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

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...

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.

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.

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

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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.

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.

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.

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

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

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

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

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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.

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

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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.

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.

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

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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.

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

Hydrous titanium oxide-supported catalysts

International Nuclear Information System (INIS)

Dosch, R.G.; Stohl, F.V.; Richardson, J.T.

1990-01-01

Catalysts were prepared on hydrous titanium oxide (HTO) supports by ion exchange of an active metal for Na + ions incorporated in the HTO support during preparation by reaction with the parent Ti alkoxide. Strong active metal-HTO interactions as a result of the ion exchange reaction can require significantly different conditions for activation as compared to catalysts prepared by more widely used incipient wetness methods. The latter catalysts typically involve conversion or while the HTO catalysts require the alteration of electrostatic bonds between the metal and support with subsequent alteration of the support itself. In this paper, the authors discuss the activation, via sulfidation or reduction, of catalysts consisting of Co, Mo, or Ni-Mo dispersed on HTO supports by ion exchange. Correlations between the activation process and the hydrogenation, hydrodeoxygenation, and hydrodesulfurization activities of the catalysts are presented

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.

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.

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.

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

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)

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

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.

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.

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)

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)

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)

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.

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...

Hydrogen Production by Steam Reforming of Ethanol over Nickel Catalysts Supported on Sol Gel Made Alumina: Influence of Calcination Temperature on Supports.

Science.gov (United States)

Yaakob, Zahira; Bshish, Ahmed; Ebshish, Ali; Tasirin, Siti Masrinda; Alhasan, Fatah H

2013-05-30

Selecting a proper support in the catalyst system plays an important role in hydrogen production via ethanol steam reforming. In this study, sol gel made alumina supports prepared for nickel (Ni) catalysts were calcined at different temperatures. A series of (Ni/Al S.G. ) catalysts were synthesized by an impregnation procedure. The influence of varying the calcination temperature of the sol gel made supports on catalyst activity was tested in ethanol reforming reaction. The characteristics of the sol gel alumina supports and Ni catalysts were affected by the calcination temperature of the supports. The structure of the sol gel made alumina supports was transformed in the order of γ → (γ + θ) → θ-alumina as the calcination temperature of the supports increased from 600 °C to 1000 °C. Both hydrogen yield and ethanol conversion presented a volcano-shaped behavior with maximum values of 4.3 mol/mol ethanol fed and 99.5%, respectively. The optimum values were exhibited over Ni/Al S.G800 (Ni catalyst supported on sol gel made alumina calcined at 800 °C). The high performance of the Ni/Al S.G800 catalyst may be attributed to the strong interaction of Ni species and sol gel made alumina which lead to high nickel dispersion and small particle size.

Preparation and Characterization of NiMo/Al2O3Catalyst for Hydrocracking Processing

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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.

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.

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.

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

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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.

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)

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)

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)

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.

Hydrogen production by steam reforming of liquefied natural gas over a nickel catalyst supported on mesoporous alumina xerogel

Science.gov (United States)

Seo, Jeong Gil; Youn, Min Hye; Cho, Kyung Min; Park, Sunyoung; Song, In Kyu

Mesoporous alumina xerogel (A-SG) is prepared by a sol-gel method for use as a support for a nickel catalyst. The Ni/A-SG catalyst is then prepared by an impregnation method, and is applied to hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of the mesoporous alumina xerogel support on the catalytic performance of Ni/A-SG catalyst is investigated. For the purpose of comparison, a nickel catalyst supported on commercial alumina (A-C) is also prepared by an impregnation method (Ni/A-C). Both the hydroxyl-rich surface and the electron-deficient sites of the A-SG support enhance the dispersion of the nickel species on the support during the calcination step. The formation of the surface nickel aluminate phase in the Ni/A-SG catalyst remarkably increases the reducibility and stability of the catalyst. Furthermore, the high-surface area and the well-developed mesoporosity of the Ni/A-SG catalyst enhance the gasification of surface hydrocarbons that are adsorbed in the reaction. In the steam reforming of LNG, the Ni/A-SG catalyst exhibits a better catalytic performance than the Ni/A-C catalyst in terms of LNG conversion and hydrogen production. Moreover, the Ni/A-SG catalyst shows strong resistance toward catalyst deactivation.

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

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.

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

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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.

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

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

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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

Nanosheet Supported Single-Metal Atom Bifunctional Catalyst for Overall Water Splitting.

Science.gov (United States)

Ling, Chongyi; Shi, Li; Ouyang, Yixin; Zeng, Xiao Cheng; Wang, Jinlan

2017-08-09

Nanosheet supported single-atom catalysts (SACs) can make full use of metal atoms and yet entail high selectivity and activity, and bifunctional catalysts can enable higher performance while lowering the cost than two separate unifunctional catalysts. Supported single-atom bifunctional catalysts are therefore of great economic interest and scientific importance. Here, on the basis of first-principles computations, we report a design of the first single-atom bifunctional eletrocatalyst, namely, isolated nickel atom supported on β 12 boron monolayer (Ni 1 /β 12 -BM), to achieve overall water splitting. This nanosheet supported SAC exhibits remarkable electrocatalytic performance with the computed overpotential for oxygen/hydrogen evolution reaction being just 0.40/0.06 V. The ab initio molecular dynamics simulation shows that the SAC can survive up to 800 K elevated temperature, while enacting a high energy barrier of 1.68 eV to prevent isolated Ni atoms from clustering. A viable experimental route for the synthesis of Ni 1 /β 12 -BM SAC is demonstrated from computer simulation. The desired nanosheet supported single-atom bifunctional catalysts not only show great potential for achieving overall water splitting but also offer cost-effective opportunities for advancing clean energy technology.

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

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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.

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

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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.

Secondary promoters in alumina-supported nickel-molybdenum hydroprocessing catalysts

Energy Technology Data Exchange (ETDEWEB)

Lewis, J.M.

1992-01-01

Two secondary promoters, phosphorus and fluoride, have been investigated for their influences on the physicochemical properties of alumina-supported nickel-molybdenum hydroprocessing catalysts. Model compound reactions and infrared spectroscopy were used to probe the functionalities of the different catalysts, and the catalysts were tested in the hydroprocessing of a low-nitrogen and a high-nitrogen (quinoline-spiked) gas oil feed to assess the utility of the model compound reaction studies. Fluoride-promoted catalysts with high cumene hydrocracking activity and with comparable thiophene hydrodesulphurization (HDS) activity to Ni-Mo/Al[sub 2]O[sub 3] can be prepared by coimpregnation of the F, Ni and Mo additives. Fluoride promotes the hydrogenation (HYD) and HDS activity of Ni-Mo/Al[sub 2]O[sub 3] in the hydroprocessing (HYD) and HDS activity of Ni-Mo/Al[sub 2]O[sub 3] in the hydroprocessing of a low-nitrogen feed. Fluoride promotes the quinoline hydrodenitrogenation (HDN) activity of Ni-Mo/Al[sub 2]O[sub 3] catalysts. Impregnation of phosphorus prior to the metal additives results in catalysts which are more active in HDS. Phosphorus increases indirectly the Broensted acidity of the catalyst by increasing the activity of the MoS[sub 2]-associated acid sites. Phosphorus promotes the HDSW and HYD activities of Ni-Mo/Al[sub 2]O[sub 3] in the hydroprocessing of the low-N feed. A promotional effect of phosphorus is seen in quinoline HDN. P- and F-promoted Ni-MO/Al[sub 2]O[sub 3] catalysts are very active in quinoline HDN and maintain good activity in HDS and HYD of the high-N feed. Thiophene HDS was a good reaction for probing the activity of catalysts in the HDS of sterically-unhindered molecules, but an inaccurate probe for the HDS of hindered compounds.

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...

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)

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)

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.

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

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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.

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

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.

Hydrogen production by steam reforming of liquefied natural gas (LNG) over nickel catalysts supported on cationic surfactant-templated mesoporous aluminas

Science.gov (United States)

Seo, Jeong Gil; Youn, Min Hye; Park, Sunyoung; Jung, Ji Chul; Kim, Pil; Chung, Jin Suk; Song, In Kyu

Two types of mesoporous γ-aluminas (denoted as A-A and A-S) are prepared by a hydrothermal method under different basic conditions using cationic surfactant (cetyltrimethylammonium bromide, CTAB) as a templating agent. A-A and A-S are synthesized in a medium of ammonia solution and sodium hydroxide solution, respectively. Ni/γ-Al 2O 3 catalysts (Ni/A-A and Ni/A-S) are then prepared by an impregnation method, and are applied to hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of a mesoporous γ-Al 2O 3 support on the catalytic performance of Ni/γ-Al 2O 3 is investigated. The identity of basic solution strongly affects the physical properties of the A-A and A-S supports. The high surface-area of the mesoporous γ-aluminas and the strong metal-support interaction of supported catalysts greatly enhance the dispersion of nickel species on the catalyst surface. The well-developed mesopores of the Ni/A-A and Ni/A-S catalysts prohibit the polymerization of carbon species on the catalyst surface during the reaction. In the steam reforming of LNG, both Ni/A-A and Ni/A-S catalysts give better catalytic performance than the nickel catalyst supported on commercial γ-Al 2O 3 (Ni/A-C). In addition, the Ni/A-A catalyst is superior to the Ni/A-S catalyst. The relatively strong metal-support interaction of Ni/A-A catalyst effectively suppresses the sintering of metallic nickel and the carbon deposition in the steam reforming of LNG. The large pores of the Ni/A-A catalyst also play an important role in enhancing internal mass transfer during the reaction.

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.

Evaluation of alumina-aluminium phosphate catalyst supports for hydrodenitrogenation of pyridine and coal-derived liquids

Energy Technology Data Exchange (ETDEWEB)

Menon, R.; Joo, H.S.; Guin, J.A.; Reucroft, P.J.; Kim, J.Y. [Auburn University, Auburn, AL (United States). Dept. of Chemical Engineering

1996-05-01

Several alumina-aluminum phosphate (AAP) catalyst supports were prepared by a coprecipitation method. Effect of variations in Al/P atomic ratios on support textural properties were examined. Finished NiMo/AAP catalysts containing nominally 3 wt% Ni and 13 wt% Mo were prepared by incipient wetness and characterized by several methods including elemental, BET, and XPS surface analysis. Initial hydrodenitrogenation (HDN) activities of the catalysts were examined in both pyridine model compound and coal liquid reactions. The AAP supports showed the opportunity to tailor the catalyst pore size by variation of the Al/P ratio. On a per unit surface areas basis, the AAP-supported catalysts had initial HDN activities comparable to those of a commercial P-promoted NiMo/Al{sub 2}O{sub 3} catalyst. Because of their unique textural properties, i.e. variable pore sizes, the AAP catalysts may offer advantages when dealing with macromolecular feedstocks where hindered diffusion may slow reaction rates. 37 refs., 8 figs., 6 tabs.

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)

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.

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

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.

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)

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)

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.

Study of Supported Nickel Catalysts Prepared by Aqueous Hydrazine Method. Hydrogenating Properties and Hydrogen Storage: Support Effect. Silver Additive Effect

International Nuclear Information System (INIS)

Wojcieszak, R.

2006-06-01

We have studied Ni or NiAg nano-particles obtained by the reduction of nickel salts (acetate or nitrate) by hydrazine and deposited by simple or EDTA-double impregnation on various supports (γ-Al 2 O 3 , amorphous or crystallized SiO 2 , Nb 2 O 5 , CeO 2 and carbon). Prepared catalysts were characterized by different methods (XRD, XPS, low temperature adsorption and desorption of N 2 , FTIR and FTIR-Pyridine, TEM, STEM, EDS, H 2 -TPR, H 2 -adsorption, H 2 -TPD, isopropanol decomposition) and tested in the gas phase hydrogenation of benzene or as carbon materials in the hydrogen storage at room temperature and high pressure. The catalysts prepared exhibited better dispersion and activity than classical catalysts. TOF's of NiAg/SiO 2 or Ni/carbon catalysts were similar to Pt catalysts in benzene hydrogenation. Differences in support acidity or preparation method and presence of Ag as metal additive play a crucial role in the chemical reduction of Ni by hydrazine and in the final properties of the materials. Ni/carbon catalysts could store significant amounts of hydrogen at room temperature and high pressure (0.53%/30 bars), probably through the hydrogen spillover effect. (author)

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.

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)

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...

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)

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.

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

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.

Study on the influence of nickel and Al{sub 2}O{sub 3} support on MoS{sub 2} as hydrodenitrogenation catalysts

Energy Technology Data Exchange (ETDEWEB)

Hein, J.; Hrabar, A.; Gutierrez, O.Y.; Lercher, J.A. [Technische Univ. Muenchen, Garching (Germany). Catalysis Research Center

2012-07-01

Alumina-supported Mo and Ni-Mo catalysts as well as an unsupported NiMo catalyst were characterized and tested in the hydrodenitrogenation (HDN) of quinoline in the presence of dibenzothiophene (DBT). The supported catalysts had a well dispersed MoS{sub 2} phase with an average stacking degree around two and slabs length below 10 nm. The unsupported NiMo sulfide catalyst exhibited long, multistacked MoS{sub 2} slabs and contained segregated Ni{sub x}S{sub y} phases. The formation of the Ni-Mo-S phase in both Ni containing catalysts was verified by X-ray absorption spectroscopy, whereas the concentration of coordinatively unsaturated sites was higher for the supported Mo and Ni-Mo catalysts than for the unsupported one. All catalysts were active in the HDN of quinoline and hydrodesulfurization of DBT. The catalytic activity increased in the order Mo/Al{sub 2}O{sub 3} < NiMo/unsupported < Ni-Mo/Al{sub 2}O{sub 3}. Thus, the influence on the catalytic activity of the promoter metal Ni is more important than the presence of a support due to the formation of the Ni-Mo-S phase (more active than MoS{sub 2}). (orig.)

Predicting catalyst-support interactions between metal nanoparticles and amorphous silica supports

Science.gov (United States)

Ewing, Christopher S.; Veser, Götz; McCarthy, Joseph J.; Lambrecht, Daniel S.; Johnson, J. Karl

2016-10-01

Metal-support interactions significantly affect the stability and activity of supported catalytic nanoparticles (NPs), yet there is no simple and reliable method for estimating NP-support interactions, especially for amorphous supports. We present an approach for rapid prediction of catalyst-support interactions between Pt NPs and amorphous silica supports for NPs of various sizes and shapes. We use density functional theory calculations of 13 atom Pt clusters on model amorphous silica supports to determine linear correlations relating catalyst properties to NP-support interactions. We show that these correlations can be combined with fast discrete element method simulations to predict adhesion energy and NP net charge for NPs of larger sizes and different shapes. Furthermore, we demonstrate that this approach can be successfully transferred to Pd, Au, Ni, and Fe NPs. This approach can be used to quickly screen stability and net charge transfer and leads to a better fundamental understanding of catalyst-support interactions.

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.

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.

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

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.

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.

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.

METHANE DRY REFORMING OVER Ni SUPPORTED ON PINE SAWDUST ACTIVATED CARBON: EFFECTS OF SUPPORT SURFACE PROPERTIES AND METAL LOADING

Directory of Open Access Journals (Sweden)

Rafael García

2015-05-01

Full Text Available The influence of metal loading and support surface functional groups (SFG on methane dry reforming (MDR over Ni catalysts supported on pine-sawdust derived activated carbon were studied. Using pine sawdust as the catalyst support precursor, the smallest variety and lowest concentration of SFG led to best Ni dispersion and highest catalytic activity, which increased with Ni loading up to 3 Ni atoms nm-2. At higher Ni loading, the formation of large metal aggregates was observed, consistent with a lower "apparen" surface area and a decrease in catalytic activity. The H2/CO ratio rose with increasing reaction temperature, indicating that increasingly important side reactions were taking place in addition to MDR.

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)

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.

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)

NiMo-sulfide supported on activated carbon to produce renewable diesel

Directory of Open Access Journals (Sweden)

Nancy Y Acelas

2017-03-01

Full Text Available Due to their weak polarity and large surface area, activated carbon supports have the potential to enhance the dispersion of metal-sulfides. It is expected that the absence of a strong metal-support interaction can result in the formation of a very active and stable Ni-Mo-S phase. In this study, catalysts with different amounts of nickel and molybdenum supported on a commercial activated carbon were prepared by a co-impregnation method and characterized by BET, XRF, and SEM techniques. The catalytic activity for hydroprocessing of Jatropha oil was evaluated in a batch reactor, and the composition of the liquid and gaseous products were determined. Results showed that gaseous products are mainly composed of high amounts of propane and small amounts of other light hydrocarbons (C1 to C5. Liquid hydrocarbon products consisted of a mixture containing mainly n-paraffins of C15-C18 and some oxygenated compounds. The catalysts with a mass fraction of 3 % Ni, 15 % Mo (Ni3Mo15/AC presented the highest selectivity toward C17-C18 hydrocarbons, with a product distribution similar to a commercial alumina-supported Ni-Mo-S catalyst.

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

HDS, HDN and HDA activities of nickel-molybdenum catalysts supported on alumina

Energy Technology Data Exchange (ETDEWEB)

Dominguez-Crespo, M.A. [Instituto Mexicano del Petroleo, Programa de Tratamiento de Crudo Maya. Avenida Eje Central Lazaro Cardenas No.152, Col. San Bartolo Atepehuacan, 07730, Mexico D. F. (Mexico); Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada (CICATA-Altamira, IPN) Km 14.5 Carretera Tampico-puerto Industrial 89600, Altamira, Tamaulipas (Mexico); Torres-Huerta, A.M.; Ramirez-Meneses, E. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada (CICATA-Altamira, IPN) Km 14.5 Carretera Tampico-puerto Industrial 89600, Altamira, Tamaulipas (Mexico); Diaz-Garcia, L. [Instituto Mexicano del Petroleo, Programa de Tratamiento de Crudo Maya. Avenida Eje Central Lazaro Cardenas No.152, Col. San Bartolo Atepehuacan, 07730, Mexico D. F. (Mexico); Arce-Estrada, E.M. [Instituto Politecnico Nacional, Departamento de Metalurgia y Materiales. A.P. 75-876, 07300 Mexico, D. F. (Mexico)

2008-08-15

In this work, NiMo-Al{sub 2}O{sub 3} catalysts were prepared by using different alumina precursors. The supports were impregnated by means of the spray at incipient wetness technique in both basic and acid media. Both the supports and fresh catalysts were characterized by the adsorption-desorption isotherms, Temperature-Programmed Reduction (TPR), Thermal Pyridine Adsorption-Desorption (TPD) and X-Ray Diffraction analyses (XRD). After sulfidation, the NiMoS metallic particles were characterized by Transmission Electron Microscopy (TEM). The initial analyses were performed in a trickle-bed reactor by using a real feedstock (Mexican heavy gas oil) and performing hydrotreating reactions (HDS, HDN and HDA) at three different temperatures: 613, 633 and 653 K; and 54 kg cm{sup -} {sup 2}. The catalytic activities are discussed in relation to the physicochemical properties of the NiMo catalysts, alumina phase and pH of the impregnating solution. The catalytic results show an increase in the conversion profiles with temperature. The sulfur conversion was increased from 89 to 99.25%, 91-99%, 90.8-97%, 83-95% and 78-96% when the crystal size of the support varied from 3 to 20 nm, respectively. The nitrogen and aromatic conversions were also increased in the range of 23-45 wt.%. It was found that the {gamma} phase reached a higher catalytic performance than the {eta} phase. The NiMo catalysts synthesized in a basic medium showed a better catalytic performance than that obtained with those prepared in acid solutions. The significance of the kinetic data to compare the catalysts is discussed. The maximum value of the catalytic activity was reached with the catalysts with the smallest particle sizes. (author)

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.

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

[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

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.

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.

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.

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)

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)

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.

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.

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

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...

Supported chromium-molybdenum and tungsten sulfide catalysts

International Nuclear Information System (INIS)

Chianelli, R.R.; Jacobson, A.J.; Young, A.R.

1988-01-01

This patent describes the process for preparing a supported hydroprocessing catalyst. The process comprising compositing a quantity of a particulate, porous catalyst support material comprising one or more refactory oxides with one or more catalyst precursor salts and heating the composite at elevated temperature of at least about 200/sup 0/C up to about 600/sup 0/, in the presence of a sulfur-bearing compound in an amount whereby sulfur in the form of the sulfur-bearing compound in an amount whereby sulfur in the form of the sulfur bearing compound is present in excess of that contained in the catalyst precursor and under oxygen-free conditions for a time sufficient to form the catalyst. The catalyst precursor salt contains a tetrathiometallate anion of Mo, W or mixture therof and a cation comprising trivalent chromium or a mixture of trivalent chromium with one or more divalent promoter metals selected from the group consisting of Fe, Ni, Co, Mn, Cu and a mixture thereof wherein the trivalent chromium and divalent promoter metals are chelated by at least one neutral, nitrogen-containing polydentate ligand, L

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...

Synthesis of supported and unsupported NiMo carbides and their properties for the catalytic hydrocracking of n-octane

International Nuclear Information System (INIS)

Torre, A I Reyes de la; Banda, J A Melo; Alamilla, R GarcIa; Sandoval Robles, G; Rojas, E Terres; Lopez Ortega, A; Dominguez, J M

2004-01-01

Unsupported and γ-Al 2 O 3 -, MCM-41-supported (Ni, Mo) carbides were prepared and modified by 'in situ' polymer (PAN: polyacrylonitrile) pyrolysis. The supported catalysts were impregnated with Ni and Mo metals, i.e. 2.8 atom Mo/nm 2 , whose atomic ratio was Ni/Ni+Mo = 0.5. X-ray diffraction (XRD) showed single NiC, MoC phases in all cases, with relatively low surface areas, as verified by N 2 adsorption (BET). The catalytic behaviour of the supported (Ni, Mo)C phases for n-C 8 hydrocracking depended on the support type. (Ni, Mo)C/MCM41-PAN-P (P = pyrolyzed) showed a total conversion of 40% while it was only 15% on Ni,MoC/γ-Al 2 O 3 . The most active catalysts were (Ni, Mo)C unsupported catalysts, i.e., 90% total conversion. In all cases the hydrocracking selectivity favoured lighter hydrocarbons (C 1 -C 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)

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

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).

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)

Enhanced hydrogen reaction kinetics of nanostructured Mg-based composites with nanoparticle metal catalysts dispersed on supports

International Nuclear Information System (INIS)

Yoo, Yeong; Tuck, Mark; Kondakindi, Rajender; Seo, Chan-Yeol; Dehouche, Zahir; Belkacemi, Khaled

2007-01-01

Hydrogen reaction kinetics of nanocrystalline MgH 2 co-catalyzed with Ba 3 (Ca 1+x Nb 2-x )O 9-δ (BCN) proton conductive ceramics and nanoparticle bimetallic catalyst of Ni/Pd dispersed on single wall carbon nanotubes (SWNTs) support has been investigated. The nanoparticle bimetallic catalysts of Ni/Pd supported by SWNTs were synthesized based on a novel polyol method using NiCl 2 .6H 2 O, PdCl 2 , NaOH and ethylene glycol (EG). The nanostructured Mg composites co-catalyzed with BCN and bimetallic supported catalysts exhibited stable hydrogen desorption capacity of 6.3-6.7 wt.% H 2 and the significant enhancement of hydrogen desorption kinetics at 230-300 deg. C in comparison to either non-catalyzed MgH 2 or the nanocomposite of MgH 2 catalyzed with BCN

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.

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.

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.

Ni–Sn-Supported ZrO2 Catalysts Modified by Indium for Selective CO2 Hydrogenation to Methanol

KAUST Repository

Hengne, Amol Mahalingappa

2018-04-02

Ni and NiSn supported on zirconia (ZrO2) and on indium (In)-incorporated zirconia (InZrO2) catalysts were prepared by a wet chemical reduction route and tested for hydrogenation of CO2 to methanol in a fixed-bed isothermal flow reactor at 250 °C. The mono-metallic Ni (5%Ni/ZrO2) catalysts showed a very high selectivity for methane (99%) during CO2 hydrogenation. Introduction of Sn to this material with the following formulation 5Ni5Sn/ZrO2 (5% Ni-5% Sn/ZrO2) showed the rate of methanol formation to be 0.0417 μmol/(gcat·s) with 54% selectivity. Furthermore, the combination NiSn supported on InZrO2 (5Ni5Sn/10InZrO2) exhibited a rate of methanol formation 10 times higher than that on 5Ni/ZrO2 (0.1043 μmol/(gcat·s)) with 99% selectivity for methanol. All of these catalysts were characterized by X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy, CO2-temperature-programmed desorption, and density functional theory (DFT) studies. Addition of Sn to Ni catalysts resulted in the formation of a NiSn alloy. The NiSn alloy particle size was kept in the range of 10–15 nm, which was evidenced by HRTEM study. DFT analysis was carried out to identify the surface composition as well as the structural location of each element on the surface in three compositions investigated, namely, Ni28Sn27, Ni18Sn37, and Ni37Sn18 bimetallic nanoclusters, and results were in agreement with the STEM and electron energy-loss spectroscopy results. Also, the introduction of “Sn” and “In” helped improve the reducibility of Ni oxide and the basic strength of catalysts. Considerable details of the catalytic and structural properties of the Ni, NiSn, and NiSnIn catalyst systems were elucidated. These observations were decisive for achieving a highly efficient formation rate of methanol via CO2 by the H2 reduction process with high methanol selectivity.

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.

{alpha}-Al{sub 2}O{sub 3} catalyst supports for synthesis gas production: influence of different alumina bonding agents on support and catalyst properties

Energy Technology Data Exchange (ETDEWEB)

Marturano, M. [Centro de Investigacion y Desarrollo en Procesos Cataliticos, La Plata (Argentina); Aglietti, E.F. [Centro de Tecnologia de Recursos Minerales y Ceramica (CETMIC), Gonnet (Argentina); Ferretti, O. [Centro de Investigacion y Desarrollo en Procesos Cataliticos, La Plata (Argentina)]|[Univ. Nacional de La Plata, Dept. de Ingenieria Quimica de la Facultad de Ingenieria, La Plata (Argentina)

1997-02-01

Aluminas are widely used as catalytic supports in chemical reactions. Reforming reactions to obtain synthesis gas requires good mechanical strength and low sintering behaviour. In this work, the influence of bentonite, aluminium phosphate and alumina gel as binder agents of a calcined {alpha}-Al{sub 2}O{sub 3} are analyzed with respect to support and catalytic properties. The {alpha}-Al{sub 2}O{sub 3} supports, calcined at 1300 C, are then impregnated with solutions of Ni and Al inorganic salts to obtain the catalysts and are finally tested in the reforming reaction of methane to synthesis gas at 500-900 C. Supports and catalysts are characterized by XRD, SEM, N{sub 2} adsorption, mechanical strength test and other techniques. Mechanical strength depends on the type and quantity of binder material used during support preparation. The influence of the support on the performance of the resulting catalyst is evidenced by means of catalytic tests. (orig.) 8 refs.

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.

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.

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...

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

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.

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

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.

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...

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.

Two-Dimensional Layered Double Hydroxide Derived from Vermiculite Waste Water Supported Highly Dispersed Ni Nanoparticles for CO Methanation

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Panpan Li

2017-03-01

Full Text Available Expanded multilayered vermiculite (VMT was successfully used as catalyst support and Ni/VMT synthesized by microwave irradiation assisted synthesis (MIAS exhibited excellent performance in our previous work. We also developed a two-dimensional porous SiO2 nanomesh (2D VMT-SiO2 by mixed-acid etching of VMT. Compared with three-dimensional (3D MCM-41, 2D VMT-SiO2 as a catalyst support provided a superior position for implantation of NiO species and the as-obtained catalyst exhibited excellent performance. In this paper, we successfully synthesized a layered double hydroxide (LDH using the spent liquor after mixed-acid etching of VMT, which mainly contained Mg2+ and Al3+. The as-calcined layered double oxide (LDO was used as a catalyst support for CO methanation. Compared with Ni/MgAl-LDO, Ni/VMT-LDO had smaller active component particles; therefore, in this study, it exhibited excellent catalytic performance over the whole temperature range of 250–500 °C. Ni/VMT-LDO achieved the best activity with 87.88% CO conversion, 89.97% CH4 selectivity, and 12.47 × 10−2·s−1 turn over frequency (TOF at 400 °C under a gas hourly space velocity of 20,000 mL/g/h. This study demonstrated that VMT-LDO as a catalyst support provided an efficient way to develop high-performance catalysts for synthetic natural gas (SNG from syngas.

Hydrogen or synthesis gas production via the partial oxidation of methane over supported nickel-cobalt catalysts

Energy Technology Data Exchange (ETDEWEB)

Koh, Alaric C.W. [Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543 (Singapore); Institute of Chemical and Engineering Sciences, 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Chen, Luwei; Lin, Jianyi [Institute of Chemical and Engineering Sciences, 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Kee Leong, Weng [Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543 (Singapore); Johnson, Brian F.G.; Khimyak, Tetyana [University Chemical Laboratory, University of Cambridge, Lensfield Road, Cambridge, UK CB2 1EW (United Kingdom)

2007-05-15

Activity, selectivity, and coking-resistance of a series of Ni{sub x}Co{sub y} (where x,y are the respective metal loadings of 0, 1, 2 or 3 wt.%; x+y=3) bimetallic catalysts supported on CaAl{sub 2}O{sub 4}/Al{sub 2}O{sub 3} have been studied for hydrogen/synthesis gas production via the catalytic partial oxidation (CPO) of methane. Catalysts were characterized by temperature programmed reduction (TPR), transmission electron microscopy (TEM) and X-ray fluorescence multi-element analysis (XRF). Their activity for the partial oxidation of methane to hydrogen and carbon monoxide (at 1 bar, gas hourly space velocity (GHSV) of 144,000cm{sup 3}g{sup -1}h{sup -1} and CH{sub 4}/O{sub 2} molar ratio of 2) was investigated, and coke deposited on the spent catalysts was studied by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and thermogravimetric analysis (TGA). The activity was found to decrease in the order of Ni{sub 2}Co>Ni{sub 3}>NiCo{sub 2}>>Co{sub 3}, while CO and H{sub 2} selectivities were found to be in the order ofNi{sub 2}Co>Ni{sub 3}{approx}NiCo{sub 2}>Co{sub 3}. Ni{sub 2}Co is also shown to be more resistant to coking as compared to Ni{sub 3}, which is a current catalyst of choice. Results show that not only does Ni{sub 2}Co have the highest activity and selectivity among all the catalysts tested, it is also relatively resistant to coking. This finding would be helpful for catalyst design to achieve high coking resistivity catalysts for hydrogen production from CPO of methane. (author)

Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

Directory of Open Access Journals (Sweden)

Galip Akay

2016-05-01

Full Text Available A novel generic method of silica supported catalyst system generation from a fluid state is presented. The technique is based on the combined flow and radiation (such as microwave, thermal or UV induced co-assembly of the support and catalyst precursors forming nano-reactors, followed by catalyst precursor decomposition. The transformation from the precursor to supported catalyst oxide state can be controlled from a few seconds to several minutes. The resulting nano-structured micro-porous silica supported catalyst system has a surface area approaching 300 m2/g and X-ray Diffraction (XRD-based catalyst size controlled in the range of 1–10 nm in which the catalyst structure appears as lamellar sheets sandwiched between the catalyst support. These catalyst characteristics are dependent primarily on the processing history as well as the catalyst (Fe, Co and Ni studied when the catalyst/support molar ratio is typically 0.1–2. In addition, Ca, Mn and Cu were used as co-catalysts with Fe and Co in the evaluation of the mechanism of catalyst generation. Based on extensive XRD, Scanning Electron Microscopy (SEM and Transmission Electron Microscopy (TEM studies, the micro- and nano-structure of the catalyst system were evaluated. It was found that the catalyst and silica support form extensive 0.6–2 nm thick lamellar sheets of 10–100 nm planar dimensions. In these lamellae, the alternate silica support and catalyst layer appear in the form of a bar-code structure. When these lamellae structures pack, they form the walls of a micro-porous catalyst system which typically has a density of 0.2 g/cm3. A tentative mechanism of catalyst nano-structure formation is provided based on the rheology and fluid mechanics of the catalyst/support precursor fluid as well as co-assembly nano-reactor formation during processing. In order to achieve these structures and characteristics, catalyst support must be in the form of silane coated silica nano

Effective Production of Sorbitol and Mannitol from Sugars Catalyzed by Ni Nanoparticles Supported on Aluminium Hydroxide

Directory of Open Access Journals (Sweden)

Rodiansono Rodiansono

2013-06-01

Full Text Available Effective production of hexitols (sorbitol and mannitol was achieved from sugars by means of nickel nanoparticles supported on aluminium hydroxide (NiNPs/AlOH catalyst. NiNPs/AlOH catalyst was prepared by a simple and benign environmentally procedure using less amount of sodium hydroxide. ICP-AES and XRD analyses confirmed that the NiNPs/AlOH catalysts comprised a large amount of remained aluminium hydroxide (i.e. bayerite and gibbsite. The presence of aluminium hydroxide caused a high dispersion Ni metal species. The average Ni crystallite sizes that derived from the Scherrer`s equation for former R-Ni and NiNPs/AlOH were 8.6 nm and 4.1 nm, respectively. The catalyst exhibited high activity and selectivity both hydrogenolysis of disaccharides (sucrose and cellobiose and monosaccharides (glucose, fructose, and xylose at 403 K for 24 h. The NiNPs/AlOH catalyst was found to be reusable for at least five consecutive runs without any significant loss of activity and selectivity. © 2013 BCREC UNDIP. All rights reservedReceived: 21st December 2012; Revised: 7th February 2013; Accepted: 10th February 2013[How to Cite: Rodiansono, R., Shimazu, S. (2013. Effective Production of Sorbitol and Mannitol from Sug-ars Catalyzed by Ni Nanoparticles Supported on Aluminium Hydroxide. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 40-46. (doi:10.9767/bcrec.8.1.4290.40-46][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4290.40-46] | View in  |

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

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.

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.%.

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

Wet chemical synthesis of nickel supported on alumina catalysts

International Nuclear Information System (INIS)

Freire, Ranny Rodrigues; Costa, Talita Kenya Oliveira; Morais, Ana Carla da Fonseca Ferreira; Costa, Ana Cristina Figueiredo de Melo; Freitas, Normanda Lino de

2016-01-01

Heterogenic catalysts are those found to be in a different phase on the reaction when compared to the reactants and products. Preferred when compared to homogeneous catalysts due to the easiness on which the separation is processed. The objective of this study is to obtain and characterize Alumina based catalysts impregnated with Nickel (Al_2O_3), by wet impregnation. The alumina was synthesized by combustion reaction. Before and after the impregnation the catalysts were characterized by X-ray diffraction (XRD), granulometric analysis, the textural analysis will be held by nitrogen adsorption (BET), energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The results show a presence of a stable crystalline phase of Al2O3 in all the studied samples and after the impregnation the second phase formed was of NiO and NiAl_2O_4. The Al_2O_3 e Ni/Al_2O_3 catalysts resulted in clusters with a medium diameter of 18.9 and 14.2 μm, respectively. The catalysts show a medium-pore characteristic (medium pore diameter between 2 and 50 nm), the superficial area to Al_2O_3 and Ni/Al_2O_3 catalysts were 8.69 m"2/g and 5.56 m"2/g, respectively. (author)

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)

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

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.

Synthesis of carbon-supported nickel catalysts for the dry reforming of CH{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Fidalgo, B.; Zubizarreta, L.; Bermudez, J.M.; Arenillas, A.; Menendez, J.A. [Instituto Nacional del Carbon, CSIC, Apartado 73, 33080 Oviedo (Spain)

2010-07-15

A series of carbon-based nickel (Ni) catalysts was prepared in order to investigate the effect of the preparation method on the dispersion of Ni and its final catalytic activity in the dry reforming of methane, i.e. CH{sub 4} + CO{sub 2} 2H{sub 2} + 2CO. Three parameters were studied: (i) the influence of the surface chemistry of the carbon used as support; (ii) the method of drying (conventional vs. microwave drying); and, (iii) the temperature of the reduction stage. In order to study the role of the surface chemistry of the commercial activated carbon used as support, the active carbon was tested as received and oxidized. Although a better Ni dispersion was achieved over the oxidized support, the conversions were much lower. It was also found that microwave drying offers various advantages over conventional drying, the main one being that less time is required to prepare the catalyst. Two reduction temperatures were used (300 and 500 C), being found that it is necessary to adjust this parameter to prevent the Ni particles from sintering. (author)

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

Influence of pore structure and chemical properties of supported Mo catalysts on their performance in upgrading heavy coal liquids

Energy Technology Data Exchange (ETDEWEB)

Song, C.; Hanaoka, K.; Nomura, M. (Pennsylvania State University, University Park, PA (USA). Dept. of Materials Science and Engineering)

In the hydroprocessing of solvent-refined coals, both the pore structure and the chemical properties of the catalysts affect the conversion of the heavy materials. Increasing median pore diameter (MPD) of unimodal Ni-Mo/Al[sub 2]O[sub 3] catalysts in the relatively small pore region (up to 150 [angstrom]) enhanced the conversion of both asphaltene and preasphaltene, but further increasing the MPD up to 730 [angstrom] mainly promoted preasphaltene conversion. In the runs of the isolated fractions, however, conversions increased with MPD up to 290 [angstrom] for asphaltene and up to 730 [angstrom] for preasphaltene. The degree of heteroatom removal is also influenced by MPD. There exist preferable pore size ranges for hydrodeoxygenation. Two Mo/SiO[sub 2] and several carbon-coated Ni-Mo/Al[sub 2]O[sub 3] catalysts with different MPD and a commercial Ni-Mo supported on silicated Al[sub 2]O[sub 3] were also compared. The increasing MPD of SiO[sub 2]-supported Mo catalysts increased the conversion of preasphaltene materials. Mo/SiO[sub 2] catalysts are more effective than Ni-Mo supported on Al[sub 2]O[sub 3] and silicated Al[sub 2]O[sub 3] for converting preasphaltene materials, while the latter two are more active for conversion of asphaltene into oil. Another interesting observation is that, for a given MPD range, the carbon-coated Ni-Mo/Al[sub 2]O[sub 3] catalysts gave higher preasphaltene conversions than fresh ones. These results point to the conclusion that larger pore and less acidic hydrogenation catalysts are more effective for preasphaltene conversion, but efficient conversion of asphaltene into oil is facilitated by mild hydrocracking catalysts having appropriate pore size ranges. 43 refs., 8 figs., 9 tabs.

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)

Preparation and characterization of alumina supported nickel-oxalate catalyst for the hydrodeoxygenation of oleic acid into normal and iso-octadecane biofuel

International Nuclear Information System (INIS)

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

2014-01-01

Highlights: • Preparation of nickel oxalate complex as catalyst precursor. • Incorporation of nickel oxalate complex into alumina support. • Characterization of the alumina supported nickel oxalate catalyst. • Hydrodeoxygenation of oleic acid with nickel oxalate catalyst. • Nickel oxalate catalyst reusability studies. - Abstract: In this study, nickel II oxalate complex (NiOx) was prepared by functionalization of nickel with oxalic acid (OxA) and incorporated into Al 2 O 3 to synthesize alumina supported nickel oxalate (NiOx/Al 2 O 3 ) catalyst for the hydrodeoxygenation (HDO) of oleic acid (OA) into biofuel. The synthesized NiOx/Al 2 O 3 was characterized and the X-ray fluorescence and elemental dispersive X-ray results showed that NiOx was successfully incorporated into the structure of Al 2 O 3 . The X-ray diffraction and Raman spectroscopy results confirmed that highly dispersed Ni species are present in the NiOx/Al 2 O 3 due to the functionalization with OxA. The catalytic activity of the NiOx/Al 2 O 3 on the HDO of OA produced a mixture of 21% iso-C18 and 72% n-C18 at a 360 °C, 20 bar, 30 mg NiOx/Al 2 O 3 loading pressure and gas flow rate of 100 mL/min. The presence of i-C 18 was ascribed to the OxA functionalization which increased the acidity of NiOx/Al 2 O 3 . The NiOx/Al 2 O 3 reusability study showed consistent HDO ability after 5 runs. These results are promising for further research into biofuel production for commercialization

The effect of catalyst support on the RWGS reaction

International Nuclear Information System (INIS)

Laosiripojana, N.; Sutthisripok, W.

2004-01-01

'Full text:' Methane steam reforming is generally applied in order to produce synthesis gas mainly consist of hydrogen and carbon monoxide for later utilization in SOFC. This reaction is always carried out with the water gas shift reaction over a catalyst at elevated temperatures resulting in some carbon dioxide production. The CO/CO2 production selectivity strongly depends on the influence of water gas shift reaction. It was observed that the reactivity of this reaction depended on the type of support material. Stabilities, activities, and kinetics of the reverse water gas shift reaction (RWGS) for commercial nickel on CeO2, ZrO2, CeO2-ZrO2, TiO2, MgO, and Al2O3 supports were studied in order to observe the influence of the support on this reaction. According to the experiment, the activities of Ni/CeO2 toward the reverse water gas shift reaction (RWGS) were very high, and reached equilibrium level at approximately 600 o C (where the conversion of CO2 was closed to 1). Other oxide supports provided lower activities toward this reaction. It was observed that the activity of Ni/Al2O3 toward this reaction was the lowest. The kinetics of this reaction was also studied. Carbon dioxide presented positive effect on the reverse water gas shift reaction. The reaction orders in carbon dioxide were observed to be positive partial value between 0-1. It slightly decreased with increasing temperature for Ni/ CeO2 and Ni/CeO2-ZrO2, whereas it seemed to be independent of the operating temperature for other materials in the range of conditions studied. Hydrogen also showed positive effect on the reverse water gas shift reaction for all materials. The reaction order in hydrogen for all materials was observed to be the positive value and less than one for the range of conditions studied. The approximate values for all catalysts were between 0.45-0.65, and seemed to be independent of the operating temperature. The estimated values of the apparent activation energy for RWGS reaction

Hydrogenation of Levulinic Acid over Nickel Catalysts Supported on Aluminum Oxide to Prepare γ-Valerolactone

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Jie Fu

2015-12-01

Full Text Available Four types of nickel catalysts supported on aluminum oxide (Ni/Al2O3 with different nickel loadings were synthesized using the co-precipitation method and were used for the hydrogenation of levulinic acid (LA to prepare γ-valerolactone (GVL. The synthesized Ni/Al2O3 catalysts exhibited excellent catalytic activity in dioxane, and the activity of the catalysts was excellent even after being used four times in dioxane. The catalytic activity in dioxane as a solvent was found to be superior to the activity in water. Nitrogen physisorption, X-ray diffraction, and transmission electron microscopy were employed to characterize the fresh and used catalysts. The effects of the nickel loading, temperature, hydrogen pressure, and substrate/catalyst ratio on the catalytic activity were investigated.

Hydrogen Production by Ethanol Steam Reforming (ESR over CeO2 Supported Transition Metal (Fe, Co, Ni, Cu Catalysts: Insight into the Structure-Activity Relationship

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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.

Defect-rich Ni-Ti layered double hydroxide as a highly efficient support for Au nanoparticles in base-free and solvent-free selective oxidation of benzyl alcohol.

Science.gov (United States)

Liu, Mengran; Fan, Guoli; Yu, Jiaying; Yang, Lan; Li, Feng

2018-04-17

Tuning the surface properties of supported metal catalysts is of vital importance for governing their catalytic performances in nanocatalysis. Here, we report highly dispersed nanometric gold nanoparticles (NPs) supported on Ni-Ti layered double hydroxides (NiTi-LDHs), which were employed in solvent-free and base-free selective oxidation of benzyl alcohol. A series of characterization techniques demonstrated that defect-rich NiTi-LDHs could efficiently stabilize Au NPs and decrease surface electron density of Au NPs. The as-formed Au/NiTi-LDH catalyst with a Ni/Ti molar ratio of 3 : 1 and an Au loading of 0.71 wt% yielded the highest turnover frequency value of ∼4981 h-1 at 120 °C among tested Au/NiTi-LDH catalysts with different Ni/Ti molar ratios, along with a high benzaldehyde selectivity of 98%. High catalytic efficiency of the catalyst was mainly correlated with surface cooperation between unique defects (i.e. defective Ti3+ species and oxygen vacancies) and abundant hydroxyl groups on the brucite-like layers of the NiTi-LDH support, which could lead to the preferential adsorption and activation of an alcohol hydroxyl moiety in benzyl alcohol and oxygen molecule, as well as the formation of more electron-deficient Ni3+ and Au0 species on the catalyst surface. Furthermore, the present Au/NiTi-LDH catalyst tolerated the oxidation of a wide variety of substrate structures into the corresponding aldehydes, acids or ketones. Our primary results illustrate that defect-rich NiTi-LDHs are promising supports which can efficiently modify surface structure and electronic properties of supported metal catalysts and consequently improve their catalytic performances.

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).

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.

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.

Rational design of Mg-Al mixed oxide-supported bimetallic catalysts for dry reforming of methane

Energy Technology Data Exchange (ETDEWEB)

Tsyganok, Andrey I. [Centre for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa, D' Iorio Hall, 10 Marie Curie Street, Ottawa, Ont. (Canada); Inaba, Mieko [Natural Gas Technology Development Team, Teikoku Oil Co., 9-23-30 Kitakarasuyama, Setagaya-ku, Tokyo 157-0061 (Japan); Tsunoda, Tatsuo; Uchida, Kunio; Suzuki, Kunio; Hayakawa, Takashi [Institute for Materials and Chemical Process, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba 305-8565 (Japan); Takehira, Katsuomi [Department of Applied Chemistry, Faculty of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527 (Japan)

2005-09-18

A novel synthetic strategy for preparing bimetallic Ru-M (M=Cr, Fe, Co, Ni and Cu) catalysts, supported on Mg-Al mixed oxide, has been introduced. It was based on a 'memory effect', i.e. on the ability of Mg-Al mixed oxide to reconstruct a layered structure upon rehydration with an aqueous solution. By repeated calcinations-rehydration cycles, layered double hydroxide (LDH) precursors of catalysts containing two different metals were synthesized. Bimetallic catalysts were then generated (1) in situ from LDH under methane reforming reaction conditions and (2) from mixed metal oxides obtained by preliminary LDH calcination. Among all the LDH-derived catalysts, a Ru{sup 0.1%}-Ni{sup 5.0%}/MgAlO{sub x} sample revealed the highest activity and selectivity to syngas, a suitable durability and a low coking capacity. A promoting effect of ruthenium on catalytic function of supported nickel was demonstrated. Preliminary LDH calcination was shown to markedly affect the catalytic activity of the derived catalysts and especially their coking properties.

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

HDO of Methyl Palmitate over Silica-Supported Ni Phosphides: Insight into Ni/P Effect

Directory of Open Access Journals (Sweden)

Irina V. Deliy

2017-10-01

Full Text Available Two sets of silica-supported nickel phosphide catalysts with a nickel content of about 2.5 and 10 wt % and Ni/P molar ratio 2/1, 1/1 and 1/2 in each set, were prepared by way of a temperature-programmed reduction method using (Ni(CH3COO2 and ((NH42HPO4 as a precursor. The NixPy/SiO2 catalysts were characterized using chemical analysis N2 physisorption, XRD, TEM, 31P MAS NMR. Methyl palmitate hydrodeoxygenation (HDO was performed in a trickle-bed reactor at 3 MPa and 290 °C with LHSV ranging from 0.3 to 16 h−1. The Ni/P ratio was found to affect the nickel phosphide phase composition, POx groups content and catalytic properties in methyl palmitate HDO with the TOF increased along with a decline of Ni/P ratio and a growth of POx groups’ content. Taking into account the possible routes of methyl palmitate conversion (metal-catalyzed hydrogenolysis or acid-catalyzed hydrolysis, we proposed that the enhancement of acid POx groups’ content with the Ni/P ratio decrease provides an enhancement of the rate of methyl palmitate conversion through the acceleration of acid-catalyzed hydrolysis.

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.

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.

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

Bifunctional Characteristics of Al2O3 supported Ni in the HI Decomposition of Sulfur-Iodine Process

Directory of Open Access Journals (Sweden)

Park Chu-Sik

2016-01-01

Full Text Available The Sulfur-Iodine process is in need of catalytic reactor for HI decomposition because the HI decomposition reaction rate is very slow. Nickel as an alternative catalyst for platinum was investigated in this study. Al2O3 supported Ni catalysts were prepared by impregnation method. Ni amounts loaded over Al2O3 were in the range of 0.1~20 wt. %. HI decompositions were carried out in the temperature range of 573 ~ 773 K using the fixed-bed quartz reactor. The difference of catalysts before and after the reaction was analyzed using BET, CO/H2 chemisorption, XRD, XRF and SEM. It was confirmed by XRD and SEM-EDX analysis that Ni was converted to NiI2 during the HI decomposition. Catalyst deactivation due to the formation of NiI2 leads to a reduction of HI conversion. Although Ni of catalyst converted to NiI2, HI decomposition with low loading (up to 3 wt. % catalyst showed a little decrease of HI conversion. However, with more than 5 wt. % catalyst, the initial HI conversion was considerably decreased. In the particular case of 20 wt. %, the initial conversion was increased close to 60 %, which is higher than 20 % as an equilibrium conversion at 723 K. These results showed that Ni had not only a catalytic function for HI decomposition, but also function as a sorbent to absorb I2 produced from HI.

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.

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 %)

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.

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

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.

Selective Hydrogenation of Biomass-derived Furfural over Supported Ni3Sn2 Alloy: Role of Supports

Directory of Open Access Journals (Sweden)

Rodiansono Rodiansono

2016-03-01

Full Text Available A highly active and selective hydrogenation of biomass-derived furfural into furfuryl alcohol was achieved using supported single phase Ni3Sn2 alloy catalysts. Various supports such as active carbon (AC, g-Al2O3, Al(OH3, ZnO, TiO2, ZrO2, MgO, Li-TN, and SiO2 have been employed in order to understand the role of the support on the formation of Ni3Sn2 alloy phase and its catalytic performance. Supported Ni3Sn2 alloy catalysts were synthesised via a simple hydrothermal treatment of the mixture of aqueous solution of nickel chloride hexahydrate and ethanol solution of tin(II chloride dihydrate in presence of ethylene glycol at 423 K for 24 h followed by H2 treatment at 673 K for 1.5 h, then characterised by using ICP-AES, XRD, H2- and N2-adsorption. XRD profiles of samples showed that the Ni3Sn2 alloy phases are readily formed during hydrothermal processes and become clearly observed at 2θ = 43-44o after H2 treatment. The presence of Ni3Sn2 alloy species that dispersed on the supports is believed to play a key role in highly active and selective hydrogenation of biomass-derived furfural towards furfuryl alcohol. Ni3Sn2 on TiO2 and ZnO supports exhibited much lower reaction temperature to achieved >99% yield of furfuryl alcohol product compared with other supports. The effects of loading amount of Ni-Sn, reaction conditions (temperature and time profile on the activity and selectivity towards the desired product are systematically discussed. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 31st December 2015; Accepted: 5th January 2016 How to Cite: Rodiansono, R., Astuti, M.D., Khairi, S., Shimazu, S. (2016. Selective Hydrogenation of Biomass-derived Furfural over Supported Ni3Sn2 Alloy: Role of Supports. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 1-9. (doi:10.9767/bcrec.11.1.393.1-9 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.393.1-9

Boosting Bifunctional Oxygen Electrocatalysis with 3D Graphene Aerogel-Supported Ni/MnO Particles.

Science.gov (United States)

Fu, Gengtao; Yan, Xiaoxiao; Chen, Yifan; Xu, Lin; Sun, Dongmei; Lee, Jong-Min; Tang, Yawen

2018-02-01

Electrocatalysts for oxygen-reduction and oxygen-evolution reactions (ORR and OER) are crucial for metal-air batteries, where more costly Pt- and Ir/Ru-based materials are the benchmark catalysts for ORR and OER, respectively. Herein, for the first time Ni is combined with MnO species, and a 3D porous graphene aerogel-supported Ni/MnO (Ni-MnO/rGO aerogel) bifunctional catalyst is prepared via a facile and scalable hydrogel route. The synthetic strategy depends on the formation of a graphene oxide (GO) crosslinked poly(vinyl alcohol) hydrogel that allows for the efficient capture of highly active Ni/MnO particles after pyrolysis. Remarkably, the resulting Ni-MnO/rGO aerogels exhibit superior bifunctional catalytic performance for both ORR and OER in an alkaline electrolyte, which can compete with the previously reported bifunctional electrocatalysts. The MnO mainly contributes to the high activity for the ORR, while metallic Ni is responsible for the excellent OER activity. Moreover, such bifunctional catalyst can endow the homemade Zn-air battery with better power density, specific capacity, and cycling stability than mixed Pt/C + RuO 2 catalysts, demonstrating its potential feasibility in practical application of rechargeable metal-air batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

In situ X-ray absorption fine structure studies on the structure of nickel phosphide catalyst supported on K-USY

CERN Document Server

Kawai, T; Suzuki, S

2003-01-01

Local structure around Ni in a nickel phosphide catalyst supported on K-USY was investigated by an situ X-ray absorption fine structure (XAFS) method during the reduction process of the catalyst and the hydrodesulfurization (HDS) reaction of thiophene. In the passivated sample, Ni phosphide was partially oxidized but after the reduction, 1.1 nm diameter Ni sub 2 P particles were formed with Ni-P and Ni-Ni distances at 0.218 and 0.261 nm, respectively, corresponding to those of bulk Ni sub 2 P. In situ XAFS cleary revealed that the Ni sub 2 P structure was stable under reaction conditions and was an active structure for the HDS process.

Influence of preparation method on supported Cu-Ni alloys and their catalytic properties in high pressure CO hydrogenation

DEFF Research Database (Denmark)

Wu, Qiongxiao; Eriksen, Winnie L.; Duchstein, Linus Daniel Leonhard

2014-01-01

(50 bar CO and 50 bar H2). These alloy catalysts are highly selective (more than 99 mol%) and active for methanol synthesis; however, loss of Ni caused by nickel carbonyl formation is found to be a serious issue. The Ni carbonyl formation should be considered, if Ni-containing catalysts (even...... high surface area silica supported catalysts (BET surface area up to 322 m2 g-1, and metal area calculated from X-ray diffraction particle size up to 29 m2 g-1). The formation of bimetallic Cu-Ni alloy nanoparticles has been studied during reduction using in situ X-ray diffraction. Compared...

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.

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.

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...

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.

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)

Effects of P/Ni ratio and Ni content on performance of γ-Al2O3-supported nickel phosphides for deoxygenation of methyl laurate to hydrocarbons

Science.gov (United States)

Zhang, Zhena; Tang, Mingxiao; Chen, Jixiang

2016-01-01

γ-Al2O3-supported nickel phosphides (mNi-Pn) were prepared by the TPR method and tested for the deoxygenation of methyl laurate to hydrocarbons. The effects of the P/Ni ratio (n = 1.0-2.5) and Ni content (m = 5-15 wt.%) in the precursors on their structure and performance were investigated. Ni/γ-Al2O3 was also studied for comparison. It was found that the formation of AlPO4 in the precursor inhibited the reduction of phosphate and so the formation of nickel phosphides. With increasing the P/Ni ratio and Ni content, the Ni, Ni3P, Ni12P5 and Ni2P phases orderly formed, accompanying with the increases of their particle size and the amount of weak acid sites (mainly due to P-OH group), while the CO uptake and the amount of medium strong acid sites (mainly related to Ni sites) reached maximum on 10%Ni-P1.5. In the deoxygenation reaction, compared with Ni/γ-Al2O3, the mNi-Pn catalysts showed much lower activities for decarbonylation, Csbnd C hydrogenolysis and methanation due to the ligand and ensemble effects of P. The conversion and the selectivity to n-C11 and n-C12 hydrocarbons achieved maximum on 10%Ni-P 2.0 for the 10%Ni-Pn catalysts and on 8%Ni-P2.0 for the mNi-P2.0 catalysts, while the turnover frequency (TOF) of methyl laurate mainly increased with the P/Ni ratio and Ni content. We propose that TOF was influenced by the nickel phosphide phases, the catalyst acidity and the particle size as well as the synergetic effect between the Ni site and acid site. Again, the hydrodeoxygenation pathway of methyl laurate was promoted with increasing P/Ni ratio and Ni content, ascribed to the phase change in the order of Ni, Ni3P, Ni12P5 and Ni2P in the prepared catalysts.

Study of Supported Nickel Catalysts Prepared by Aqueous Hydrazine Method. Hydrogenating Properties and Hydrogen Storage: Support Effect. Silver Additive Effect; Catalyseurs de nickel supportes prepares par la methode de l'hydrazine aqueuse. Proprietes hydrogenantes et stockage d'hydrogene. Effet du support. Effet de l'ajout d'argent

Energy Technology Data Exchange (ETDEWEB)

Wojcieszak, R

2006-06-15

We have studied Ni or NiAg nano-particles obtained by the reduction of nickel salts (acetate or nitrate) by hydrazine and deposited by simple or EDTA-double impregnation on various supports ({gamma}-Al{sub 2}O{sub 3}, amorphous or crystallized SiO{sub 2}, Nb{sub 2}O{sub 5}, CeO{sub 2} and carbon). Prepared catalysts were characterized by different methods (XRD, XPS, low temperature adsorption and desorption of N{sub 2}, FTIR and FTIR-Pyridine, TEM, STEM, EDS, H{sub 2}-TPR, H{sub 2}-adsorption, H{sub 2}-TPD, isopropanol decomposition) and tested in the gas phase hydrogenation of benzene or as carbon materials in the hydrogen storage at room temperature and high pressure. The catalysts prepared exhibited better dispersion and activity than classical catalysts. TOF's of NiAg/SiO{sub 2} or Ni/carbon catalysts were similar to Pt catalysts in benzene hydrogenation. Differences in support acidity or preparation method and presence of Ag as metal additive play a crucial role in the chemical reduction of Ni by hydrazine and in the final properties of the materials. Ni/carbon catalysts could store significant amounts of hydrogen at room temperature and high pressure (0.53%/30 bars), probably through the hydrogen spillover effect. (author)

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)

thesis of high-purity carbon nanotubes over alumina and silica supported bimetallic catalysts

Directory of Open Access Journals (Sweden)

Sanja Ratković

2009-10-01

Full Text Available Carbon nanotubes (CNTs were synthesized by a catalytic chemical vapor deposition method (CCVD of ethylene over alumina and silica supported bimetallic catalysts based on Fe, Co and Ni. The catalysts were prepared by a precipitation method, calcined at 600 °C and in situ reduced in hydrogen flow at 700 °C. The CNTs growth was carried out by a flow the mixture of C2H4 and nitrogen over the catalyst powder in a horizontal oven. The structure and morphology of as-synthesized CNTs were characterized using SEM. The as-synthesized nanotubes were purified by acid and basic treatments in order to remove impurities such as amorphous carbon, graphite nanoparticles and metal catalysts. XRD and DTA/TG analyses showed that the amounts of by-products in the purified CNTs samples were reduced significantly. According to the observed results, ethylene is an active carbon source for growing high-density CNTs with high yield but more on alumina-supported catalysts than on their silica- supported counterparts. The last might be explained by SMSI formed in the case of alumina-supported catalysts, resulting in higher active phase dispersion.

Catalytic reduction of 4-nitrophenol over Ni-Pd nanodimers supported on nitrogen-doped reduced graphene oxide

Energy Technology Data Exchange (ETDEWEB)

Liu, Lijun, E-mail: liulj@wtu.edu.cn [College of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430073, People' s Republic of China (China); Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Chen, Ruifen; Liu, Weikai [College of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430073, People' s Republic of China (China); Wu, Jiamin [Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Gao, Di, E-mail: gaod@pitt.edu [Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States)

2016-12-15

Catalytic reduction of toxic 4-nitrophenol to 4-aminophenol over magnetically recoverable nanocatalysts has attracted much attention. Herein, we report a Ni-Pd/NrGO catalyst through the growth of Ni-Pd nanodimers (NDs) on nitrogen-doped reduced graphene oxide (NrGO). The Ni-Pd NDs show a heterogeneous nanostructure with Ni and Pd subparts contacting with each other, remarkably different from the frequently-observed core/shell nanoparticles (NPs) or nanoalloy. The formation of Ni-Pd NDs follows an initial deposition of Pd NPs on the graphene and in-situ catalytic generation of Ni subparts over the newly-generated Pd NPs. The resulting Ni-Pd/NrGO exhibits a superior catalytic activity towards the reduction of 4-nitrophenol at room temperature with a high rate constant (3400 s{sup -1} g{sup -1}) and a low activated energy (29.1 kJ mol{sup -1}) as compared to unsupported Ni-Pd NDs and supported monometallic catalysts. The conversion rate of 4-NP is calculated to be 99.5% and the percent yield (%) of 4-AP is as high as 99.1%. A synergistic catalysis mechanism is rationally proposed, which is ascribed to the electronic modification of Ni-Pd metals due to the strong metal/support interaction (SMSI) effect as well as the electron transfer between Ni and Pd. The hybrid catalyst shows soft ferromagnetic properties and can be magnetically separated and recycled without obvious loss of activity.

Effect study of the support in nickel and cobalt catalysts for obtaining hydrogen from ethanol steam reforming

International Nuclear Information System (INIS)

Silva, Sirlane Gomes da

2013-01-01

A range of oxide-supported metal catalysts have been investigated for the steam reforming of ethanol for the production of hydrogen and subsequent application in fuel cells. The catalysts were synthesized by the co-precipitation and internal gelification methods using cobalt and nickel as active metals supported on aluminum, zirconium, lanthanum and cerium oxides. After prepared and calcined at 550 Cº the solids were fully characterized by different techniques such as X-rays diffraction(DRX), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy, nitrogen adsorption (B.E.T), temperature-programmed reduction in H2 (TPR-H2) and thermogravimetric analysis. The catalytic tests were performed in a monolithic quartz reactor and submitted to different thermodynamic conditions of steam reforming of ethanol at temperatures varying from 500º C to 800 ºC. The product gas streams from the reactor were analyzed by an on-line gas chromatograph. The cobalt/nickel catalyst supported on a ceria-lanthania mixture (Co 10% / Ni 5% - CeO 2 La 2 O 3 ) showed good catalytic performance in hydrogen selectivity reaching a concentration greater than 65%, when compared to other catalytic systems such as: Co 10% / Ni5% - CeO 2 ; Co 10% / Ni 5% - CeO 2 ZrO 2 ; Co 10% / Ni 5% - ZrO 2 ; Co 10% / Ni 5% - La 2 O 3 ; Co 10% / Ni 5% - CeO 2 La 2 O 3 /K 2% ; Co 10 % / Ni 5% - CeO 2 La 2 O 3 / Na 2% ; Ni 10% / Co 5% - CeO 2 La 2 O 3 ; Co-Al 2 O 3 e Co-Al 2 O 3 CeO 2 . (author)

Extended X-ray absorption fine structure (EXAFS) studies of supported catalysts

International Nuclear Information System (INIS)

Joyner, R.W.

1979-01-01

Since the rebirth of interest in extended X-ray absorption fine structure there have been several studies of systems of catalytic interest. This note is a preliminary account of an investigation of supported platinum catalysts and NiO/Al 2 O 3 catalysts. Experiments were performed on pressed disc samples at the DESY synchrotron, Hamburg, using the EXAFS spectrometer. The synchrotron operated at 7 GeV energy with a circulating current of approximately 4 mA; spectrum accumulation time was typically 45 minutes. (author)

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.

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.

Selective Hydrodeoxygenation of Alkyl Lactates to Alkyl Propionates with Fe-based Bimetallic Supported Catalysts.

Science.gov (United States)

Khokarale, Santosh Govind; He, Jian; Schill, Leonhard; Yang, Song; Riisager, Anders; Saravanamurugan, Shunmugavel

2018-02-22

Hydrodeoxygenation (HDO) of methyl lactate (ML) to methyl propionate (MP) was performed with various base-metal supported catalysts. A high yield of 77 % MP was obtained with bimetallic Fe-Ni/ZrO 2 in methanol at 220 °C and 50 bar H 2 . A synergistic effect of Ni increased the yield of MP significantly when using Fe-Ni/ZrO 2 instead of Fe/ZrO 2 alone. Moreover, the ZrO 2 support contributed to improve the yield as a phase transition of ZrO 2 from tetragonal to monoclinic occurred after metal doping giving rise to fine dispersion of the Fe and Ni on the ZrO 2 , resulting in a higher catalytic activity of the material. Interestingly, it was observed that Fe-Ni/ZrO 2 also effectively catalyzed methanol reforming to produce H 2 in situ, followed by HDO of ML, yielding 60 % MP at 220 °C with 50 bar N 2 instead of H 2 . Fe-Ni/ZrO 2 also catalyzed HDO of other short-chain alkyl lactates to the corresponding alkyl propionates in high yields around 70 %. No loss of activity of Fe-Ni/ZrO 2 occurred in five consecutive reaction runs demonstrating the high durability of the catalyst system. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

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.

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.

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.

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.

Catalytic oxidation of dichloromethane over sol-gel oxides supported Pd or Ni

International Nuclear Information System (INIS)

Martinez; Leidy Marcela; Montes, Consuelo

2004-01-01

Several supported Pd or Ni catalysts were synthesized by the sol-gel method using y-alumina, silica, sulfated zirconium and sulfated titanium as carriers. The resulting catalysts were characterized by XRD and nitrogen adsorption, and evaluated in the catalytic oxidation of dichloromethane. The effect of different parameters were determined, i.e. method of synthesis, temperature and the type of support. The durability of the best catalyst (0,5% Pd impregnated over sulfated titanium) was tested between 300 degrades Celsius and 350 degrades Celsius during 48 h. Under the conditions of this study, impregnated catalysts exhibited higher activity than those prepared by cogelation. Pd loaded catalysts showed higher conversion into CO 2 and HCl. Catalyst activity also increased with increasing temperature. Y-Alumina and sulfated titanium showed good activity but the formation of CO is favored instead of CO 2 . Therefore, bifunctional catalysts, i.e. containing metallic and acid sites appear to be required for the decomposition of methylene chloride into CO 2 and HCI

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.

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)

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.

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

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)

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...

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.

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)

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.)

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.

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.

Effects of P/Ni ratio and Ni content on performance of γ-Al_2O_3-supported nickel phosphides for deoxygenation of methyl laurate to hydrocarbons

International Nuclear Information System (INIS)

Zhang, Zhena; Tang, Mingxiao; Chen, Jixiang

2016-01-01

Graphical abstract: - Highlights: • The formation of AlPO_4 was unfavorable for that of nickel phosphides. • The phase compositions of nickel phosphide depended on the amount of reduced P. • Catalytic activity was determined by surface Ni site density and catalyst acidity. • HDO pathway was promoted by increasing P/Ni ratio and Ni content. • Nickel phosphide gave much higher carbon yield and lower H_2 consumption than Ni. - Abstract: γ-Al_2O_3-supported nickel phosphides (mNi-Pn) were prepared by the TPR method and tested for the deoxygenation of methyl laurate to hydrocarbons. The effects of the P/Ni ratio (n = 1.0–2.5) and Ni content (m = 5–15 wt.%) in the precursors on their structure and performance were investigated. Ni/γ-Al_2O_3 was also studied for comparison. It was found that the formation of AlPO_4 in the precursor inhibited the reduction of phosphate and so the formation of nickel phosphides. With increasing the P/Ni ratio and Ni content, the Ni, Ni_3P, Ni_1_2P_5 and Ni_2P phases orderly formed, accompanying with the increases of their particle size and the amount of weak acid sites (mainly due to P-OH group), while the CO uptake and the amount of medium strong acid sites (mainly related to Ni sites) reached maximum on 10%Ni-P1.5. In the deoxygenation reaction, compared with Ni/γ-Al_2O_3, the mNi-Pn catalysts showed much lower activities for decarbonylation, C−C hydrogenolysis and methanation due to the ligand and ensemble effects of P. The conversion and the selectivity to n-C11 and n-C12 hydrocarbons achieved maximum on 10%Ni-P 2.0 for the 10%Ni-Pn catalysts and on 8%Ni-P2.0 for the mNi-P2.0 catalysts, while the turnover frequency (TOF) of methyl laurate mainly increased with the P/Ni ratio and Ni content. We propose that TOF was influenced by the nickel phosphide phases, the catalyst acidity and the particle size as well as the synergetic effect between the Ni site and acid site. Again, the hydrodeoxygenation pathway of methyl

Ni–Sn-Supported ZrO2 Catalysts Modified by Indium for Selective CO2 Hydrogenation to Methanol

KAUST Repository

Hengne, Amol Mahalingappa; Samal, Akshaya Kumar; Enakonda, Linga Reddy; Harb, Moussab; Gevers, Lieven; Anjum, Dalaver H.; Hedhili, Mohamed N.; Saih, Youssef; Huang, Kuo-Wei; Basset, Jean-Marie

2018-01-01

Ni and NiSn supported on zirconia (ZrO2) and on indium (In)-incorporated zirconia (InZrO2) catalysts were prepared by a wet chemical reduction route and tested for hydrogenation of CO2 to methanol in a fixed-bed isothermal flow reactor at 250 °C

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)

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...

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

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%.

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.

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)

Understanding the performance and mechanism of Mg-containing oxides as support catalysts in the thermal dry reforming of methane.

Science.gov (United States)

Khairudin, Nor Fazila; Sukri, Mohd Farid Fahmi; Khavarian, Mehrnoush; Mohamed, Abdul Rahman

2018-01-01

Dry reforming of methane (DRM) is one of the more promising methods for syngas (synthetic gas) production and co-utilization of methane and carbon dioxide, which are the main greenhouse gases. Magnesium is commonly applied in a Ni-based catalyst in DRM to improve catalyst performance and inhibit carbon deposition. The aim of this review is to gain better insight into recent developments on the use of Mg as a support or promoter for DRM catalysts. Its high basicity and high thermal stability make Mg suitable for introduction into the highly endothermic reaction of DRM. The introduction of Mg as a support or promoter for Ni-based catalysts allows for good metal dispersion on the catalyst surface, which consequently facilitates high catalytic activity and low catalyst deactivation. The mechanism of DRM and carbon formation and reduction are reviewed. This work further explores how different constraints, such as the synthesis method, metal loading, pretreatment, and operating conditions, influence the dry reforming reactions and product yields. In this review, different strategies for enhancing catalytic activity and the effect of metal dispersion on Mg-containing oxide catalysts are highlighted.

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

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).

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

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.

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.

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.

PtNi alloy nanoparticles supported on carbon-doped TiO2 nanotube arrays for photo-assisted methanol oxidation

International Nuclear Information System (INIS)

He, Huichao; Xiao, Peng; Zhou, Ming; Liu, Feila; Yu, Shujuan; Qiao, Lei; Zhang, Yunhuai

2013-01-01

To develop anode catalysts for photo-assisted direct methanol fuel cell (PDMFC), carbon-doped TiO 2 nanotube arrays-supported PtNi alloy nanoparticles with different Pt/Ni atomic ratio (PtNi/C-TiO 2 NTs) prepared by pulsed electrodeposition method are evaluated as catalysts for photo-assisted methanol oxidation. The cyclic voltammetry (CV) and chronoamperometry results show that the PtNi/C-TiO 2 NTs prepared at t onPt :t onNi : = 10:7 (t on is the current-on time) with a Pt:Ni atomic ratio of 6.1:5.7 presents the highest catalytic activity for methanol oxidation both in the dark and under illumination. In addition, according to the results obtained from the CO stripping voltammetry and electrochemical impedance spectroscopy (EIS) tests, it was found that the light play an accelerative role in the oxidation of methanol on PtNi/C-TiO 2 NTs under illumination. The effect of illumination which enhancing the catalytic activity of PtNi/C-TiO 2 NTs are attributed to (1) methanol and the intermediates be oxidized directly on C-TiO 2 NTs for the light-induced catalytic effect; (2) more abundant oxygen-donating species be produced on C-TiO 2 NTs in the presence of light; (3) less CO ads adsorbing on catalysts due to the presence of stronger metal–support interactions between PtNi alloy nanoparticles and C-TiO 2 NTs under illumination

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.

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.

Effects of P/Ni ratio and Ni content on performance of γ-Al{sub 2}O{sub 3}-supported nickel phosphides for deoxygenation of methyl laurate to hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhena; Tang, Mingxiao; Chen, Jixiang, E-mail: jxchen@tju.edu.cn

2016-01-01

Graphical abstract: - Highlights: • The formation of AlPO{sub 4} was unfavorable for that of nickel phosphides. • The phase compositions of nickel phosphide depended on the amount of reduced P. • Catalytic activity was determined by surface Ni site density and catalyst acidity. • HDO pathway was promoted by increasing P/Ni ratio and Ni content. • Nickel phosphide gave much higher carbon yield and lower H{sub 2} consumption than Ni. - Abstract: γ-Al{sub 2}O{sub 3}-supported nickel phosphides (mNi-Pn) were prepared by the TPR method and tested for the deoxygenation of methyl laurate to hydrocarbons. The effects of the P/Ni ratio (n = 1.0–2.5) and Ni content (m = 5–15 wt.%) in the precursors on their structure and performance were investigated. Ni/γ-Al{sub 2}O{sub 3} was also studied for comparison. It was found that the formation of AlPO{sub 4} in the precursor inhibited the reduction of phosphate and so the formation of nickel phosphides. With increasing the P/Ni ratio and Ni content, the Ni, Ni{sub 3}P, Ni{sub 12}P{sub 5} and Ni{sub 2}P phases orderly formed, accompanying with the increases of their particle size and the amount of weak acid sites (mainly due to P-OH group), while the CO uptake and the amount of medium strong acid sites (mainly related to Ni sites) reached maximum on 10%Ni-P1.5. In the deoxygenation reaction, compared with Ni/γ-Al{sub 2}O{sub 3}, the mNi-Pn catalysts showed much lower activities for decarbonylation, C−C hydrogenolysis and methanation due to the ligand and ensemble effects of P. The conversion and the selectivity to n-C11 and n-C12 hydrocarbons achieved maximum on 10%Ni-P 2.0 for the 10%Ni-Pn catalysts and on 8%Ni-P2.0 for the mNi-P2.0 catalysts, while the turnover frequency (TOF) of methyl laurate mainly increased with the P/Ni ratio and Ni content. We propose that TOF was influenced by the nickel phosphide phases, the catalyst acidity and the particle size as well as the synergetic effect between the Ni site and

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.

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.

Carbon supported Pt-NiO nanoparticles for ethanol electro-oxidation in acid media

Science.gov (United States)

Comignani, Vanina; Sieben, Juan Manuel; Brigante, Maximiliano E.; Duarte, Marta M. E.

2015-03-01

In the present work, the influence of nickel oxide as a co-catalyst of Pt nanoparticles for the electro-oxidation of ethanol in the temperature range of 23-60 °C was investigated. The carbon supported nickel oxide and platinum nanoparticles were prepared by hydrothermal synthesis and microwave-assisted polyol process respectively, and characterized by XRD, EDX, TEM and ICP analysis. The electrocatalytic activity of the as-prepared materials was studied by cyclic voltammetry and chronoamperometry. Small metal nanoparticles with sizes in the range of 3.5-4.5 nm were obtained. The nickel content in the as-prepared Pt-NiO/C catalysts was between 19 and 35 at.%. The electrochemical experiments showed that the electrocatalytic activity of the Pt-NiO/C materials increase with NiO content in the entire temperature range. The apparent activation energy (Ea,app) for the overall ethanol oxidation reaction was found to decrease with NiO content (24-32 kJ mol-1 at 0.3 V), while for Pt/C the activation energy exceeds 48 kJ mol-1. The better performance of the Pt-NiO/C catalysts compared to Pt/C sample is ascribed to the activation of both the C-H and O-H bonds via oxygen-containing species adsorbed on NiO molecules and the modification of the surface electronic structure (changes in the density of states near the Fermi level).

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 %.

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%.

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.

Well-dispersed NiO nanoparticles supported on nitrogen-doped carbon nanotube for methanol electrocatalytic oxidation in alkaline media

Energy Technology Data Exchange (ETDEWEB)

Wang, Pengcheng; Zhou, Yingke, E-mail: zhouyk888@hotmail.com; Hu, Min; Chen, Jian

2017-01-15

Highlights: • Nitrogen-doped carbon nanotube supporting ultrafine NiO nanoparticles with high dispersity are facile synthesized. • The nitrogen doping, calcination temperature and NiO loading present great effects on the catalyst morphology, structure and electrochemical performance. • NiO-NCNT-3x-400 demonstrates remarkable catalytic activity and stability for the methanol electrolytic oxidation reaction. - Abstract: Nitrogen-doped carbon nanotube supporting NiO nanoparticles were synthesized by a chemical precipitation process coupled with subsequent calcination. The morphology and structure of the composites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and the electrochemical performance was evaluated using cyclic voltammetry and chronoamperometric technique. The effects of nitrogen doping, calcination temperature and content of NiO nanoparticles on the electrocatalytic activity toward methanol oxidation were systematically studied. The results show that the uniformly dispersed ultrafine NiO nanoparticles supported on nitrogen-doped carbon nanotube are obtained after calcination at 400 °C. The optimized composite catalysts present high electrocatalytic activity, fast charge-transfer process, excellent accessibility and stability for methanol oxidation reaction, which are promising for application in the alkaline direct methanol fuel cells.

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.

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

EFFECT OF THE REDUCTION TEMPERATURE INTO CATALYTIC ACTIVITY OF Ni SUPPORTED BY TiO2, AL2O2 AND TiO2/AL2O3 FOR CONVERSION CO2 INTO METHANE

Directory of Open Access Journals (Sweden)

Hery Haerudin

2010-06-01

Full Text Available Nickel catalysts, containing 6% (w/w of nickel, have been prepared using TiO2, Al2O3 and mixture of TiO2-Al2O3 (1:9. The catalysts were used for CO2 conversion into methane. The characteristics of catalysts were studied by determination of its specific surface area, temperature programmed reaction technique and X-ray diffraction. The specific surface area were varied slightly by different temperature of reduction, namely after reduction at 300°C it was 39, 120 and 113 m2/g and after reduction at 400°C it was 42, 135  and 120 m2/g for 6% nickel catalysts supported on TiO2, Al2O3 and mixture of TiO2-Al2O3 (1:9 respectively. Temperature program reaction studies (TPO and TPR showed that NiTiOx species were possibly formed during the pretreatments which has shown by the shift of its peak to the lower temperature on Ni catalyst, that supported on mixture of TiO2-Al2O3 compared with catalysts supported on individual TiO2 or Al2O3. The nickel species on reduced Ni catalysts supported on TiO2 and on mixture of TiO2-Al2O3 could be detected by X-ray diffraction. The catalyst's activities toward CH4 formation were affected by the reduction temperature. Activity for CH4 formation was decreased in the following order: Ni/ TiO2 > Ni/ TiO2: Al2O3 > Ni/ Al2O3 and Ni/ TiO2: Al2O3 > Ni/ TiO2> Ni/ Al2O3, when catalysts were reduced at 300°C or 400°C respectively. The CO2 conversion was decreased in the following order: Ni/ Al2O3 > Ni/ TiO2: Al2O3 > Ni/ TiO2 when catalysts were reduced at 300°C or 400°C respectively.   Keywords: nickel catalyst, carbondioxide, methane

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)

Influence of supports on catalytic behavior of nickel catalysts in carbon dioxide reforming of toluene as a model compound of tar from biomass gasification.

Science.gov (United States)

Kong, Meng; Fei, Jinhua; Wang, Shuai; Lu, Wen; Zheng, Xiaoming

2011-01-01

A series of supported Ni catalysts including Ni/MgO, Ni/γ-Al2O3, Ni/α-Al2O3, Ni/SiO2 and Ni/ZrO2 was tested in CO2 reforming of toluene as a model compound of tar from biomass gasification in a fluidized bed reactor, and characterized by the means of temperature programmed reduction with hydrogen (H2-TPR), XRD, TEM and temperature programmed oxidation (TPO). Combining the characterization results with the performance tests, the activity of catalyst greatly depended on Ni particles size, and the stability was affected by the coke composition. Both of them (Ni particle size and coke composition) were closely related to the interaction between nickel and support which would determine the chemical environment where Ni inhabited. The best catalytic performance was observed on Ni/MgO due to the strong interaction between NiO and MgO via the formation of Ni-Mg-O solid solution, and the highest dispersion of Ni particle in the basic environment. Copyright © 2010 Elsevier Ltd. All rights reserved.

Magnetically Recoverable Supported Ruthenium Catalyst for Hydrogenation of Alkynes and Transfer Hydrogenation of Carbonyl Compounds

Science.gov (United States)

A ruthenium (Ru) catalyst supported on magnetic nanoparticles (NiFe2O4) has been successfully synthesized and used for hydrogenation of alkynes at room temperature as well as transfer hydrogenation of a number of carbonyl compounds under microwave irradiation conditions. The cata...

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.

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.

Spray pyrolysis synthesis of γ-Al_2O_3 supported metal and metal phosphide catalysts and their activity in the hydrodeoxygenation of a bio-oil model compound

International Nuclear Information System (INIS)

Ly, Hoang Vu; Im, Kyungmin; Go, Youngchae; Galiwango, Emmanuel; Kim, Seung-Soo; Kim, Jinsoo; Choi, Jae Hyung; Woo, Hee Chul

2016-01-01

Highlights: • Spherical γ-Al_2O_3 supported metal and metal phosphide catalysts were synthesized by spray pyrolysis method. • Hydrodeoxygenation (HDO) of 2-furyl methyl ketone (FMK) was conducted using metal/metal phosphide catalysts. • FMK was converted into 2-allyl furan and methyl cyclohexane. • The highest FMK conversion of 83% was achieved over 10 wt% Ni/γ-Al_2O_3 catalysts at reaction temperature of 400 °C. - Abstract: In this study, spherical γ-Al_2O_3 supported metal and metal phosphide (Ni, Co, Ni_2P and CoP) catalysts were successfully prepared by combining sol-gel and spray pyrolysis methods. First boehmite sol was prepared based on the Yoldas process and then the corresponding metal salts were added to the sol at the desired concentration, followed by spray pyrolysis of the mixed solution. As the well-mixed solution was transformed to spherical γ-Al_2O_3 supported metal and metal phosphide catalysts during spray pyrolysis process, the metal species were uniformly distributed in the mesoporous γ-Al_2O_3 supports. The product catalysts were investigated under different conditions for hydrodeoxygenation of bio-oil model compound, 2-furyl methyl ketone (FMK), which is the main component of the bio-oil product from pyrolysis of Saccharina japonica. Among the investigated catalysts, the 10 wt% Ni/γ-Al_2O_3 catalyst after calcination at 800 °C showed the highest FMK conversion of 83.02% at the reaction temperature of 400 °C. The gas and liquid products were analyzed by gas chromatography (GC) with TCD/FID detectors and GC–MS, respectively, to determine the product compositions.

Oxidative desulfurization of synthetic diesel using supported catalysts. Part 3. Support effect on vanadium-based catalysts

Energy Technology Data Exchange (ETDEWEB)

Cedeno-Caero, Luis; Gomez-Bernal, Hilda; Fraustro-Cuevas, Adriana; Guerra-Gomez, Hector D.; Cuevas-Garcia, Rogelio [UNICAT, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria 04510, Mexico D.F. (Mexico)

2008-04-15

Oxidesulfurization (ODS) of benzothiophenic compounds prevailing in diesel was conducted with hydrogen peroxide in presence of various catalysts, using a model diesel and actual diesel fuel. ODS activities of dibenzothiophenes (DBTs) in hexadecane for a series of V{sub 2}O{sub 5} catalysts supported on alumina, titania, ceria, niobia and silica, were evaluated. Results show that the oxidation activity of DBTs depends on the support used. It was observed that the sulfone yield is not proportional to textural properties or V content. For all catalysts, ODS of benzothiophene (BT), dibenzothiophene (DBT), 4-methyl dibenzothiophene (4-MDBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT) decreased in the following order: DBT > 4-MDBT > 4,6-DMDBT > BT. This trend does not depend on the catalyst used or the textural properties of the catalysts and supports. In presence of indole ODS activities diminish, except with catalysts supported on alumina-titania mixed oxide, whereas with V{sub 2}O{sub 5}/TiO{sub 2} catalyst the performance is the highest. ODS of Mexican diesel fuel was carried out in presence of this catalyst and S level was diminished in about 99%. (author)

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.

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.

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

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.

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.

Effect of Ni Core Structure on the Electrocatalytic Activity of Pt-Ni/C in Methanol Oxidation

Directory of Open Access Journals (Sweden)

Vladimir Linkov

2013-07-01

Full Text Available Methanol oxidation catalysts comprising an outer Pt-shell with an inner Ni-core supported on carbon, (Pt-Ni/C, were prepared with either crystalline or amorphous Ni core structures. Structural comparisons of the two forms of catalyst were made using transmission electron microscopy (TEM, X-ray diffraction (XRD and X-ray photoelectron spectroscopy (XPS, and methanol oxidation activity compared using CV and chronoamperometry (CA. While both the amorphous Ni core and crystalline Ni core structures were covered by similar Pt shell thickness and structure, the Pt-Ni(amorphous/C catalyst had higher methanol oxidation activity. The amorphous Ni core thus offers improved Pt usage efficiency in direct methanol fuel cells.

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.

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)

Impeded solid state reactions and transformations in ceramic catalysts supports and catalysts

Directory of Open Access Journals (Sweden)

Ernő E. Kiss

2012-12-01

Full Text Available Impeded chemical reactions and impeded polymorphous transformation in materials are discussed, as desired effects, for stabilization of ceramic catalyst supports and ceramic based catalysts. This paper gives a short overview about the possibilities of slowing down the aging processes in ceramic catalyst supports and catalysts. Special attention is given to alumina and titania based catalysts.

Effect of NiAl2O4 Formation on Ni/Al2O3 Stability during Dry Reforming of Methane

KAUST Repository

Zhou, Lu; Li, Lidong; Wei, Nini; Li, Jun; Basset, Jean-Marie

2015-01-01

A series of alumina-supported Ni catalysts were prepared to examine their activity and carbon deposition during dry reforming of methane (DRM). With an increase in the final calcination temperature to T=900 °C to form exclusively NiAl2O4, a catalyst with strong metal–support interactions was obtained. During a long-term DRM reaction (of about t=100 h) at T=700 °C and with CH4/CO2=1:1, reduced Ni (from NiAl2O4) showed a high resistance to sintering and coking. The DRM kinetics behaviors of the catalysts calcined at different temperatures were also investigated. Carbon growth models were proposed to rationalize the different carbon morphologies observed on the catalysts.

Effect of NiAl2O4 Formation on Ni/Al2O3 Stability during Dry Reforming of Methane

KAUST Repository

Zhou, Lu

2015-07-16

A series of alumina-supported Ni catalysts were prepared to examine their activity and carbon deposition during dry reforming of methane (DRM). With an increase in the final calcination temperature to T=900 °C to form exclusively NiAl2O4, a catalyst with strong metal–support interactions was obtained. During a long-term DRM reaction (of about t=100 h) at T=700 °C and with CH4/CO2=1:1, reduced Ni (from NiAl2O4) showed a high resistance to sintering and coking. The DRM kinetics behaviors of the catalysts calcined at different temperatures were also investigated. Carbon growth models were proposed to rationalize the different carbon morphologies observed on the catalysts.

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.

Carbons and carbon supported catalysts in hydroprocessing

Energy Technology Data Exchange (ETDEWEB)

Furimsky, Edward

2009-07-01

This book is a comprehensive summary of recent research in the field and covers all areas of carbons and carbon materials. The potential application of carbon supports, particularly those of carbon black (CB) and activated carbon (AC) in hydroprocessing catalysis are covered. Novel carbon materials such as carbon fibers and carbon nano tubes (CNT) are also covered, including the more recent developments in the use of fullerenes in hydroprocessing applications. Although the primary focus of this book is on carbons and carbon supported catalysts, it also identifies the difference in the effect of carbon supports compared with the oxidic supports, particularly that of the Al{sub 2}O{sub 3}. The difference in catalyst activity and stability was estimated using both model compounds and real feeds under variable conditions. The conditions applied during the preparation of carbon supported catalysts are also comprehensively covered and include various methods of pretreatment of carbon supports to enhance catalyst performance. The model compounds results consistently show higher hydrodesulfurization and hydrodeoxygenation activities of carbon supported catalysts than that of the Al{sub 2}O{sub 3} supported catalysts. Also, the deactivation of the former catalysts by coke deposition was much less evident. Chapter 6.3.1.3 is on carbon-supported catalysts: coal-derived liquids.

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.

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�

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.%).

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%.

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)

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.

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 ...

Selective Hydrodeoxygenation of Alkyl Lactates to Alkyl Propionates with Fe-based Bimetallic Supported Catalysts

DEFF Research Database (Denmark)

Khokarale, Santosh Govind; He, Jian; Schill, Leonhard

2018-01-01

Hydrodeoxygenation (HDO) of methyl lactate (ML) to methyl propionate (MP) was performed with various base-metal supported catalysts. A high yield of 77 % MP was obtained with bimetallic Fe-Ni/ZrO2 in methanol at 220 °C and 50 bar H2 . A synergistic effect of Ni increased the yield of MP...... of the material. Interestingly, it was observed that Fe-Ni/ZrO2 also effectively catalyzed methanol reforming to produce H2 in situ, followed by HDO of ML, yielding 60 % MP at 220 °C with 50 bar N2 instead of H2. Fe-Ni/ZrO2 also catalyzed HDO of other short-chain alkyl lactates to the corresponding alkyl...

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.

Oxidation catalysts on alkaline earth supports

Science.gov (United States)

Mohajeri, Nahid

2017-03-21

An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

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)

The Effect of WO3 Modification of ZrO2 Support on the Ni-Catalyzed Dry Reforming of Biogas Reaction for Syngas Production

Directory of Open Access Journals (Sweden)

Nikolaos D. Charisiou

2017-10-01

Full Text Available The time-on-stream catalytic performance and stability of 8 wt. % Ni catalyst supported on two commercially available catalytic supports, ZrO2 and 15 wt.% WO3-ZrO2, was investigated under the biogas dry reforming reaction for syngas production, at 750°C and a biogas quality equal to CH4/CO2 = 1.5, that represents a common concentration of real biogas. A number of analytical techniques such as N2 adsorption/desorption (BET method, XRD, H2-TPR, NH3- and CO2-TPD, SEM, ICP, thermal analysis (TGA/DTG and Raman spectroscopy were used in order to determine textural, structural and other physicochemical properties of the catalytic materials, and the type of carbon deposited on the catalytic surface of spent samples. These techniques were used in an attempt to understand better the effects of WO3-induced modifications on the catalyst morphology, physicochemical properties and catalytic performance. Although Ni dispersion and reducibility characteristics were found superior on the modified Ni/WZr sample than that on Ni/Zr, its dry reforming of methane (DRM performance was inferior; a result attributed to the enhanced acidity and complete loss of the basicity recorded on this catalyst, an effect that competes and finally overshadows the benefits of the other superior properties. Raman studies revealed that the degree of graphitization decreases with the insertion of WO3 in the crystalline structure of the ZrO2 support, as the ID/IG peak intensity ratio is 1.03 for the Ni/Zr and 1.29 for the Ni/WZr catalyst.

Increased photocatalytic activity of NiO and ZnO in photodegradation of a model drug aqueous solution: Effect of coupling, supporting, particles size and calcination temperature

Energy Technology Data Exchange (ETDEWEB)

Derikvandi, Hadis [Department of Chemistry, Shahreza Branch, Islamic Azad University, P.O. Box 311-86145, Shahreza, Isfahan, Iran (Iran, Islamic Republic of); Young Researchers and Elite Club, Shahreza Branch, Islamic Azad University, Shahreza (Iran, Islamic Republic of); Nezamzadeh-Ejhieh, Alireza, E-mail: arnezamzadeh@iaush.ac.ir [Department of Chemistry, Shahreza Branch, Islamic Azad University, P.O. Box 311-86145, Shahreza, Isfahan, Iran (Iran, Islamic Republic of); Young Researchers and Elite Club, Shahreza Branch, Islamic Azad University, Shahreza (Iran, Islamic Republic of); Razi Chemistry Research Center (RCRC), Shahreza Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of)

2017-01-05

Highlights: • Increased photoactivity of hybridized/supported NiO-ZnO whit respect to monocomponent one. • Strong dependence of photocatalytic activity of NiO-ZnO to calcination temperature. • Calcination temperature varied the crystallite forms of the semiconductors. • Red shifts in band gaps of the supported coupled semiconductors whit respect to monocomponent one. - Abstract: Mechanically ball-mill prepared clinoptilolite nanoparticles (NC) were used for increasing photocatalytic activity of NiO and ZnO as alone and binary systems. The semiconductors were supported onto the zeolite during calcination of Ni(II)-Zn(II)-exchanged NC at different calcinations temperatures. XRD, FTIR, SEM-EDX, X-ray mapping, DRS, TEM and BET techniques were used for characterization of the samples. The calcined catalysts at 400 °C for 4 h showed the best photocatalytic activity for metronidazole (MNZ) in aqueous solution. The mole ratio of ZnO/NiO affected the photodegradation efficiency because activity of the coupled catalysts depends to the both e/h production and electron scavenging processes. In the used system, NiO acted as e/h production source and ZnO as an electron sink. Red shifts in band gaps of the supported coupled semiconductors was observed whit respect to monocomponent one, confirming formation of nanoparticles of the semiconductors onto the zeolitic bed. The best activities were obtained for the NiO{sub 1.3}–ZnO{sub 1.5}/NC (NZ-NC) and NiO{sub 0.7}–ZnO{sub 4.3}/NC (NZ{sub 3}-NC) catalysts at pH 3, 1.2 g L{sup −1} of the catalysts and 1 g L{sup −1} of MNZ.

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

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.

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.

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.

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.

Hydrothermal performance of catalyst supports

Energy Technology Data Exchange (ETDEWEB)

Elam, Jeffrey W.; Marshall, Christopher L.; Libera, Joseph A.; Dumesic, James A.; Pagan-Torres, Yomaira J.

2018-04-10

A high surface area catalyst with a mesoporous support structure and a thin conformal coating over the surface of the support structure. The high surface area catalyst support is adapted for carrying out a reaction in a reaction environment where the thin conformal coating protects the support structure within the reaction environment. In various embodiments, the support structure is a mesoporous silica catalytic support and the thin conformal coating comprises a layer of metal oxide resistant to the reaction environment which may be a hydrothermal environment.

Investigation of the supported nickel catalysts by XAS and XRD, using synchrotron radiation

International Nuclear Information System (INIS)

Aldea, N.; Marginean, P.; Gluhoi, A.; Yaning, Xie; Dong, Bazohong

2001-01-01

In the first part of the 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 elucidating the local structure of Ni atoms and their interaction with oxide support. In this case, we analyse the first three shells of coordination. The second aim of the paper consists in X-ray diffraction on the same samples. X-ray diffraction method which 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 X-Ray diffraction profiles such as (111) (200) and (220). We are going to work out a chemisorption model by the correlation of the local and global structure connected with the specific surface. On the other hand, we will try to estimate specific surface values determined by classical method with occupation factor evaluated by the geometrical Ni clusters. 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)

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.

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

Transition Metal Phosphide Nanoparticles Supported on SBA-15 as Highly Selective Hydrodeoxygenation Catalysts for the Production of Advanced Biofuels.

Science.gov (United States)

Yang, Yongxing; Ochoa-Hernández, Cristina; de la Peña O'Shea, Víctor A; Pizarro, Patricia; Coronado, Juan M; Serrano, David P

2015-09-01

A series of catalysts constituted by nanoparticles of transition metal (M = Fe, Co, Ni and Mo) phosphides (TMP) dispersed on SBA-15 were synthesized by reduction of the corresponding metal phosphate precursors previously impregnated on the mesostructured support. All the samples contained a metal-loading of 20 wt% and with an initial M/P mole ratio of 1, and they were characterized by X-ray diffraction (XRD), N2 sorption, H2-TPR and transmission electron microscopy (TEM). Metal phosphide nanocatalysts were tested in a high pressure continuous flow reactor for the hydrodeoxygenation (HDO) of a methyl ester blend containing methyl oleate (C17H33-COO-CH3) as main component (70%). This mixture constitutes a convenient surrogate of triglycerides present in vegetable oils, and following catalytic hydrotreating yields mainly n-alkanes. The results of the catalytic assays indicate that Ni2P/SBA-15 catalyst presents the highest ester conversion, whereas the transformation rate is about 20% lower for MoP/SBA-15. In contrast, catalysts based on Fe and Co phosphides show a rather limited activity. Hydrocarbon distribution in the liquid product suggests that both hydrodeoxygenation and decarboxylation/decarbonylation reactions occur simultaneously over the different catalysts, although MoP/SBA-15 possess a selectivity towards hydrodeoxygenation exceeding 90%. Accordingly, the catalyst based on MoP affords the highest yield of n-octadecane, which is the preferred product in terms of carbon atom economy. Subsequently, in order to conjugate the advantages of both Ni and Mo phosphides, a series of catalysts containing variable proportions of both metals were prepared. The obtained results reveal that the mixed phosphides catalysts present a catalytic behavior intermediate between those of the monometallic phosphides. Accordingly, only marginal enhancement of the yield of n-octadecane is obtained for the catalysts with a Mo/Ni ratio of 3. Nevertheless, owing to this high selectivity

Preparation and characterization of nickel catalysts supported on cerium for obtaining hydrogen from steam reforming of ethanol

International Nuclear Information System (INIS)

Urbaninho, A.B.; Bergamaschi, V.S.; Ferreira, J.C.

2016-01-01

The Ni/Ce catalysts for were prepared by co- precipitation method with a view to their use in steam reforming of ethanol to produce a hydrogen-rich gas mixture. The catalysts were characterized by scanning electron microscopy; x-ray dispersive Spectroscopy and surface area BET method. This paper proposes to prepare, characterize and test nickel catalyst supported on cerium in order to obtain a material with higher activity and selectivity of the catalyst using the steam reforming reaction of ethanol, by varying the reaction temperature, molar ratio water/ethanol and uptime. The catalytic tests were monitored by chemical analysis of syngas from steam reforming of ethanol using an analysis online by gas Chromatograph in the reactor. (author)

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...

Hydrodeoxygenation of Pyrolysis Bio-Oil Over Ni Impregnated Mesoporous Materials.

Science.gov (United States)

Lee, In-Gu; Lee, Heejin; Kang, Bo Sung; Kim, Young-Min; Kim, Sang Chai; Jung, Sang-Chul; Ko, Chang Hyun; Park, Young-Kwon

2018-02-01

The catalytic hydrodeoxygenation (HDO) of bio-oil over Ni-supported mesoporous materials was performed using a high pressure autoclave reactor. The actual pyrolysis oil of cork oak wood was used as a sample, and Ni/Al-SBA-15 and Ni/Al-MSU-F were used as catalysts. In addition, supercritical ethanol was added as solvent. Both Ni-supported mesoporous catalysts showed efficient HDO reaction ability. A higher heating value and pH of bio-oil were achieved by the HDO reaction over both catalysts and upgraded bio-oil had a lower viscosity. Compared to Ni/Al-MSU-F, Ni/Al- SBA-15 produced more upgraded bio-oil with a lower oxygen content and higher heating value via a catalytic HDO process.

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.

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.

On the potential of nickel catalysts for steam reforming in membrane reactors

Energy Technology Data Exchange (ETDEWEB)

Pieterse, J.A.Z.; Boon, J.; Van Delft, Y.C.; Dijkstra, J.W.; Van den Brink, R.W. [Energy research Center of the Netherlands, P.O. Box 1, 1755 ZG Petten (Netherlands)

2010-10-15

Hydrogen membrane reactors have been identified as a promising option for hydrogen production for power generation from natural gas with pre-combustion decarbonisation. While Pd or Pd-alloy membranes already provide good hydrogen permeances the most suitable catalyst design for steam reforming in membrane reactors (SRMR) is yet to be identified. This contribution aims to provide insight in the suitability of nickel based catalysts in SRMR. The use of nickel (Ni) catalysts would benefit the cost-effectiveness of membrane reactors and therefore its feasibility. For this, the activity of nickel catalysts in SRMR was assessed with kinetics reported in literature. A 1D model was composed in order to compare the hydrogen production rates derived from the kinetics with the rate of hydrogen withdrawal by permeation. Catalyst stability was studied by exposing the catalysts to reformate gas with two different H/C ratios to mimic the hydrogen lean reformate gas in the membrane reactor. For both the activity (modeling) and stability study the Ni-based catalysts were compared to relevant catalyst compositions based on rhodium (Rh). Using the high pressure kinetics reported for Al2O3 supported Rh and MgAl2O4 and Al2O3 supported Ni catalyst it showed that Ni and Rh catalysts may very well provide similar hydrogen production rates. Interestingly, the stability of Ni-based catalysts proved to be superior to precious metal based catalysts under exposure to simulated reformate feed gas with low H/C molar ratio. A commercial (pre-)reforming Ni-based catalyst was selected for further testing in an experimental membrane reactor for steam reforming at high pressure. During the test period 98% conversion at 873 K could be achieved. The conversion was adjusted to approximately 90% and stable conversion was obtained during the test period of another 3 weeks. Nonetheless, carbon quantification tests of the Ni catalyst indicated that a small amount of carbon had deposited onto the catalyst

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).

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.

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.

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.

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

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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  

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)

Co-Processing of Jatropha-Derived Bio-Oil with Petroleum Distillates over Mesoporous CoMo and NiMo Sulfide Catalysts

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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

Supported catalyst systems and method of making biodiesel products using such catalysts

Science.gov (United States)

Kim, Manhoe; Yan, Shuli; Salley, Steven O.; Ng, K. Y. Simon

2015-10-20

A heterogeneous catalyst system, a method of preparing the catalyst system and a method of forming a biodiesel product via transesterification reactions using the catalyst system is disclosed. The catalyst system according to one aspect of the present disclosure represents a class of supported mixed metal oxides that include at least calcium oxide and another metal oxide deposited on a lanthanum oxide or cerium oxide support. Preferably, the catalysts include CaO--CeO.sub.2ZLa.sub.2O.sub.3 or CaO--La.sub.2O.sub.3/CeO.sub.2. Optionally, the catalyst may further include additional metal oxides, such as CaO--La.sub.2O.sub.3--GdOxZLa.sub.2O.sub.3.

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.

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)

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.

Attrition resistant Fischer-Tropsch catalyst and support

Science.gov (United States)

Singleton, Alan H.; Oukaci, Rachid; Goodwin, James G.

2004-05-25

A catalyst support having improved attrition resistance and a catalyst produced therefrom. The catalyst support is produced by a method comprising the step of treating calcined .gamma.-alumina having no catalytic material added thereto with an acidic aqueous solution having an acidity level effective for increasing the attrition resistance of the calcined .gamma.-alumina.

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.

Development of Coke-tolerant Transition Metal Catalysts for Dry Reforming of Methane

KAUST Repository

Al-Sabban, Bedour E.

2016-11-07

Dry reforming of methane (DRM) is an attractive and promising process for the conversion of methane and carbon dioxide which are the most abundant carbon sources into valuable syngas. The produced syngas, which is a mixture of hydrogen and carbon monoxide, can be used as intermediates in the manufacture of numerous chemicals. To achieve high conversion, DRM reaction is operated at high temperatures (700-900 °C) that can cause major drawbacks of catalyst deactivation by carbon deposition, metal sintering or metal oxidation. Therefore, the primary goal is to develop a metal based catalyst for DRM that can completely suppress carbon formation by designing the catalyst composition. The strategy of this work was to synthesize Ni-based catalysts all of which prepared by homogeneous deposition precipitation method (HDP) to produce nanoparticles with narrow size distribution. In addition, control the reactivity of the metal by finely tuning the bimetallic composition and the reaction conditions in terms of reaction temperature and pressure. The highly endothermic dry reforming of methane proceeds via CH4 decomposition to leave surface carbon species, followed by removal of C with CO2-derived species to give CO. Tuning the reactivity of the active metal towards these reactions during DRM allows in principle the catalyst surface to remain active and clean without carbon deposition for a long-term. The initial attempt was to improve the resistance of Ni catalyst towards carbon deposition, therefore, a series of 5 wt.% bimetallic Ni9Pt1 were supported on various metal oxides (Al2O3, CeO2, and ZrO2). The addition of small amount of noble metal improved the stability of the catalyst compared to their monometallic Ni and Pt catalysts, but still high amount of carbon (> 0.1 wt.%) was formed after 24 h of the reaction. The obtained results showed that the catalytic performance, particle size and amount of deposited carbon depends on the nature of support. Among the tested

Ammonia treated Mo/AC catalysts for CO hydrogenation with ...

Indian Academy of Sciences (India)

SHARIF F ZAMAN

the influence of acid treated AC as a support with K-Ni-. Mo active ... K-Ni-Mo/AC catalyst was more selective to oxygenates. (>40% ... mineral impurities (K, Si, Sn and Fe) <1%. ...... edge technical support with thanks Science and Technology.

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

Hybrid NiCoOx adjacent to Pd nanoparticles as a synergistic electrocatalyst for ethanol oxidation

Science.gov (United States)

Wang, Wei; Yang, Yan; Liu, Yanqin; Zhang, Zhe; Dong, Wenkui; Lei, Ziqiang

2015-01-01

To improve the electrocatalytic activity of Pd for ethanol oxidation, hybrid NiCoOx adjacent to Pd catalyst (Pd-NiCoOx/C) is successfully synthesized. Physical characterization shows NiCoOx is closely adjacent to Pd nanoparticles in Pd-NiCoOx/C catalyst, which leads to Strong Metal-Support Interactions (SMSI) between the NiCoOx and Pd nanoparticles, in favor of the electrocatalytic properties. The Pd-NiCoOx/C catalyst is estimated to own larger electrochemically active surface area than Pd/C and Pd-NiO/C catalysts. Moreover, compared to Pd/C catalyst, the onset potential of Pd-NiCoOx/C catalyst is negative 40 mV for ethanol oxidation. Noticeably, the current density of Pd-NiCoOx/C catalyst is 2.05 and 1.43 times higher contrasted to Pd/C and Pd-NiO/C catalysts accordingly. Importantly, the Pd-NiCoOx/C catalyst exhibits better stability during ethanol oxidation, which is a promising electrocatalyst for application in direct alkaline alcohol fuel cells.

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

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.

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

Stable hydrogen production from ethanol through steam reforming reaction over nickel-containing smectite-derived catalyst.