statistical analysis has been used for the model discrimination. The suggested kinetic model relates to the mechanism when the dissociative adsorption of methane molecule is the rate-determining stage and the estimated activation energy is 50.4 kJ/mol in agreement with the literature. The catalyst deactivation was found to be dependent on the time, reaction temperature, and partial pressures of methane and hydrogen. Inspection of the behavior of the catalyst activity in relation to time, led to a model of second order for catalyst deactivation. (author)

  10. Hydrodeoxygenation of heavy oils derived from low-temperature coal gasification over NiW catalysts-effect of pore structure

    Energy Technology Data Exchange (ETDEWEB)

    Dieter Leckel [Sasol Technology Research and Development, Sasolburg (South Africa). Fischer-Tropsch Refinery Catalysis

    2008-01-15

    The effect of the pore structure on the hydroprocessing of heavy distillate oils derived from low-temperature coal gasification residues was studied using four NiW catalysts with different pore size distributions. The hydroprocessing was conducted at a pressure of 17.5 MPa, a temperature range of 370-410{sup o}C, and a 0.50 h{sup -1} space velocity. The degree of hydrodeoxygenation (HDO) in terms of phenolics removal was influenced by the catalyst pore structure, with the most preferable peak pore diameter for HDO ranging between 6.8 and 16 nm. The catalyst with the highest volume of pores in the 3.5-6 nm range showed the lowest HDO activity. The apparent activation energies for the HDO reaction varied between 59 and 87 kJ/mol, whereby the lowest values are obtained for the catalysts with a peak pore diameter of 11 and 16 nm. 30 refs., 5 figs., 6 tabs.

  11. Effect of WO{sub x} on Co and Ni/Hydrotalcite catalysts to obtain hydrogen from bioethanol; Efecto del WO{sub x} sobre catalizadores de Co, Ni/hidrotalcita para obtener hidrogeno a partir de bioetanol

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, M.A.; Contreras, J. L. [Universidad Autonoma Metropolitana-Azcapotzalco, Mexico, D.F. (Mexico)]. E-mail: jlcl@correo.azc.uam.mx; Fuentes, G.A. [Universidad Autonoma Metropolitana-Iztapalapa, Mexico, D.F. (Mexico); Luna, R. [Universidad Autonoma Metropolitana-Azcapotzalco, Mexico, D.F. (Mexico); Salmones, J.; Zeifert, B. [ESIQIE, Instituto Politecnico Nacional, Mexico, D.F. (Mexico)] Vazquez, A. [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico)

    2009-09-15

    This work studies the effect of tungsten oxides on the synthesis, characterization and reaction of Co catalysts, Ni exchanges in hydrotalcite, to produce H{sub 2} from ethanol. The catalysts were characterized by BET area, x-ray diffraction and Raman, Infrared and UV-vis spectroscopies. The catalytic evaluation was performed with micro-reaction equipment using a water/ethanol ratio of 4 at 450 degrees Celsius. The effect of the W contents was from 0.5 to 3%. X-ray diffraction of the Co and Ni series showed a continuous decrease in crystallinity as W contents increased. Other findings include a pore morphology in the form of parallel plates and a mesoporous distribution (bimodal) with areas of 150-250 m{sup 2}/g. Infrared OH vibrations found, H{sub 2}O, Al-OH, Mg-and CO32-OH, also a low intensity peak related to vibration of type W = O. For Raman found links the W-O-W. UV-vis a band was found in the ultraviolet region, which in the case of the series of cobalt decreases as the content of W. The opposite occurred for the series of Ni. W was observed that promotes the conversion of Co in the range up to 80% while not promoted in the case of Ni. W showed that promotes catalyst stability (after 430 min), Co series showed a conversion of 80% and reached 90% Ni, no catalyst was deactivated before 350 min. [Spanish] En este trabajo se estudia el efecto de los oxidos de tungsteno en la sintesis, caracterizacion y reaccion de catalizadores de Co, Ni intercambiados en hidrotalcita, para la produccion de H{sub 2} a partir de etanol. Los catalizadores se caracterizaron por area BET, difraccion de rayos X, espectroscopias: Raman, Infrarrojo y UV-vis. La evaluacion catalitica se llevo a cabo en un equipo de microrreaccion usando una relacion agua/etanol de 4 a 450 grados centigrados se estudio el efecto del contenido de W desde 0.5 hasta 3%. La difraccion de rayos X para las series de Co y Ni mostro una disminucion continua de la cristalinidad conforme aumento el contenido de W

  12. The Study on the Performance of Carbon Supported PtSnM (M = W, Pd, and Ni) Ternary Electro-Catalysts for Ethanol Electro-Oxidation Reaction.

    Science.gov (United States)

    Noh, Chang Soo; Heo, Dong Hyun; Lee, Ki Rak; Jeon, Min Ku; Sohn, Jung Min

    2016-05-01

    PtSn/C and Pt5Sn4M/C (M = W, Pd, Ni) electrocatalysts were prepared by impregnation method using NaBH4 as a reducing agent. Chemical composition, crystalline size, and alloy formation were determined by EDX, XRD and TEM. The average particle sizes of the synthesized catalysts were approximately 3.64-4.95 nm. The electro-chemical properties were measured by CO stripping, cyclic voltammetry, linear sweep voltammetry, and chronoamperometry. The maximum specific activity of the electro-catalysts for ethanol electro-oxidation was 406.08 mA m(-2) in Pt5Sn4Pd/C. The poisoning rate of the Pt5Sn4Pd/C (0.0017% s(-1)) was 4.5 times lower than that of the PtSn/C (0.0076% s(-1)).

  13. Heat and mass transfer in a reforming catalyst bed. Analytical prediction of distributions in the catalyst bed; Kaishitsu shokubaiso ni okeru netsu oyobi busshitsu ido. Suchi kaiseki ni yoru sonai bunpu no yosoku

    Energy Technology Data Exchange (ETDEWEB)

    Usami, Y [Tokyo Electric Power Co. Inc., Tokyo (Japan); Fukusako, S; Yamada, M [Hokkaido University, Sapporo (Japan)

    2000-01-25

    Heat and mass transfer characteristics within a reforming catalyst bed have been analytically investigated. A numerical analysis was carried out in a two-dimensional steady-state model of reforming catalyst layer. Reforming tube was filled with catalyst and the tube wall was uniformly heated, a mixture of steam and methane was reformed through the catalyst bed. Predicted temperature, formed gas composition, methane conversion rate, and heat transfer coefficient distributions in the catalyst layer showed good agreement with experimental data. The effects of space velocity, steam carbon molar ratio, and wall temperature on the heat transfer coefficient were analytically presented. From temperature and composition distributions simulated by two-dimensional analysis, the effects of these factors above mentioned and diffusion on the transport phenomena were qualitatively predicted. (author)

  14. Design of bimetal catalysts Pt-Ni/CeO{sub 2}-1D for generation of H{sub 2} by the reforming reaction of methanol; Diseno de catalizadores bimetalicos Pt-Ni/CeO{sub 2}-1D para generacion de H{sub 2} mediante la reaccion de reformado de metanol

    Energy Technology Data Exchange (ETDEWEB)

    Sarmiento F, I.

    2016-07-01

    CeO{sub 2} nano rods were synthesized by hydrothermal method and were used as support for preparing catalysts bimetallic Pt Ni / CeO{sub 2}-1D. The catalysts were prepared by classical impregnation by the conventional wet method. The prepared catalysts are Pt (0.5 %) - Ni (5 %) / CeO{sub 2} and Pt (0.5 %) - Ni (15 %) / CeO{sub 2}, which were characterized by different physico-chemical techniques: Bet, Sem, TPR and XRD, that were evaluated in the Auto thermal Steam reforming of Methanol for H{sub 2} production. The Bet surface area results, show that the surface area of the catalysts decreases as the nominal load of Ni in the catalyst, increases. Sem shows, that the catalyst support (CeO{sub 2}-1D) and the bimetallic catalysts are conformed by nano rods. By XRD were identified the crystalline phases present, in the catalytic material: cerianite distinctive phase of cerium oxide and metallic Ni; however it was not possible to observe diffraction peaks of Platinum using this technique. The temperature-programmed reduction (TPR) analysis allowed to obtain the reduction profiles, of the different species present on the catalysts. The catalytic activity tests carried out, showed that the catalysts total 100% methanol conversion is achieved at 300 degrees Celsius, making them excellent, to be used in reactions at low temperature conditions. Selectivity towards H{sub 2}, is very similar in both catalysts, and it reaches a 50% yield per mole of methanol fed stoichiometrically. (Author)

  15. Study on purification of carbon nano tubes grown on Fe/Ni bimetallic catalyst supported on Mg O by thermal chemical vapor deposition

    International Nuclear Information System (INIS)

    Mirershadi, S.; Mortazavi, Z.; Reyhani, A.; Norouzian, Sh.; Moniri, N.; Novinrooz, A. J.

    2007-01-01

    Carbon nano tubes grown on Fe/Ni bimetallic catalysts supported on Mg O by thermal chemical vapor deposition. Then purification of carbon nano tubes by oxidation under air at atmospheric pressure and acid treatment with HCl, have been studied. The Scanning electron microscopy observation showed impurities with carbon nano tubes. Scanning electron microscopy, XRD, Raman spectroscopy and Thermogravimetric analysis/Differential Scanning Calorimetry techniques have been used to investigate the effect of purification of carbon nano tubes on morphology and structural quality of them. The weight ratio of carbon nano tubes in purified sample re saved to 85/8 %.

  16. Surface and bulk modifications of 1.5 mole % Sr/La{sub 2}O{sub 3} catalyst with different Co, Ni, and Cu amounts

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Cortes, Sergio; Fontal, Bernardo [Universidad de los Andes, Merida (Venezuela); Moronta, Delfin [Universidad Central de Venezuela, Caracas (Venezuela)

    2001-08-01

    The effects of Co, Ni and Cu oxide content on the surface and bulk of the 1.5 mole % Sr/La{sub 2}O{sub 3} catalysts were studied. Series of M/Sr-La catalysts (MCo, Ni, Cu) were prepared by successive immersion impregnation. The solids were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), temperature-programmed reduction (TPR), electron paramagnetic resonance (EPR), specific surface area measurements (BET) and thermogravimetric analysis (TGA). The Sr/La{sub 2}O{sub 3} modified with different Co, Ni, and Cu loading shows a strong metal oxide interaction with La{sub 2}O{sub 3}. This probably begin over anionic vacancies or structure defects favoring LaSrMO{sub x} solid solution formation with island-like structures according to a Volmer-Weber growth. It is proposed that the growth mode of La-Co, La-Ni and La-Cu stoichiometric phases occur from solid solutions. The formation of only a La-M single phase, probably non-stoichiometric, increases the material porosity while different phases favor the agglomeration or sintering of the particles. [Spanish] En este trabajo se estudia el efecto de la cantidad de cobalto, niquel y cobre sobre las estructuras superficial y masica del sistema 1.5% molar Sr/La{sub 2}O{sub 3}. Los catalizadores M/Sr-La (M = Co, Ni, Cu) fueron preparados por el metodo de impregnacion con exceso de solucion. Los solidos se caracterizaron por difraccion de rayos-X, espectroscopia infrarroja con transformada de Fourier, reduccion a temperatura programada, resonancia paramagnetica del electron, medidas del area superficial especifica por el metodo de BET y analisis termogravimetrico. El catalizador Sr/La{sub 2}O{sub 3} modificado con diferentes cantidades de Co, Ni y Cu muestra una interaccion fuerte con el oxido del metal de transicion, probablemente sobre las vacancias anionicas o defectos estructurales que favorecen la formacion de la solucion solida LaSrMox en forma de isla, segun el mecanismo de crecimiento de fase de Volmer

  17. High-speed conversion of carbon dioxide into methanol using catalyst. Shokubai ni yoru nisanka tanso no kosoku methanol ka

    Energy Technology Data Exchange (ETDEWEB)

    Inui, T. (Kyoto University, Kyoto (Japan). Faculty of Enineering)

    1993-02-01

    This paper describes high-speed conversion of CO2 into methanol. When a Cu-Zn-Cr-Al oxide-based catalyst (MSCp catalyst) prepared by using a sedimentation process used for synthesizing methanol from CO is applied to converting CO2 into methanol, the methanol yield decreases down to a several fraction of CO to methanol conversion, with a possibility of greater catalytic deactivation. If this catalyst prepared by using a homogeneous gelation process (MSCg catalyst) is used, the yield of methanol from CO2 increases by 240 plus percent over the case of using the MSCp catalyst, and no catalytic deactivation occurs at all during a use for ten and odd hours. Further, when La2O3 is added to the MSCg catalyst at 4% by weight, the methanol yield increases by about two times as much as the case without addition, and the temperature at which the maximum yield is achieved shifts to a lower temperature side by about 20[degree]C. Combining Ag or Pd with the MSCg catalyst provides the same effects. The paper touches on an attempt of high-speed CO2 conversion using this catalyst loaded with ceramic fibers. 15 refs., 5 figs., 2 tabs.

  18. Mono-, bi-, and tri-metallic Ni-based catalysts for the catalytic hydrotreatment of pyrolysis liquids

    NARCIS (Netherlands)

    Yin, Wang; Venderbosch, Robbie H.; He, Songbo; Bykova, Maria V.; Khromova, Sofia A.; Yakovlev, Vadim A.; Heeres, Hero J.

    Catalytic hydrotreatment is a promising technology to convert pyrolysis liquids into intermediates with improved properties. Here, we report a catalyst screening study on the catalytic hydrotreatment of pyrolysis liquids using bi- and tri-metallic nickel-based catalysts in a batch autoclave (initial

  19. Studies on the hydroprocessing of deashed Oil. 12. ; Characterization of the used catalyst in the pilot plant (2). Deashed oil no suisoka bunkai hanno ni kansuru kenkyu. 12. ; Pilot shiyozumi shokubai no characterization (2)

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, T.; Oshima, K. (Mitsubishi Kasei Corp., Tokyo (Japan)); Kageyama, Y. (Nippon Brown Coal Liquefaction Co. Ltd., Tokyo (Japan))

    1991-11-07

    With an objective to clarify causes of deactivation of catalysts used in brown coal liquefaction process, discussions were given on catalysts recovered after use of 3400 hours as to their behavior of accumulating ash metals and carbonaceous substances, changes in the catalyst properties, and remaining activity. The catalysts used were Ca-Ni-Mo/Al2O3. Metals in the catalysts were quantitatively analyzed using ICP emission spectral analysis and atomic absorption analysis, and the C-amount using a CHN coder. The surface area was measured using the BET process and the pore volume using a porosimeter. The remaining activity in the used catalysts was evaluated by modelled hydrogenation of 1-methylnaphthalene. The results may be summarized as follows: Metals deposited on the catalysts are Mg, Ca, Fe, Na, Si and K, identically with the case of 1000-hour used catalysts; carbonaceous mass on the catalysts would range from 10% to 15%; the catalyst surface area and pore volume decrease with increasing carbonaceous matter accumulation; and hydrogenation activity was found decreased in the model hydrogenation, which should be because the activity has correlation with alkaline metal accumulation, and the metals enter fine pores to poison activity points. 3 refs., 6 figs.

  20. Ni2+ supported on hydroxyapatite-core@shell γ-Fe2O3 nanoparticles as new and green catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H-ones under solvent-free condition

    Directory of Open Access Journals (Sweden)

    Eshagh Rezaee Nezhad

    2013-10-01

    Full Text Available The aim of this research is to study Ni2+ supported on hydroxyapatite-core-shell magnetic γ-Fe2O3 nanoparticles (γ-Fe2O3@HAp-Ni2+ as a green and recyclable catalyst for the Biginelli reaction under solvent-free conditions. One-pot multi-component condensation of 1,3-dicarbonyl compounds, urea and aldehydes at 80 oC affords the corresponding compounds in high yields and in short reaction times using γ-Fe2O3@HAp-Ni2+. The catalyst can be readily isolated using an external magnet and no obvious loss of activity was observed when the catalyst was reused in seven consecutive runs. The mean size and the surface morphology of the nanoparticles were characterized by transmission electron microscopy, scanning electron microscope, vibrating sample magnetometry, X-ray powder diffraction and Fourier transform infrared techniques.

  1. Produção de hidrogênio a partir da reforma a vapor de etanol utilizando catalisadores Cu/Ni/gama-Al2o3 Hydrogen production by ethanol steam reforming using Cu/Ni/gamma-Al2o3 catalysts

    Directory of Open Access Journals (Sweden)

    Thaísa A. Maia

    2007-04-01

    Full Text Available Cu/Ni/gamma-Al2O3 catalysts were prepared by an impregnation method with 2.5 or 5% wt of copper and 5 or 15% wt of nickel and applied in ethanol steam reforming. The catalysts were characterized by atomic absorption spectrophotometry, X-ray diffraction, temperature programmed reduction with hydrogen and nitrogen adsorption. The samples showed low crystallinity, with the presence of CuO and NiO, both as crystallites and in dispersed phase, as well as of NiO-Al2O3. The catalytic tests carried out at 400 ºC, with a 3:1 water/ethanol molar ratio, indicated the 5Cu/5Ni/Al2O3 catalyst as the most active for hydrogen production, with a hydrogen yield of 77% and ethanol conversion of 98%.

  2. Synthesis and Electrocatalytic Activity of Ammonium Nickel Phosphate, [NH4]NiPO4·6H2O, and β-Nickel Pyrophosphate, β-Ni2P2O7: Catalysts for Electrocatalytic Decomposition of Urea.

    Science.gov (United States)

    Meguerdichian, Andrew G; Jafari, Tahereh; Shakil, Md R; Miao, Ran; Achola, Laura A; Macharia, John; Shirazi-Amin, Alireza; Suib, Steven L

    2018-02-19

    Electrocatalytic decomposition of urea for the production of hydrogen, H 2, for clean energy applications, such as in fuel cells, has several potential advantages such as reducing carbon emissions in the energy sector and environmental applications to remove urea from animal and human waste facilities. The study and development of new catalyst materials containing nickel metal, the active site for urea decomposition, is a critical aspect of research in inorganic and materials chemistry. We report the synthesis and application of [NH 4 ]NiPO 4 ·6H 2 O and β-Ni 2 P 2 O 7 using in situ prepared [NH 4 ] 2 HPO 4 . The [NH 4 ]NiPO 4 ·6H 2 O is calcined at varying temperatures and tested for electrocatalytic decomposition of urea. Our results indicate that [NH 4 ]NiPO 4 ·6H 2 O calcined at 300 °C with an amorphous crystal structure and, for the first time applied for urea electrocatalytic decomposition, had the greatest reported electroactive surface area (ESA) of 142 cm 2 /mg and an onset potential of 0.33 V (SCE) and was stable over a 24-h test period.

  3. X-ray Crystallographic, Multifrequency Electron Paramagnetic Resonance, and Density Functional Theory Characterization of the Ni(P(Cy)2N(tBu)2)2(n+) Hydrogen Oxidation Catalyst in the Ni(I) Oxidation State.

    Science.gov (United States)

    Niklas, Jens; Westwood, Mark; Mardis, Kristy L; Brown, Tiara L; Pitts-McCoy, Anthony M; Hopkins, Michael D; Poluektov, Oleg G

    2015-07-06

    The Ni(I) hydrogen oxidation catalyst [Ni(P(Cy)2N(tBu)2)2](+) (1(+); P(Cy)2N(tBu)2 = 1,5-di(tert-butyl)-3,7-dicyclohexyl-1,5-diaza-3,7-diphosphacyclooctane) has been studied using a combination of electron paramagnetic resonance (EPR) techniques (X-, Q-, and D-band, electron-nuclear double resonance, hyperfine sublevel correlation spectroscopy), X-ray crystallography, and density functional theory (DFT) calculations. Crystallographic and DFT studies indicate that the molecular structure of 1(+) is highly symmetrical. EPR spectroscopy has allowed determination of the electronic g tensor and the spin density distribution on the ligands, and revealed that the Ni(I) center does not interact strongly with the potentially coordinating solvents acetonitrile and butyronitrile. The EPR spectra and magnetic parameters of 1(+) are found to be distinctly different from those for the related compound [Ni(P(Ph)2N(Ph)2)2](+) (4(+)). One significant contributor to these differences is that the molecular structure of 4(+) is unsymmetrical, unlike that of 1(+). DFT calculations on derivatives in which the R and R' groups are systematically varied have allowed elucidation of structure/substituent relationships and their corresponding influence on the magnetic resonance parameters.

  4. Effect of CO{sub 2}-admixture on the catalytic performance of Ni-Nb-M-O catalysts in oxidative dehydrogenation of ethane to ethylene

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, A.; Kalevaru, V.N.; Martin, A. [Rostock Univ. (Germany). Leibniz-Institut fuer Katalyse e.V.; Hari Kumar, A. Sri; Lingaiah, N.; Prasad, P.S. Sai [Indian Institute of Chemical Technology, Hyderabad (India). Inorganic and Physical Chemistry Div.

    2012-07-01

    In this work, we report the synthesis, characterization and application of Ni-Nb-M-O catalysts with different promoters (M = Cr, Mo, W) for the oxidative dehydrogenation (ODH) of ethane to ethylene. Ni:Nb:M ratio was kept at 1:0.176:0.1 (atomic ratio). The catalysts were calcined at 450 C/5h/air. Catalytic tests were carried out in a fixed bed quartz reactor in the temperature range from 300 to 450 C, with a fixed W/F (1.02 g/cm{sup 3} . s{sup -1}) but with changing mole ratios of C{sub 2}H{sub 6}:O{sub 2}:CO{sub 2}:N{sub 2} (1:0-1.4:1.4-0:2). The product analysis was made off-line using GC equipped with FID. It is evident that the CO{sub 2}-admixture to the reactant feed caused a slight decrease in the conversion of ethane but considerably improved the selectivity of ethylene. Among the three promoters of the same group applied, Cr exhibited superior performance compared to other two. This means increase in d-character of transition metal (i.e. from 3d to 5d) has shown an adverse effect on the conversion of ethane and selectivity of ethylene. (orig.)

  5. Quaternary Pt{sub 2}Ru{sub 1}Fe{sub 1}M{sub 1}/C (M=Ni, Mo, or W) catalysts for methanol electro-oxidation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Min Ku; Lee, Ki Rak; Kang, Kweon Ho; Park, Geun Il [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Jeon, Hyung Joon [Kyoto University, Kyoto (Japan); McGinn, Paul J. [University of Notre Dame, Indiana (United States)

    2015-02-15

    Quaternary Pt{sub 2}Ru{sub 1}Fe{sub 1}M{sub 1}/C (M=Ni, Mo, or W) catalysts were investigated for the methanol electro-oxidation reaction (MOR). Electrocatalytic activities of the quaternary catalysts for CO electro-oxidation were studied via CO stripping experiments, and the Pt{sub 2}Ru{sub 1}Fe{sub 1}Ni{sub 1}/C and Pt{sub 2}Ru{sub 1}Fe{sub 1}W{sub 1}/C catalysts exhibited lowered on-set potential compared to that of a commercial PtRu/C catalyst. MOR activities of the quaternary catalysts were determined by linear sweep voltammetry (LSV) experiments, and the Pt{sub 2}Ru{sub 1}Fe{sub 1}W{sub 1}/C catalyst outperformed the commercial PtRu/C catalyst by 170 and 150% for the mass and specific activities, respectively. X-ray photoelectron spectroscopy (XPS) was employed to analyze surface oxidation states of constituent atoms, and it was identified that the structure of the synthesized catalysts are close to a nano-composite of Pt and constituent metal hydroxides and oxides. In addition, the XPS results suggested that the bi-functional mechanism accounts for the improved performance of the Pt{sub 2}Ru{sub 1}Fe{sub 1}Ni{sub 1}/C and Pt{sub 2}Ru{sub 1} Fe{sub 1}W{sub 1}/C catalysts.

  6. Treatment of a non-azo dye aqueous solution by CWAO in continuous reactor using a Ni catalyst derived from hydrotalcite-like precursor

    Energy Technology Data Exchange (ETDEWEB)

    Vallet, Ana, E-mail: avallet@quim.ucm.es [Grupo de Catalisis y Procesos de Separacion (CyPS), Departamento de Ingenieria Quimica, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain); Besson, Michele, E-mail: michele.besson@ircelyon.univ-lyon1.fr [IRCELYON, Institut de recherches sur la catalyse et l' environnement de Lyon, UMR5256 CNRS-Universite Lyon1, 2 Avenue Albert Einstein, F-69626 Villeurbanne Cedex (France); Ovejero, Gabriel; Garcia, Juan [Grupo de Catalisis y Procesos de Separacion (CyPS), Departamento de Ingenieria Quimica, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Ni supported over hydrotalcite calcined precursors as catalyst. Black-Right-Pointing-Pointer Catalytic wet air oxidation in trickle bed reactor for Basic Yellow 11 removal. Black-Right-Pointing-Pointer Dye removal depends on temperature, initial dye concentration and flow rate. Black-Right-Pointing-Pointer The catalyst proved to be stable and efficient for the dye degradation. - Abstract: Catalytic wet air oxidation (CWAO) of a Basic Yellow 11 (BY11) aqueous solution, chosen as a model of a hardly biodegradable non-azo dye was carried out in a continuous-flow trickle-bed reactor, using nickel supported over hydrotalcite precursor calcined at 550 Degree-Sign C. An increase in the reaction temperature (120-180 Degree-Sign C), and a decrease in dye concentration (1000-3000 ppm) or liquid flow rate (0.1-0.7 mL min{sup -1}) enhanced the CWAO performance in a 30 and 19% for the variation of the temperature and concentration respectively. After a small leaching observed within the first hours, the catalyst proved to be very stable during the 65-day reaction. The CWAO process was found to be very efficient, achieving BY11 conversion up to 95% and TOC conversion up to 85% at 0.1 mL min{sup -1} and 180 Degree-Sign C under 5 MPa air.

  7. Treatment of a non-azo dye aqueous solution by CWAO in continuous reactor using a Ni catalyst derived from hydrotalcite-like precursor

    International Nuclear Information System (INIS)

    Vallet, Ana; Besson, Michèle; Ovejero, Gabriel; García, Juan

    2012-01-01

    Highlights: ► Ni supported over hydrotalcite calcined precursors as catalyst. ► Catalytic wet air oxidation in trickle bed reactor for Basic Yellow 11 removal. ► Dye removal depends on temperature, initial dye concentration and flow rate. ► The catalyst proved to be stable and efficient for the dye degradation. - Abstract: Catalytic wet air oxidation (CWAO) of a Basic Yellow 11 (BY11) aqueous solution, chosen as a model of a hardly biodegradable non-azo dye was carried out in a continuous-flow trickle-bed reactor, using nickel supported over hydrotalcite precursor calcined at 550 °C. An increase in the reaction temperature (120–180 °C), and a decrease in dye concentration (1000–3000 ppm) or liquid flow rate (0.1–0.7 mL min −1 ) enhanced the CWAO performance in a 30 and 19% for the variation of the temperature and concentration respectively. After a small leaching observed within the first hours, the catalyst proved to be very stable during the 65-day reaction. The CWAO process was found to be very efficient, achieving BY11 conversion up to 95% and TOC conversion up to 85% at 0.1 mL min −1 and 180 °C under 5 MPa air.

  8. NiO-NF/MWCNT nanocomposite catalyst as a counter electrode for high performance dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Raissan Al-bahrani, Majid [Center for Nanoscale Characterization & Devices (CNCD), Wuhan National Laboratory for Optoelectronics (WNLO)-School of Physics, Huazhong University of Science and Technology - HUST, Luoyu Road 1037, Wuhan 430074 (China); Faculty of Science, Thi-Qar University, Nassiriya (Iraq); Liu, Linfeng [Michael Grätzel Center for Mesoscopic Solar Cells, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074 (China); Ahmad, Waqar; Tao, Jiayou; Tu, Fanfan [Center for Nanoscale Characterization & Devices (CNCD), Wuhan National Laboratory for Optoelectronics (WNLO)-School of Physics, Huazhong University of Science and Technology - HUST, Luoyu Road 1037, Wuhan 430074 (China); Cheng, Ze [School of Physics, Huazhong University of Science and Technology (HUST), Luoyu Road 1037, Wuhan 430074 (China); Gao, Yihua, E-mail: gaoyihua@hust.edu.cn [Center for Nanoscale Characterization & Devices (CNCD), Wuhan National Laboratory for Optoelectronics (WNLO)-School of Physics, Huazhong University of Science and Technology - HUST, Luoyu Road 1037, Wuhan 430074 (China)

    2015-03-15

    Highlights: • High-performance NiO-NF/MWCNT CE was incorporated in a Pt-CE in DSSCs. • NiO-NF/MWCNT CE exhibits a high power conversion efficiency (PCE) of 7.63%. • NiO-NF/MWCNT composite has a high catalytic activity for the reduction of I{sub 3}{sup −}. • NiO-NF/MWCNT composite has a low R{sub ct} on the electrolyte/CE interface. - Abstract: In this paper, we fabricated nickel oxide nanofilament/multiwall carbon nanotubes (NiO-NF/MWCNT) nanocomposite by a simple hydrothermal synthesis method as a counter- electrode (CE) in a dye-sensitized solar cell (DSSC). Transmission electron microscopy, scanning electron microscopy images and X-ray diffraction analysis clearly indicated the formation of NiO-NF/MWCNT nanocomposite. The electro-chemical properties of NiO-NF/MWCNT CE are studied by cyclic voltammetry and electrochemical impedance spectroscopy. In particular, current-voltage measurements indicated superior power conversion efficiency (PCE) of 7.63% of the NiO-NF/MWCNT CE compared to 6.72% for the platinum (Pt). The superior photovoltaic performance and low cost of the NiO-NF/MWCNT nanocomposite can be potentially exploited as a new counter-electrode in DSSCs.

  9. NiO-NF/MWCNT nanocomposite catalyst as a counter electrode for high performance dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Raissan Al-bahrani, Majid; Liu, Linfeng; Ahmad, Waqar; Tao, Jiayou; Tu, Fanfan; Cheng, Ze; Gao, Yihua

    2015-01-01

    Highlights: • High-performance NiO-NF/MWCNT CE was incorporated in a Pt-CE in DSSCs. • NiO-NF/MWCNT CE exhibits a high power conversion efficiency (PCE) of 7.63%. • NiO-NF/MWCNT composite has a high catalytic activity for the reduction of I 3 − . • NiO-NF/MWCNT composite has a low R ct on the electrolyte/CE interface. - Abstract: In this paper, we fabricated nickel oxide nanofilament/multiwall carbon nanotubes (NiO-NF/MWCNT) nanocomposite by a simple hydrothermal synthesis method as a counter- electrode (CE) in a dye-sensitized solar cell (DSSC). Transmission electron microscopy, scanning electron microscopy images and X-ray diffraction analysis clearly indicated the formation of NiO-NF/MWCNT nanocomposite. The electro-chemical properties of NiO-NF/MWCNT CE are studied by cyclic voltammetry and electrochemical impedance spectroscopy. In particular, current-voltage measurements indicated superior power conversion efficiency (PCE) of 7.63% of the NiO-NF/MWCNT CE compared to 6.72% for the platinum (Pt). The superior photovoltaic performance and low cost of the NiO-NF/MWCNT nanocomposite can be potentially exploited as a new counter-electrode in DSSCs

  10. Upgrading of liquid fuel from the vacuum pyrolysis of biomass over the Mo-Ni/{gamma}-Al{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ying; Wang, Lu [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou Guangdong 510640 (China); Key Laboratory of Renewable Energy and Gas Hydrate, CAS, Guangzhou Guangdong 510640 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Wang, Tiejun; Ma, Longlong; Zhang, Qi [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou Guangdong 510640 (China); Key Laboratory of Renewable Energy and Gas Hydrate, CAS, Guangzhou Guangdong 510640 (China)

    2009-08-15

    High amounts of acid compounds in bio-oil not only lead to the deleterious properties such as corrosiveness and high acidity, but also set up many obstacles to its wide applications. By hydrotreating the bio-oil under mild conditions, some carboxylic acid compounds could be converted to alcohols which would esterify with the unconverted acids in the bio-oil to produce esters. The properties of the bio-oil could be improved by this method. In the paper, the raw bio-oil was produced by vacuum pyrolysis of pine sawdust. The optimal production conditions were investigated. A series of nickel-based catalysts were prepared. Their catalytic activities were evaluated by upgrading of model compound (glacial acetic acid). Results showed that the reduced Mo-10Ni/{gamma}-Al{sub 2}O{sub 3} catalyst had the highest activity with the acetic acid conversion of 33.2%. Upgrading of the raw bio-oil was investigated over reduced Mo-10Ni/{gamma}-Al{sub 2}O{sub 3} catalyst. After the upgrading process, the pH value of the bio-oil increased from 2.16 to 2.84. The water content increased from 46.2 wt.% to 58.99 wt.%. The H element content in the bio-oil increased from 6.61 wt.% to 6.93 wt.%. The dynamic viscosity decreased a little. The results of GC-MS spectrometry analysis showed that the ester compounds in the upgraded bio-oil increased by 3 times. It is possible to improve the properties of bio-oil by hydrotreating and esterifying carboxyl group compounds in the bio-oil. (author)

  11. Hydrodenitrogenation and hydrodesulphurization of heavy gas oil using NiMo/Al{sub 2}O{sub 3} catalyst containing phosphorous : experimental and kinetic studies

    Energy Technology Data Exchange (ETDEWEB)

    Ferdous, D.; Dalai, A.K. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Chemical Engineering; Adjaye, J. [Syncrude Canada Ltd., Edmonton, AB (Canada). Edmonton Research Centre

    2005-10-01

    Oil sand bitumens and their derived products contain high levels of nitrogen and sulfur compounds which cause the formation of SOx and NOx in the atmosphere. These compounds also deactivate the catalysts used in fluid catalytic cracking and hydrocracking. This study focused on finding a better catalyst to efficiently remove sulphur and nitrogen from oil sand-derived heavy gas oils. The NiMo/Al{sub 2}O{sub 3} catalyst with phosphorous (P) was used in a trickle-bed reactor under a range of temperature and pressure conditions to study the reactivity of vacuum, atmospheric and hydrocracked heavy gas oils produced from Athabasca bitumen. The concentration of phosphorous was maintained at 2.7 wt per cent, while the hydrogen flow rate and catalyst weight were maintained constant at 50 mL/min and 4 g respectively. An ANOVA analysis of experimental data was performed to optimize the process conditions for hydrodenitrogenation (HDN) and hydrodesulphurization (HDS) reactions. Kinetic studies for HDN and HDS reactions were studied within the temperature range of 340 to 400 degrees C using the power law model and the Langmuir-Hinshelhood model. It was shown that HDN and HDS of heavy gas oil follows first order kinetics. The activation energies for HDN and HDS reactions from the power law and Langmuir-Hinshelhood models were 94 and 96 kJ/mol and 113 and 137 kJ/mol, respectively. It was concluded that nitrogen and hydrogen sulfide adsorption have a significant influence on HDN and HDS reactions. 32 refs., 8 tabs., 7 figs.

  12. Effect of SiO 2-ZrO 2 supports prepared by a grafting method on hydrogen production by steam reforming of liquefied natural gas over Ni/SiO 2-ZrO 2 catalysts

    Science.gov (United States)

    Seo, Jeong Gil; Youn, Min Hye; Song, In Kyu

    SiO 2-ZrO 2 supports with various zirconium contents are prepared by grafting a zirconium precursor onto the surface of commercial Carbosil silica. Ni(20 wt.%)/SiO 2-ZrO 2 catalysts are then prepared by an impregnation method, and are applied to hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of SiO 2-ZrO 2 supports on the performance of the Ni(20 wt.%)/SiO 2-ZrO 2 catalysts is investigated. SiO 2-ZrO 2 prepared by a grafting method serves as an efficient support for the nickel catalyst in the steam reforming of LNG. Zirconia enhances the resistance of silica to steam significantly and increases the interaction between nickel and the support, and furthermore, prevents the growth of nickel oxide species during the calcination process through the formation of a ZrO 2-SiO 2 composite structure. The crystalline structures and catalytic activities of the Ni(20 wt.%)/SiO 2-ZrO 2 catalysts are strongly influenced by the amount of zirconium grafted. The conversion of LNG and the yield of hydrogen show volcano-shaped curves with respect to zirconium content. Among the catalysts tested, the Ni(20 wt.%)/SiO 2-ZrO 2 (Zr/Si = 0.54) sample shows the best catalytic performance in terms of both LNG conversion and hydrogen yield. The well-developed and pure tetragonal phase of ZrO 2-SiO 2 (Zr/Si = 0.54) appears to play an important role in the adsorption of steam and subsequent spillover of steam from the support to the active nickel. The small particle size of the metallic nickel in the Ni(20 wt.%)/SiO 2-ZrO 2 (Zr/Si = 0.54) catalyst is also responsible for its high performance.

  13. Structure and coke preventing characteristics of Ca-Ni-Mo/Al sub 2 O sub 3 catalyst for hydrogenation of brown coal liquid bottoms. Kattan ekikaabura suisokayo Ca-Ni-Mo/Al sub 2 O sub 3 shokubai no kozo to tansoshitsu seisei yokusei sayo

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, T. (Cosmo Oil Co. Ltd., Tokyo (Japan)); Kaneko, T.; Kageyama, Y. (Mitsubishi Kasei Corp., Tokyo (Japan). Research Center); Kawai, S. (Nippon Brown Coal Liquefaction Co. Ltd., Tokyo (Japan))

    1990-09-01

    Operating a 50 t/d fixed bed pilot plant, hydroprocessing of de-ashed coal liquid bottoms (DAO) derived from Victorial Brown coal liquefaction has been carried out in Australia using a newly developed Ca-Ni-Mo/Al {sub 2} O {sub 3} catalyst. This catalyst has a great advantage compared with conventional molybdenum catalysts in that there is less coke formation using this catalyst as indicated by 5,000 h runs in a 0.1 t/d bench scale plant. In this paper, the catalyst active center and the role of Ca in the Ca-Ni-Mo/Al {sub 2} O {sub 3} catalyst were analyzed using Raman, TPS-XPS, EXAFS and AES methods. Molybdenum is loaded as CaMoO {sub 4} and X-ray diffraction data. But the oxide is changed to MoS {sub 2} after sulfiding treatment. Data of the Mo-S bond obtained from EXAFS analysis indicated that MoS {sub 2} has a tendency to pile up on the Ca-Ni-Mo/Al {sub 2} O {sub 3} catalyst. 20 refs., 12 figs., 5 tabs.

  14. NiO-NF/MWCNT nanocomposite catalyst as a counter electrode for high performance dye-sensitized solar cells

    Science.gov (United States)

    Raissan Al-bahrani, Majid; Liu, Linfeng; Ahmad, Waqar; Tao, Jiayou; Tu, Fanfan; Cheng, Ze; Gao, Yihua

    2015-03-01

    In this paper, we fabricated nickel oxide nanofilament/multiwall carbon nanotubes (NiO-NF/MWCNT) nanocomposite by a simple hydrothermal synthesis method as a counter- electrode (CE) in a dye-sensitized solar cell (DSSC). Transmission electron microscopy, scanning electron microscopy images and X-ray diffraction analysis clearly indicated the formation of NiO-NF/MWCNT nanocomposite. The electro-chemical properties of NiO-NF/MWCNT CE are studied by cyclic voltammetry and electrochemical impedance spectroscopy. In particular, current-voltage measurements indicated superior power conversion efficiency (PCE) of 7.63% of the NiO-NF/MWCNT CE compared to 6.72% for the platinum (Pt). The superior photovoltaic performance and low cost of the NiO-NF/MWCNT nanocomposite can be potentially exploited as a new counter-electrode in DSSCs.

  15. Generalizable, Electroless, Template-Assisted Synthesis and Electrocatalytic Mechanistic Understanding of Perovskite LaNiO3 Nanorods as Viable, Supportless Oxygen Evolution Reaction Catalysts in Alkaline Media.

    Science.gov (United States)

    McBean, Coray L; Liu, Haiqing; Scofield, Megan E; Li, Luyao; Wang, Lei; Bernstein, Ashley; Wong, Stanislaus S

    2017-07-26

    The oxygen evolution reaction (OER) is a key reaction for water electrolysis cells and air-powered battery applications. However, conventional metal oxide catalysts, used for high-performing OER, tend to incorporate comparatively expensive and less abundant precious metals such as Ru and Ir, and, moreover, suffer from poor stability. To attempt to mitigate for all of these issues, we have prepared one-dimensional (1D) OER-active perovskite nanorods using a unique, simple, generalizable, and robust method. Significantly, our work demonstrates the feasibility of a novel electroless, seedless, surfactant-free, wet solution-based protocol for fabricating "high aspect ratio" LaNiO 3 and LaMnO 3 nanostructures. As the main focus of our demonstration of principle, we prepared as-synthesized LaNiO 3 rods and correlated the various temperatures at which these materials were annealed with their resulting OER performance. We observed generally better OER performance for samples prepared with lower annealing temperatures. Specifically, when annealed at 600 °C, in the absence of a conventional conductive carbon support, our as-synthesized LaNiO 3 rods not only evinced (i) a reasonable level of activity toward OER but also displayed (ii) an improved stability, as demonstrated by chronoamperometric measurements, especially when compared with a control sample of commercially available (and more expensive) RuO 2 .

  16. Experimental and kinetics studies of aromatic hydrogenation in a two-stage hydrotreating process using NiMo/Al{sub 2}O{sub 3} and NiW/Al{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Owusu-Boakye, A.; Dalai, A.K.; Ferdous, D. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Chemical Engineering, Catalysis and Chemical Reaction Engineering Laboratories; Adjaye, J. [Syncrude Canada Ltd., Edmonton, AB (Canada)

    2006-10-15

    The degree of hydrogenation of aromatics in light gas oil (LGO) feed from Athabasca bitumen was examined using a two-stage process. Experiments were conducted in a trickle-bed reactor using 2 catalysts, namely nickel molybdenum alumina (NiMo/Al{sub 2}O{sub 3}) in stage one and nickel tungsten alumina (NiW/Al{sub 2}O{sub 3}) in the second stage. NiMo/Al{sub 2}O{sub 3} was used in the first stage in order to remove nitrogen and sulphur containing heteroatoms. NiW/Al{sub 2}O{sub 3} was used in the second stage for saturation of the aromatic rings in the hydrocarbon species. The catalysts were used under a range of temperature and pressure condition. Temperature and liquid hourly space velocity ranged from 350 to 390 degrees C and 1.0 to 1.5 per hour, respectively. Pressure was kept constant at 11.0 MPa for all experiments. Reaction time results from the two-stage process were compared with those from a single-stage where hydrotreating was performed over NiMo/AL{sub 2}O{sub 3}. Product samples from different feedstocks were analyzed with respect to sulfur, nitrogen and aromatic content. Gasoline selectivity and kinetic parameters for hydrodesulphurization (HDS) or hydrodenitrogenation (HDN) reactions for the feed materials were also compared. The effect of hydrogen sulphide (H{sub 2}S) inhibition on aromatics hydrogenation (HDA) was also kinetically modelled using the Langmuir-Hinshelwood approach. Kinetic analysis of the single-stage hydrotreating process showed that HDA and HDS activities were slowed by the presence of hydrogen sulphide that is produced as a by-product of the HDS process. However, with inter-stage removal of hydrogen sulphide in the two-stage process, significant improvement of the HDA and HDS activities were noted. It was concluded that the experimental data was successfully predicted by the Langmuir-Hinshelwood kinetic models. 27 refs., 4 tabs., 8 figs.

  17. Synthesis of nanostructured NiO/Co3O4 through thermal decomposition of a bimetallic (Ni/Co) metal-organic framework as catalyst for cyclooctene epoxidation

    Science.gov (United States)

    Abbasi, Alireza; Soleimani, Mohammad; Najafi, Mahnaz; Geranmayeh, Shokoofeh

    2017-04-01

    Hydrothermal approach has led to the formation of a three-dimensional metal-organic framework (MOF), [NiCo(μ2-tp)(μ4-tp)(4,4‧-bpy)2]n (1) (tp = terephthalic acid and 4,4‧-bpy = 4,4‧-bipyridine) which was characterized by means of single-crystal X-ray diffraction analysis, powder X-ray diffraction (PXRD), FT-IR spectroscopy, scanning electron microscopy (SEM) and inductive coupled plasma optical emission spectroscopy (ICP-OES). Thermal decomposition of the MOF afforded nanostructured mixed metal oxide, namely NiO/Co3O4. The XRD and SEM analysis confirm the formation of the mixed metal oxide. The nanostructured NiO/Co3O4 demonstrated good catalytic activity and selectivity in the epoxidation of cyclooctene in the presence of tert-butyl hydroperoxide (TBHP) as oxidant.

  18. The effect of radiation-thermal treatment on the physicochemical properties of the Ni-Mo/Al2O3 hydrotreatment catalyst. II. UV-Vis diffuse reflectance spectra of surface compounds after irradiation

    International Nuclear Information System (INIS)

    Solovetskii, Yu.I.; Miroshinichenko, I.I.; Lunin, V.V.

    1993-01-01

    Radiation-thermal damage of the surface and the active metal phases of hydrodesulfurization Ni-Mo/Al 2 O 3 catalysts by a fast electron beam of up to 2.0 MeV energy was studied. UV-Vis diffuse reflectance spectra of the industrial and model coked systems after radiation-thermal treatment were measured. 14 refs., 2 figs

  19. Studies on the hydroprocessing of deashed oil. 13. ; Characterization of the catalyst used for 7800 hours. De-ashed-oil no suisoka bunkai hanno ni kansuru kenkyu. 13. ; 7800 jikan shiyozumi shokubai no characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, T. (Mitsubishi Kasei Corp., Tokyo (Japan)); Kimura, T. (Cosmo Research Institute, Tokyo (Japan)); Kageyama, Y. (Nippon Brown Coal Liquefaction Co. Ltd., Tokyo (Japan))

    1992-11-05

    It was intended to darify long-term performance of a secondary hydrogenation catalyst used for about one year in a 50t/d brown coal liquefaction pilot plant built in Australia. A catalyst used for about 3,400 hours in the pilot plant was used to perform a life test of 7,800 hours in total to investigate the catalyst deactivation behavior, ashed metal and carbonaceous material deposition behavior, and changes in catalyst properties. A catalyst is considered to deactivate mainly because of deposition of carbonaceous materials on the catalyst in the initial stage of reaction and accumulation of alkaline metals (Na and K). The catalyst activity is estimated to reduce to about half the initial activity in about 1,000 hours, but it was found that the activity reduces and the properties change very little thereafter. From the fact that changes in selectivity to reaction associated with reduced activity and in product properties are small, and so are in the apparent activation energy, it was made clear that Cu-Ni-Mo/Al2O3 catalyst can be used for about one year. 3 refs., 9 figs., 1 tab.

  20. Estudo microestrutural do catalisador Ni/gama-Al2O3: efeito da adição de CeO2 na reforma do metano com dióxido de carbono Microstructural study of Ni/gamma-Al2O3 catalyst: addition effects of CeO2 on carbon dioxide reforming of methane

    Directory of Open Access Journals (Sweden)

    Antoninho Valentini

    2003-10-01

    Full Text Available The carbon dioxide reforming of methane was carried out over nickel catalysts supported on the gamma-Al2O3/CeO2 system prepared by wet impregnation. With the increase of the CeO2 weight in the catalyst, a higher stability was observed in the catalytic activity, together with an excellent resistance to carbon deposition and a better Ni dispersion. The catalysts were characterized by means of surface area measurements, TPR, H2 chemisorption, XRD, SEM, EDX, XPS and TEM. An interaction between Ni and CeO2 was observed to the Ni/CeO2 sample after activation in a H2 atmosphere above 300 ºC. Such behavior has a significantly influence on the catalytic activity.

  1. Polyphosphoric acid supported on Ni0.5Zn0.5Fe2O4 nanoparticles as a magnetically-recoverable green catalyst for the synthesis of pyranopyrazoles

    Directory of Open Access Journals (Sweden)

    Farid Moeinpour

    2017-05-01

    Full Text Available Polyphosphoric acid supported on silica coated Ni0.5Zn0.5Fe2O4 nanoparticles was found to be magnetically separable, highly efficient, eco-friendly, green and recyclable heterogeneous catalyst. This new catalyst at first was fully characterized by TEM, SEM, FTIR and XRD techniques and then catalytic activity of this catalyst was investigated in the synthesis of 5-cyano-1,4-dihydropyrano[2,3-c]pyrazoles. Also the Ni0.5Zn0.5Fe2O4 magnetic nanoparticle-supported polyphosphoric acid could be reused at least six times without significant loss of activity. It could be recovered easily by applying an external magnet.

  2. Solar-Driven Reduction of Aqueous Protons Coupled to Selective Alcohol Oxidation with a Carbon Nitride-Molecular Ni Catalyst System.

    Science.gov (United States)

    Kasap, Hatice; Caputo, Christine A; Martindale, Benjamin C M; Godin, Robert; Lau, Vincent Wing-Hei; Lotsch, Bettina V; Durrant, James R; Reisner, Erwin

    2016-07-27

    Solar water-splitting represents an important strategy toward production of the storable and renewable fuel hydrogen. The water oxidation half-reaction typically proceeds with poor efficiency and produces the unprofitable and often damaging product, O2. Herein, we demonstrate an alternative approach and couple solar H2 generation with value-added organic substrate oxidation. Solar irradiation of a cyanamide surface-functionalized melon-type carbon nitride ((NCN)CNx) and a molecular nickel(II) bis(diphosphine) H2-evolution catalyst (NiP) enabled the production of H2 with concomitant selective oxidation of benzylic alcohols to aldehydes in high yield under purely aqueous conditions, at room temperature and ambient pressure. This one-pot system maintained its activity over 24 h, generating products in 1:1 stoichiometry, separated in the gas and solution phases. The (NCN)CNx-NiP system showed an activity of 763 μmol (g CNx)(-1) h(-1) toward H2 and aldehyde production, a Ni-based turnover frequency of 76 h(-1), and an external quantum efficiency of 15% (λ = 360 ± 10 nm). This precious metal-free and nontoxic photocatalytic system displays better performance than an analogous system containing platinum instead of NiP. Transient absorption spectroscopy revealed that the photoactivity of (NCN)CNx is due to efficient substrate oxidation of the material, which outweighs possible charge recombination compared to the nonfunctionalized melon-type carbon nitride. Photoexcited (NCN)CNx in the presence of an organic substrate can accumulate ultralong-lived "trapped electrons", which allow for fuel generation in the dark. The artificial photosynthetic system thereby catalyzes a closed redox cycle showing 100% atom economy and generates two value-added products, a solar chemical, and solar fuel.

  3. Effects of solvent and catalysts on the hydrogenolysis of alkylnaphthalenes; Alkylnaphthalene no suisoka bunkai ni okeru yobai to shokubai no koka

    Energy Technology Data Exchange (ETDEWEB)

    Futamura, S. [National Institute for Resources and Environment, Tsukuba (Japan)

    1996-10-28

    Catalytic effects of metal and carbon materials, which promote hydrogen transfer from hydrogen donor solvents, are investigated during hydrogenolysis of benzyl-1-methylnaphthalenes (BMN) selected as a hydrogen acceptor. For the isomer distribution of BMN after the reaction, almost the same molecular ratio before the reaction was obtained independent of the presence of catalysts. Selectivity of position during the addition of hydrogen atoms from tetralin was not found. For the reaction of BMN in tetralin, 1-methylnaphthalene and toluene were obtained as products, but the formation of benzylnaphthalene was not found. As for the nuclear hydride of BMN, the trace amount formation was confirmed by gas chromatography. For the hydrogen transfer from tetralin progressed catalytically, it was found that the nuclear of naphthalene can not be hydrogenated easily. This was considered to be due to the obstruction of hydrogen transfer from tetralin by the strong adsorption of BMN on the Ni surface. 1 ref., 1 fig., 2 tabs.

  4. XRD (X-Ray Diffraction) and nitrogen adsorption characterization of Ni-Pt/mordenite catalysts; Caracterizacao por EDX (Espectrometria de Raios-X), DRX (Difracao de Raios-X) e adsorcao de nitrogenio de catalisadores Ni/Pt/mordenita visando sua aplicacao na isomerizacao de n-hexano

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Geovana do Socorro V.; Sousa, Bianca V.; Rodrigues, Meiry Glaucia F. [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2008-07-01

    The search for molecules of high octane arose great interest in the isomerization processes. Catalysts to the zeolite base have been wide developed for the n-paraffins isomerization. In this work, bimetallic bifunctional catalysts supported on Mordenite zeolite were prepared samples containing 60Pt40Ni (wt.%) metal (Pt). The catalysts were obtained by competitive ion exchange using aqueous solutions of [Pt(NH{sub 3}){sub 4}]Cl{sub 2} and Ni(NH{sub 3}){sub 6}]Cl{sub 2} complexes. The EDS characterization analyses showed incorporation of the nickel and platinum mordenite zeolite. The diffractograms showed competitive ion exchange and calcination processes did not provoke appreciable changes in the zeolitic support framework. The peaks attributed to nickel and platinum oxides was possible to observe in the bimetallic catalysts 60Ni40Pt/MOR. The results of the N{sub 2} physical adsorption of the 60Ni40Pt/MOR showed that it did not have modification in the superficial area of the catalysts. (author)

  5. Synthesis and characterization of carbon nanotubes synthesized over NiO/Na-montmorillonite catalyst and application to a hydrogen peroxide sensor

    International Nuclear Information System (INIS)

    Hsu, H.-L.; Jehng, J.-M.; Liu, Y.-C.

    2009-01-01

    In this study, we demonstrate the synthesis of carbon nanotubes (CNTs) on clay mineral layers, and the preparation of hydrogen peroxide (H 2 O 2 ) sensor based on CNT/Nafion/Na-montmorillonite (Clay) composite film for the detection of H 2 O 2 . The nickel oxide metallic catalyst (NiO) has been prepared by the polyol method and then dispersed onto the clay mineral layers. The CNTs were successfully synthesized over the NiO/Clay catalyst onto clay layers to form a three-dimensional CNT/Clay network by thermal chemical vapor deposition method. From field-emission scanning electron microscope images, the results of X-ray diffraction and Fourier transfer infrared spectra; the layered clay platelets are apparently delaminated and exfoliated after the growth of CNTs onto the surface of clay minerals. The mixed hybrid film of Nafion and CNT/Clay is coated on the glassy carbon electrode to detect hydrogen peroxide (H 2 O 2 ). This composite film performs a detection limit of 1.0 x 10 -4 M for H 2 O 2 and the current is linear for H 2 O 2 concentrations from 0.1 to 12.8 mM. Furthermore, the sensitivity of the GCE modified with the CNT/Clay/Nafion hybrid film to H 2 O 2 was calculated to be 1.71 x 10 5 μA M -1 cm -2 . Consequently, the CNT/Clay/Nafion medium can probably be a useful electrode for the development of sensors due to its high sensitivity and applicability

  6. Studies on the catalysts for coal liquefaction. ; Specific behaviours of coals of different ranks in their hydrogenolysis reactions catalyzed by various kinds of catalysts. Sekitan ekikayo shokubai ni kansuru kenkyu. ; Suisoka bunkai seiseibutsu sosei ni oyobosu kakushu shokubai no koka

    Energy Technology Data Exchange (ETDEWEB)

    Takechi, Y; Ikenaga, N; Oda, H; Yokokawa, C [Kansai University, Osaka (Japan). Faculty of Engineering

    1991-11-07

    Three kinds of coals with different rank of 76, 85 and 87C% were hydrocracked to study the specific reaction behavior of four kinds of 1coal liquefaction catalysts such as CuCrO4, Fe2O3+S, MoO3-TiO2 and MoS3-Al2O3. The reaction was conducted without any solvent to find out the specific phenomenon of each combination of coal and catalyst, and terminated at the point where nearly 30% of an initial amount of coal is converted to benzene-soluble. The products were separated by GPC into four fractions, and their average molecular weights and intrinsic viscosities were measured to study characteristics of each combination. As a result, the molecular weight distribution was obviously dependent on the combination of coal and catalyst, and no specific relation was observed between the molecular weight and intrinsic viscosity. The molecular of each fraction had a bar shape with an elliptic section indicating no apparent correlation with the molecular weight. 3 refs., 1 figs., 2 tabs.

  7. A new high temperature reactor for operando XAS: Application for the dry reforming of methane over Ni/ZrO2 catalyst

    Science.gov (United States)

    Aguilar-Tapia, Antonio; Ould-Chikh, Samy; Lahera, Eric; Prat, Alain; Delnet, William; Proux, Olivier; Kieffer, Isabelle; Basset, Jean-Marie; Takanabe, Kazuhiro; Hazemann, Jean-Louis

    2018-03-01

    The construction of a high-temperature reaction cell for operando X-ray absorption spectroscopy characterization is reported. A dedicated cell was designed to operate as a plug-flow reactor using powder samples requiring gas flow and thermal treatment at high temperatures. The cell was successfully used in the reaction of dry reforming of methane (DRM). We present X-ray absorption results in the fluorescence detection mode on a 0.4 wt. % Ni/ZrO2 catalyst under realistic conditions at 750 °C, reproducing the conditions used for a conventional dynamic microreactor for the DRM reaction. The setup includes a gas distribution system that can be fully remotely operated. The reaction cell offers the possibility of transmission and fluorescence detection modes. The complete setup dedicated to the study of catalysts is permanently installed on the Collaborating Research Groups French Absorption spectroscopy beamline in Material and Environmental sciences (CRG-FAME) and French Absorption spectroscopy beamline in Material and Environmental sciences at Ultra-High Dilution (FAME-UHD) beamlines (BM30B and BM16) at the European Synchrotron Radiation Facility in Grenoble, France.

  8. Synthesis and characterization of Co and Ni catalysts supported on alumina, synthesized from aluminum industry wastes and its use in the reforming reaction of ethanol, to hydrogen production

    International Nuclear Information System (INIS)

    Saborio Gonzalez, Maricruz

    2013-01-01

    Alumina was synthesized from aluminum anodizing process wastes through a process of mechanical and thermal treatment of calcination,1373 K with a heating rate of 5 K/min to 8h, obtaining a pure alumina of corundum type, a crystal size of 9.77 nm. This material is used as a microporous support and have elaborated Cobalt heterogeneous catalysts (CO 3 O 4 / Al 2 O 3 ) and Nickel (NiO/Al 2 O 3 ) which were calcined at different temperatures (573 K, 773 K, 973 K, 1173 K). From these is produced hydrogen by ethenol catalytic reforming. Two techniques were used for driving the mixture EtOH:H 2 O (1:3) of starting gas. A first technique has involved trawling through boiling of the mixture. High percentages were obtained of hydrogen but to a lesser reaction time, consuming all starting reagent, the most efficient catalyst has been the CO 2 O 3 / Al 2 O 3 calcined at 973K with a production of H 2 of 50% v/v as well as CH 4 and CO of 10%v/v. The second type of starting reagent carryover has been mild heating at 333 K and nitrogen sweep, with the following results 11% v/v H 2 , 12% v/v CH 4 and 7% v/v CO. Addition of ethanol conversion maximums of 76% and hydrogen yield of 29%, of the theoretical yield based on the ethanol consumed. (author) [es

  9. A new high temperature reactor for operando XAS: Application for the dry reforming of methane over Ni/ZrO2 catalyst

    KAUST Repository

    Aguilar Tapia, Antonio

    2018-03-22

    The construction of a high-temperature reaction cell for operando X-ray absorption spectroscopy characterization is reported. A dedicated cell was designed to operate as a plug-flow reactor using powder samples requiring gas flow and thermal treatment at high temperatures. The cell was successfully used in the reaction of dry reforming of methane (DRM). We present X-ray absorption results in the fluorescence detection mode on a 0.4 wt. % Ni/ZrO2 catalyst under realistic conditions at 750 °C, reproducing the conditions used for a conventional dynamic microreactor for the DRM reaction. The setup includes a gas distribution system that can be fully remotely operated. The reaction cell offers the possibility of transmission and fluorescence detection modes. The complete setup dedicated to the study of catalysts is permanently installed on the Collaborating Research Groups French Absorption spectroscopy beamline in Material and Environmental sciences (CRG-FAME) and French Absorption spectroscopy beamline in Material and Environmental sciences at Ultra-High Dilution (FAME-UHD) beamlines (BM30B and BM16) at the European Synchrotron Radiation Facility in Grenoble, France.

  10. Deactivating Carbon Formation on a Ni/Al2O3 Catalyst under Methanation Conditions

    DEFF Research Database (Denmark)

    Olesen, Sine Ellemann; Andersson, Klas J.; Damsgaard, Christian Danvad

    2017-01-01

    . The longer the duration of the methanation test, the more carbon was built up on the Ni surfaces and the highest observed amount was quantified to be as much as eight carbon atoms per Ni surface atom (8 C/Nisurf), which would roughly correspond to an average coverage of four monolayers of graphene. From H2...... desorption measurements after reaction the 650 K TPH peak carbon structure is proposed to be partially hydrogenated, possibly resembling polycyclic aromatic-like carbon. The 775 K peak carbon species are likely more graphene-like. Results indicate that although carbon deposition nucleation may be initiated...

  11. Studies on the hydroprocessing of deashed oil. 9. ; Characterization of the used catalyst in the pilot plant. Deashed oil no suisoka bunkai hanno ni kansuru kenkyu. 9. ; Pilot plant shiyozumi shokubai no characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, T.; Hijiriyama, M. (Mitsubishi Kasei Co., Tokyo (Japan)); Kageyama, Y. (Nippon Brown Coal Liquefaction Co. Ltd., Tokyo (Japan))

    1990-11-29

    The secondary hydroprocessing process in the two-stage hydrogenating liquefaction equipment under development at Nippon Brown Coal Liquefaction Company uses a fixed bed system. To elucidate causes of catalyst activity degradation related therewith, catalyst used for about 1000 hours in a S -t/d pilot plant was collected to investigate deposition behavior of cokes and ashed metals and changes in catalyst properties. The catalyst is made of Ca-Ni-Mo/Al2O3, which was recovered from baskets placed in each layer in a reactor, washed in a predetermined manner, dried, and analyzed. In addition, in order to investigate remaining activity, 1-methylnaphthalene was hydrogenated, and deashed oil (DAO) was hydrocracked. The result may be summarized as follows: The major cause for the catalyst activity degradation is deposition of carbonaceous materials and ashed metals on the catalyst; and especially alkali metals (Na and K) were considered to be the major cause for the catalyst deactivation with time. 2 refs., 8 figs.

  12. Catalysts development to base of Cu and Ni supported in ZrO2 for the H2 generation by the methanol reformed in oxidizing atmosphere

    International Nuclear Information System (INIS)

    Lopez C, P.; Gutierrez, A.; Gutierrez W, C.; Mendoza A, D.; Martinez, G.; Perez H, R.

    2009-01-01

    The search of new alternating sources of energy is at the present time one of the primordial objectives to world level because of the global heating caused by the high emissions of CO 2 at the atmosphere. In this sense the employment of H 2 through the fuel cells offers a more viable alternative for the use of the energy coming from the connection H-H that can be appointed for use of mobile, industrial and homemade applications. However, to generate H 2 in enough quantities is a great challenge at technological level for the necessity of to count with highly selective and efficient catalysts to low reaction temperatures as well as a source that comes from renewable resources. Under this context the methanol reformed in oxidizing atmosphere offers great ecological as energetics and industrial advantages; inside this investigation plane, the Cu seems to be one of the suitable candidates for this reaction due to its high capacity to generate H 2 , besides the great potential of improvement in its physical-chemical properties when being worked in nano metric size and /or associated with other materials. On the other hand, it is known that the Ni addition improvement the catalytic properties because of a better material dispersion, what offers big possibilities of being applied in the H 2 generation in situ by means of the methanol reformed reaction in oxidizing atmosphere; and that the conformation of bimetallic particles Cu/Ni presented high selectivity and catalytic activity for the reaction in question. (Author)

  13. Heavy Oil Upgrading and Enhanced Recovery in a Steam Injection Process Assisted by NiO- and PdO-Functionalized SiO2 Nanoparticulated Catalysts

    Directory of Open Access Journals (Sweden)

    Luisana Cardona

    2018-03-01

    Full Text Available This work aims to investigate the effect of active catalytic nanoparticles on the improvement of the efficiency in recovery of a continuous steam injection process. Catalytic nanoparticles were selected through batch-adsorption experiments and the subsequent evaluation of the temperature for catalytic steam gasification in a thermogravimetric analyzer. A nanoparticulated SiO2 support was functionalized with 1.0 wt % of NiO and PdO nanocrystals, respectively, to improve the catalytic activity of the nanoparticles. Oil recovery was evaluated using a sand pack in steam injection scenarios in the absence and presence of a 500 mg/L SiNi1Pd1 nanoparticles-based nanofluid. The displacement test was carried out by constructing the base curves with water injection followed by steam injection in the absence and presence of the prepared treatment. The oil recovery increased 56% after steam injection with nanoparticles in comparison with the steam injection in the absence of the catalysts. The API gravity increases from 7.2° to 12.1°. Changes in the asphaltenes fraction corroborated the catalytic effect of the nanoparticles by reducing the asphaltenes content and the 620 °C+ residue 40% and 47%, respectively. Also, rheological measurements showed that the viscosity decreased by up to 85% (one order of magnitude after the nanofluid treatment during the steam injection process.

  14. Ni-SiO2 Catalysts for the Carbon Dioxide Reforming of Methane: Varying Support Properties by Flame Spray Pyrolysis

    Directory of Open Access Journals (Sweden)

    Emma C. Lovell

    2015-03-01

    Full Text Available Silica particles were prepared by flame spray pyrolysis (FSP as a support for nickel catalysts. The impact of precursor feed rate (3, 5 and 7 mL/min during FSP on the silica characteristics and the ensuing effect on catalytic performance for the carbon dioxide, or dry, reforming of methane (DRM was probed. Increasing the precursor feed rate: (i progressively lowered the silica surface area from ≈340 m2/g to ≈240 m2/g; (ii altered the silanol groups on the silica surface; and (iii introduced residual carbon-based surface species to the sample at the highest feed rate. The variations in silica properties altered the (5 wt % nickel deposit characteristics which in turn impacted on the DRM reaction. As the silica surface area increased, the nickel dispersion increased which improved catalyst performance. The residual carbon-based species also appeared to improve nickel dispersion, and in turn catalyst activity, although not to the same extent as the change in silica surface area. The findings illustrate both the importance of silica support characteristics on the catalytic performance of nickel for the DRM reaction and the capacity for using FSP to control these characteristics.

  15. Synthesis and characterization of bimetallic Pd-Ni catalysts in a CeO{sub 2} matrix for the generation of H{sub 2} by the reforming reaction of methanol; Sintesis y caracterizacion de catalizadores bimetalicos Pd-Ni en una matriz de CeO{sub 2} para la generacion de H{sub 2} mediante la reaccion de reformado de metanol

    Energy Technology Data Exchange (ETDEWEB)

    Contreras C, R.

    2016-07-01

    The hydrothermal method was used for the synthesis of CeO{sub 2} nano rods using Ce(NO{sub 3}){sub 3}·6H{sub 2}O and NH{sub 4}OH. The catalytic support was calcined at 700 degrees Celsius. The synthesis of CeO{sub 2} nano rods were impregnated with an aqueous solution of Ni(NO{sub 3}){sub 2}·6H{sub 2}O by an incipient wetness impregnation method at an appropriate concentration to yield 5 and 15% of Ni in the catalysts. Then 0.5% of Pd was impregnated using PdCl{sub 2}. The samples obtained were calcined at 400 and reduced at 450 degrees Celsius. The catalytic materials were characterized by: temperature programmed reduction (TPR), Scanning Electron Microscopy (Sem) , surface area and X-ray diffraction (XRD) . Sem results showed that the CeO{sub 2} is formed by nano rods and in lesser proportion semi spherical particles. Bet surface area of the catalysts decreases with Ni loading onto the CeO{sub 2} nano rods. Pd O and Ni O were reduced at low and high temperature as was observed by TPR. The CeO{sub 2} one-dimensional nano rods showed a highly crystalline structure with sharp diffraction peaks, with a typical fluorite structure (cubic structure of the CeO{sub 2}) and characteristic peaks corresponding to metallic Ni. No diffraction peaks of Pd were found. This is due to the low concentration of this metal in the catalyst. These catalysts showed high activity and selectivity to H{sub 2} at maximum reaction temperature. According to the results of activity and selectivity, the catalysts with Pd-Ni are an alternative for the H{sub 2} production in auto thermal reforming reaction of methanol. (Author)

  16. Effect of heat treatment on the physical properties of bimetallic doped catalyst, Cu-Ni/TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Bashiri, Robabeh, E-mail: noranimuti-mohamed@petronas.com.my; Sufian, Suriati [Chemical Engineering Dept. Universiti Teknologi PETRONAS, 31750 Tronoh, Perak (Malaysia); Mohamed, Norani Muti, E-mail: noranimuti-mohamed@petronas.com.my; Kait, Chong Fai, E-mail: chongfaikait@petronas.com.my [Fundamental and Applied Sciences Dept., Universiti Teknologi PETRONAS, 31750 Tronoh, Perak (Malaysia)

    2015-07-22

    Post heat treatment is critical for the doped semiconductor oxide in order to improve its photocatalytic performance. Thus work had been carried out to understand the effect of different calcination temperature (400, 450 and 500°C) on the physical properties of nanosized Cu-Ni/TiO{sub 2}Cu-Ni doped TiO{sub 2} nanoparticles prepared using a combined method of sol-gel and hydrothermal. The treated samples were characterized using Raman spectroscopy, Brunauer–Emmett–teller (BET) measurement, high resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FESEM), and diffuse reflectance UV-Vis spectroscopy (DR-UV-Vis). Raman analysis showed that all samples displayed anatase (101) phase of TiO{sub 2}, which is in good agreement with the TEM results. BET data showed that all prepared Cu-Ni/TiO{sub 2} with different calcination temperature are mesoporous. SEM images displayed spherical particles with typical size of about 15 to 20 nm. UV-Vis spectra illustrated that the absorbance edge of all prepared Cu-Ni/TiO{sub 2} have extended to the visible region with bandgap energies (2-2.1 eV) less than the pure anatase TiO{sub 2} (3.2 eV). Calcination temperature of 450°C is considered to be the optimum as it converts the synthesized Cu-Ni/TiO{sub 2} sample to have smaller average particle size with higher surface area that lead to more absorbance in the visible region and lower bandgap energy.

  17. Effect of heat treatment on the physical properties of bimetallic doped catalyst, Cu-Ni/TiO2

    International Nuclear Information System (INIS)

    Bashiri, Robabeh; Sufian, Suriati; Mohamed, Norani Muti; Kait, Chong Fai

    2015-01-01

    Post heat treatment is critical for the doped semiconductor oxide in order to improve its photocatalytic performance. Thus work had been carried out to understand the effect of different calcination temperature (400, 450 and 500°C) on the physical properties of nanosized Cu-Ni/TiO 2 Cu-Ni doped TiO 2 nanoparticles prepared using a combined method of sol-gel and hydrothermal. The treated samples were characterized using Raman spectroscopy, Brunauer–Emmett–teller (BET) measurement, high resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FESEM), and diffuse reflectance UV-Vis spectroscopy (DR-UV-Vis). Raman analysis showed that all samples displayed anatase (101) phase of TiO 2 , which is in good agreement with the TEM results. BET data showed that all prepared Cu-Ni/TiO 2 with different calcination temperature are mesoporous. SEM images displayed spherical particles with typical size of about 15 to 20 nm. UV-Vis spectra illustrated that the absorbance edge of all prepared Cu-Ni/TiO 2 have extended to the visible region with bandgap energies (2-2.1 eV) less than the pure anatase TiO 2 (3.2 eV). Calcination temperature of 450°C is considered to be the optimum as it converts the synthesized Cu-Ni/TiO 2 sample to have smaller average particle size with higher surface area that lead to more absorbance in the visible region and lower bandgap energy

  18. 镍催化剂催化硝基苯一步全加氢制备环己胺的研究%The highly selective hydrogenation of nitrobenzene tocyclohexylamine over Ni/carbon catalysts

    Institute of Scientific and Technical Information of China (English)

    何杰; 鲁新环; 景润; 胡傲; 赵亚榕; 陶佩佩; 夏清华

    2018-01-01

    采用微波加热浸渍法制备生物炭负载的Ni催化剂,催化剂XRD、TEM和XPS对催化剂进行表征.10%Ni/CSC-Ⅱ催化剂在硝基苯选择性加氢制环己胺反应中表现出很好的活性,在200℃,2.0 MPa H2,100 mg氢氧化锂的条件下,硝基苯的转化率为100%,目标产物环己胺选择性高达96.7%.结果表明微波加热有助于提高催化剂的活性.%Biocarbon supported Ni catalysts have been prepared by facile impregnation of Ni species by microwave-heating and used for selective hydrogenation of nitrobenzene to cyclohexylamine.These catalysts were characterized by X-ray diffraction, transmission electron microscope and X-ray photoelectron spectroscopy.For the hydrogenation of nitrobenzene, 10% Ni/CSC-II exhibits the best catalytic activity to achieve 100%conversion of nitrobenzene and 96 .7% selectivity of cyclohexylamine under reaction conditions of 200℃, 2.0 MPa H2 and 100 mg LiOH.The results show that microwave heating can improve the activity of the catalyst.

  19. Session 6: Catalytic hydro-dehalogenation of halon 1211 (CBrClF{sub 2}) over carbon supported Pd-Fe, Pd-Co and Pd-Ni bimetallic catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hai, Yu; Kennedy, E.M.; Md Azhar, Uddin; Dlugogorski, B.Z. [Newcastle Univ., Process Safety and Environment Protection Group, School of Engineering, Callaghan, NSW (Australia)

    2004-07-01

    In the current study, we present the result of our investigation on the hydro-dehalogenation of halon 1211 with hydrogen over carbon supported Pd-Fe, Pd-Co and Pd-Ni bimetallic catalysts. In addition to dissociatively adsorbing hydrogen, Fe, Co and Ni themselves can facilitate cleavage of C-halogen bonds. The effect of the interaction of a second metal (Fe, Co and Ni) with Pd on the conversion of halon 1211 and selectivity to CH{sub 2}F{sub 2} for the catalytic hydro-dehalogenation of halon 1211 is discussed. Activated carbon is chosen as support in order to minimize the interaction of support with the metals. The obtained experimental results show that the introduction of Fe, Co and Ni to Pd catalysts has a significant influence on the catalytic hydro-dehalogenation of halon 1211, especially with respect to the selectivity to CH{sub 2}F{sub 2}. The presence of Fe increases the amount of halon 1211 adsorbed on the surface of catalysts and enhances the cleavage of C-halogen bonds in halon 1211, resulting in a higher halon 1211 conversion level and selectivity to hydrocarbons. Higher selectivity to CHBrF{sub 2} is ascribed to the secondary reaction: CF{sub 2} + HBr {yields} CHBrF{sub 2}. (authors)

  20. Comparative study between traditional and modified Pechini synthesis methods in the preparation of LaNiO{sub 3} and LaNi{sub 0,8}Co{sub 0,2}O{sub 3} catalysts; Estudo comparativo entre os metodos de sintese Pechini tradicional e modificado na confeccao dos catalisadores LaNiO{sub 3} e LaNi{sub 0,8}Co{sub 0,2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Silva, F.E.F.; Aquino, F.M.; Silva, M.C.M.F., E-mail: fabio@cear.ufpb.br [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Departamento de Engenharia de Energias Renovaveis

    2016-07-01

    One of the ways of obtaining hydrogen is from the methane reforming reaction, which is an endothermic and non-spontaneous reaction. In order to minimize this energy, nickel catalysts are used. This work aims to synthesize and characterize the catalysts LaNiO{sub 3} and LaNi{sub 0,8}Co{sub 0,2}O{sub 3} using the Pechini method, making use of citric acid and ethylene glycol and modified Pechini, using the edible gelatin as a chelating and polymerizing agent. The obtained materials were characterized by X-Ray Diffraction (XRD), where the formation of peaks characteristic of perovskite and monophasic structures was observed. Scanning Electron Microscopy (SEM) showed that porosity and powders with few agglomerates were observed by both methods. In the analysis of determination of the specific surface area (BET) the materials were shown with areas that are according to the literature.

  1. In-situ Measurements of the Effect of Au Doping in Ni Catalysts on the Yield of Tubular Carbon Nanostructures

    DEFF Research Database (Denmark)

    Sharma, Renu; Chee, S.; Rez, P.

    characterization of as-deposited films, the samples were heated in vacuum up to reaction temperatures (500-650 °C). Acetylene was introduced in the sample region and pressures were kept constant during each experiment but varied between 1-3 mTorr for each individual experiment. Digital videos (15 frames/s) at low....... Formation of different structures depended upon the rate of growth, which was in turn controlled by pressure and temperature. Both in-situ and ex-situ analysis of the composition of the catalyst particles, effect of temperature and pressure on the morphology and structural mechanism for the formation...

  2. Growth of vertically aligned multiwalled carbon nanotubes forests on metal alloy Ni-Nb-N with low content of catalyst

    Science.gov (United States)

    Dubkov, S.; Trifonov, A.; Shaman, Yu; Pavlov, A.; Shulyat'ev, A.; Skorik, S.; Kirilenko, E. P.; Rygalin, B.

    2016-08-01

    This research shows the possibility of carbon nanotubes (CNTs) formation on the surface of low nickel (∼ 10 at.%) Ni-Nb-N amorphous metal alloy film by CVD method at 550 °C of the gas mixture based on acetylene. The structure of CNT were studied by transmission and scanning-electron microscopy, energy-dispersive X-ray and the Raman spectroscopy.

  3. Evaluation of the urea content in the synthesis by combustion reaction of the NiAl2O4 catalysts

    International Nuclear Information System (INIS)

    Leal, E.; Sousa, J.-P.L.M.L.; Costa, A.C.F.M.; Gama, L.; Argolo, F.; Sasaki, J.M.

    2009-01-01

    The aim of this work is to evaluate the influence of the urea fuel in the structure and morphology of the NiAl 2 O 4 prepared by combustion reaction. The powders were prepared according to the propellants and explosives theory, using urea in the stoichiometric composition, with 10% of excess and deficiency of this fuel. The samples were characterized by XRD, FTIR, particle size distribution and textural analysis by nitrogen adsorption (BET/BJH). The DRX results showed the presence of NiAl 2 O 4 as major phase and traces of NiO for all the samples. Also show crystallites size between 13 and 21 nm. All the samples showed large agglomerates size distribution, with D 50% between 18.6 and 20.4 μm, and morphology with irregular plates shape. The increase of the urea content caused an increase in the particle size and a reduction in the surface area, from 270 to 52 m 2 /g. (author)

  4. 2D NiFe/CeO2 Basic-Site-Enhanced Catalyst via in-Situ Topotactic Reduction for Selectively Catalyzing the H2 Generation from N2H4·H2O.

    Science.gov (United States)

    Wu, Dandan; Wen, Ming; Gu, Chen; Wu, Qingsheng

    2017-05-17

    An economical catalyst with excellent selectivity and high activity is eagerly desirable for H 2 generation from the decomposition of N 2 H 4 ·H 2 O. Here, a bifunctional two-dimensional NiFe/CeO 2 nanocatalyst with NiFe nanoparticles (∼5 nm) uniformly anchored on CeO 2 nanosheets supports has been successfully synthesized through a dynamic controlling coprecipitation process followed by in-situ topotactic reduction. Even without NaOH as catalyst promoter, as-designed Ni 0.6 Fe 0.4 /CeO 2 nanocatalyst can show high activity for selectively catalyzing H 2 generation (reaction rate (mol N2H4 mol -1 NiFe h -1 ): 5.73 h -1 ). As ceria is easily reducible from CeO 2 to CeO 2-x , the surface of CeO 2 could supply an extremely large amount of Ce 3+ , and the high-density electrons of Ce 3+ can work as Lewis base to facilitate the absorption of N 2 H 4 , which can weaken the N-H bond and promote NiFe active centers to break the N-H bond preferentially, resulting in the high catalytic selectivity (over 99%) and activity for the H 2 generation from N 2 H 4 ·H 2 O.

  5. The Synergy Effect of Ni-M (M = Mo, Fe, Co, Mn or Cr Bicomponent Catalysts on Partial Methanation Coupling with Water Gas Shift under Low H2/CO Conditions

    Directory of Open Access Journals (Sweden)

    Xinxin Dong

    2017-02-01

    Full Text Available Ni-M (M = Mo, Fe, Co, Mn or Cr bicomponent catalysts were prepared through the co-impregnation method for upgrading low H2/CO ratio biomass gas into urban gas through partial methanation coupling with water gas shift (WGS. The catalysts were characterized by N2 isothermal adsorption, X-ray diffraction (XRD, H2 temperature programmed reduction (H2-TPR, H2 temperature programmed desorption (H2-TPD, scanning electron microscopy (SEM and thermogravimetry (TG. The catalytic performances demonstrated that Mn and Cr were superior to the other three elements due to the increased fraction of reducible NiO particles, promoted dispersion of Ni nanoparticles and enhanced H2 chemisorption ability. The comparative study on Mn and Cr showed that Mn was more suitable due to its smaller carbon deposition rate and wider adaptability to various H2/CO and H2O/CO conditions, indicating its better synergy effect with Ni. A nearly 100 h, the lifetime test and start/stop cycle test further implied that 15Ni-3Mn was stable for industrial application.

  6. Ni/La2O3 catalyst containing low content platinum-rhodium for the dehydrogenation of N2H4·H2O at room temperature

    Science.gov (United States)

    O, Song-Il; Yan, Jun-Min; Wang, Hong-Li; Wang, Zhi-Li; Jiang, Qing

    2014-09-01

    Ni/La2O3 nanocatalyst with Pt and Rh content as low as 5 mol%, respectively, is successfully synthesized by a facile co-reduction method in the presence of hexadecyl trimethyl ammonium chloride aqueous solution under ambient atmosphere. Interestingly, the resulted Ni/La2O3 catalyst with low cost exhibits excellent catalytic activity to dehydrogenation of hydrous hydrazine (N2H4·H2O), producing hydrogen with 100% selectivity at room temperature (298 K), which represents a promising step toward the practical application for N2H4·H2O system on fuel cells.

  7. Effectiveness factors for a commercial steam reforming (Ni) catalyst and for a calcined dolomite used downstream biomass gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Corella, J; Narvaez, I; Orio, A [Madrid Univ. (Spain). Dept. of Chem. Eng.

    1997-12-31

    A commercial steam reforming catalyst from BASF, the G1-25 S one, and a calcined dolomite, Norte-1, from Cantabria-Spain, have been used, once crushed and sieved to different particle fractions between 1.0 and 4.0 mm. The materials have been tested downstream small pilot biomass gasifiers, bubbling fluidized bed type, gasifying with air and with steam. The Thiele modulus and the effectiveness factor have been calculated at temperatures of 750-850 deg C. It is experimentally shown that diffusion control plays an important part when particle size is larger than ca. 0.5 mm. This has to be taken into account when comparing the quality of the solids for tar elimination. (author) (5 refs.)

  8. Effectiveness factors for a commercial steam reforming (Ni) catalyst and for a calcined dolomite used downstream biomass gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Corella, J.; Narvaez, I.; Orio, A. [Madrid Univ. (Spain). Dept. of Chem. Eng.

    1996-12-31

    A commercial steam reforming catalyst from BASF, the G1-25 S one, and a calcined dolomite, Norte-1, from Cantabria-Spain, have been used, once crushed and sieved to different particle fractions between 1.0 and 4.0 mm. The materials have been tested downstream small pilot biomass gasifiers, bubbling fluidized bed type, gasifying with air and with steam. The Thiele modulus and the effectiveness factor have been calculated at temperatures of 750-850 deg C. It is experimentally shown that diffusion control plays an important part when particle size is larger than ca. 0.5 mm. This has to be taken into account when comparing the quality of the solids for tar elimination. (author) (5 refs.)

  9. In-situ growing NiCo2O4 nanoplatelets on carbon cloth as binder-free catalyst air-cathode for high-performance microbial fuel cells

    International Nuclear Information System (INIS)

    Cao, Chun; Wei, Liling; Wang, Gang; Shen, Jianquan

    2017-01-01

    Highlights: • NiCo 2 O 4 nanoplatelets were in-situ growing on carbon cloth as ORR catalyst in biofuel cells. • Binder-free cathode with the lower internal resistance. • Binder-free cathode was low-cost. • NiCo 2 O 4 -CFC shows better power generation performance than Pt/C. - Abstract: Air-cathode microbial fuel cells (MFCs) was one of most promising sustainable new energy device as well as an advanced sewage treatment technology, and thoroughly studies have been devoted to lower its cost and enhance its power generation. Herein, a binder-free and low-cost catalyst air-cathode was fabricated by in-situ electro-deposition of NiCo 2 O 4 nanoplatelets on carbon cloth, followed by feasible calcinations. The catalytic activity of catalyst air-cathode was optimized by varying the deposition time. And the optimal air-cathode was installed in real MFCs and exhibited distinct maximum out-put power density (645 ± 6 mW m −2 ), which was 12.96% higher than commercial Pt/C (571 ± 11 mW m −2 ). Noted that its remarkable electricity generation performance in MFCs should absolutely attributed to the well catalytic activity for oxygen reduction reaction, and more likely ascribed to its low internal resistance since binder-free catalyst air-cathode can facilitate the electron/charge transfer process. Therefore, it was an efficient strategy to improve the electricity generation performance of MFCs by using this binder-free catalyst air-cathode, which was also potential for application in many other electrochemical devices.

  10. Moessbauer Study of the Ni/Ca0.8Sr0.2Ti1-xFexO3-α Catalyst System for Partial Oxidation of Methane to Synthesis Gas

    International Nuclear Information System (INIS)

    Homonnay, Z.; Nomura, K.; Hamakawa, S.; Hayakawa, T.; Juhasz, G.; Kuzmann, E.; Vertes, A.

    2002-01-01

    The Ni/Ca 0.8 Sr 0.2 TiO 3 catalyst system prepared by the citrate method shows high activity in partial oxidation of methane to synthesis gas. It is assumed that the interaction of Ni with the perovskite lattice may be responsible for the increased catalytic activity. 1% 57 Fe dopant substituted for Ti was used in order to see if the presence of Ni has any perturbation effect on the structure of the perovskite. One may expect systematic changes in the Moessbauer parameters of the substitutional Fe impurity as a function of the NiO content if the bulk properties of the perovskite are affected. Samples with different Ni/Ca 0.8 Sr 0.2 Ti 0.99 57 Fe 0.01 O 3-α ratios from 0:1 to 1:1, and others having Fe substitutions for Ti up to 30%, all prepared by the citrate method, have been investigated. The Moessbauer spectra contained doublets of paramagnetic Fe 3+ and Fe 4+ species as well as paramagnetically relaxed Fe 3+ . These species were assigned to the bulk perovskite, the perovskite surface and the NiO/perovskite interface. The perturbation of the perovskite structure by Ni could not be verified.

  11. Catalisadores sol-gel de Ni-SiO2 e Ni-Al2O3 aplicados na reforma de metano com CO2 = Ni-SiO2 and Ni-Al2O3 sol-gel catalysts applied to methane reforming with CO2

    Directory of Open Access Journals (Sweden)

    Giane Gonçalves

    2005-01-01

    Full Text Available A reação de reforma do metano com CO2 apresenta-se como um processopromissor de geração de gás de síntese e hidrogênio. Neste sentido, foram preparados catalisadores de níquel-sílica e níquel-alumina pelo método sol-gel, com carga metálica nominal de 8% em massa. Os catalisadores foram caracterizados por redução à temperatura programada, análise termogravimétrica e determinação da área superficial específica. A reação de reforma do metano com CO2 foi realizada em um micro-reator contendo 500 mg de catalisador, previamente ativado em uma mistura redutora contendo hidrogênio. Osensaios de reforma a seco do metano foram realizados a 800°C, na pressão atmosférica, por um período de 12 horas, com uma razão molar de alimentação de [CO2:CH4] = 6. Os produtos da reação foram analisados por cromatografia gasosa. Dentre os catalisadoresavaliados, nas condições de reação estudadas, o catalisador de níquel suportado em sílica foi o que apresentou o melhor desempenho.The dry reforming reaction of methane comes as a promising process of syngas and hydrogen. Nickel catalysts on Al2O3 and SiO2 were synthesized by sol-gel method, with metalic load of 8% weight. The catalysts were characterized by temperature programmed reduction (TPR, termogravimetry analysis (TGA and specific surface area measurements (BET. The dry reforming reaction was performed in a micro reactor packed with 500 mg of catalyst, previously activated in atmosphere of hydrogen. The dry reforming tests were done at 800oC and atmospheric pressure by a period of 12 hours, with a molar ratio in the feeding of [CO2:CH4] = 6. The products of the reaction were analyzed by gas chromatograph. The Ni-SiO2 catalysts showed better performance.

  12. Thermodynamic Constraints in Using AuM (M = Fe, Co, Ni, and Mo) Alloys as N₂ Dissociation Catalysts: Functionalizing a Plasmon-Active Metal.

    Science.gov (United States)

    Martirez, John Mark P; Carter, Emily A

    2016-02-23

    The Haber-Bosch process for NH3 synthesis is arguably one of the greatest inventions of the 20th century, with a massive footprint in agriculture and, historically, warfare. Current catalysts for this reaction use Fe for N2 activation, conducted at high temperatures and pressures to improve conversion rate and efficiency. A recent finding shows that plasmonic metal nanoparticles can either generate highly reactive electrons and holes or induce resonant surface excitations through plasmonic decay, which catalyze dissociation and redox reactions under mild conditions. It is therefore appealing to consider AuM (M = Fe, Co, Ni, and Mo) alloys to combine the strongly plasmonic nature of Au and the catalytic nature of M metals toward N2 dissociation, which together might facilitate ammonia production. To this end, through density functional theory, we (i) explore the feasibility of forming these surface alloys, (ii) find a pathway that may stabilize/deactivate surface M substituents during fabrication, and (iii) define a complementary route to reactivate them under operational conditions. Finally, we evaluate their reactivity toward N2, as well as their ability to support a pathway for N2 dissociation with a low thermodynamic barrier. We find that AuFe possesses similar appealing qualities, including relative stability with respect to phase separation, reversibility of Fe oxidation and reduction, and reactivity toward N2. While AuMo achieves the best affinity toward N2, its strong propensity toward oxidation could greatly limit its use.

  13. Production of bio-hydrogenated diesel by catalytic hydrotreating of palm oil over NiMoS2/γ-Al2O3 catalyst.

    Science.gov (United States)

    Srifa, Atthapon; Faungnawakij, Kajornsak; Itthibenchapong, Vorranutch; Viriya-Empikul, Nawin; Charinpanitkul, Tawatchai; Assabumrungrat, Suttichai

    2014-04-01

    Catalytic hydrotreating of palm oil (refined palm olein type) to produce bio-hydrogenated diesel (BHD) was carried out in a continuous-flow fixed-bed reactor over NiMoS2/γ-Al2O3 catalyst. Effects of dominant hydrotreating parameters: temperature: 270-420°C; H2 pressure: 15-80 bar; LHSV: 0.25-5.0 h(-1); and H2/oil ratio: 250-2000 N(cm(3)/cm(3)) on the conversion, product yield, and a contribution of hydrodeoxygenation (HDO) and decarbonylation/decarboxylation (DCO/DCO2) were investigated to find the optimal hydrotreating conditions. All calculations including product yield and the contribution of HDO and DCO/DCO2 were extremely estimated based on mole balance corresponding to the fatty acid composition in feed to fully understand deoxygenation behaviors at different conditions. These analyses demonstrated that HDO, DCO, and DCO2 reactions competitively occurred at each condition, and had different optimal and limiting conditions. The differences in the hydrotreating reactions, liquid product compositions, and gas product composition were also discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Ganoderma-Like MoS2 /NiS2 with Single Platinum Atoms Doping as an Efficient and Stable Hydrogen Evolution Reaction Catalyst.

    Science.gov (United States)

    Guan, Yongxin; Feng, Yangyang; Wan, Jing; Yang, Xiaohui; Fang, Ling; Gu, Xiao; Liu, Ruirui; Huang, Zhengyong; Li, Jian; Luo, Jun; Li, Changming; Wang, Yu

    2018-05-27

    Herein, a unique ganoderma-like MoS 2 /NiS 2 hetero-nanostructure with isolated Pt atoms anchored is reported. This novel ganoderma-like heterostructure can not only efficiently disperse and confine the few-layer MoS 2 nanosheets to fully expose the edge sites of MoS 2 , and provide more opportunity to capture the Pt atoms, but also tune the electronic structure to modify the catalytic activity. Because of the favorable dispersibility and exposed large specific surface area, single Pt atoms can be easily anchored on MoS 2 nanosheets with ultrahigh loading of 1.8 at% (the highest is 1.3 at% to date). Owing to the ganoderma-like structure and platinum atoms doping, this catalyst shows Pt-like catalytic activity for the hydrogen evolution reaction with an ultralow overpotential of 34 mV and excellent durability of only 2% increase in overpotential for 72 h under the constant current density of 10 mA cm -2 . © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Preparation and characterization of micro-arc-induced Pd/TM(TM = Ni, Co and Ti) catalysts and comparison of their electrocatalytic activities toward ethanol oxidation

    International Nuclear Information System (INIS)

    Wang, Xiaoguang; Ma, Guanshui; Zhu, Fuchun; Lin, Naiming; Tang, Bin; Zhang, Zhonghua

    2013-01-01

    Using the electro-spark deposition technique, a novel kind of Pd/TM (TM = Ni, Co and Ti) electrode was successfully prepared by arc-depositing Pd on the transition metal substrates. The structure, morphology and chemical composition of the arc-deposited films were investigated using thin-film X-ray diffraction (TF-XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The results show that, a coarsening topographical morphology can be obtained, being composed of numerous craters/spots with sizes ranging from nano-scales to several microns. The electrochemical measurements indicate that the arc-deposited Pd/TM electrodes exhibit distinct electrochemical behaviors and the catalytic activity toward ethanol electro-oxidation reaction (EOR) is highly dependent upon the nature of substrate. Among the Pd/TM electrodes investigated, the arc-deposited Pd/Co reveals the best activity and superior poisoning tolerance towards ethanol oxidation and will find promising applications as a candidate for the anode catalyst of direct ethanol fuel cells (DEFCs)

  16. Ni/CeO{sub 2}-Al{sub 2}O{sub 3} catalysts promoted with noble metals for the hydrogen production by ethanol vapor reforming; Catalisadores de Ni/CeO{sub 2}-Al{sub 2}O{sub 3} promovidos com metais nobres para a producao de hidrogenio por reforma a vapor de etanol

    Energy Technology Data Exchange (ETDEWEB)

    Profeti, Luciene P.R.; Ticianelli, Edson Antonio; Assaf, Elisabete Moreira [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil). Inst. de Quimica]. E-mail: eassaf@iqsc.usp.br

    2008-07-01

    The catalytic activity of Ni/CeO{sub 2}-Al{sub 2}O{sub 3} catalysts modified with noble metals (Ru, Ir, Pt and Pd) was investigated in the steam reforming of ethanol. The catalysts were characterized by energy dispersive spectroscopy, X-ray diffraction, UV-Vis diffuse reflectance spectroscopy and H{sub 2} temperature-programmed reduction-X-ray absorption fine structure (XANES). The results showed that the formation of inactive nickel aluminate was avoided due to the presence of a CeO{sub 2} dispersed on the alumina. The promoting effect of noble metals included a decrease of the reduction temperatures of NiO species interacting with the support due to the hydrogen spillover effect, leading to an increase of the reducibilities of the promoted catalysts The better catalytic performance for the ethanol steam reforming was obtained for the NiPd/CeAl catalyst, which presented an effluent gaseous mixture with the highest H{sub 2} yield. (author)

  17. Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO2 reforming of methane

    KAUST Repository

    Biausque, Gregory; Laveille, Paco; Anjum, Dalaver H.; Caps, Valerie; Basset, Jean-Marie

    2015-01-01

    Embodiments of the present disclosure provide for NiPt nanoparticles, compositions and supports including NiPt nanoparticles, methods of making NiPt nanoparticles, methods of supporting NiPt nanoparticles, methods of using NiPt nanoparticles, and the like.

  18. Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO2 reforming of methane

    KAUST Repository

    Biausque, Gregory

    2015-09-24

    Embodiments of the present disclosure provide for NiPt nanoparticles, compositions and supports including NiPt nanoparticles, methods of making NiPt nanoparticles, methods of supporting NiPt nanoparticles, methods of using NiPt nanoparticles, and the like.

  19. Hydrotreating of heavy gas oil derived from Athabasca bitumen using NiMo/Al2O3 catalyst containing boron and phosphorus : effects of process conditions on the product selectivity

    Energy Technology Data Exchange (ETDEWEB)

    Ferdous, D.; Dalai, A.K. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Chemistry and Chemical Engineering; Adjaye, J. [Syncrude Canada Ltd., Edmonton, AB (Canada). Edmonton Research Centre

    2004-07-01

    In response to concerns regarding the depletion of conventional oil reserves, there has been much interest in modifying the hydrotreating process for upgrading tar sands and shale oils for producing transportation fuels. Oil sand bitumens and their derived products have a high level of nitrogen which deactivates the catalysts used in fluid catalytic cracking and hydrocracking. A better catalyst is needed to efficiently remove nitrogen from oil sand-derived gas oils. In this study, a trickle-bed reactor containing NiMo/Al{sub 2}O{sub 3} catalysts with boron and phosphorous was used to remove the sulfur and nitrogen from heavy gas oils derived from Athabasca bitumen. The operating conditions of the reactor in terms of temperature and pressure were described. Sulfur and nitrogen conversion was found to increase substantially with the boron catalysts. Gasoline selectivity also increased with an increase in temperature. However, a change in operating conditions did not significantly affect the net content of the gas oil fraction. This study also compared the results of using either the boron or phosphorous catalyst.

  20. Steam reforming of cyclic model compounds of bio-oil over Ni-based catalysts: Product distribution and carbon formation

    DEFF Research Database (Denmark)

    Trane-Restrup, Rasmus; Jensen, Anker Degn

    2015-01-01

    Steam reforming (SR) and oxidative steam reforming (OSR) of furfural, 2-methylfuran, and guaiacol have been investigated in the temperature range 400-800°C at a steam to carbon (S/C)-ratio of 5 and oxygen to carbon (O/C)-ratio of 0.2-1.4 over Ni/CeO2-K/MgAl2O4. Carbon oxides and H2 were the major...... products in the SR of 2-methylfuran and furfural, while the by-products were methane, ethanol, 2-propanol, and acetone. Temperatures of 500°C or above were needed to minimize the formation of by-products in the SR of 2-methylfuran and furfural. Phenolics, like benzenediols and phenol, were produced in high...... yields in the SR of guaiacol and temperatures of 780°C were needed to totally convert guaiacol to carbon oxides and H2.Carbon deposition was observed in the SR of all three model compounds and was most severe for guaiacol followed by furfural and 2-methylfuran. The carbon deposition could be reduced...

  1. Structure-activity relations for Ni-containing zeolites during NO reduction. II. Role of the chemical state of Ni

    NARCIS (Netherlands)

    Mosqueda Jimenez, B.I.; Jentys, A.; Seshan, Kulathuiyer; Lercher, J.A.

    2003-01-01

    The influence of the metal in Ni-containing zeolites used as catalysts for the reduction of NO with propane and propene was studied. In the fresh catalysts, Ni is located in ion exchange positions for Ni/MOR, Ni/ZSM-5, and Ni/MCM-22. The formation of carbonaceous deposits, the removal of Al from

  2. Tuning the composition of metastable CoxNiyMg100−xy(OH)(OCH3) nanoplates for optimizing robust methane dry reforming catalyst

    DEFF Research Database (Denmark)

    Fan, Xiaoli; Liu, Zhiting; Zhu, Yi-An

    2015-01-01

    of the metastable precursor CoxNiyMg100−x−y(OH)(OCH3) derived from solvothermal synthesis. The catalyst composition and reaction conditions have been modulated to achieve maximum coke resistance and catalyst stability. Long-term stability for 1000 h time on stream at 800°C has been achieved for the optimized Co0.......075Ni7.425Mg92.5O catalyst. The role of Co in the catalyst has been disclosed through kinetic measurements and detailed characterization of the spent catalysts. Co is enriched on the Co–Ni alloy surface under reforming conditions and accelerates the gasification of coke intermediates. Co also enhances...

  3. BTX production by in-situ contact reforming of low-temperature tar from coal with zeolite-derived catalysts; Zeolite kei shokubai wo mochiita sekitan teion tar no sesshoku kaishitsu ni yoru BTX no seisei

    Energy Technology Data Exchange (ETDEWEB)

    Matsunaga, T.; Fuda, K.; Murakami, K.; Kyo, M.; Hosoya, S.; Kobayashi, S. [Akita University, Akita (Japan). Mining College

    1996-10-28

    On BTX production process from low-temperature tar obtained by pyrolysis of coal, the effect of exchanged metallic species and reaction temperature were studied using metallic ion-exchanged Y-zeolite as catalyst. In experiment, three kinds of coals with different produced tar structures such as Taiheiyo and PSOC-830 sub-bituminous coals and Loy Yang brown coal were used. Y-zeolite ion-exchanged with metal chloride aqueous solution was used as catalyst. Zn{sup 2+}, Ni{sup 2+} and In{sup 3+} were used as metal ions to be exchanged. The experiment was conducted by heating a pyrolysis section up to 600{degree}C for one hour after preheating a contact reforming section up to a certain proper temperature. As a result, the Ni system catalyst was effective for BTX production from aromatic-abundant tar, while the Zn system one from lower aromatic tar. In general, relatively high yields of toluene and xylene were obtained at lower temperature, while those of benzene at higher temperature. 4 figs., 1 tab.

  4. Chlorodiethylaluminum supported on silica: A dinuclear aluminum surface species with bridging μ2-Cl-ligand as a highly efficient co-catalyst for the Ni-catalyzed dimerization of ethene

    KAUST Repository

    Kermagoret, Anthony

    2014-05-01

    Silica-supported chloro alkyl aluminum co-catalysts (DEAC@support) were prepared via Surface Organometallic Chemistry by contacting diethylaluminum chloride (DEAC) and high specific surface silica materials, i.e. SBA-15, MCM-41, and Aerosil SiO2. Such systems efficiently activate NiCl 2(PBu3)2 for catalytic ethene dimerization, with turnover frequency (TOF) reaching up to 498,000 molC2H4/ (molNi h) for DEAC@MCM-41. A detailed analysis of the DEAC@SBA-15 co-catalyst structure by solid-state aluminum-27 NMR at high-field (17.6 T and 20.0 T) and ultrafast spinning rates allows to detect six sites, characterized by a distribution of quadrupolar interaction principal values CQ and isotropic chemical shifts δiso. Identification of the corresponding Al-grafted structures was possible by comparison of the experimental NMR signatures with these calculated by DFT on a wide range of models for the aluminum species (mono- versus di-nuclear, mono- versus bis-grafted with bridging Cl or ethyl). Most of the sites were identified as dinuclear species with retention of the structure of DEAC, namely with the presence of μ2-Cl-ligands between two aluminum, and this probably explains the high catalytic performance of this silica-supported co-catalysts. © 2014 Elsevier Inc. All rights reserved.

  5. Enhanced catalytic performance in hydrogen generation from NaBH4 hydrolysis by super porous cryogel supported Co and Ni catalysts

    Science.gov (United States)

    Seven, Fahriye; Sahiner, Nurettin

    2014-12-01

    The neutral 3-D superporous cryogel is prepared from a poly(acrylamide) (p(AAm)) hydrogel network modified with an amidoximation reaction to induce chemical changes to produce superporous amidoximated-p(AAm) (amid-p(AAm)) cryogel. The newly-formed strongly ionizable matrices can readily absorb metal ions such as Co(II) and Ni(II) enabling in situ preparation of corresponding metal nanoparticles by NaBH4 treatments. It is found that the superporous amid-p(AAm)-Co cryogel composite is very effective as a catalyst for H2 generation from hydrolysis of NaBH4 in alkaline medium. Furthermore, it is demonstrated that the metal ion loading capacity and catalytic activity of superporous amid-p(AAm)-Co cryogel composites increased with 2nd and 3rd Co(II) ion loading and reduction cycles. The hydrogen generation rate of p(AAm)-Co metal composites is increased to 1926.3 ± 1.1 from 1130.2 ± 1.5 (mL H2) (min)-1 (g of M)-1. The effect of various parameters such as porosity, metal type, the number of reloading and reduction cycles of the metal ion, and temperature are investigated for the hydrolysis of NaBH4. The kinetic parameters such as energy, enthalpy and entropy are determined as Ea = 39.7 ± 0.2 kJ mol-1, ΔH = 37.2 ± 0.1 kJ mol-1 and ΔS = -171.9 ± 0.5 J mol-1 K-1, respectively.

  6. Development of the Ni/Al{sub 2}O{sub 3}/ZrO{sub 2} catalyst to steam reforming of the natural gas process; Desenvolvimento do catalisador Ni/Al2O3/ZrO2 para o processo de reforma do gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Neiva, Laedna Souto; Ramalho, Melanea A.F.; Costa, Ana Cristina Figueiredo de Melo; Gama, Lucianna [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Andrade, Heloysa M.C. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Kiminami, Ruth Herta G.A. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil)

    2008-07-01

    The aim of this work is to develop catalyst of the type Ni/{alpha}-Al{sub 2}O{sub 3} modified with 0.005 mol of ZrO{sub 2} and structural, morphologic and catalytic characterizations, aiming employ in the reforming process of the natural gas. The catalytic supports were obtained by synthesis method for combustion reaction according to the concepts of the propellants chemistry. The active species of the catalyst (nickel) was deposited over the support by humid impregnation method. The catalytic supports were characterized by XRD, morphologic analysis by SEM and TEM, textural analysis by BET method before and after of the impregnation with nickel and were done catalytic tests in laboratory. The catalytic supports shows structure without any secondary phase with crystallinity elevated degree and crystal size varying between 5.7 and 7.0 nm. The catalytic test shows that these catalysts promoted a conversion percentile considerable of the natural gas in syngas. (author)

  7. The impact of copper in LaNi{sub 1-x}Cu{sub x}O{sub 3} perovskite-like structures used as catalyst precursors for dry reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Vlach, K.; Hoang, D.L.; Armbruster, U.; Martin, A. [Leibniz-Institut fuer Katalyse e.V. an der Universitaet Rostock (Germany)

    2013-11-01

    This work deals with the synthesis of perovskite-like catalyst precursors (LaNi{sub 1-x}Cu{sub x}O{sub 3} with x = 0, 0.2, 0.5, 0.8, 1). These precursors were used to catalyse the dry reforming of methane (DRM) reaction carried out at 973 K, CH{sub 4}/CO{sub 2} = 1 and a GHSV = 18,000 ml/g/h. The precursors were transformed during the course of the reaction to give Ni-Cu/La{sub 2}O{sub 3} solids. We found out that the activity increases with raising Ni content but small Cu admixture suppresses the coke formation substantially. XRD and TEM measurements showed that the transformation led to the formation of small metallic Ni and/or Cu particles. In addition also alloying can be observed. The best catalytic system with respect to activity and suppressed carbon deposition was Ni{sub 0.8}-Cu{sub 0.2}/La{sub 2}O{sub 3} (X{sub CH4} = 61%, X{sub CO2} = 67%). (orig.)

  8. Hydroprocessing catalyst development

    Energy Technology Data Exchange (ETDEWEB)

    Boorman, P.M.; Kydd, R.A.; Sorensen, T.S.; Chong, K.; Lewis, J.

    1992-08-01

    Co-Mo and Ni-Mo hydroprocessing catalysts were examined for their activity in removal of sulfur from thiophene in model compounds, and in the cracking and hydrocracking of cumene. Three types of support materials were examined: carbon, modified carbon, and carbon covered alumina. The objective of the study was to examine the correlation between catalyst activity in the hydrodenitrogenation of model compounds, and the resistance of the catalyst to nitrogen poisoning during use in the hydroprocessing of gas oils. The use of model compound testing provided information on the individual catalytic reactions promoted by those materials. Infrared spectroscopy was used to study surface species on the catalysts and to explain many of the trends in activity observed, revealing the role of fluoride and phosphorus as a secondary promoter. Testing of the catalysts in hydrotreating of gas oils allowed comparison of model compound results with those from a real feedstock. The gas oil was also spiked with a model nitrogen compound and the results from catalytic hydrotreating of this material were compared with those from unspiked material. A key finding was that the carbon supported catalysts were the most effective in treating high-nitrogen feeds. The very favorable deactivation properties of carbon and carbon-covered alumina supported catalysts make these promising from an industrial point of view where catalyst deactivation is a limiting factor. 171 refs., 25 figs., 43 tabs.

  9. Oxidation catalyst

    Science.gov (United States)

    Ceyer, Sylvia T.; Lahr, David L.

    2010-11-09

    The present invention generally relates to catalyst systems and methods for oxidation of carbon monoxide. The invention involves catalyst compositions which may be advantageously altered by, for example, modification of the catalyst surface to enhance catalyst performance. Catalyst systems of the present invention may be capable of performing the oxidation of carbon monoxide at relatively lower temperatures (e.g., 200 K and below) and at relatively higher reaction rates than known catalysts. Additionally, catalyst systems disclosed herein may be substantially lower in cost than current commercial catalysts. Such catalyst systems may be useful in, for example, catalytic converters, fuel cells, sensors, and the like.

  10. Studies on the catalysts for coal liquefaction. ; Kinetic discussion in initial stage of coal liquefaction. Sekitan ekikayo shokubai ni kansuru kenkyu. ; Sekitan ekika shoki dankai no sokudoronteki kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Muraoka, T; Ikenaga, N; Oda, H; Yokokawa, C [Kansai University, Osaka (Japan). Faculty of Engineering

    1990-11-29

    Discussions were given on features of various kinds of coal liquefaction catalysts exhibited by them in hydrocracking of coal (Taiheiyo coal), and particularly on selectivity of the reaction in its initial stage. Four kinds of catalysts were tested: Adkins catalyst which is an oxide of copper and chromium, Fe2O3+S, Mo-TiO2 and MoS3-Al2O3. Three grams of coal and 0.3 gram each of the catalysts were charged into an autoclave reactor and experiment was conducted under an initial hydrogen pressure of 10 MPa, temperatures from 653 K to 693 K and for durations of 0 to 120 minutes to derive apparent reaction rate constants. The MoS3-Al2O3 catalyst has promoting the reaction apparently in the primary reaction at any temperature, while the other catalysts had the rate constants varied in the initial and the later stages. It was recognized that the temperature dependence of rate constants varies considerably according to the types of catalyst. Particularly the MoO3-TiO3 catalyst has small temperature dependence in the rate constants, and high molecular weight reducing power. 3 refs., 4 figs., 3 tabs.

  11. Catalytic effects of various catalysts in hydroprocessing of Cold Lake vacuum bottom. Cold Lake zansayu no hydroprocessing ni okeru kakushu shokubai no koka

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, S.; Yamamoto, M.; Maekawa, Y.; Kotanigawa, T. (Government Industrial Development Laboratory, Hokkaido, Sapporo (Japan))

    1991-11-07

    The effects of various types of catalysts were studied on hydroprocessing of Cold Lake vacuum bottom (CLVB). FeS2 [Py] of an analytical reagent grade was used as sulfide catalyst, Fe2O3(SO4)[sup 2[minus

  12. A Study of Deactivating Carbon Species during Methanation on a Ni/Al2O3 Catalyst

    DEFF Research Database (Denmark)

    Olesen, Sine Ellemann

     natural gas and as the infrastructure is already in place for natural gas, it is an attractive alternative to depleting oil resources. Catalysts based on nickel are the most common choice within industry due to the relatively low price of nickel and its acceptable performance. However, nickel catalysts...

  13. Synthesis and characterization of ternary Pt-Ni-M/C (M=Cu, Fe, Ce, Mo, W) nano-catalysts for low temperature fuel cells

    International Nuclear Information System (INIS)

    Ahmed, Riaz; Jamil, Rabia; Ansari, Muhammad Shahid

    2014-01-01

    Ternary metal catalysts were synthesized by impregnation method. The mixture of metal solutions was reduced slowly under inert atmosphere and the reduced metals were deposited on the Vulcan Carbon(VC). Tungsten, molybdenum, cerium, iron and copper were added to specified amounts of platinum and nickel. Addition of nickel generally improves catalytic activity of platinum. The XRD of the catalysts was done and the crystallite size and other parameters were calculated. Crystallite sizes were in the range of 5 to 16 nm. Electrochemical surface areas of the catalysts were determined by cyclic voltammetry (CV) in acidic media and are compared. Electro oxidation of methanol on the catalysts was done and peak potential, peak current, mass activity of the catalysts were calculated and are compared. These parameters were determined in acidic and basic media. It was found that mass activity increased significantly in basic media. Rate constants for the electro oxidation of methanol were also calculated in acidic and basic media and are compared and discussed. Rate constants were generally higher in basic media. Ternary catalysts showed improved catalytic activity than the binary catalyst. Nano alloying improved the catalytic activity and stability of the ternary catalysts

  14. Parametric study on the steam reforming of phenol-PET solution to hydrogen production over Ni promoted on Al_2O_3-La_2O_3 catalyst

    International Nuclear Information System (INIS)

    Nabgan, Bahador; Nabgan, Walid; Tuan Abdullah, Tuan Amran; Tahir, Muhammad; Gambo, Yahya; Ibrahim, Maryam; Syie Luing, Wong

    2017-01-01

    Highlights: • Parametric study of H_2 production from phenol-PET steam reforming was studied. • Optimised conditions were 800 °C, 0.10 ml/min feed flow rate, and 7% PET. • High amount of aliphatic branched-chains and cyclic compounds were produced. • PET was efficiently converted to hydrogen and valuable fuels at optimized condition. • Significant influence resulted for all the main independent factors. - Abstract: Production of hydrogen from plastic waste could be a prospective key to the ecological problems resulted from waste. To further explore the process, a 32-runs parametric study on the steam reforming of Polyethylene terephthalate (PET) dissolved in phenol was conducted in a fixed bed reactor using Ni over La_2O_3-Al_2O_3 support. The five factors studied were temperature (A), feed flow rate (B), mass flow (C), phenol concentration (D), and concentration of PET solution (E), whereas the responses were phenol conversion (Y_1) and hydrogen selectivity (Y_2). From the result, it was observed that significant influence resulted for all the main independent variables on the dependent variable of Y_1 and Y_2 with the range of 47.24–97.6% and 49–70.96%, respectively. Moreover, the Y_1 and Y_2 responses have influenced by some interaction variables like AC, CD, CE, ACE, and BCE. As evident from the design, initial variables such as 800 °C, 0.10 ml/min feed flow rate, 10 SCCM mass flow, 10 wt.% of phenol in the feed, and 7% PET concentration were the best preliminary conditions that formed maximum Y_1 (94%) and Y_2 (71%) responses. However, analyses on the product composition revealed that high amount of aliphatic branched-chains along with moderate amount of cyclic compounds were produced from steam reforming of PET-phenol. Due to the short retention time of the compounds on the catalysts bed, the aromatization of PET cracking products was small.

  15. Report on the research achievements in the Sunshine Project in fiscal 1992. Studies on a direct gasification catalyst; 1992 nendo chokusetsu ekika shokubai ni kansuru kenkyu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-10-01

    This paper describes the research achievements in the Sunshine Project in fiscal 1992 in studies on a direct gasification catalyst. The paper summarizes the points where the catalyst research has reached to date. The catalyst surface effective for hydrogenation is the metal surface that can dissociate hydrogen. However, metals having large adsorption heat against hydrogen do not show the activity greatly because these metals are difficult of desorbing hydrogen having high dissociating activity. The coal liquefaction system has the surface oxidized by water content, wherein hydrogen dissociation cannot be expected, and sulfides are suitable. When a sulfide catalyst contacts hydrogen, the catalyst itself is desulfurized, producing H{sub 2}S and becomes a low-order sulfide. When atmospheric H{sub 2}S contacts this sulfide, it dissociates into HS and H, and this H behaves as active hydrogen. However, the liquefaction activity can be recognized even in a sulfuric acid type catalyst containing no sulfide whatsoever, wherein the H{sub 2}S partial pressure in the reaction system becomes extremely low. This fact means that the active hydrogen is not necessarily generated by the dissociation of H{sub 2}S. There is no other way but to think that hydrogen is dissociated directly without going through H{sub 2}S. If this is true, it provides a new guideline in developing and designing the future catalysts. (NEDO)

  16. Synthesis of NiO–Al{sub 2}O{sub 3} nanocomposites by sol–gel process and their use as catalyst for the oxidation of styrene

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Sudheer Kumar; Jeevanandam, P., E-mail: jeevafcy@iitr.ac.in

    2014-10-15

    Highlights: • NiO–Al{sub 2}O{sub 3} nanocomposites have been synthesized by sol–gel method. • The synthesis takes shorter time (∼48 h) compared to reported methods. • The nanocomposites show high catalytic activity for the oxidation of styrene compared to NiO. - Abstract: NiO–Al{sub 2}O{sub 3} nanocomposites were prepared by sol–gel method. The synthesized nanocomposites were characterized by X-ray diffraction, FT-IR spectroscopy, Raman spectroscopy, field emission scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy, diffuse reflectance spectroscopy and magnetic measurements. XRD results indicate that the NiO–Al{sub 2}O{sub 3} nanocomposites consist of small NiO crystallites (mean size ∼2.6 nm). TEM results indicate uniform distribution of NiO nanoparticles in the Al{sub 2}O{sub 3} matrix. Increase in the band gap of NiO in the nanocomposites compared to pure NiO nanoparticles is observed and the nanocomposites show superparamagnetic behaviour. The NiO–Al{sub 2}O{sub 3} nanocomposites show high catalytic activity for the oxidation of styrene using tert-butyl hydroperoxide as the oxidant and also show higher selectivity for styrene oxide with higher total conversion compared to pure NiO nanoparticles.

  17. Core/shell AgNi/PtAgNi nanoparticles as methanol-tolerant oxygen reduction electrocatalysts

    International Nuclear Information System (INIS)

    Wu, Dengfeng; Cheng, Daojian

    2015-01-01

    A core/shell AgNi/PtAgNi nanoparticle (NP) was synthesized via a new seed-mediated growth method in organic solvent medium. The as-synthesized AgNi/PtAgNiNP exhibits an AgNi core coated with PtAgNi shell, which was confirmed by transmission electron microscopy (TEM), ultraviolet–visible absorption spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The AgNi/PtAgNiNPs/C catalyst possesses higher oxygen reduction reaction (ORR) activity and better durability compared with the commercial Pt/C catalyst. It is found that the ORR polarization curve of the AgNi/PtAgNiNPs/C catalyst shows an onset potential of 0.91 V vs. RHE, which is superior to the commercial Pt/C (0.88 V vs. RHE). In addition, the AgNi/PtAgNiNPs/C catalyst shows much better durability than the commercial Pt/C catalyst. More interestingly, the AgNi/PtAgNiNPs/C catalyst displays much higher methanol tolerance than the commercial Pt/C catalyst in 0.1 M KOH solution in the presence of 0.5 M methanol. Our results show that core/shell AgNi/PtAgNiNPs possess selective activity for ORR even in the presence of methanol, showing potential application as methanol-tolerant cathode catalysts in direct methanol fuel cells.

  18. Hydrodeoxygenation of methyl esters on sulphided NiMo/{gamma}-Al{sub 2}O{sub 3} and CoMo/{gamma}-Al{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Senol, O.I; Viljava, T.R.; Krause, A.O.I. [Laboratory of Industrial Chemistry, Helsinki University of Technology, P.O. Box 6100, FIN-02015 Hut (Finland)

    2005-02-28

    Wood-derived bio-oil contains high amounts of compounds with different oxygen-containing functional groups that must be removed to improve the fuel characteristics. Elimination of oxygen from carboxylic groups was studied with model compounds, methyl heptanoate and methyl hexanoate, on sulphided NiMo/{gamma}-Al{sub 2}O{sub 3} and CoMo/{gamma}-Al{sub 2}O{sub 3} catalysts in a flow reactor. Catalyst performances and reaction schemes were addressed. Aliphatic methyl esters produced hydrocarbons via three main paths: The first path gave alcohols followed by dehydration to hydrocarbons. Deesterification yielded an alcohol and a carboxylic acid in the second path. Carboxylic acid was further converted to hydrocarbons either directly or with an alcohol intermediate. Decarboxylation of the esters led to hydrocarbons in the third path. No oxygen-containing compounds were detected at complete conversions. However, the product distributions changed with time, even at complete conversions, indicating that both catalysts deactivated under the studied conditions.

  19. Characterization of catalysts Rh and Ni/Ce{sub x}Zr{sub 1-x}O{sub 2} for hydrogen production by ethanol steam reforming; Caracterisation de catalyseurs Rhodium et Nickel/ Ce{sub x}Zr{sub 1-x}O{sub 2} pour la production d'hydrogene par vaporeformage de l'ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Birot, A

    2005-07-01

    This work concerned a study on catalytic behaviour of metallic catalysts (Rh or Ni) supported on earth rare oxides Ce{sub x}Zr{sub 1-x}O{sub 2} in ethanol steam reforming in order to produce hydrogen. Catalyst 1%Rh/Ce0,50Zr0,50O{sub 2} showed a good activity with a good hydrogen yield. We turned a study onto understanding inter-conversion reaction between H{sub 2}, CO and CO{sub 2} which lead to CH{sub 4} formation. We also studied intrinsic properties of catalysts. We confirmed basic character of catalysts and a good hydrogenation activity. A good activity in CO hydrogenation allowed to evidence a necessity to use a catalyst which is less active in hydrogenation reaction and with a basic character in order to improve hydrogen yield. (author)

  20. Hydroprocessing catalysts utilization and regeneration schemes

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E.

    The catalyst reactor inventory represents an important part of the cost of hydroprocessing operation. The selection of a suitable catalyst and reactor is influenced by feedstock properties. Processes ensuring an uninterrupted operation during catalyst addition and withdrawal are preferred for processing high asphaltene and metal content feedstocks. The spent catalyst can be regenerated and returned to the operation if the extent of its deactivation is not high. The regeneration may be performed either in-situ or off-site. The former is suitable for fixed bed reactors whereas the catalyst from ebullated bed reactors must be regenerated off-site. The regeneration of spent catalysts heavily loaded with metals such as V, Ni and Fe may not be economic. Such catalysts may be suitable for metal reclamation. An environmentally safe method for catalyst disposal must be found if neither regeneration nor metal reclamation from spent catalysts can be performed.

  1. Performance of polyethylene based radiation grafted anion exchange membrane with polystyrene-b-poly (ethylene/butylene)-b-polystyrene based ionomer using NiCo2O4 catalyst for water electrolysis

    Science.gov (United States)

    Gupta, Gaurav; Scott, Keith; Mamlouk, Mohamed

    2018-01-01

    A soluble anion exchange ionomer with high OH- ion conductivity comparable to that of H+ conductivity of Nafion is synthesised by chloromethylation of polystyrene-b-poly (ethylene/butylene)-b-polystyrene (SEBS) and used with NiCo2O4 electro-catalyst for water electrolysis. The ionomer has an ion exchange capacity of 1.9 mmol g-1 and ionic conductivity of 0.14 S cm-2 at 50 °C. The cell voltage at 20 °C at 100 mA cm-2 is 1.77 and 1.72 V in, 0.1 and 1.0 M NaOH, respectively, for an optimum loading of 10 mg cm-2 NiCo2O4. At 10 mg cm-2 NiCo2O4 electrolyser cell performance is at least equal to or superior to that of IrO2 at 2 mg cm-2 with excellent stability over 1 h. When the catalyst is sprayed on the GDL instead of CCM, the performance is further improved to 1.65 V at 100 mA cm-2 at 60 °C & 0.1 M KOH. The limited AEM electrolyser performance when operating with deionised water in comparison to PEM and alkaline electrolyser arises from the sluggish OER in the AEM environment equivalent to pH of 11.5 and the two orders of magnitude lower HER activity with respect to acid medium combined with the high Tafel slope of 120 mV dec-1.

  2. Current status and prospect on photo-catalyst application in environmental problems; Kankyo mondai ni okeru hikari shokubai oyo no ganjo to tenbo

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, T. [Toto Ltd., Kitakyushu (Japan)

    1995-09-30

    This paper summarizes application of photo-catalysts in environmental problems. The paper lists examples of the application in residential environments. Photo-catalytic decomposition is possible by using ultraviolet rays contained in room illumination if the bacterial presence is sparse. The examples thereof may be cited as follows: if colon bacilli are suspended on a tile with TiO2 photo-catalyst sintered in it and exposed to room illumination, the bacteria are disinfected; using photo-catalysts in a bathroom suppresses deposition of Pseudomonas aeruginosa; a photo-catalyst tile (TiO2 loaded with Cu) and light irradiation reduce intensity of tobacco smoke odor; and adsorbents may be used simultaneously if intermediate products are odor generating substances. The examples of applying photo-catalysts to regional environments may be quoted as follows: growth of algae in a Petri dish is suppressed by presence of Cu loaded TiO2 under room illumination; this leads to an expectation on its effect in a relatively clean water environment; glass beads loaded with a TiO2 photo-catalyst placed in a gold fish breeding tank reduces turbidity, the number of colon bacilluses, and COD value; and the mortality in gold fish shows no change. With an objective of application to exterior building materials, photo-catalyst applied tiles were left outdoors for 160 days. Nitric acid ions were detected that are thought to have been generated by decomposition of microorganisms that have deposited on the tiles. 6 refs., 5 figs., 3 tabs.

  3. Studies on recycling and utilization of spent catalysts. Preparation of active hydrodemetallization catalyst compositions from spent residue hydroprocessing catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Marafi, Meena; Stanislaus, Antony [Petroleum Refining Department, Petroleum Research and Studies Center, Kuwait Institute for Scientific Research, P.O. Box 24885, Safat (Kuwait)

    2007-02-15

    Spent catalysts form a major source of solid wastes in the petroleum refining industries. Due to environmental concerns, increasing emphasis has been placed on the development of recycling processes for the waste catalyst materials as much as possible. In the present study the potential reuse of spent catalysts in the preparation of active new catalysts for residual oil hydrotreating was examined. A series of catalysts were prepared by mixing and extruding spent residue hydroprocessing catalysts that contained C, V, Mo, Ni and Al{sub 2}O{sub 3} with boehmite in different proportions. All prepared catalysts were characterized by chemical analysis and by surface area, pore volume, pore size and crushing strength measurements. The hydrodesulfurization (HDS) and hydrodemetallization (HDM) activities of the catalysts were evaluated by testing in a high pressure fixed-bed microreactor unit using Kuwait atmospheric residue as feed. A commercial HDM catalyst was also tested under similar operating conditions and their HDS and HDM activities were compared with that of the prepared catalysts. The results revealed that catalyst prepared with addition of up to 40 wt% spent catalyst to boehmite had fairly high surface area and pore volume together with large pores. The catalyst prepared by mixing and extruding about 40 wt% spent catalyst with boehmite was relatively more active for promoting HDM and HDS reactions than a reference commercial HDM catalyst. The formation of some kind of new active sites from the metals (V, Mo and Ni) present in the spent catalyst is suggested to be responsible for the high HDM activity of the prepared catalyst. (author)

  4. Change in catalyst properties during coal liquefaction; Kokoritsu sekitan ekika shokubai no kaihatsu (Hanno no shinko ni tomonau shokubai seijo no henka). 1

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, T.; Sato, K.; Kaneko, T.; Shimasaki, K. [Nippon Brown Coal Liquefaction Co. Ltd., Tokyo (Japan)

    1996-10-28

    The purpose of this study is to prevent the deactivation of catalysts recycled in the 0.1 t/d bench scale unit (BSU). Catalysts recovered during reactions in the BSU and after reactions in the 5-liter autoclave were analyzed, to investigate the influences of the reaction condition on the property and activity of catalysts. Were used {gamma}-iron oxyhydroxide ({gamma}-FeOOH), {alpha}-iron oxyhydroxide ({alpha}-FeOOH), and natural pyrite (FeS2) as catalysts. At the S/Fe atomic ration of 1.2 under the BSU reaction condition, troilite was more easily formed from {gamma}-FeOOH compared with pyrite and {alpha}-FeOOH. As the reaction proceeded through the first, second, and third reactors, the crystal size increased, the pyrrhotite content decreased, and the troilite content increased. Deactivation due to the formation of troilite was irreversible. At the S/Fe of 3.0, however, both the formation of troilite and the crystal growth of pyrrhotite were not observed. It was found that the deactivation of catalysts can be remarkably suppressed. 5 refs., 6 figs., 1 tab.

  5. Effect of Ni/Al2O3-SiO2 and Ni/Al2O3-SiO2 with K2O Promoter Catalysts on H2, CO and CH4 Concentration by CO2 Gasification of Rosa Multiflora Biomass

    Directory of Open Access Journals (Sweden)

    Tursunov Obid

    2017-11-01

    Full Text Available The thermal behaviour of the Rosa mutiflora biomass by thermogravimetric analysis was studied at heating rate 3 K min−1 from ambient temperature to 950 °C. TGA tests were performed in high purity carbon dioxide (99 998% with a flow rate 200 ml/min and 100 mg of sample, milled and sieved to a particle size below 250 µm. Moreover, yields of gasification products such as hydrogen (H2, carbon monoxide (CO and methane (CH4 were determined based on the thermovolumetric measurements of catalytic (Ni/Al2O3-SiO2 and Ni/Al2O3-SiO2 with K2O promoter catalysts and non-catalytic gasification of the Rosa multiflora biomass. Additionally, carbon conversion degrees are presented. Calculations were made of the kinetic parameters of carbon monoxide and hydrogen formation reaction in the catalytic and non-catalytic CO2 gasification processes. A high temperature of 950 °C along with Ni/Al2O3-SiO2and Ni/Al2O3-SiO2 with K2O promoter catalysts resulted in a higher conversion of Rosa multiflora biomass into gaseous yield production with greatly increasing of H2 and CO contents. Consequently, H2 and CO are the key factors to produce renewable energy and bio-gases (synthesis gas. The parameters obtained during the experimental examinations enable a tentative assessment of plant biomasses for the process of large-scale gasification in industrial sectors.

  6. Fast microwave-assisted solvothermal synthesis of metal nanoparticles (Pd, Ni, Sn) supported on sulfonated MWCNTs: Pd-based bimetallic catalysts for ethanol oxidation in alkaline medium

    CSIR Research Space (South Africa)

    Ramulifho, T

    2012-01-01

    Full Text Available The preparation of metal nanoparticles (Pd, Ni, Sn) supported on sulfonated multi-walled carbon nanotubes (SF-MWCNTs) using a very rapid microwave-assisted solvothermal strategy has been described. Electrocatalytic behaviour of the SF...

  7. Investigation of the Process Conditions for Hydrogen Production by Steam Reforming of Glycerol over Ni/Al₂O₃ Catalyst Using Response Surface Methodology (RSM).

    Science.gov (United States)

    Ebshish, Ali; Yaakob, Zahira; Taufiq-Yap, Yun Hin; Bshish, Ahmed

    2014-03-19

    In this work; a response surface methodology (RSM) was implemented to investigate the process variables in a hydrogen production system. The effects of five independent variables; namely the temperature (X₁); the flow rate (X₂); the catalyst weight (X₃); the catalyst loading (X₄) and the glycerol-water molar ratio (X₅) on the H₂ yield (Y₁) and the conversion of glycerol to gaseous products (Y₂) were explored. Using multiple regression analysis; the experimental results of the H₂ yield and the glycerol conversion to gases were fit to quadratic polynomial models. The proposed mathematical models have correlated the dependent factors well within the limits that were being examined. The best values of the process variables were a temperature of approximately 600 °C; a feed flow rate of 0.05 mL/min; a catalyst weight of 0.2 g; a catalyst loading of 20% and a glycerol-water molar ratio of approximately 12; where the H₂ yield was predicted to be 57.6% and the conversion of glycerol was predicted to be 75%. To validate the proposed models; statistical analysis using a two-sample t -test was performed; and the results showed that the models could predict the responses satisfactorily within the limits of the variables that were studied.

  8. Reuse of Hydrotreating Spent Catalyst

    International Nuclear Information System (INIS)

    Habib, A.M.; Menoufy, M.F.; Amhed, S.H.

    2004-01-01

    All hydro treating catalysts used in petroleum refining processes gradually lose activity through coking, poisoning by metal, sulfur or halides or lose surface area from sintering at high process temperatures. Waste hydrotreating catalyst, which have been used in re-refining of waste lube oil at Alexandria Petroleum Company (after 5 years lifetime) compared with the same fresh catalyst were used in the present work. Studies are conducted on partial extraction of the active metals of spent catalyst (Mo and Ni) using three leaching solvents,4% oxidized oxalic acid, 10% aqueous sodium hydroxide and 10% citric acid. The leaching experiments are conducting on the de coked extrude [un crushed] spent catalyst samples. These steps are carried out in order to rejuvenate the spent catalyst to be reused in other reactions. The results indicated that 4% oxidized oxalic acid leaching solution gave total metal removal 45.6 for de coked catalyst samples while NaOH gave 35% and citric acid gave 31.9 % The oxidized leaching agent was the most efficient leaching solvent to facilitate the metal removal, and the rejuvenated catalyst was characterized by the unchanged crystalline phase The rejuvenated catalyst was applied for hydrodesulfurization (HDS) of vacuum gas oil as a feedstock, under different hydrogen pressure 20-80 bar in order to compare its HDS activity

  9. Synthesis NiAl{sub 1,0}Fe{sub 1,0}O{sub 4} catalyst by the combustion reaction to their use in the shift reaction (WGSR); Sintese do catalisador de NiAl{sub 1,0}Fe{sub 1,0}O{sub 4} por reacao de combustao visando sua utilizacao na reacao de shift (WGSR)

    Energy Technology Data Exchange (ETDEWEB)

    Santos, P.T.A.; Costa, A.C.F.M.; Neiva, L.S.; Gama, L. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Dept. de Engenharia de Materiais; Argolo, F.; Andrade, H.M.C. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica

    2009-07-01

    This work aims at the synthesis of catalyst NiAl{sub 1,0}Fe{sub 1,0}O{sub 4} by combustion reaction using urea as fuel, to evaluate its performance in the production of hydrogen by the reaction of displacement of water vapor (WGSR). The initial composition of the solution was based on valencia total oxidizing and reducing reagents based on the concepts of the chemistry of propellants, using container as a crucible of glassy silica. The resulting powder was characterized by X-ray diffraction, infrared spectroscopy, nitrogen adsorption isotherms (BET), scanning electronic microscope and catalytic tests. The DRX results reveal the presents majoritary phase NiAl{sub 1,0}Fe{sub 1,0}O{sub 4} spinel, the catalyst presents surface area 28 m{sup 2}/g and isotherms type III. Higher conversion CO/CO{sub 2} of 75% CO conversion observed at 500 deg C and catalytic activity of 43 mmolg{sup -1}.h{sup -1} at 450 deg C. (author)

  10. Transmission electron microscopy on live catalysts

    NARCIS (Netherlands)

    Bremmer, G.M.

    2017-01-01

    The dissertation describes TEM experiments on heterogeneous catalysts. Starting with characterization of (Ni/Co)MoS2 on Alumina and the effect of oxidation, and sequential resulfidation. After that, Co-based catalysts are used for high-resolution (S)TEM/EDX caracterization studies, and in situ

  11. Electrochemical behavior of Ni{sub x}W{sub 1-x} materials as catalyst for hydrogen evolution reaction in alkaline media

    Energy Technology Data Exchange (ETDEWEB)

    Oliver-Tolentino, Miguel A. [UPIBI-IPN, Departamento de Ciencias Basicas, Av. Acueducto s/n, Barrio La Laguna, Col. Ticoman, Mexico D.F. 07340 (Mexico); Arce-Estrada, Elsa M. [ESIQIE-IPN Departamento de Ingenieria en Metalurgia y Materiales, UPALM, UPALM, Mexico D.F. 07738 (Mexico); Cortes-Escobedo, Claudia A. [Centro de Investigacion e Innovacion Tecnologica del IPN, Cda. Cecati s/n, Col. Sta. Catarina, CP 02250 Azcapotzalco D.F. (Mexico); Bolarin-Miro, Ana M.; Sanchez-De Jesus, Felix [Area Academica de Ciencias de la Tierra y Materiales, Universidad Autonoma del Estado de Hidalgo, CU, Carr. Pachuca-Tulancingo Km. 4.5, Mineral de la Reforma, CP 42184 Hidalgo (Mexico); Gonzalez-Huerta, Rosa de G. [ESIQIE-IPN, Departamento de Ingenieria Quimica - Laboratorio de Electroquimica y Corrosion, Edif. Z-5 3er piso, UPALM, Mexico D.F. 07738 (Mexico); Manzo-Robledo, Arturo, E-mail: amanzor@ipn.mx [ESIQIE-IPN, Departamento de Ingenieria Quimica - Laboratorio de Electroquimica y Corrosion, Edif. Z-5 3er piso, UPALM, Mexico D.F. 07738 (Mexico)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer The electrochemical techniques used in this study elucidated the Ni-W surface state. Black-Right-Pointing-Pointer The Ni-W materials were effective for the hydrogen evolution reaction. Black-Right-Pointing-Pointer The prepared alloys exhibited higher catalytic activity than their precursors. Black-Right-Pointing-Pointer The preparation method is relatively simple and effective procedure. - Abstract: In the present work, results of electrochemical evaluation, as well as morphological and structural characterization of Ni{sub x}W{sub 1-x} materials with x = 0.77, 0.64, 0.4, 0.19 and 0.07 processed by means of high energy ball milling from high purity powders are presented. Also, the electrocatalytic performance on the hydrogen evolution reaction (HER) of the Ni{sub x}W{sub 1-x} materials evaluated by linear polarization and cyclic voltammetry techniques in alkaline media at room temperature is discussed. The structural and morphological characterization of the as-prepared materials was carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results indicated a small-particle clusters and solid solution formation. According to the kinetics parameters the best electrocatalytic activity was observed at Ni{sub 64}W{sub 36}.

  12. Modelling the active site of NiFe hydrogenases: new catalysts for the electro-production of H2 and mechanistic studies

    International Nuclear Information System (INIS)

    Canaguier, S.

    2009-01-01

    NiFe hydrogenases are unique metalloenzymes that catalyze H + /H 2 interconversion with remarkable efficiency close to the thermodynamic potential. Their active site consists of a hetero-bimetallic complex containing a nickel ion in a sulphur-rich environment connected by two thiolate bridges to an organometallic cyano-carbonyl iron moiety. In order to improve the understanding of the enzymatic mechanism and to obtain new base-metal electrocatalysts for H 2 production, we synthesized a series of bio-inspired low molecular weight model complexes with the butterfly structure Ni(μ-S 2 )M (M= Ru, Mn and Fe). All these compounds displayed a catalytic activity of hydrogen production. Modulating the electronic and steric properties of the ruthenium center allowed optimizing the catalytic performances of these compounds in terms of stability, catalytic rate and overpotential. Mechanistic studies of the catalytic cycle of the Ni-Ru complexes have also been carried out. They allowed us to suggest a bio-relevant bridging hydride as the catalytic intermediate. Finally, we synthesized one of the first Ni-Fe complexes that is both a structural and a functional model of NiFe hydrogenase. (author) [fr

  13. Biodiesel production in methyl esterification in the frying oil using catalyst Ni{sub 0,5}Zn{sub 0,5}Fe{sub 2}O{sub 4} to produce biodiesel; Producao de biodiesel por esterificacao metalica utilizando o ferroespinelio Ni{sub 0,5}Zn{sub 0,5}Fe{sub 2}O{sub 4} como catalisador e oleo de fritura como materia prima

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, E.V.; Dantas, J.; Pereira, K.B.O.; Barros, A.B.; Moura, T.F.B.; Costa, A.C.F.M., E-mail: erikvilar12@gmail.com [Universidade Federal de campina Grande, PB (Brazil)

    2016-07-01

    The use of magnetic catalysts for biodiesel production has gaining prominence because of possibility about its recovery and its reuse, as well as, the reuse of materials that would be discarded in the environment. Thus, we propose to evaluate the efficiency of the catalyst Ni{sub 0,5}Zn{sub 0,5}Fe{sub 2}O{sub 4} in methyl esterification in the frying oil to produce biodiesel. The catalyst was produced by combustion reaction using containers with different production capacity and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and infrared spectrometry with Fourier transform (FTIR). The catalytic tests were conducted in a stainless steel reactor at 180°C/1h, 2% of catalyst, oil/ethanol ratio of 1:12. Regardless of the container production capacity it was verified the catalyst obtaining with the major phase formation of the inverse spinel and traces of segregated phases with an average crystallite size of 42.13, 32.07 and 36.93 nm. All catalysts showed satisfactory results with conversions of 74%, 77% and 71%. (author)

  14. Co-Pyrolysis Behaviors of the Cotton Straw/PP Mixtures and Catalysis Hydrodeoxygenation of Co-Pyrolysis Products over Ni-Mo/Al2O3 Catalyst

    Directory of Open Access Journals (Sweden)

    Derun Hua

    2015-12-01

    Full Text Available The doping of PP (polypropylene with cotton straw improved the bio-oil yield, which showed there was a synergy in the co-pyrolysis of the cotton straw and PP at the range of 380–480 °C. In a fixed-bed reactor, model compounds and co-pyrolysis products were used for reactants of hydrodeoxygenation (HDO over Ni-Mo/Al2O3. The deoxygenation rate of model compounds decreased over Ni-Mo/Al2O3 in the following order: alcohol > aldehyde > acetic acid > ethyl acetate. The upgraded oil mainly consisted of C11 alkane.

  15. Estudo de catalisadores a base de cobre e nióbia na reação de reforma a vapor de etanol = Study of catalysts based on copper and niobium oxide in steam reforming of ethanol

    Directory of Open Access Journals (Sweden)

    Roberta Carolina Pelissari Rizzo-Domingues

    2007-01-01

    Full Text Available Catalisadores Cu/Nb2O5 foram modificados pela incorporação de MgO ouK2O (redutores da acidez do suporte ou Ni (um facilitador da quebra da ligação C-C para serem utilizados na reforma do etanol em unidade de bancada com leito catalítico de 7 g a 573 K, variando-se a velocidade espacial e a razão molar dos reagentes de modo a otimizar oprocesso de produção de hidrogênio com conseqüente diminuição de subprodutos. Os catalisadores foram caracterizados por área superficial específica, difração de raios-X e redução à temperatura programada. Pôde-se verificar que a introdução de óxido dopante daacidez ou de um segundo metal provocou um aumento da porosidade e da temperatura de início de redução do cobre nos catalisadores, alterando dessa forma a superfície catalítica. A redução da acidez do suporte diminuiu a formação de subprodutos e aumentou a dehidrogênio. Níquel como segundo metal aumentou a produção de CO e CH4.Cu/Nb2O5 catalysts were modified by the incorporation of MgOor K2O (support acidity reducer and Ni (a facilitator of the bond break C-C to be used in the ethanol reforming in bench-scale unit with catalytic bed of 7 g at 573 K, varying the space velocity and the molar rate of the reagents in order to optimize the process ofproduction of hydrogen with consequent decrease of by-products. The catalysts were characterized by specific superficial area, X-ray diffraction and temperature programmed reduction. Results showed that the introduction of the basic oxide or a second metal, nickel, lead to an increase in the porosity and in the temperature at the beginning of copper reduction in the catalyst. The acidity reduction of the support decreased the formation of by-products and increased the hydrogen formation. Nickel as a second metal increased theproduction of CO and CH4.

  16. SYNGAS PRODUCTION FROM CO2-REFORMING OF CH4 OVER SOL-GEL SYNTHESIZED Ni-Co/Al2O3-MgO-ZrO2 NANOCATALYST: EFFECT OF ZrO2 PRECURSOR ON CATALYST PROPERTIES AND PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Seyed Mehdi Sajjadi

    2015-05-01

    Full Text Available Ni-Co/Al2O3-MgO-ZrO2 nanocatalyst with utilization of two different zirconia precursors, namely, zirconyl nitrate hydrate (ZNH and zirconyl nitrate solution (ZNS, was synthesized via the sol-gel method. The physiochemical properties of nanocatalysts were characterized by XRD, FESEM, EDX, BET and FTIR analyses and employed for syngas production from CO2-reforming of CH4. XRD patterns, exhibiting proper crystalline structure and homogeneous dispersion of active phase for the nanocatalyst ZNS precursor employed (NCAMZ-ZNS. FESEM and BET results of NCAMZ-ZNS presented more uniform morphology and smaller particle size and consequently higher surface areas. In addition, average particle size of NCAMZ-ZNS was 15.7 nm, which is close to the critical size for Ni-Co catalysts to avoid carbon formation. Moreover, FESEM analysis indicated both prepared samples were nanoscale. EDX analysis confirmed the existence of various elements used and also supported the statements made in the XRD and FESEM analyses regarding dispersion. Based on the excellent physiochemical properties, NCAMZ-ZNS exhibited the best reactant conversion across all of the evaluated temperatures, e.g. CH4 and CO2 conversions were 97.2 and 99% at 850 ºC, respectively. Furthermore, NCAMZ-ZNS demonstrated a stable yield with H2/CO close to unit value during the 1440 min stability test.

  17. Unsupported NiPt alloy metal catalysts prepared by water-in-oil (W/O) microemulsion method for methane cracking

    KAUST Repository

    Zhou, Lu; Basset, Jean-Marie

    2016-01-01

    for methane cracking. By XRD (X-ray powder diffraction), XPS (X-ray photoelectron spectroscopy) and TEM (Transmission electron microscopy) analyses, the formation of Ni(0)Pt(0) alloy is believed to be the main reason for the reactivity improvement