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Sample records for nx photocatalytic films

  1. Effect of SiNx diffusion barrier thickness on the structural properties and photocatalytic activity of TiO2 films obtained by sol–gel dip coating and reactive magnetron sputtering

    Directory of Open Access Journals (Sweden)

    Mohamed Nawfal Ghazzal

    2015-10-01

    Full Text Available We investigate the effect of the thickness of the silicon nitride (SiNx diffusion barrier on the structural and photocatalytic efficiency of TiO2 films obtained with different processes. We show that the structural and photocatalytic efficiency of TiO2 films produced using soft chemistry (sol–gel and physical methods (reactive sputtering are affected differentially by the intercalating SiNx diffusion barrier. Increasing the thickness of the SiNx diffusion barrier induced a gradual decrease of the crystallite size of TiO2 films obtained by the sol–gel process. However, TiO2 obtained using the reactive sputtering method showed no dependence on the thickness of the SiNx barrier diffusion. The SiNx barrier diffusion showed a beneficial effect on the photocatalytic efficiency of TiO2 films regardless of the synthesis method used. The proposed mechanism leading to the improvement in the photocatalytic efficiency of the TiO2 films obtained by each process was discussed.

  2. Structure and Friction Behavior of CrNx/a-C:H Nanocomposite Films

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    Lunlin Shang

    2014-01-01

    Full Text Available CrN and CrNx/a-C:H nanocomposite films were deposited on Si substrates by the magnetron sputtering technique. The structure, chemical state, and friction behavior of the CrNx/a-C:H films prepared at various CH4 content were studied systematically. The CrN film shows strong (111 and (220 orientation, while the CrNx/a-C:H films consist of the nanocrystalline CrNx or Cr particles embedded in an amorphous hydrocarbon (a-C:H matrix and show weak diffraction peaks, which is in accordance with the XPS analysis results. The typical Raman D and G peaks are observed, indicating that the separated amorphous carbon or CNx phase appears in the CrNx/a-C:H films. However, no chromium carbide was observed in all the as-deposited samples. From the SEM graphs, all the deposited films depicted a dense and compact microstructure with well-attached interface with the substrate. The average friction coefficient of the CrNx/a-C:H films largely decreased with increasing CH4 content.

  3. Fabrication and Photocatalytic Property of One-Dimensional SrTiO3/TiO2-xNx Nanostructures

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    Huarong Zhang

    2013-01-01

    Full Text Available One-dimensional SrTiO3/TiO2−xNx nanostructures were prepared by the hydrothermal method and investigated by X-ray diffraction (XRD, transmission electron microscopy (TEM, X-ray photoelectron spectroscopy (XPS, and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS measurements. The photocatalytic activities of the prepared samples were evaluated by photodegrading the methylene blue (MB solution. According to the characterizations, the intermediate product of SrTiO3/titanate nanotubes was presented after hydrothermal processing of the TiO2−xNx nanoparticles with the mixed solution of NaOH and Sr(NO32. The final product of SrTiO3/TiO2−xNx nanorods was obtained after calcining the intermediate. As compared to the TiO2−xNx nanoparticles, the absorption performance of SrTiO3/titanate nanotubes or SrTiO3/TiO2−xNx nanorods was depressed, instead of improving it. The mechanisms of the absorption property changes were discussed. The SrTiO3/TiO2−xNx nanorods presented better photocatalytic activity than the TiO2−xNx nanoparticles or nanorods. However, due to overmuch adsorption, the SrTiO3/titanate nanotubes gave ordinary photocatalytic performances.

  4. Influence of nitrogen flow rates on materials properties of CrNx films ...

    Indian Academy of Sciences (India)

    Influence of nitrogen flow rates on materials properties of CrNx films grown by reactive magnetron sputtering. B SUBRAMANIAN. ∗. , K PRABAKARAN and M JAYACHANDRAN. Electrochemical Materials Science Division, CSIR- Central Electrochemical Research Institute, Karaikudi 630 006, India. MS received 9 April 2011 ...

  5. Ni-toughened nc-TiN/a-SiNx nanocomposite thin films

    NARCIS (Netherlands)

    Zhang, Sam; Sun, Deen; Fu, Yongqing; Pei, Y.T.; Hosson, J.Th.M. De

    2005-01-01

    Nanocomposite nc-TiN/a-SiNx thin films containing Ni up to similar to 40 at.% were prepared by co-sputtering of Ti, TiNi and Si3N4 targets in ArN2 gas atmosphere. Adjusting TiNi/(Ti+TiNi) target power ratio altered chemical composition, microstructure and consequently mechanical properties. X-ray

  6. Fabrication of SiNx Thin Film of Micro Dielectric Barrier Discharge Reactor for Maskless Nanoscale Etching

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    Qiang Li

    2016-12-01

    Full Text Available The prevention of glow-to-arc transition exhibited by micro dielectric barrier discharge (MDBD, as well as its long lifetime, has generated much excitement across a variety of applications. Silicon nitride (SiNx is often used as a dielectric barrier layer in DBD due to its excellent chemical inertness and high electrical permittivity. However, during fabrication of the MDBD devices with multilayer films for maskless nano etching, the residual stress-induced deformation may bring cracks or wrinkles of the devices after depositing SiNx by plasma enhanced chemical vapor deposition (PECVD. Considering that the residual stress of SiNx can be tailored from compressive stress to tensile stress under different PECVD deposition parameters, in order to minimize the stress-induced deformation and avoid cracks or wrinkles of the MDBD device, we experimentally measured stress in each thin film of a MDBD device, then used numerical simulation to analyze and obtain the minimum deformation of multilayer films when the intrinsic stress of SiNx is −200 MPa compressive stress. The stress of SiNx can be tailored to the desired value by tuning the deposition parameters of the SiNx film, such as the silane (SiH4–ammonia (NH3 flow ratio, radio frequency (RF power, chamber pressure, and deposition temperature. Finally, we used the optimum PECVD process parameters to successfully fabricate a MDBD device with good quality.

  7. The SiNx films process research by plasma-enhanced chemical vapor deposition in crystalline silicon solar cells

    Science.gov (United States)

    Chen, Bitao; Zhang, Yingke; Ouyang, Qiuping; Chen, Fei; Zhan, Xinghua; Gao, Wei

    2017-07-01

    SiNx thin film has been widely used in crystalline silicon solar cell production because of the good anti-reflection and passivation effect. We can effectively optimize the cells performance by plasma-enhanced chemical vapor deposition (PECVD) method to change deposition conditions such as temperature, gas flow ratio, etc. In this paper, we deposit a new layer of SiNx thin film on the basis of double-layers process. By changing the process parameters, the compactness of thin films is improved effectively. The NH3 passivation technology is augmented in a creative way, which improves the minority carrier lifetime. In sight of this, a significant increase is generated in the photoelectric performance of crystalline silicon solar cell.

  8. The growth of the metallic ZrNx thin films on P-GaN substrate by pulsed laser deposition

    Science.gov (United States)

    Gu, Chengyan; Sui, Zhanpeng; Li, Yuxiong; Chu, Haoyu; Ding, Sunan; Zhao, Yanfei; Jiang, Chunping

    2018-03-01

    Although metal nitride thin films have attractive prospects in plasmonic applications due to its stable properties in harsh environments containing high temperatures, shock, and contaminants, the effect of deposition parameters on the properties of the metallic ZrN grown on III-N semiconductors by pulse laser deposition still lacks of detailed exploration. Here we have successfully prepared metallic ZrNx films on p-GaN substrate by pulsed laser deposition in N2 ambient of various pressures at a fixed substrate temperature (475 °C). It is found that the films exhibit quite smooth surfaces and (111) preferred orientation. The X-ray photoelectron spectroscopy measurements indicate that carbon contamination can be completely removed and oxygen contamination is significantly reduced on the film surfaces after cleaning using Ar+ sputtering. The N/Zr ratio increases from 0.64 to 0.75 when the N2 pressure increases from 0.5 Pa to 3 Pa. The optical reflectivity spectra measured by the UV-vis-NIR spectrophotometer show that the ZrNx is a typical and good metallic-like material and its metallic properties can be tuned with changing the film compositions.

  9. Effect of annealing treatments on photoluminescence and charge storage mechanism in silicon-rich SiNx:H films

    Directory of Open Access Journals (Sweden)

    Sahu Bhabani

    2011-01-01

    Full Text Available Abstract In this study, a wide range of a-SiNx:H films with an excess of silicon (20 to 50% were prepared with an electron-cyclotron resonance plasma-enhanced chemical vapor deposition system under the flows of NH3 and SiH4. The silicon-rich a-SiNx:H films (SRSN were sandwiched between a bottom thermal SiO2 and a top Si3N4 layer, and subsequently annealed within the temperature range of 500-1100°C in N2 to study the effect of annealing temperature on light-emitting and charge storage properties. A strong visible photoluminescence (PL at room temperature has been observed for the as-deposited SRSN films as well as for films annealed up to 1100°C. The possible origins of the PL are briefly discussed. The authors have succeeded in the formation of amorphous Si quantum dots with an average size of about 3 to 3.6 nm by varying excess amount of Si and annealing temperature. Electrical properties have been investigated on Al/Si3N4/SRSN/SiO2/Si structures by capacitance-voltage and conductance-voltage analysis techniques. A significant memory window of 4.45 V was obtained at a low operating voltage of ± 8 V for the sample containing 25% excess silicon and annealed at 1000°C, indicating its utility in low-power memory devices.

  10. Cathode encapsulation of OLEDs by atomic layer deposited Al2O3 films and Al2O3/a-SiNx:H stacks

    NARCIS (Netherlands)

    Keuning, W.; Van de Weijer, P.; Lifka, H.; Kessels, W.M.M.; Creatore, M.

    2011-01-01

    Al2O3 thin films synthesized by plasma-enhanced atomic layer deposition(ALD) at room temperature (25 ºC) have been tested as water vapor per-meation barriers for OLED devices. Silicon nitride films (a-SiNx:H)deposited by plasma-enhanced chemical vapor deposition (PE-CVD) servedas reference and were

  11. W/Cu thin film infrared reflector for TiNxOy based selective solar absorber with high thermal stability

    Science.gov (United States)

    Zhang, J.; Chen, T. P.; Liu, Y. C.; Liu, Z.; Yang, H. Y.

    2017-05-01

    The W/Cu thin film structure is deposited by magnetron sputtering to form the infrared reflector for the TiNxOy based selective solar absorber (SSA) that can be used in the low- and middle-temperature applications. The structural, chemical, and optical properties of the SSA layers that experienced thermal annealing at different temperatures for various durations have been investigated with the characterization techniques, including X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy, spectroscopic ellipsometry, and spectrophotometry. Without a W layer, the reflectance in both visible and infrared ranges of the SSA increases as a result of the crystallization of the Cu layer at elevated temperatures. With a W layer with appropriate film thickness, the increase of the reflectance in the visible range can be suppressed to maintain a high solar absorptance, whereas a high infrared reflectance can be maintained to achieve a low thermal emittance. It is shown that for the SiO2-TiNxOy-W-Cu-Glass SSA with a 15 nm W thin film, thermal annealing can significantly reduce the thermal emittance to a low value (e.g., 4.4% at the temperature of 400 °C for annealing at 400 °C for 6 h), whereas the solar absorptance can be maintained at a high value (e.g., 92.2% for the annealing at 400 °C for 6 h).

  12. Fabrication and visible-light photocatalytic activity of novel Ag/TiO2-xNx nanocatalyst

    Science.gov (United States)

    The efforts of the scientific community are directed towards the preparation of photocatalysts that are active under solar or artificial visible light irradiation. TiO2 is one of the most 15 widely used photocatalyst that is employed in self-cleaning coatings, photocatalytic proc...

  13. Surface Properties of Photocatalytic Nano-Crystalline Titania Films and Reactor for Photocatalytic Degradation of Chloroform

    DEFF Research Database (Denmark)

    Søgaard, Erik Gydesen; Simonsen, Morten Enggrob; Jensen, Henrik

    2006-01-01

    In this work two immobilizations techniques of TiO2 onto glass were investigated; deposition of previously made titania powder (PMTP) and a sol-gel method. The titania powder used in this work was Degussa P25, Hombikat UV100 and a powder prepared in our laboratory SC134. The prepared TiO2 films...... were characterized using XRD, XPS, AFM, UV-Vis spectroscopy and the photocatalytic activity was assessed using stearic acid as a model compound. Investigation of the prepared films showed that the films prepared from Degussa P25 was the most active, followed by the Hombikat UV100 film, Sol-gel film...

  14. Role of SiNx Barrier Layer on the Performances of Polyimide Ga2O3-doped ZnO p-i-n Hydrogenated Amorphous Silicon Thin Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Fang-Hsing Wang

    2014-02-01

    Full Text Available In this study, silicon nitride (SiNx thin films were deposited on polyimide (PI substrates as barrier layers by a plasma enhanced chemical vapor deposition (PECVD system. The gallium-doped zinc oxide (GZO thin films were deposited on PI and SiNx/PI substrates at room temperature (RT, 100 and 200 °C by radio frequency (RF magnetron sputtering. The thicknesses of the GZO and SiNx thin films were controlled at around 160 ± 12 nm and 150 ± 10 nm, respectively. The optimal deposition parameters for the SiNx thin films were a working pressure of 800 × 10−3 Torr, a deposition power of 20 W, a deposition temperature of 200 °C, and gas flowing rates of SiH4 = 20 sccm and NH3 = 210 sccm, respectively. For the GZO/PI and GZO-SiNx/PI structures we had found that the GZO thin films deposited at 100 and 200 °C had higher crystallinity, higher electron mobility, larger carrier concentration, smaller resistivity, and higher optical transmittance ratio. For that, the GZO thin films deposited at 100 and 200 °C on PI and SiNx/PI substrates with thickness of ~1000 nm were used to fabricate p-i-n hydrogenated amorphous silicon (α-Si thin film solar cells. 0.5% HCl solution was used to etch the surfaces of the GZO/PI and GZO-SiNx/PI substrates. Finally, PECVD system was used to deposit α-Si thin film onto the etched surfaces of the GZO/PI and GZO-SiNx/PI substrates to fabricate α-Si thin film solar cells, and the solar cells’ properties were also investigated. We had found that substrates to get the optimally solar cells’ efficiency were 200 °C-deposited GZO-SiNx/PI.

  15. Preparation of B-doped Si quantum dots embedded in SiNx films for Si quantum dot solar cells

    Science.gov (United States)

    Chen, Xiaobo; Yang, Peizhi

    2018-01-01

    Silicon quantum dots (Si-QDs) embedded B-doped SiNx films were fabricated by magnetron co-sputtering. The effects of B content on the structural, optical and electrical properties of the films were studied. The study found that the amount of B dopant has no significant effect on the crystallization characteristics of the films. B atoms may be doped in the Si-QDs or exist in the silicon nitride or the interface between Si-QDs and the matrix. PL intensity increases with increasing B content, but increases at first and then decreases. The conductivity as a function of the dopant concentration increases at first from a value of 2.71 × 10-4 S/cm to 5.83 × 10-2 S/cm until 0.9 at.% and then decreases. By employing B-doped Si-QDs films, Si-QDs/c-Si heterojunction solar cells were fabricated and the effect of B doping concentration on the photovoltaic properties was studied. It was found that, with the increase of B doping amount, the photovoltaic performance is improved, when the B doping amount is 0.9 at.%, the efficiency reaches the highest value of 4.26%.

  16. Solution-derived photocatalytic films for environmental cleaning applications

    International Nuclear Information System (INIS)

    Štangar, U Lavrencic; Kete, M; Šuligoj, A; Tasbihi, M

    2012-01-01

    When photocatalytic water treatment is concerned, suspended catalyst in the aqueous phase is usually more efficient than immobilized on an inert support, but in the former case an undesirable separation/recycling step is needed. We have therefore concentrated on the preparation of immobilized catalysts in the form of films on glass and aluminium supports. The low-temperature sol-gel processing route to obtain transparent thin TiO 2 /SiO 2 films for self-cleaning purposes and thicker TiO 2 /SiO 2 coatings for efficient removal of pollutants in water and air are presented. The synthesis is based on a production of a nanocrystalline titania sol with a silica binder that after deposition does not require thermal treatment at high temperatures. Depending on the target application, some specific synthesis parameters and photocatalytic activity testing conditions are illustrated. For water-cleaning coatings fast kinetics is required, which was achieved by addition of a highly active titania powder into the sol. The same preparation procedure was used to prepare efficient air-cleaning coatings. On the other hand, self-cleaning films were thinner and transparent to keep the original appearance of the substrate and they solidified at ambient conditions. Advanced methodologies to evaluate photocatalytic activity of the films were applied.

  17. Hydrogen loss and its improved retention in hydrogen plasma treated a-SiNx:H films: ERDA study with 100 MeV Ag7+ ions

    Science.gov (United States)

    Bommali, R. K.; Ghosh, S.; Khan, S. A.; Srivastava, P.

    2018-05-01

    Hydrogen loss from a-SiNx:H films under irradiation with 100 MeV Ag7+ ions using elastic recoil detection analysis (ERDA) experiment is reported. The results are explained under the basic assumptions of the molecular recombination model. The ERDA hydrogen concentration profiles are composed of two distinct hydrogen desorption processes, limited by rapid molecular diffusion in the initial stages of irradiation, and as the fluence progresses a slow process limited by diffusion of atomic hydrogen takes over. Which of the aforesaid processes dominates, is determined by the continuously evolving Hydrogen concentration within the films. The first process dominates when the H content is high, and as the H concentration falls below a certain threshold (Hcritical) the irradiation generated H radicals have to diffuse through larger distances before recombining to form H2, thereby significantly bringing down the hydrogen evolution rate. The ERDA measurements were also carried out for films treated with low temperature (300 °C) hydrogen plasma annealing (HPA). The HPA treated films show a clear increase in Hcritical value, thus indicating an improved diffusion of atomic hydrogen, resulting from healing of weak bonds and passivation of dangling bonds. Further, upon HPA films show a significantly higher H concentration relative to the as-deposited films, at advanced fluences. These results indicate the potential of HPA towards improved H retention in a-SiNx:H films. The study distinguishes clearly the presence of two diffusion processes in a-SiNx:H whose diffusion rates differ by an order of magnitude, with atomic hydrogen not being able to diffuse further beyond ∼ 1 nm from the point of its creation.

  18. WO3 Nanoplates Film: Formation and Photocatalytic Oxidation Studies

    Directory of Open Access Journals (Sweden)

    Chin Wei Lai

    2015-01-01

    Full Text Available High surface area of tungsten oxide (WO3 nanoplates films was prepared via simple electrochemical anodization technique by controlling the fluoride content (NH4F in electrolyte. The design and development of WO3-based nanostructure assemblies have gained significant interest in order to maximize specific surface area for harvesting more photons to trigger photocatalytic oxidation reaction. This study aims to determine the optimum content of NH4F in forming WO3 nanoplates on W film with efficient photocatalytic oxidation reaction for organic dye degradation by utilizing our solar energy. The NH4F was found to influence the chemical dissolution and field-assisted dissolution rates, thus modifying the final morphological of WO3-based nanostructure assemblies film. It was found that 0.7 wt% of NH4F is the minimum amount to grow WO3 nanoplates film on W film. The photocatalysis oxidation experimental results showed that WO3 nanoplates film exhibited a maximum degradation of methyl orange dye (≈75% under solar illumination for 5 hours. This behavior was attributed to the better charge carriers transportation and minimizes the recombination losses with specific surface area of nanoplates structure.

  19. Nanostructured porous ZnO film with enhanced photocatalytic activity

    International Nuclear Information System (INIS)

    Wang Lina; Zheng Yingying; Li Xiaoyun; Dong Wenjun; Tang Weihua; Chen Benyong; Li Chaorong; Li Xiao; Zhang Tierui

    2011-01-01

    Well-defined ZnO nanostructured films have been fabricated directly on Zn foil via hydrothermal synthesis. During the fabrication of the ZnO nanostructured films, the Zn foil serves as the Zn source and also the substrate. Porous nanosheet-based, nanotube-based and nanoflower-based ZnO films can all be easily prepared by adjusting the alkali type, reaction time and reaction temperature. The composition, morphology and structure of ZnO films are characterized by X-ray diffraction, scanning electron microscope and high-resolution transmission electron microscope. The porous ZnO nanosheet-based film exhibits enhanced photocatalytic activity in the degradation of Rhodamine B under UV light irradiation. This can be attributed to the high surface area of the ZnO nanosheet and the large percentage of the exposed [001] facet. Moreover, the self-supporting, recyclable and stable ZnO photocatalytic film can be readily recovered and potentially applied for pollution disposal.

  20. Photocatalytic oxide films in the built environment

    Science.gov (United States)

    Österlund, Lars; Topalian, Zareh

    2014-11-01

    The possibility to increase human comfort in buildings is a powerful driving force for the introduction of new technology. Among other things our sense of comfort depends on air quality, temperature, lighting level, and the possibility of having visual contact between indoors and outdoors. Indeed there is an intimate connection between energy, comfort, and health issues in the built environment, leading to a need for intelligent building materials and green architecture. Photocatalytic materials can be applied as coatings, filters, and be embedded in building materials to provide self-cleaning, antibacterial, air cleaning, deodorizing, and water cleaning functions utilizing either solar light or artificial illumination sources - either already present in buildings, or by purposefully designed luminaries. Huge improvements in indoor comfort can thus be made, and also alleviate negative health effects associated with buildings, such as the sick-house syndrome. At the same time huge cost savings can be made by reducing maintenance costs. Photocatalytic oxides can be chemically modified by changing their acid-base surface properties, which can be used to overcome deactivation problems commonly encountered for TiO2 in air cleaning applications. In addition, the wetting properties of oxides can be tailored by surface chemical modifications and thus be made e.g. oleophobic and water repellent. Here we show results of surface acid modified TiO2 coatings on various substrates by means of photo-fixation of surface sulfate species by a method invented in our group. In particular, we show that such surface treatments of photocatalytic concrete made by mixing TiO2 nanoparticles in reactive concrete powders result in concrete surfaces with beneficial self-cleaning properties. We propose that such approaches are feasible for a number of applications in the built environment, including glass, tiles, sheet metals, plastics, etc.

  1. Photocatalytic oxide films in the built environment

    International Nuclear Information System (INIS)

    Österlund, Lars; Topalian, Zareh

    2014-01-01

    The possibility to increase human comfort in buildings is a powerful driving force for the introduction of new technology. Among other things our sense of comfort depends on air quality, temperature, lighting level, and the possibility of having visual contact between indoors and outdoors. Indeed there is an intimate connection between energy, comfort, and health issues in the built environment, leading to a need for intelligent building materials and green architecture. Photocatalytic materials can be applied as coatings, filters, and be embedded in building materials to provide self-cleaning, antibacterial, air cleaning, deodorizing, and water cleaning functions utilizing either solar light or artificial illumination sources – either already present in buildings, or by purposefully designed luminaries. Huge improvements in indoor comfort can thus be made, and also alleviate negative health effects associated with buildings, such as the sick-house syndrome. At the same time huge cost savings can be made by reducing maintenance costs. Photocatalytic oxides can be chemically modified by changing their acid-base surface properties, which can be used to overcome deactivation problems commonly encountered for TiO 2 in air cleaning applications. In addition, the wetting properties of oxides can be tailored by surface chemical modifications and thus be made e.g. oleophobic and water repellent. Here we show results of surface acid modified TiO 2 coatings on various substrates by means of photo-fixation of surface sulfate species by a method invented in our group. In particular, we show that such surface treatments of photocatalytic concrete made by mixing TiO 2 nanoparticles in reactive concrete powders result in concrete surfaces with beneficial self-cleaning properties. We propose that such approaches are feasible for a number of applications in the built environment, including glass, tiles, sheet metals, plastics, etc

  2. Annealing effects on photoluminescence of SiNx films grown by PECVD

    International Nuclear Information System (INIS)

    Komarov, F.F.; Parkhomenko, I.N.; Vlasukova, L.A.; Milchanin, O.V.; Togambayeva, A.K.; Kovalchuk, N.S.

    2013-01-01

    Si-rich and N-rich silicon nitride films were deposited at low temperature 300 °C by using plasma-enhanced chemical vapor deposition (PECVD). The optical and structural properties of these films have been investigated by ellipsometry, Rutherford backscattering (RBS), transmission electron microscopy (TEM), Raman spectroscopy (RS) and photoluminescence (PL). The formation of silicon clusters in both Si-rich and N-rich silicon nitride films after annealing at 900 °C and 1000 °C for hour in N 2 ambient has been revealed by TEM. Dependency of PL spectra on stoichiometry and post-annealing temperature was analyzed. The contribution of Si and N-related defects in emitting properties of Si-rich and N-rich SiN x has been discussed. (authors)

  3. Atom beam sputtered Ag-TiO{sub 2} plasmonic nanocomposite thin films for photocatalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Jaspal; Sahu, Kavita [School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, NewDelhi 110078 (India); Pandey, A. [Solid State Physics Laboratory, Defence Research and Development Organization, Timarpur, Delhi 110054 (India); Kumar, Mohit [Institute of Physics, Sachivalaya Marg, Bhubaneswar, Odisha 751005 (India); Ghosh, Tapas; Satpati, B. [Saha Institute of Nuclear Physics, HBNI, 1/AF, Bidhannagar, Kolkata 700064 (India); Som, T.; Varma, S. [Institute of Physics, Sachivalaya Marg, Bhubaneswar, Odisha 751005 (India); Avasthi, D.K. [Amity Institute of Nanotechnology, Noida 201313, Uttar Pradesh (India); Mohapatra, Satyabrata, E-mail: smiuac@gmail.com [School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, NewDelhi 110078 (India)

    2017-07-31

    The development of nanocomposite coatings with highly enhanced photocatalytic activity is important for photocatalytic purification of water and air. We report on the synthesis of Ag-TiO{sub 2} nanocomposite thin films with highly enhanced photocatalytic activity by atom beam co-sputtering technique. The effects of Ag concentration on the structural, morphological, optical, plasmonic and photocatalytic properties of the nanocomposite thin films were investigated. UV–visible DRS studies revealed the presence of surface plasmon resonance (SPR) peak characteristic of Ag nanoparticles together with the excitonic absorption peak originating from TiO{sub 2} nanoparticles in the nanocomposites. XRD studies showed that the nanocomposite thin films consist of Ag nanoparticles and rutile TiO{sub 2} nanoparticles. The synthesized Ag-TiO{sub 2} nanocomposite thin films with 5 at% Ag were found to exhibit highly enhanced photocatalytic activity for sun light driven photocatalytic degradation of methylene blue in water, indicating their potential application in water purification.

  4. Influence of nitrogen flow rates on materials properties of CrNx films ...

    Indian Academy of Sciences (India)

    Chromium nitride (CrN) hard thin films were deposited on different substrates by reactive direct current ... use as hard wear protective coatings for cutting tools and ... Power. 50 Watt. Substrate temperature. 200. ◦. C and Si (100) wafers using a d.c. magnetron sputter deposition unit HIND HIVAC. High purity argon (99·99%) ...

  5. Influence of nitrogen flow rates on materials properties of CrNx films ...

    Indian Academy of Sciences (India)

    Chromium nitride (CrN) hard thin films were deposited on different substrates by reactive direct current (d.c.) magnetron sputtering with different nitrogen flow rates. The X-ray diffraction patterns showed mixed Cr2N and CrN phases. The variations in structural parameters are discussed. The grain size increased with ...

  6. Fabrication and Photocatalytic Properties of ZnSe Nanorod Films

    Directory of Open Access Journals (Sweden)

    Jiajia Yin

    2016-01-01

    Full Text Available ZnSe nanorod films grown on fused quartz glass substrates via a simple two-step synthesis protocol were demonstrated to be environmentally safe and effective recyclable photocatalysts. These films showed greatly enhanced photocatalytic activity compared to pulsed laser deposition ZnSe films in the degradation of methyl orange dye solutions. The well-crystalized ZnSe nanorods had a length of 15 µm and a diameter of 200 nm and were densely grown on the substrate. The morphology, crystal structure, crystal phase, and photophysical properties of the ZnSe nanorod films were investigated using field-emission scanning electron microscopy (FE-SEM, UV-Vis spectroscopy, X-ray diffraction (XRD, transmission electron microscopy (TEM, and high resolution transmission electron microscopy (HRTEM.

  7. Large negative magnetoresistance in reactive sputtered polycrystalline GdNx films

    KAUST Repository

    Mi, W. B.

    2013-06-07

    Polycrystalline ferromagnetic GdN x films were fabricated at different N2 flow rates ( fN2 ) to modify N-vacancy concentration so as to study its influence on electrotransport. Metal-semiconductor transition appears at Curie temperature (TC ) of ∼40 K. Temperature-dependent magnetoresistance (MR) shows a peak at T C. The films at fN2  = 5, 10, 15, and 20 sccm show MR of −38%, −42%, −46%, and −86% at 5 K and 50 kOe, respectively. Above 15 K, MR is from colossal MR and from both colossal and tunneling MR below 15 K. The enhanced MR at fN2  = 20 sccm is attributed to large spin polarization of half-metallicity in GdN x with low N vacancies.

  8. Investigation of polypyrrole/polyvinyl alcohol-titanium dioxide composite films for photo-catalytic applications

    Science.gov (United States)

    Cao, Shaoqiang; Zhang, Hongyang; Song, Yuanqing; Zhang, Jianling; Yang, Haigang; Jiang, Long; Dan, Yi

    2015-07-01

    Polypyrrole/polyvinyl alcohol-titanium dioxide (PPy/PVA-TiO2) composite films used as photo-catalysts were fabricated by combining TiO2 sol with PPy/PVA solution in which PPy was synthesized by in situ polymerization of pyrrole (Py) in polyvinyl alcohol (PVA) matrix and loaded on glass. The prepared photo-catalysts were investigated by X-ray diffraction (XRD), ultraviolet-visible diffuse reflection spectroscopy (UV-vis DRS), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectra and photoluminescence (PL). The results indicate that the composites have same crystal structure as the TiO2 and extend the optic absorption from UV region to visible light region. By detecting the variation ratio, detected by ultraviolet-vis spectroscopy, of model pollutant rhodamine B (RhB) solution in the presence of the composite films under both UV and visible light irradiation, the photo-catalytic performance of the composite films was investigated. The results show that the PPy/PVA-TiO2 composite films show better photo-catalytic properties than TiO2 film both under UV and visible light irradiation, and the photo-catalytic degradation of RhB follows the first-order kinetics. The effects of the composition of composite films and the concentration of RhB on the photo-catalytic performance, as well as the possible photo-catalytic mechanism, were also discussed. By photo-catalytic recycle experiments, the structure stability of the PPy/PVA-TiO2 composite film was investigated and the results show that the photo-catalytic activity under both UV and visible light irradiation have no significant decrease after four times of recycle experiments, suggesting that the photo-catalyst film is stable during the photo-catalytic process, which was also confirmed by the XRD pattern and FT-IR spectra of the composite film before and after photo-catalytic.

  9. Porous-ZnO-Nanobelt Film as Recyclable Photocatalysts with Enhanced Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Wang Min

    2010-01-01

    Full Text Available Abstract In this article, the porous-ZnO-nanobelt film was synthesized by oxidizing the ZnSe-nanobelt film in air. The experiment results show that the porous-ZnO-nanobelt film possesses enhanced photocatalytic activity compared with the ZnO-nanobelt film, and can be used as recyclable photocatalysts. The enhanced photocatalytic activity of the porous-ZnO-nanobelt film is attributed to the increased surface area. Therefore, turning the 1D-nanostructure film into porous one may be a feasible approach to meet the demand of photocatalyst application.

  10. Transparent titania-zirconia thin films for self-cleaning and photocatalytic application

    OpenAIRE

    Vodišek, Nives; Ramanujachary, Kandalam; Brezová, Vlasta; Lavrenčič Štangar, Urška

    2017-01-01

    Thin films were prepared by sol-gel process, where different amount of zirconia were added to titania. Photocatalytic activity of thin films was measured by two methods i) determination of degradation ration of methyl stearate with measuring the contact angle and ii) formation of hydroxyterephthalic acid was measured by spectrofluorometer. Prepared samples were characterized by UV-Vis spectrophotometer, SEM, XRD, FT-IR ATR, and BET. The result of measurements of photocatalytic acti...

  11. Investigation of polypyrrole/polyvinyl alcohol–titanium dioxide composite films for photo-catalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Shaoqiang; Zhang, Hongyang; Song, Yuanqing; Zhang, Jianling; Yang, Haigang; Jiang, Long, E-mail: jianglong@scu.edu.cn; Dan, Yi, E-mail: danyichenweiwei@163.com

    2015-07-01

    Graphical abstract: - Highlights: • The study provides an easy and convenient method to fabricate films, which will give guidance for the preparation of three-dimensional materials. • The PPy/PVA–TiO{sub 2} films can keep better photo-catalytic activities both under UV and visible light irradiation when compared with TiO{sub 2} film. • There exist electron transfers between PPy/PVA and TiO{sub 2}. - Abstract: Polypyrrole/polyvinyl alcohol–titanium dioxide (PPy/PVA–TiO{sub 2}) composite films used as photo-catalysts were fabricated by combining TiO{sub 2} sol with PPy/PVA solution in which PPy was synthesized by in situ polymerization of pyrrole (Py) in polyvinyl alcohol (PVA) matrix and loaded on glass. The prepared photo-catalysts were investigated by X-ray diffraction (XRD), ultraviolet–visible diffuse reflection spectroscopy (UV–vis DRS), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectra and photoluminescence (PL). The results indicate that the composites have same crystal structure as the TiO{sub 2} and extend the optic absorption from UV region to visible light region. By detecting the variation ratio, detected by ultraviolet–vis spectroscopy, of model pollutant rhodamine B (RhB) solution in the presence of the composite films under both UV and visible light irradiation, the photo-catalytic performance of the composite films was investigated. The results show that the PPy/PVA–TiO{sub 2} composite films show better photo-catalytic properties than TiO{sub 2} film both under UV and visible light irradiation, and the photo-catalytic degradation of RhB follows the first-order kinetics. The effects of the composition of composite films and the concentration of RhB on the photo-catalytic performance, as well as the possible photo-catalytic mechanism, were also discussed. By photo-catalytic recycle experiments, the structure stability of the PPy/PVA–TiO{sub 2} composite film was investigated and the results show that

  12. Inactivation of E. Coli in Water Using Photocatalytic, Nanostructured Films Synthesized by Aerosol Routes

    Directory of Open Access Journals (Sweden)

    Pratim Biswas

    2013-03-01

    Full Text Available TiO2 nanostructured films were synthesized by an aerosol chemical vapor deposition (ACVD method with different controlled morphologies: columnar, granular, and branched structures for the photocatalytic inactivation of Escherichia coli (E. coli in water. Effects of film morphology and external applied voltage on inactivation rate were investigated. As-prepared films were characterized using scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffractometry (XRD, and UV-VIS. Photocatalytic and photoelectrochemical inactivation of E. coli using as-prepared TiO2 films were performed under irradiation of UVA light (note: UVA has a low efficiency to inactivate E. coli. Inactivation rate constants for each case were obtained from their respective inactivation curve through a 2 h incubation period. Photocatalytic inactivation rate constants of E. coli are 0.02/min (using columnar films, and 0.08/min (using branched films. The inactivation rate constant for the columnar film was enhanced by 330% by applied voltage on the film while that for the branched film was increased only by 30%. Photocatalytic microbial inactivation rate of the columnar and the branched films were also compared taking into account their different surface areas. Since the majority of the UV radiation that reaches the Earth’s surface is UVA, this study provides an opportunity to use sunlight to efficiently decontaminate drinking water.

  13. Effects of Ni doping on photocatalytic activity of TiO2 thin films ...

    Indian Academy of Sciences (India)

    Ni-doped TiO2 thin films can be used as photocatalyst for the photodegradation of methyl orange dye. It was found that, organic dye undergoes degradation efficiently in presence of non-uniformly Ni-doped TiO2 thin films when compared to uniformly doped films and pure TiO2 films under visible light. The photocatalytic ...

  14. Covalent attachment and growth of nanocrystalline films of photocatalytic TiOF 2

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Jian [Chinese Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials; Shanghai Normal University; Shanghai, China; Lv, Fujian [Chinese Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials; Shanghai Normal University; Shanghai, China; Xiao, Shengxiong [Chinese Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials; Shanghai Normal University; Shanghai, China; Bian, Zhenfeng [Chinese Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials; Shanghai Normal University; Shanghai, China; Buntkowsky, Gerd [Eduard-Zintl-Institut für Anorganische und Physikalische Chemie Technische Universität Darmstadt; , Germany; Nuckolls, Colin [Chinese Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials; Shanghai Normal University; Shanghai, China; Department of Chemistry; Columbia University; Li, Hexing [Chinese Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials; Shanghai Normal University; Shanghai, China

    2014-01-01

    An evaporation induced alcoholysis process has been applied to synthesize nanocrystalline TiOF2film. The nanocrystalline TiOF2becomes chemically attached to the surface of the glass slide. These films show potential applications in both photocatalytic and antibacterial fields.

  15. Temperature dependent optical characterization of Ni-TiO2 thin films as potential photocatalytic material

    Science.gov (United States)

    De, Rajnarayan; Haque, S. Maidul; Tripathi, S.; Rao, K. Divakar; Singh, Ranveer; Som, T.; Sahoo, N. K.

    2017-09-01

    Along with other transition metal doped titanium dioxide materials, Ni-TiO2 is considered to be one of the most efficient materials for catalytic applications due to its suitable energy band positions in the electronic structure. The present manuscript explores the possibility of improving the photocatalytic activity of RF magnetron sputtered Ni-TiO2 films upon heat treatment. Optical, structural and morphological and photocatalytic properties of the films have been investigated in detail for as deposited and heat treated samples. Evolution of refractive index (RI) and total film thickness as estimated from spectroscopic ellipsometry characterization are found to be in agreement with the trend in density and total film thickness estimated from grazing incidence X-ray reflectivity measurement. Interestingly, the evolution of these macroscopic properties were found to be correlated with the corresponding microstructural modifications realized in terms of anatase to rutile phase transformation and appearance of a secondary phase namely NiTiO3 at high temperature. Corresponding morphological properties of the films were also found to be temperature dependent which leads to modifications in the grain structure. An appreciable reduction of optical band gap from 2.9 to 2.5 eV of Ni-TiO2 thin films was also observed as a result of post deposition heat treatment. Testing of photocatalytic activity of the films performed under UV illumination demonstrates heat treatment under atmospheric ambience to be an effective means to enhance the photocatalytic efficiency of transition metal doped titania samples.

  16. Sprayed nanostructured TiO2 films for efficient photocatalytic degradation of textile azo dye.

    Science.gov (United States)

    Stambolova, Irina; Shipochka, Capital Em Cyrillicaria; Blaskov, Vladimir; Loukanov, Alexandrе; Vassilev, Sasho

    2012-12-05

    Spray pyrolysis procedure for preparation of nanostructured TiO(2) films with higher photocatalytic effectiveness and longer exploitation life is presented in this study. Thin films of active nanocrystalline TiO(2) were obtained from titanium isopropoxide, stabilized with acetyl acetone and characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The activity of sprayed nanostructured TiO(2) is tested for photocatalytic degradation of Reactive Black 5 dye with concentrations up to 80 ppm. Interesting result of the work is the reduction of toxicity after photocatalytic treatment of RB5 with TiO(2), which was confirmed by the lower percentage of mortality of Artemia salina. It was proved that the film thickness, conditions of post deposition treatment and the type of the substrate affected significantly the photocatalytic reaction. Taking into account that the parameters are interdependent, it is necessary to optimize the preparation conditions in order to synthesize photocatalytic active films. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Silver film on nanocrystalline TiO{sub 2} support: Photocatalytic and antimicrobial ability

    Energy Technology Data Exchange (ETDEWEB)

    Vukoje, Ivana D., E-mail: ivanav@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Tomašević-Ilić, Tijana D., E-mail: tommashev@gmail.com [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Zarubica, Aleksandra R., E-mail: zarubica2000@yahoo.com [Department of Chemistry, Faculty of Science and Mathematics, University of Niš, Višegradska 33, 18000 Niš (Serbia); Dimitrijević, Suzana, E-mail: suzana@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade (Serbia); Budimir, Milica D., E-mail: mickbudimir@gmail.com [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Vranješ, Mila R., E-mail: mila@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Šaponjić, Zoran V., E-mail: saponjic@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia); Nedeljković, Jovan M., E-mail: jovned@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia)

    2014-12-15

    Highlights: • Simple photocatalytic rout for deposition of Ag on nanocrystalline TiO{sub 2} films. • High antibactericidal efficiency of deposited Ag on TiO{sub 2} support. • Improved photocatalytic performance of TiO{sub 2} films in the presence of deposited Ag. - Abstract: Nanocrystalline TiO{sub 2} films were prepared on glass slides by the dip coating technique using colloidal solutions consisting of 4.5 nm particles as a precursor. Photoirradiation of nanocrystalline TiO{sub 2} film modified with alanine that covalently binds to the surface of TiO{sub 2} and at the same time chelate silver ions induced formation of metallic silver film. Optical and morphological properties of thin silver films on nanocrystalline TiO{sub 2} support were studied by absorption spectroscopy and atomic force microscopy. Improvement of photocatalytic performance of nanocrystalline TiO{sub 2} films after deposition of silver was observed in degradation reaction of crystal violet. Antimicrobial ability of deposited silver films on nanocrystalline TiO{sub 2} support was tested in dark as a function of time against Escherichia coli, Staphylococcus aureus, and Candida albicans. The silver films ensured maximum cells reduction of both bacteria, while the fungi reduction reached satisfactory 98.45% after 24 h of contact.

  18. The effect of surface modification by nitrogen plasma on photocatalytic degradation of polyvinyl chloride films

    Science.gov (United States)

    Xiao-jing, L.; Guan-jun, Q.; Jie-rong, C.

    2008-08-01

    The solid-phase photocatalytic degradation of poly(vinyl chloride) (PVC) films was investigated under the ambient air in order to assess the feasibility of developing photodegradable polymers. Nitrogen plasma was used to modify PVC films to enhance the photocatalytic degradation of PVC with nano-sized anatase TiO 2. The plasma parameter varied in this study is discharge power from 30 to 120 W for a constant treatment time of 60 s and a constant gas pressure of 10 Pa. The photodegradation of the plasma-treated PVC-TiO 2 films was compared with that of pure PVC films and PVC-TiO 2 films performing weight loss monitoring, scanning electron microscopy (SEM) analysis, contact angle measurements, electron spin resonance (ESR), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The wettability of the plasma-treated PVC is improved significantly. ESR revealed that the signal of radicals on the surface of the plasma-treated PVC film was enhanced after the treatment. Furthermore, the weight loss indicated that TiO 2 speeds up the photocatalytic degradation of PVC chains. The SEM image of the plasma-treated PVC-TiO 2 film showed a lot of crack on the film surface after irradiation. XPS indicated that the C and Cl atomic concentration reached minimum values on the surface of plasma-treated PVC-TiO 2 under identical photocatalytic condition. The experimental results reveal that plasma treatment can obviously enhance the photocatalytic degradation of PVC.

  19. Controlled preparation of Ag nanoparticle films by a modified photocatalytic method on TiO{sub 2} films with Ag seeds for surface-enhanced Raman scattering

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Xin; Pan, Lujun, E-mail: lpan@dlut.edu.cn; Li, Shuai; Wang, Qiao; Qin, Jun; Huang, Yingying

    2016-02-15

    Graphical abstract: - Highlights: • Uniform Ag nanoparticle films were synthesized by a modified photocatalytic method on TiO{sub 2} films with Ag seeds for surface-enhanced Raman scattering. • This modified photocatalytic method combine the advantages of the spurting method (high nucleation density) and the traditional photocatalytic method (suitable particle size). • The Raman enhancement of as-prepared Ag NP films was calculated by finite-difference time-domain to validate the experiment data. - Abstract: Uniform Ag nanoparticle (NP) films were synthesized by a modified photocatalytic method on TiO{sub 2} films with Ag seeds for surface-enhanced Raman scattering, which combine the advantages of the spurting method (high nucleation density) and the traditional photocatalytic method (suitable particle size). The Ag seeds were prepared by magnetron sputtering with different time, which would adjust the distribution and transfer of electrons on the surface of TiO{sub 2} film in the process of photocatalytic reduction. The distribution and morphology of Ag NP films can be adjusted by the sputtering time and the UV irradiation time. The Raman enhancement of as-prepared Ag NP films was calculated by finite-difference time-domain to validate the experiment data. It is found that the Ag NP films synthesized on TiO{sub 2} films with suitable pre-deposited Ag seeds exhibit a much higher Raman enhancement activity than the optimum Ag NP film synthesized directly on the TiO{sub 2} film without Ag seeds.

  20. Visible-light photocatalytic activity of nitrided TiO2 thin films

    International Nuclear Information System (INIS)

    Camps, Enrique; Escobar-Alarcon, L.; Camacho-Lopez, Marco Antonio; Casados, Dora A. Solis

    2010-01-01

    TiO 2 thin films have been applied in UV-light photocatalysis. Nevertheless visible-light photocatalytic activity would make this material more attractive for applications. In this work we present results on the modification of titanium oxide (anatase) sol-gel thin films, via a nitriding process using a microwave plasma source. After the treatment in the nitrogen plasma, the nitrogen content in the TiO 2 films varied in the range from 14 up to 28 at%. The titanium oxide films and the nitrided ones were characterized by XPS, micro-Raman spectroscopy and UV-vis spectroscopy. Photocatalytic activity tests were done using a Methylene Blue dye solution, and as catalyst TiO 2 and nitrided TiO 2 films. The irradiation of films was carried out with a lamp with emission in the visible (without UV). The results showed that the nitrided TiO 2 films had photocatalytic activity, while the unnitrided films did not.

  1. Visible-light photocatalytic activity of nitrided TiO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Camps, Enrique, E-mail: enrique.camps@inin.gob.mx [Departamento de Fisica, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, Mexico DF 11801 (Mexico); Escobar-Alarcon, L. [Departamento de Fisica, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, Mexico DF 11801 (Mexico); Camacho-Lopez, Marco Antonio [Laboratorio de Investigacion y Desarrollo de Materiales Avanzados, Facultad de Quimica, UAEM, km 14.5 Carretera Toluca-Atlacomulco (Mexico); Casados, Dora A. Solis [Centro de Investigacion en Quimica Sustentable, Facultad de Quimica, UAEM, km 14.5 Carretera Toluca-Atlacomulco (Mexico)

    2010-10-25

    TiO{sub 2} thin films have been applied in UV-light photocatalysis. Nevertheless visible-light photocatalytic activity would make this material more attractive for applications. In this work we present results on the modification of titanium oxide (anatase) sol-gel thin films, via a nitriding process using a microwave plasma source. After the treatment in the nitrogen plasma, the nitrogen content in the TiO{sub 2} films varied in the range from 14 up to 28 at%. The titanium oxide films and the nitrided ones were characterized by XPS, micro-Raman spectroscopy and UV-vis spectroscopy. Photocatalytic activity tests were done using a Methylene Blue dye solution, and as catalyst TiO{sub 2} and nitrided TiO{sub 2} films. The irradiation of films was carried out with a lamp with emission in the visible (without UV). The results showed that the nitrided TiO{sub 2} films had photocatalytic activity, while the unnitrided films did not.

  2. Enhanced photocurrent and photocatalytic properties of porous ZnO thin film by Ag nanoparticles

    Science.gov (United States)

    Lv, Jianguo; Zhu, Qianqian; Zeng, Zheng; Zhang, Miao; Yang, Jin; Zhao, Min; Wang, Wenhao; Cheng, Yuebing; He, Gang; Sun, Zhaoqi

    2017-12-01

    ZnO thin films were deposited using an electrodeposition method and porous morphologies could be achieved by annealing treatment. A variety of Ag nanoparticles were loaded on the surface of the ZnO thin films. Surface morphology, chemical composition, crystal phase and optical properties were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), UV-vis spectrophotometer and micro-Raman spectroscopy. Evidence of Ag nanoparticles on the Ag-4/ZnO thin film was be verified by the SEM and XPS measurements. The XRD results indicated that the Ag nanoparticles had little effect on crystallinity of the thin films. The photoresponse and photocatalytic results indicated that the photocurrent and photocatalytic performance could be enhanced by moderate Ag nanoparticles modification on the surface of the ZnO thin film. The best photoresponse and photocatalytic activity in Ag-4/ZnO thin film results from the moderate Ag nanoparticles on the surface of ZnO thin film, which could enhanced separation and suppressed recombination of photogenerated electron-hole pairs.

  3. Controlled morphologies and optical properties of ZnO films and their photocatalytic activities

    Energy Technology Data Exchange (ETDEWEB)

    Duan Jingjing [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China); Liu Xiaoheng, E-mail: xhliu@mail.njust.edu.cn [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China); Han Qiaofeng [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China); Wang Xin, E-mail: wangx@mail.njust.edu.cn [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China)

    2011-09-15

    Highlights: > Gelatin acts as a capping reagent in the morphology synthesis of ZnO films. > The microstructures of ZnO films are hexagonal prisms, plates and rose-like crystals. > The hexagonal prisms and rose-like films exhibit excellent photocatalytic activities. - Abstract: ZnO films with three different microstructures including hexagonal prisms, plates and rose-like twinned crystals were fabricated using chemical bath deposition with different concentration of gelatin. The growth mechanisms of ZnO films were discussed, and the gelatin played a vital role as a polyelectrolyte capping the formation of microstructures. The photoluminescence and Raman properties were found sensitive to the crystal morphologies of ZnO films. Significantly, the photodegradation efficiencies of methylene blue under UV light irradiation in the presence of ZnO films consisted of hexagonal prisms and rose-like twinned crystals were 95% and 96%, respectively. The excellent photocatalytic activities can be ascribed to the high oxygen vacancies concentration and high percentage of polar planes, and this result was important in addressing the origin of high photocatalytic activity.

  4. Increased photocatalytic activity induced by TiO2/Pt/SnO2 heterostructured films

    Science.gov (United States)

    Testoni, Glaucio O.; Amoresi, Rafael A. C.; Lustosa, Glauco M. M. M.; Costa, João P. C.; Nogueira, Marcelo V.; Ruiz, Miguel; Zaghete, Maria A.; Perazolli, Leinig A.

    2018-02-01

    In this work, a high photocatalytic activity was attained by intercalating a Pt layer between SnO2 and TiO2 semiconductors, which yielded a TiO2/Pt/SnO2 - type heterostructure used in the discoloration of blue methylene (MB) solution. The porous films and platinum layer were obtained by electrophoretic deposition and DC Sputtering, respectively, and were both characterized morphologically and structurally by FE-SEM and XRD. The films with the Pt interlayer were evaluated by photocatalytic activity through exposure to UV light. An increase in efficiency of 22% was obtained for these films compared to those without platinum deposition. Studies on the reutilization of the films pointed out high efficiency and recovery of the photocatalyst, rendering the methodology favorable for the construction of fixed bed photocatalytic reactors. A proposal associated with the mechanism is discussed in this work in terms of the difference in Schottky barrier between the semiconductors and the electrons transfer and trapping cycle. These are fundamental factors for boosting photocatalytic efficiency.

  5. Macrostructure-dependent photocatalytic property of high-surface-area porous titania films

    Directory of Open Access Journals (Sweden)

    T. Kimura

    2014-11-01

    Full Text Available Porous titania films with different macrostructures were prepared with precise control of condensation degree and density of the oxide frameworks in the presence of spherical aggregates of polystyrene-block-poly(oxyethylene (PS-b-PEO diblock copolymer. Following detailed explanation of the formation mechanisms of three (reticular, spherical, and large spherical macrostructures by the colloidal PS-b-PEO templating, structural variation of the titania frameworks during calcination were investigated by X-ray diffraction and X-ray photoelectron spectroscopy. Then, photocatalytic performance of the macroporous titania films was evaluated through simple degradation experiments of methylene blue under an UV irradiation. Consequently, absolute surface area of the film and crystallinity of the titania frameworks were important for understanding the photocatalytic performance, but the catalytic performance can be improved further by the macrostructural design that controls diffusivity of the targeted molecules inside the film and their accessibility to active sites.

  6. Deposition of Visible Light Active Photocatalytic Bismuth Molybdate Thin Films by Reactive Magnetron Sputtering.

    Science.gov (United States)

    Ratova, Marina; Kelly, Peter J; West, Glen T; Xia, Xiaohong; Gao, Yun

    2016-01-22

    Bismuth molybdate thin films were deposited by reactive magnetron co-sputtering from two metallic targets in an argon/oxygen atmosphere, reportedly for the first time. Energy dispersive X-ray spectroscopy (EDX) analysis showed that the ratio of bismuth to molybdenum in the coatings can be effectively controlled by varying the power applied to each target. Deposited coatings were annealed in air at 673 K for 30 min. The crystalline structure was assessed by means of Raman spectroscopy and X-ray diffraction (XRD). Oxidation state information was obtained by X-ray photoelectron spectroscopy (XPS). Photodegradation of organic dyes methylene blue and rhodamine B was used for evaluation of the photocatalytic properties of the coatings under a visible light source. The photocatalytic properties of the deposited coatings were then compared to a sample of commercial titanium dioxide-based photocatalytic product. The repeatability of the dye degradation reactions and photocatalytic coating reusability are discussed. It was found that coatings with a Bi:Mo ratio of approximately 2:1 exhibited the highest photocatalytic activity of the coatings studied; its efficacy in dye photodegradation significantly outperformed a sample of commercial photocatalytic coating.

  7. Photocatalytic efficiency of reusable ZnO thin films deposited by sputtering technique

    Energy Technology Data Exchange (ETDEWEB)

    Ahumada-Lazo, R.; Torres-Martínez, L.M. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Civil, Departamento de Ecomateriales y Energía, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza, Nuevo León C.P. 66450, México (Mexico); Ruíz-Gómez, M.A. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Civil, Departamento de Ecomateriales y Energía, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza, Nuevo León C.P. 66450, México (Mexico); Departmento de Física Aplicada, CINVESTAV-IPN, Antigua Carretera a Progreso km 6, Mérida, Yucatán 97310, México (Mexico); Vega-Becerra, O.E. [Centro de Investigación en Materiales Avanzados S.C, Alianza norte 202, Parque de Investigación e Innovación Tecnológica, C.P. 66600 Apodaca Nuevo León, México (Mexico); and others

    2014-12-15

    Graphical abstract: - Highlights: • Decolorization of Orange G dye using highly c-axis-oriented ZnO thin films. • The flake-shaped film shows superior and stable photoactivity at a wide range of pH. • The highest photodecolorization was achieved at pH of 7. • The exposure of (101) and (100) facets enhanced the photoactivity. • ZnO thin films exhibit a promising performance as recyclable photocatalysts. - Abstract: The photocatalytic activity of ZnO thin films with different physicochemical characteristics deposited by RF magnetron sputtering on glass substrate was tested for the decolorization of orange G dye aqueous solution (OG). The crystalline phase, surface morphology, surface roughness and the optical properties of these ZnO films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM) and UV–visible spectroscopy (UV–Vis), respectively. The dye photodecolorization process was studied at acid, neutral and basic pH media under UV irradiation of 365 nm. Results showed that ZnO films grow with an orientation along the c-axis of the substrate and exhibit a wurtzite crystal structure with a (002) preferential crystalline orientation. A clear relationship between surface morphology and photocatalytic activity was observed for ZnO films. Additionally, the recycling photocatalytic abilities of the films were also evaluated. A promising photocatalytic performance has been found with a very low variation of the decolorization degree after five consecutive cycles at a wide range of pH media.

  8. Sprayed Pyrolyzed ZnO Films with Nanoflake and Nanorod Morphologies and Their Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Nora S. Portillo-Vélez

    2016-01-01

    Full Text Available There is an increasing interest on the application of ZnO nanorods in photocatalysis and many growth methods have been applied, in particular the spray pyrolysis technique which is attractive for large scale production. However it is interesting to know if the nanorod morphology is the best considering its photocatalytic activity, stability, and cost effectiveness compared to a nonoriented growth. In this work we present a systematic study of the effect of the precursor solution (type of salt, solvent, and concentration on the morphology of sprayed ZnO films to obtain nanoflakes and nanorods without the use of surfactants or catalysts. The surface properties and structural characteristics of these types of films were investigated to elucidate which morphology is more favorable for photocatalytic applications. Wettability and photocatalytic experiments were carried out in the same conditions. After UV irradiation both morphologies became hydrophilic and achieved a dye discoloration efficiency higher than 90%; however, the nanoflake morphology provided the highest photocatalytic performance (99% dye discoloration and stability and the lowest energy consumption during the synthesis process. The surface-to-volume ratio revealed that the nanoflake morphology is more adequate for photocatalytic water treatment applications and that the thin nanorods should be preferred over the large ones.

  9. Microstructures and photocatalytic properties of porous ZnO films synthesized by chemical bath deposition method

    International Nuclear Information System (INIS)

    Wang Huihu; Dong, Shijie; Chang Ying; Zhou Xiaoping; Hu Xinbin

    2012-01-01

    Different porous ZnO film structures on the surface of alumina substrates were prepared through a simple chemical bath deposition method in the methanolic zinc acetate solution. The surface morphology and phase structure of porous ZnO film were determined by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Both initial zinc acetate concentration and sintering temperature have great impact on the final film structures. With the increase of initial zinc acetate concentration, the porous structures can be finely tuned from circular nest like assemblies composed film into successive nest like film, and finally to globular aggregates composed film. By increasing the sintering temperature, the porous structure of successive nest like film can be further controlled. Furthermore, the crystallinity of photocatalysts also can be greatly improved. The photodegradation results of Methyl Orange revealed that porous ZnO film with successive nest like structure sintered at 500 °C exhibited the highest photocatalytic activity under UV illumination.

  10. Solid-phase photocatalytic degradation of polyethylene film with manganese oxide OMS-2

    Science.gov (United States)

    Liu, Guanglong; Liao, Shuijiao; Zhu, Duanwei; Cui, Jingzhen; Zhou, Wenbing

    2011-01-01

    Solid-phase photocatalytic degradation of polyethylene (PE) film with cryptomelane-type manganese oxide (OMS-2) as photocatalyst was investigated in the ambient air under ultraviolet and visible light irradiation. The properties of the composite films were compared with those of the pure PE film through performing weight loss monitoring, IR spectroscopy, scanning electron microscopic (SEM) and X-ray photoelectron spectroscopy (XPS). The photoinduced degradation of PE-OMS-2 composite films was higher than that of the pure films, while there has been little change under the visible light irradiation. The weight loss of PE-OMS-2 (1.0 wt%) composite films steadily decreased and reached 16.5% in 288 h under UV light irradiation. Through SEM observation there were some cavities on the surface of composite films, but few change except some surface chalking phenomenon occurred in pure PE film. The degradation rate with ultraviolet irradiation is controllable by adjusting the content of OMS-2 particles in PE plastic. Finally, the mechanism of photocatalytic degradation of the composite films was briefly discussed.

  11. Reusable photocatalytic titanium dioxide-cellulose nanofiber films

    Science.gov (United States)

    Alexandra Snyder; Zhenyu Bo; Robert Moon; Jean-Christophe Rochet; Lia. Stanciu

    2013-01-01

    Titanium dioxide (TiO2) is a well-studied photocatalyst that is known to break down organic molecules upon ultraviolet (UV) irradiation. Cellulose nanofibers (CNFs) act as an attractive matrix material for the suspension of photocatalytic particles due to their desirable mechanical and optical properties. In this work, TiO2...

  12. Photocatalytic Activity of TiO2 Thin Films Obtained by the Sputtering RF in Wastewater

    Science.gov (United States)

    Cardona Bedoya, Jairo Armando; Sanchez Velandia, Wilmer Asmed; Delgado Rosero, Miguel Iban; Florido Cuellar, Alex Enrique; Zelaya Angel, Orlando; Mendoza Alvarez, Julio G.

    2011-03-01

    The photocatalytic activity of Ti O2 thin films in wastewater, under an UV irradiation, is studied. The films were prepared on corning glass substrates by the sputtering RF technique. We present evidence on the photocatalytic degradation, carried out by advanced oxidation processes (AOPs) in domestic wastewater pretreated with UASB (upflow anaerobic sludge blanket) reactors. Ti O2 films were illuminated with ultraviolet light during a time of 4 hours (λ ≅ 264 nm). We could see the effect of degraded operation in the absorbance measurement using UV-VIS spectrophotometry. The results show an increased rate of degradation of the wastewater by 30% compared to the values reflected biologically treated wastewater by anaerobic reactors.

  13. Enhanced photocatalytic activity of Ag-TiO2/Ag heterogeneous films

    Science.gov (United States)

    Liang, Ying; Wang, ShaoHua; Guo, PengFeng

    2015-11-01

    Ag-deposited TiO2 and Ag (Ag-TiO2/Ag) films coated on glass substrates were prepared using a simple sol-gel and dip-coating method. The Ag chemical state was investigated through X-ray diffractometry and X-ray photoelectron spectroscopy. Results showed that the Ag mainly exists in metallic state in the Ag-TiO2 film. Ag-TiO2/Ag exhibits higher photocatalytic activity than individual Ag-TiO2 and TiO2/Ag films. This enhanced photocatalytic activity was attributed to high surface plasmon resonance effects and separation rates of photoinduced electron-hole pairs of Ag nanoparticles. Results were verified by photoluminescence and UV-Vis spectroscopy.

  14. Wastewater treatment by sonophotocatalysis using PEG modified TiO2film in a circular Photocatalytic-Ultrasonic system.

    Science.gov (United States)

    Hu, Xiaohong; Zhu, Qi; Gu, Zhibin; Zhang, Nan; Liu, Na; Stanislaus, Mishma S; Li, Dawei; Yang, Yingnan

    2017-05-01

    TiO 2 photocatalyst film recently has been utilized as the potential candidate for the wastewater treatment, due to its high stability and low toxicity. In order to further increase the photocatalytic ability and stability, different molecular weight of polyethylene glycol (PEG) were used to modify TiO 2 structure to synthesize porous thin film used in the developed Photocatalytic-Ultrasonic system in this work. The results showed that PEG2000 modified TiO 2 calcinated under 450°C for 2h exhibited the highest photocatalytic activity, attributed to the smallest crystallite size and optimal particle size. Over 95.0% of rhodamine B (Rh B) was photocatalytically degraded by optimized PEG 2000 -TiO 2 film after 60min of UV irradiation, while only about 50.8% of Rh B was decolored over pure TiO 2 film. Furthermore, optimized PEG 2000 -TiO 2 film was used in a circular Photocatalytic-Ultrasonic system, and the obtained synergy (0.6519) of sonophotocatalysis indicated its extremely high efficiency for Rh B degradation. In this Photocatalytic-Ultrasonic system, larger amount of PEG 2000 -TiO 2 coated glass beads, stronger ultrasonic power and longer experimental time could result to higher degradation efficiency of Rh B. In addition, repetitive experiments showed that about 97.2% of Rh B were still degraded in the fifth experiment by sonophotocatalysis using PEG 2000 -TiO 2 film. Therefore, PEG 2000 -TiO 2 film used in Photocatalytic-Ultrasonic system has promising potential for wastewater treatment, due to its excellent photocatalytic activity and high stability. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Photocatalytic Reduction of CO2 to Methane on Pt/TiO2 Nanosheet Porous Film

    Directory of Open Access Journals (Sweden)

    Li Qiu-ye

    2014-01-01

    Full Text Available Anatase TiO2 nanosheet porous films were prepared by calcination of the orthorhombic titanic acid films at 400°C. They showed an excellent photocatalytic activity for CO2 photoreduction to methane, which should be related to their special porous structure and large Brunauer-Emmett-Teller (BET surface area. In order to further improve the photocatalytic activity, Pt nanoparticles were loaded uniformly with the average size of 3-4 nm on TiO2 porous films by the photoreduction method. It was found that the loading of Pt expanded the light absorption ability of the porous film and improved the transformation efficiency of CO2 to methane. The conversion yield of CO2 to methane on Pt/TiO2 film reached 20.51 ppm/h·cm2. The Pt/TiO2 nanosheet porous film was characterized by means of X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscope (TEM, and ultraviolet-visible light diffuse reflectance spectra (UV-vis DRS. Moreover, the transient photocurrent-time curves showed that the Pt/TiO2 nanosheet porous film exhibited higher photocurrent, indicating that the higher separation efficiency of the photogenerated charge carriers was achieved.

  16. [Study on preparation of lanthanum-doped TiO2 nanometer thin film materials and its photocatalytic activity].

    Science.gov (United States)

    Zheng, Huai-li; Tang, Ming-fang; Gong, Ying-kun; Deng, Xiao-jun; Wu, Bang-hua

    2003-04-01

    In this paper, lanthanum-doped TiO2 nanometer film materials coated on glass were prepared in Ti(OBu)4 precursor solutions by sol-gel processing. Transmittance and photocatalytic activity were respectively investigated and tested for these nanometer thin films prepared with different amount of lanthanum (La), different amount of polyethylene glycol (PEG), and different coating layer times. Some reactive mechanisms were also discussed. For one layer La-addition had little effect on the film transmissivity; but the photocatalytic activity was significantly improved due to La-addition. With increasing PEG, the transmittance of the film decreased for one layer film; but its photocatalytic activity did not rise. Increasing layer number did not affect the transmissivity of multilayer film. After coating two times, increasing layer number did not significantly improve the photocatalytic activity. The highest photocatalytic activity and best transmissivity were obtained for two layer TiO2 film when the dosage of lanthanum was 0.5 g and the dosage of polyethylene was 0.2 g in the precursor solutions. These materials will probably be used in the protection of environment, waste water treatment, and air purification.

  17. Photocatalytically active Au/TiO2 films deposited by two-step spray pyrolysis

    International Nuclear Information System (INIS)

    Balashev, Konstantin; Georgiev, Petar; Simeonova, Sylvia; Stambolova, Irina; Blaskov, Vladimir; Vassilev, Sasho; Eliyas, Alexander

    2016-01-01

    Nanocrystalline TiO 2 and surface gold-modified films (Au/TiO 2 ) are obtained by two step spray pyrolysis process. Titanium tetrachloride (TiCl 4 ) was used as inorganic titanium precursor. The Au nanoparticles were deposited on the surface of sprayed TiO 2 films, obtained by the classical Turkevich method. The AFM analyses have revealed that the roughness of Au/TiO 2 is twice lower than that of the reference titania film. Some globular species are visible on the surface, which could be either individual Au nanoparticles or Au nanoparticles’ agglomerates embedded into the TiO 2 film. The photocatalytic activity in the oxidative degradation of Reactive Black 5 dye under visible light of the Au/TiO 2 films was estimated in a semi-batch reactor. Surface gold modified TiO 2 films revealed higher photocatalytic efficiency than the reference sample. Key words: Au nanoparticles, photocatalysis, azo dye, titania, nanosized

  18. Photocatalytic and magnetic behaviors of BiFeO3 thin films deposited on different substrates

    Science.gov (United States)

    Xu, Hao-Min; Wang, Huan-Chun; Shen, Yang; Lin, Yuan-Hua; Nan, Ce-Wen

    2014-11-01

    Single phase polycrystalline BiFeO3 thin films were grown on three different substrates via chemical solution deposition. Our results indicate that the band gap of as-prepared BiFeO3 films can be tuned (2.02-2.67 eV) by the grain size effects caused by the substrates. These BiFeO3 films show good photocatalytic properties by the degradation of Congo red solution under visible-light irradiation ( λ> 400 nm). Additionally, weak ferromagnetic behaviors can be observed at room temperature in all the films, which should be correlated to the destruction of the incommensurate cycloid spin structure of BiFeO3 phase and the coexistence of Fe3+ and Fe2+ as confirmed by X-ray photoelectron spectroscopy.

  19. Kinetic analysis on photocatalytic degradation of gaseous acetaldehyde, ammonia and hydrogen sulfide on nanosized porous TiO2 films

    Directory of Open Access Journals (Sweden)

    Iis Sopyan

    2007-01-01

    Full Text Available The characteristics of the UV illumination-assisted degradation of gaseous acetaldehyde, hydrogen sulfide, and ammonia on highly active nanostructured-anatase and rutile films were investigated. It was found that the anatase film showed a higher photocatalytic activity than the counterpart did, however, the magnitude of difference in the photocatalytic activity of both films decreased in the order ammonia>acetaldehyde>hydrogen sulfide. To elucidate the reasons for the observation, the adsorption characteristics and the kinetics of photocatalytic degradation of the three reactants on both films were analyzed. The adsorption analysis examined using a simple Langmuir isotherm, showed that adsorbability on both films decreased in the order ammonia>acetaldehyde>hydrogen sulfide, which can be explained in terms of the decreasing electron-donor capacity. Acetaldehyde and ammonia adsorbed more strongly and with higher coverage on anatase film (1.2 and 5.6 molecules/nm2, respectively than on rutile (0.6 and 4.7 molecules/nm2, respectively. Conversely, hydrogen sulfide molecules adsorbed more strongly on rutile film (0.7 molecules/nm2 than on anatase (0.4 molecules/nm2. Exposure to UV light illumination brought about the photocatalytic oxidation of the three gases in contact with both TiO2 films, and the decrease in concentration were measured, and their kinetics are analyzed in terms of the Langmuir–Hinshelwood kinetic model. From the kinetic analysis, it was found that the anatase film showed the photocatalytic activities that were factors of ~8 and ~5 higher than the rutile film for the degradation of gaseous ammonia and acetaldehyde, respectively. However, the activity was only a factor of ~1.5 higher for the photodegradation of hydrogen sulfide. These observations are systematically explained by the charge separation efficiency and the adsorption characteristics of each catalyst as well as by the physical and electrochemical properties of each

  20. TiO2 film/Cu2O microgrid heterojunction with photocatalytic activity under solar light irradiation.

    Science.gov (United States)

    Zhang, Junying; Zhu, Hailing; Zheng, Shukai; Pan, Feng; Wang, Tianmin

    2009-10-01

    Coupling a narrow-band-gap semiconductor with TiO(2) is an effective method to produce photocatalysts that work under UV-vis light irradiation. Usually photocatalytic coupled-semiconductors exist mainly as powders, and photocatalytic activity is only favored when a small loading amount of narrow-band-gap semiconductor is used. Here we propose a heavy-loading photocatalyst configuration in which 51% of the surface of the TiO(2) film is covered by a Cu(2)O microgrid. The coupled system shows higher photocatalytic activity under solar light irradiation than TiO(2) and Cu(2)O films. This improved performance is due to the efficient charge transfer between the two phases and the similar opportunity each has to be exposed to irradiation and adsorbates.

  1. Photocatalytic decomposition of diclofenac potassium using silver-modified TiO2 thin films

    International Nuclear Information System (INIS)

    Cavalheiro, A.A.; Bruno, J.C.; Saeki, M.J.; Valente, J.P.S.; Florentino, A.O.

    2008-01-01

    The effects of silver insertion on the TiO 2 photocatalytic activity for the degradation of diclofenac potassium were reported here. Techniques such as X-ray diffraction, scanning electron microscopy and UV-Vis spectroscopy were used to comprehend the relation between structure and properties of the silver-modified TiO 2 thin films obtained by the sol-gel method. The lattice parameters and the crystallinity of TiO 2 anatase phase were affected by inserted silver, and the film thickness increased about 4 nm for each 1 wt.% of silver inserted. The degradation of diclofenac potassium and by-products reached an efficiency of 4.6 mg C W -1 when the material was modified with silver. Although the first step of degradation involves only the photochemical process related to the loss of the chlorine and hydrogen atoms. This cyclization reaction leads to the formation of intermediate, which degradation is facilitated by the modified material

  2. Photocatalytic degradation of Lissamine Green B dye by using nanostructured sol–gel TiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Ćurković, Lidija, E-mail: lcurkov@fsb.hr [Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 5, 10000 Zagreb (Croatia); Ljubas, Davor [Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 5, 10000 Zagreb (Croatia); Šegota, Suzana [Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb (Croatia); Bačić, Ivana [Forensic Science Centre Ivan Vučetić, Ministry of the Interior, Ilica 335, Zagreb (Croatia)

    2014-08-01

    Highlights: • Nanostructured photocatalytic TiO{sub 2} films were prepared by sol–gel methods. • The addition of PEG to the TiO{sub 2} film changes the surface morphology and roughness parameters. • The addition of PEG to the initial sols increases photocatalytic properties of TiO{sub 2}. • LGB water solution could be decolourised within 2 h. • The influence of photolysis and adsorption on the LGB removal from the solution is negligible. - Abstract: Nanostructured sol–gel TiO{sub 2} films were prepared on a glass substrate by means of the dip-coating technique with titanium tetraisopropoxide as a precursor. TiO{sub 2} sols were synthesized with and without the addition of polyethylene glycol (PEG) as a structure-directing agent. The synthesized sol–gel TiO{sub 2} were characterized by XRD, AFM, FTIR and Micro-Raman spectroscopy. The photocatalytic activity of the films was evaluated by the photocatalytic degradation of Lissamine Green B (LGB) dye (dissolved in water) as a model pollutant with the predominant irradiation wavelength of 365 nm (UV-A). It was found that the addition of PEG to the initial sol affects the surface morphology and the photocatalytic properties of prepared sol–gel TiO{sub 2} films. AFM analysis confirmed the presence of nanostructured sol–gel titania films on the glass substrate. Roughness parameters (R{sub a}, R{sub q}, and Z{sub max}) of the sol–gel TiO{sub 2} film with the addition of PEG are higher than the parameters of the sol–gel TiO{sub 2} film without the addition of PEG. The TiO{sub 2} film prepared with the addition of PEG has a higher surface density (a larger active surface area) and better photocatalytic activity in the degradation of the LGB dye solution than the TiO{sub 2} film prepared without the addition of PEG.

  3. Photocatalytic activity and stability of TiO{sub 2} and WO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Carcel, Radu Adrian; Andronic, Luminita, E-mail: andronic-luminita@unitbv.ro; Duta, Anca, E-mail: a.duta@unitbv.ro

    2012-08-15

    Photocatalysis represents a viable option for complete degrading the dye molecules resulted in the textile industry, up to products that do not represent environmental threats. The photocatalytic degradation of methyl orange has been investigated using TiO{sub 2}, WO{sub 3} and mixed thin films. The photodegradation efficiency is examined in correlation with the experimental parameters (irradiation time, H{sub 2}O{sub 2} addition and stability), along with the morphology and crystallinity data. The H{sub 2}O{sub 2} addition increases the photodegradation efficiency by providing additional hydroxyl groups and further reducing the recombination of the electron-hole pairs by reacting with the electrons at the catalyst interface. To test the stability of the photocatalytic films in long time running processes, batch series of experiments were conducted using contact periods up to 9 days. The results show that the thin films maintained their photocatalytic properties confirming their stability and viability for up-scaling. Highlights: Black-Right-Pointing-Pointer TiO{sub 2}, WO{sub 3} and mixed thin films Black-Right-Pointing-Pointer We tested the photocatalytic activity and photocatalyst stability over a period up to 9 days of continuous irradiation. Black-Right-Pointing-Pointer The influence of medium pH and oxidizing agent (H{sub 2}O{sub 2}) was analyzed.

  4. Morphology-tailored synthesis of tungsten trioxide (hydrate) thin films and their photocatalytic properties.

    Science.gov (United States)

    Jiao, Zhihui; Wang, Jinmin; Ke, Lin; Sun, Xiao Wei; Demir, Hilmi Volkan

    2011-02-01

    Tungsten trioxide hydrate (3WO(3)·H(2)O) films with different morphologies were directly grown on fluorine doped tin oxide (FTO) substrate via a facile crystal-seed-assisted hydrothermal method. Scanning electron microscopy (SEM) analysis showed that 3WO(3)·H(2)O thin films composed of platelike, wedgelike, and sheetlike nanostructures could be selectively synthesized by adding Na(2)SO(4), (NH(4))(2)SO(4), and CH(3)COONH(4) as capping agents, respectively. X-ray diffraction (XRD) studies indicated that these films were of orthorhombic structure. The as-prepared thin films after dehydration showed obvious photocatalytic activities. The best film grown using CH(3)COONH(4) as a capping agent generated anodic photocurrents of 1.16 mA/cm(2) for oxidization of methanol and 0.5 mA/cm(2) for water splitting with the highest photoconversion efficiency of about 0.3% under simulated solar illumination.

  5. Photocatalytical Decomposition of Contaminants on Thin Film Gas Sensors

    International Nuclear Information System (INIS)

    Radecka, M.; Lyson, B.; Lubecka, M.; Czapla, A.; Zakrzewska, K.

    2010-01-01

    Gas sensing materials have been prepared in a form of TiO 2 -SnO 2 thin films by rf reactive sputtering from Ti:SnO 2 and Sn:TiO 2 targets. Material studies have been performed by scanning electron microscopy, atomic force microscopy, X-ray diffraction at grazing incidence, Moessbauer spectroscopy, X-ray photoelectron spectroscopy and optical spectrophotometry. Dynamic gas sensing responses have been recorded as reproducible changes in the electrical resistance upon introduction of hydrogen at a partial pressure of 100-6000 ppm over a wide temperature range 473-873 K. Contamination experiments have been carried out with the motor oil (40 vol.% solution in CCl 4 ) in order to study the effect of UV light illumination on the gas sensor response. Optical spectroscopy has been applied to monitor the photodecomposition of the test compound, bromothymol blue. The Electronic Nose, ALPHA MOS FOX 4000 has been used in order to differentiate between different groups of motor oil vapors. (author)

  6. Photocatalytical Antibacterial Activity of Mixed-Phase TiO2 Nanocomposite Thin Films against Aggregatibacter actinomycetemcomitans

    Directory of Open Access Journals (Sweden)

    Sinem Yeniyol

    2015-01-01

    Full Text Available Mixed-phase TiO2 nanocomposite thin films consisting of anatase and rutile prepared on commercially pure Ti sheets via the electrochemical anodization and annealing treatments were investigated in terms of their photocatalytic activity for antibacterial use around dental implants. The resulting films were characterized by scanning electron microscopy (SEM, and X-ray diffraction (XRD. The topology was assessed by White Light Optical Profiling (WLOP in the Vertical Scanning Interferometer (VSI mode. Representative height descriptive parameters of roughness Ra and Rz were calculated. The photocatalytic activity of the resulting TiO2 films was evaluated by the photodegradation of Rhodamine B (RhB dye solution. The antibacterial ability of the photocatalyst was examined by  Aggregatibacter actinomycetemcomitans suspensions in a colony-forming assay. XRD showed that anatase/rutile mixed-phase TiO2 thin films were predominantly in anatase and rutile that were 54.6 wt% and 41.9 wt%, respectively. Craters (2–5 µm and protruding hills (10–50 µm on Ti substrates were produced after electrochemical anodization with higher Ra and Rz surface roughness values. Anatase/rutile mixed-phase TiO2 thin films showed 26% photocatalytic decolorization toward RhB dye solution. The number of colonizing bacteria on anatase/rutile mixed-phase TiO2 thin films was decreased significantly in vitro. The photocatalyst was effective against A. actinomycetemcomitans colonization.

  7. Synthesis and characterization of Ag doped TiO{sub 2} heterojunction films and their photocatalytic performances

    Energy Technology Data Exchange (ETDEWEB)

    Demirci, Selim, E-mail: selim.demirci@marmara.edu.tr [Marmara University, Department of Metallurgical and Materials Engineering, Kadiköy, 34722 Istanbul (Turkey); Dikici, Tuncay [Izmir Katip Celebi University, Department of Materials Science and Engineering, Cigli, 35620 Izmir (Turkey); Yurddaskal, Metin [Department of Metallurgical and Materials Engineering, Dokuz Eylul University, 35390 Izmir (Turkey); Center for Fabrication and Application of Electronic Materials, Dokuz Eylul University, 35390 Izmir (Turkey); Gultekin, Serdar [Department of Nanoscience and Nanoengineering, Dokuz Eylul University, 35390 İzmir (Turkey); Experimental Science Applications and Research Center, Celal Bayar University, 45140 Manisa (Turkey); Toparli, Mustafa; Celik, Erdal [Department of Metallurgical and Materials Engineering, Dokuz Eylul University, 35390 Izmir (Turkey); Department of Nanoscience and Nanoengineering, Dokuz Eylul University, 35390 İzmir (Turkey); Center for Fabrication and Application of Electronic Materials, Dokuz Eylul University, 35390 Izmir (Turkey)

    2016-12-30

    Highlights: • Ag doped TiO{sub 2} films were successfully synthesized by sol–gel spin coating method. • Ag in TiO{sub 2} lattice enters in intermediate states to decrease TiO{sub 2} bandgap energy. • Ag dopants increase the photoactivity and superhydrophilicity. • The degradation kinetics of methylene blue was studied. • The 0.7 mol% of Ag was found to be the optimum concentration. - Abstract: In this study, undoped and silver (Ag) doped titanium dioxide (TiO{sub 2}) films were successfully synthesized by sol-gel spin coating technique on the Si substrates. Photocatalytic activities of the TiO{sub 2} films with different Ag content were investigated for the degradation of methylene blue (MB) under UV light irradiation. The crystal phase structure, surface morphology, chemical and optical properties of Ag-doped TiO{sub 2} films were characterized using an X-ray diffractometer (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–vis spectrophotometer, and FTIR spectrophotometer. The results showed that the Ag-doped TiO{sub 2} films calcined at 500 °C had the crystalline anatase phases and the surface morphologies with some cracks. Ag substitution into TiO{sub 2} matrix enhanced the photocatalytic activity of TiO{sub 2} films under UV light irradiation as compared to the undoped TiO{sub 2} film. Furthermore, the results indicated that the 0.7% Ag doped TiO{sub 2} film exhibited a superior photocatalytic activity than that of undoped and other Ag-doped TiO{sub 2} films. This study demonstrated the potential of an application of Ag doped films to efficiently treat dissolved organic contaminants in water.

  8. Preparation and characterization of photocatalytic performance of hierarchical heterogeneous nanostructured ZnO/TiO2 films made by DC magnetron sputtering

    International Nuclear Information System (INIS)

    Le Phuc Quy; Vu Thi Hanh Thu

    2013-01-01

    With the aim to enhance photocatalytic properties and anti-Ecoli bacteria abilities of TiO 2 thin films; hierarchical heterogeneous nanostructured ZnO/TiO 2 (HN s ) films were deposited by DC magnetron sputtering. The obtained results showed that both the photocatalytic performance and anti-Ecoli bacteria ability of HN s films exhibited enhancement in comparison with standard TiO 2 films. This enhancement was explained due to the reduction of the electron - hole recombination and the red shift of absorption edge of the HNs films. (author)

  9. Preparation of mesoporous Ag-containing TiO{sub 2} heterojunction film and its photocatalytic property

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Q. Y., E-mail: wangqingyao0532@163.com [Ludong University, School of Chemistry and Materials Science (China); Qiao, J. L. [Jilin Agricultural University, College of Horticulture (China); Cui, X. Y. [Mudanjiang Medical University, School of Public Health (China); Zhong, J. S. [Hangzhou Dianzi University, College of Materials and Environmental Engineering (China); Xu, Y. B.; Zhang, S. H.; Zhang, Q. H.; Chang, P.; Li, M.; Zhang, C.; Gao, S. M., E-mail: gaosm@ustc.edu [Ludong University, School of Chemistry and Materials Science (China)

    2015-03-15

    Mesoporous Ag/TiO{sub 2} heterojunction films (Ag-MTHF) with enhanced photocatalytic activity were synthesized by a three-step approach including an electrochemical anodization technique followed by successive ionic layer adsorption and reaction (SILAR) and solvothermal methods. The distribution of Ag nanoparticles on the inner structure of the mesoporous TiO{sub 2} film was confirmed by field emission scanning electron (FE-SEM) and transmission electron microscopes (TEM). The formation progress of the novel mesoporous Ag/TiO{sub 2} nanojunction film with Ag average diameter of 17 nm was illuminated. The formed nanojunction between Ag and TiO{sub 2} nanoparticles largely enhanced the photocatalytic degradation of methyl orangey (MO), and the corresponding mechanism was proposed.

  10. Microwave-assisted synthesis of TiO2 nanoparticles: photocatalytic activity of powders and thin films

    Science.gov (United States)

    Falk, G. S.; Borlaf, M.; López-Muñoz, M. J.; Fariñas, J. C.; Rodrigues Neto, J. B.; Moreno, R.

    2018-02-01

    A simple, rapid, and effective synthesis methodology for the preparation of high-performance TiO2 nanoparticles and thin films by combining colloidal sol-gel and microwave-assisted hydrothermal synthesis was developed. The obtained results indicate that the heating with microwaves at 180 °C for 20 min was enough to synthesize crystalline TiO2 nanoparticles, presenting anatase as a major phase with a crystal size of 7 nm and a specific surface area of 220 m2 g-1. A secondary thermal treatment improved the crystallinity and induced the anatase-to-rutile transformation. The highest photocatalytic activity was found for the as-synthesized powder without any additional thermal treatment. Thin films were also prepared by dip-coating and its high photocatalytic activity showed a kinetic curve comparable to that of a thin film of commercial TiO2 powder prepared under similar conditions.

  11. I-TiO2/PVC film with highly photocatalytic antibacterial activity under visible light.

    Science.gov (United States)

    Deng, Weihua; Ning, Shangbo; Lin, Qianying; Zhang, Hualei; Zhou, Tanghua; Lin, Huaxiang; Long, Jinlin; Lin, Qun; Wang, Xuxu

    2016-08-01

    Iodine-modified TiO2(I-TiO2) film were coated on medical-grade PVC material by impregnation-deposition method and subsequently characterized by XRD, SEM, TEM, AFM, DRS and XPS. The photocatalytic anti-bacterial activity of I-TiO2/PVC was investigated both by in vitro anti-bacterial experiments and by clinical study. The results revealed that I-TiO2/PVC exhibit excellent photocatalytic antibacterial activity, which can destroy the propagation of the Escherichia coli and cause the deactivation and death of most E. coli bacteria within 30min visible light illumination. Clinical study on animals showed that I-TiO2 coated on PVC decrease the formation of biofilm on PVC surface in the mechanical ventilation. Furthermore, I-TiO2/PVC can effectively reduce inflammation of tracheal tissue of bam suckling pig and prevents the occurrence of VAP. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. The immobilization of titania nanoparticles on hyaluronan films and their photocatalytic properties

    International Nuclear Information System (INIS)

    Pasqui, Daniela; Atrei, Andrea; Barbucci, Rolando

    2009-01-01

    We have developed a method to bind titania nanoparticles onto hyaluronic films (HA) photoimmobilized on silanized glass. Titania nanoparticles were deposited on the HA films from commercially available dispersions by casting and dip-coating methods at various pH values. XPS was used to monitor the deposition of titania and to estimate the surface coverage of the nanoparticles. The topography of the titania-modified HA films was investigated by means of AFM. XPS results indicate that the titania surface coverage depends on the preparation method and the pH of the dispersion. We found that the maximum titania nanoparticle surface coverage was obtained by the casting method with the formation of aggregates and multilayers of particles. The titania surface coverage for the surfaces prepared by the dip-coating method is pH-dependent. The surfaces prepared at pH 2 show a surface coverage of 65% and a rather uniform distribution of particles. We found that titania nanoparticles are anchored in a stable way to the HA substrate in a phosphate buffer solution (PBS) and that the interaction between the HA and the titania is through the carbonyl group of carboxylates and amidic groups of the polymer. AFM images clearly show that titania nanoparticles are uniformly distributed over the HA films. By measuring the average diameter and the average height of the nanoparticles deposited on HA films it appears that the particles are partially embedded in the polysaccharide films. The results of the study on the photobleaching of methylene blue indicate that the characteristic photocatalytic activity of titania is maintained when the nanoparticles are anchored to the HA substrate.

  13. Photocatalytic degradation of dimethoate using LbL fabricated TiO2/polymer hybrid films.

    Science.gov (United States)

    Priya, D Neela; Modak, Jayant M; Trebše, Polonca; Zabar, Romina; Raichur, Ashok M

    2011-11-15

    Degradation of dimethoate under UV irradiation using TiO(2)/polymer films prepared by the layer-by-layer (LbL) method was investigated. The thin films were fabricated on glass slides and the surface morphology and roughness of the thin films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The effect of lamp intensity, catalyst loading in the layers, number of bilayers, pH and initial dimethoate concentration on the degradation of dimethoate was systematically studied. The degradation was monitored using high performance liquid chromatography (HPLC) analysis and total organic carbon (TOC) measurements as a function of irradiation time, to see the change in concentration of dimethoate and mineralization, respectively. Complete degradation of dimethoate was achieved under TiO(2) optimum loading of 4 g/L at an UV irradiation time of 180 min. Increase in the lamp intensity, catalyst loading and number of bilayers increased the rate of degradation. At a pH of 4.62, complete degradation of dimethoate was observed. The degradation efficiency decreased with increase in initial dimethoate concentration. The degradation byproducts were analyzed and confirmed by gas chromatography-mass spectra (GC-MS). Toxicity of the irradiated samples was measured using the luminescence of bacteria Vibrio fischeri after 30 min of incubation and the results showed more toxicity than the parent compound. Catalyst reusability studies revealed that the fabricated thin films could be repeatedly used for up to ten times without affecting the photocatalytic activity of the films. The findings of the present study are very useful for the treatment of wastewaters contaminated with pesticides. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Efficient photocatalytic decolorization of some textile dyes using Fe ions doped polyaniline film on ITO coated glass substrate.

    Science.gov (United States)

    Haspulat, Bircan; Gülce, Ahmet; Gülce, Handan

    2013-09-15

    In this study, the photocatalytic decolorization of four commercial textile dyes with different structures has been investigated using electrochemically synthesized polyaniline and Fe ions doped polyaniline on ITO coated glass substrate as photocatalyst in aqueous solution under UV irradiation for the first time. Scanning electron microscopy, atomic force microscopy, FT-IR spectra, UV-vis spectroscopy measurements were used to characterize the electrochemically synthesized polymer film photocatalyst. Film hydrophilicity was assessed from contact angle measurements. The results show that both of the polymer films exhibit good photocatalytic performance. Surprisingly, it was determined that by using Fe(II) ions during polymerization, it is possible to modify the surface roughness and wettability of the produced polyaniline films which favors their photocatalytic activity in water-based solutions. All four of the used dyes (methylene blue, malachite green, methyl orange and methyl red) were completely decolorizated in 90 min of irradiation under UV light by using Fe ions doped polyaniline at the dye concentration of 1.5 × 10(-5)M, while the decolorization of those dyes were between 43% and 83% by using polyaniline as photocatalyst. Hence, it may be a viable technique for the safe disposal of textile wastewater into waste streams. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Highly Transparent Poly(vinyl alcohol)(PVA)/TiO₂ Nanocomposite Films with Remarkable Photocatalytic Performance and Recyclability.

    Science.gov (United States)

    Yan, Wenwen; Chen, Qirong; Du, Mengfan; Yang, Kai Meng; Cai, Xinxin; Meng, Xiangfu; Wang, Lei

    2018-08-01

    Titanium dioxide (TiO2) has been regarded as an efficient photocatalyst for degradation of environmental pollutants. However, recovery of TiO2 nanoparticles from suspension limits its practical application. Herein, we reported a novel highly transparent poly(vinyl alcohol)(PVA)/TiO2 photocatalytic film via in-situ growth and solution casting method. TiO2 nanoparticles with average size of 10 nm were uniformly dispersed in transparent PVA matrix. The photocatalytic performance was investigated by photodegradation of methyl orange (MO) aqueous solution under solar light irradiation. PVA/TiO2 photocatalytic film exhibited remarkably high photocatalytic activity and excellent recyclable properties during multi-cycle use. PVA not only acted as a transparent supports for TiO2, but also worked as an efficient holes scavenger. The hydroxyl groups on PVA chains played a key role in separation of photo-generated electrons and holes, thus increased the photodegradation rate of MO. This work gives an easy and reliable way for polymer/TiO2 nanocomposites in practical environmental applications.

  16. Photocatalytic decomposition of diclofenac potassium using silver-modified TiO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Cavalheiro, A.A. [Depto de Quimica - Instituto de Biociencias - UNESP, Distrito de Rubiao Junior, s/n, Zip Code 18.618-000, P.O. Box 510, Botucatu, SP (Brazil)], E-mail: albecava@bol.com.br; Bruno, J.C.; Saeki, M.J.; Valente, J.P.S.; Florentino, A.O. [Depto de Quimica - Instituto de Biociencias - UNESP, Distrito de Rubiao Junior, s/n, Zip Code 18.618-000, P.O. Box 510, Botucatu, SP (Brazil)

    2008-07-31

    The effects of silver insertion on the TiO{sub 2} photocatalytic activity for the degradation of diclofenac potassium were reported here. Techniques such as X-ray diffraction, scanning electron microscopy and UV-Vis spectroscopy were used to comprehend the relation between structure and properties of the silver-modified TiO{sub 2} thin films obtained by the sol-gel method. The lattice parameters and the crystallinity of TiO{sub 2} anatase phase were affected by inserted silver, and the film thickness increased about 4 nm for each 1 wt.% of silver inserted. The degradation of diclofenac potassium and by-products reached an efficiency of 4.6 mg{sub C} W{sup -1} when the material was modified with silver. Although the first step of degradation involves only the photochemical process related to the loss of the chlorine and hydrogen atoms. This cyclization reaction leads to the formation of intermediate, which degradation is facilitated by the modified material.

  17. Photocatalytic Activity and Stability of Porous Polycrystalline ZnO Thin-Films Grown via a Two-Step Thermal Oxidation Process

    Directory of Open Access Journals (Sweden)

    James C. Moore

    2014-08-01

    Full Text Available The photocatalytic activity and stability of thin, polycrystalline ZnO films was studied. The oxidative degradation of organic compounds at the ZnO surface results from the ultraviolet (UV photo-induced creation of highly oxidizing holes and reducing electrons, which combine with surface water to form hydroxyl radicals and reactive oxygen species. Therefore, the efficiency of the electron-hole pair formation is of critical importance for self-cleaning and antimicrobial applications with these metal-oxide catalyst systems. In this study, ZnO thin films were fabricated on sapphire substrates via direct current sputter deposition of Zn-metal films followed by thermal oxidation at several annealing temperatures (300–1200 °C. Due to the ease with which they can be recovered, stabilized films are preferable to nanoparticles or colloidal suspensions for some applications. Characterization of the resulting ZnO thin films through atomic force microscopy and photoluminescence indicated that decreasing annealing temperature leads to smaller crystal grain size and increased UV excitonic emission. The photocatalytic activities were characterized by UV-visible absorption measurements of Rhodamine B dye concentrations. The films oxidized at lower annealing temperatures exhibited higher photocatalytic activity, which is attributed to the increased optical quality. Photocatalytic activity was also found to depend on film thickness, with lower activity observed for thinner films. Decreasing activity with use was found to be the result of decreasing film thickness due to surface etching.

  18. Photocatalytic degradation of organic contaminants by g-C3N4/EPDM nanocomposite film: Viable, efficient and facile recoverable.

    Science.gov (United States)

    Selvam, V; Senthil Kumar, P; Navaneetha Krishnan, G; Senthil Andavan, G T

    2018-03-01

    The original metal free graphitic carbon nitride/ethylene propylene diene monomer nanocomposite film (g-C 3 N 4 /EPDM NCF) was fabricated by facile solution cast method. g-C 3 N 4 /EPDM NCF with diameter (50mm) and thickness (4mm) was investigated towards the photocatalytic degradation of methylene blue (MB) and methyl orange (MO) dye solution under visible light irradiation. The as synthesized g-C 3 N 4 /EPDM NCF was exhibited high crystalline nature with the crystalline size of 21.53nm, the smooth surface nature and the particle size was observed from the TEM analysis is 20nm. Furthermore, the influence of operational parameters was carried out which demonstrated that 100mg photocatalyst and 25μM of dye concentration were obtained as an optimized condition for the best photocatalytic degradation results. As a result of scavenger experiment, it was concluded that the hydroxyl radical (OH) was actively involved in the photocatalytic degradation. The g-C 3 N 4 /EPDM NCF were recoverable from the photocatalytic reaction system and the present find findings may open up a new platform for the simple handpicked photocatalyst. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Photocatalytic hydroxyapatite/titanium dioxide multilayer thin film deposited onto glass using an rf magnetron sputtering technique

    Science.gov (United States)

    Ozeki, K.; Janurudin, Juliana M.; Aoki, H.; Fukui, Y.

    2007-01-01

    Hydroxyapatite (HA)/titanium dioxide (TiO2) thin film was deposited on glass using a radio frequency magnetron sputtering. X-ray diffraction (XRD), Fourier-transform infrared spectrometry, ultraviolet-visible spectroscopy and measurement of its photocatalytic activity by the decomposition of formaldehyde gas and the bacterial survival test of Escherichia coli (E. coli) cells were applied to characterize the film. After heat treatment (at 500 °C), XRD analysis of the HA/TiO2 film showed a crystalline TiO2 crystal structure with anatase phase. The transmittance of the HA/TiO2 film decreased after the heat treatment, however, the average transmittance remained at 87% in the visible light range. In the decomposition of formaldehyde gas, the HA/TiO2 film showed a higher decomposition rate than either the TiO2 or the HA film alone. However, in the bacterial survival test, survival of cells on the HA/TiO2 film was higher than that on the TiO2 film, which indicates the HA/TiO2 film has a lower bactericidal effect than the TiO2 film alone.

  20. Synthesis of Ag ion-implanted TiO{sub 2} thin films for antibacterial application and photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xinggang, E-mail: hou226@mail.tjnu.edu.cn [Department of Physics, Tianjin Normal University, Tianjin 300387 (China); Ma, Huiyan; Liu, Feng; Deng, Jianhua; Ai, Yukai; Zhao, Xinlei; Mao, Dong; Li, Dejun [Department of Physics, Tianjin Normal University, Tianjin 300387 (China); Liao, Bin [Key Laboratory of Beam Technology and Material Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China)

    2015-12-15

    Highlights: • Implanted TiO{sub 2} films with excellent antibacterial and photocatalytic ability was prepared. • Bactericidal effect of released Ag ions was confirmed using VC as radical scavenger. • Excitation of TiO{sub 2} to visible region is attributed to subtitutional Ag. • Synergetic effect of Ag{sup 3+} and Ag{sup +} accounts for the enhanced ability of TiO{sub 2}. - Abstract: TiO{sub 2} thin films were deposited by spin coating method. Silver ions were implanted into the films using a Metal Vapor Vacuum Arc implanter. The antibacterial ability of implanted films was tested using Escherichia coli removal under fluorescent irradiation and in the dark. The concentration of E. coli was evaluated by plating technique. The photocatalytic efficiency of the implanted films was studied by degradation of methyl orange under fluorescent illumination. The surface free energy of the implanted TiO{sub 2} films was calculated by contact angle testing. Vitamin C was used as radical scavengers to explore the antibacterial mechanism of the films. The results supported the model that both generation of reactive oxygen species and release of silver ions played critical roles in the toxic effect of implanted films against E. coli. XPS experimental results demonstrated that a portion of the Ag(Ag{sup 3+}) ions were doped into the crystalline lattice of TiO{sub 2}. As demonstrated by density functional theory calculations, the impurity energy level of subtitutional Ag was responsible for enhanced absorption of visible light. Ag ion-implanted TiO{sub 2} films with excellent antibacterial efficiency against bacteria and decomposed ability against organic pollutants could be potent bactericidal surface in moist environment.

  1. Self-organized nanocrack networks: a pathway to enlarge catalytic surface area in sputtered ceramic thin films, showcased for photocatalytic TiO2

    Science.gov (United States)

    Henkel, B.; Vahl, A.; Aktas, O. C.; Strunskus, T.; Faupel, F.

    2018-01-01

    Sputter deposited photocatalytic thin films offer high adherence and mechanical stability, but typically are outperformed in their photocatalytic properties by colloidal TiO2 nanostructures, which in turn typically suffer from problematic removal. Here we report on thermally controlled nanocrack formation as a feasible and batch applicable approach to enhance the photocatalytic performance of well adhering, reactively sputtered TiO2 thin films. Networks of nanoscopic cracks were induced into tailored columnar TiO2 thin films by thermal annealing. These deep trenches are separating small bundles of TiO2 columns, adding their flanks to the overall catalytically active surface area. The variation of thin film thickness reveals a critical layer thickness for initial nanocrack network formation, which was found to be about 400 nm in case of TiO2. The columnar morphology of the as deposited TiO2 layer with weak bonds between respective columns and with strong bonds to the substrate is of crucial importance for the formation of nanocrack networks. A beneficial effect of nanocracking on the photocatalytic performance was experimentally observed. It was correlated by a simple geometric model for explaining the positive impact of the crack induced enlargement of active surface area on photocatalytic efficiency. The presented method of nanocrack network formation is principally not limited to TiO2 and is therefore seen as a promising candidate for utilizing increased surface area by controlled crack formation in ceramic thin films in general.

  2. Electrochemical and structural characterization of nanocomposite Agy:TiNx thin films for dry bioelectrodes: the effect of the N/Ti ratio and Ag content

    International Nuclear Information System (INIS)

    Pedrosa, P.; Machado, D.; Fiedler, P.; Alves, E.; Barradas, N.P.; Haueisen, J.; Vaz, F.; Fonseca, C.

    2015-01-01

    Highlights: • Ag y :TiN x thin films were sputtered with different N/Ti atomic ratios and Ag contents. • The electroactive area increases (1000-fold) with increasing N/Ti atomic ratios. • The films display impedances <10 kΩ at the 1–50 Hz interval (EEG range). • No Ag surface segregation was visible in the under-stoichiometric samples. • The samples with N/Ti atomic ratio = 0.3 (15 at.% Ag) and 0.7 (32 at.% Ag) are the most appropriate for bioelectrode applications. - ABSTRACT: Ag y :TiN x nanocomposite thin films sputtered with different N/Ti atomic ratios and Ag atomic contents were characterized from the structural and morphological points of view. Their electrochemical behaviour was studied in a synthetic sweat solution, aiming at selecting a suitable material for biolectrode applications. An increase of the N/Ti atomic ratio, which is accompanied by an increase of the Ag atomic content, leads to a substantial increase of the roughness and porosity of the samples, especially for N/Ti ratios >0.2. For N/Ti atomic ratios up to 0.3 (15 at.% Ag) no metallic Ag segregation is visible in the TiN x matrix. Hence, the possible formation of TiAg and Ti 2 Ag intermetallics or even a Ag/TiAg/Ti 2 Ag phase mixture, although not demonstrated, should not be disregarded. As for the N/Ti atomic ratio = 0.7 (32 at.% Ag) sample, the Ag phases are predominantly concentrated near the interface with the substrate. The amount of Ag phases at the surface of the films remains somewhat low for all TiN under-stoichiometric films, even for Ag atomic contents up to 32 at.%. When the TiN x matrix reaches the stoichiometric condition (sample with N/Ti atomic ratio = 1 and 20 at.% Ag), Ag segregation occurs and metallic Ag aggregates are visible at the surface of the film, leading to a substantially different electrochemical behaviour. The impedance of the Ag y :TiN x films in synthetic sweat solution is mainly ruled by the roughness/porosity variation, thus the higher the N

  3. The Photocatalytic Activity and Compact Layer Characteristics of TiO2 Films Prepared Using Radio Frequency Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    H. C. Chang

    2014-01-01

    Full Text Available TiO2 compact layers are used in dye-sensitized solar cells (DSSCs to prevent charge recombination between the electrolyte and the transparent conductive substrate (indium tin oxide, ITO; fluorine-doped tin oxide, FTO. Thin TiO2 compact layers are deposited onto ITO/glass by means of radio frequency (rf magnetron sputtering, using deposition parameters that ensure greater photocatalytic activity and increased DSSC conversion efficiency. The photoinduced decomposition of methylene blue (MB and the photoinduced hydrophilicity of the TiO2 thin films are also investigated. The photocatalytic performance characteristics for the deposition of TiO2 films are improved by using the Grey-Taguchi method. The average transmittance in the visible region exceeds 85% for all samples. The XRD patterns of the TiO2 films, for sol-gel with spin coating of porous TiO2/TiO2 compact/ITO/glass, show a good crystalline structure. In contrast, without the TiO2 compact layer (only porous TiO2, the peak intensity of the anatase (101 plane in the XRD patterns for the TiO2 film has a lower value, which demonstrates inferior crystalline quality. With a TiO2 compact layer to prevent charge recombination, a higher short-circuit current density is obtained. The DSSC with the FTO/glass and Pt counter electrode demonstrates the energy conversion efficiency increased.

  4. Photocatalytic activity of erbium-doped TiO{sub 2} nanoparticles immobilized in macro-porous silica films

    Energy Technology Data Exchange (ETDEWEB)

    Castaneda-Contreras, J., E-mail: jcc050769@yahoo.com.mx [C.U. de los Lagos, Universidad de Guadalajara, Lagos de Moreno, Jalisco (Mexico); Maranon-Ruiz, V.F.; Chiu-Zarate, R.; Perez-Ladron de Guevara, H.; Rodriguez, R. [C.U. de los Lagos, Universidad de Guadalajara, Lagos de Moreno, Jalisco (Mexico); Michel-Uribe, C. [C. U. de Ciencias Exactas e Ingenieria, Universidad de Guadalajara, Guadalajara, Jalisco (Mexico)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Erbium-doped TiO{sub 2} nanoparticles were immobilized on macro-porous silica films. Black-Right-Pointing-Pointer The films were obtained by a phase separation process. Black-Right-Pointing-Pointer The samples exhibited photo-catalytic activity under visible light. Black-Right-Pointing-Pointer The sensitization of TiO{sub 2} was attributed to a red shift in the TiO{sub 2} band-gap. -- Abstract: A macro-porous silica film served as mechanical support to immobilize TiO{sub 2} nanoparticles, which were doped with erbium. The films and the nanoparticles were prepared by sol-gel route. The nanoparticles exhibited photocatalytic activity under visible light. We obtained a degradation rate of methylene blue that followed first order kinetics. The sensitization of the nanoparticles to visible light was attributed to a red shift in the band-gap of the TiO{sub 2} due to the addition of erbium ions.

  5. High photocatalytic degradation activity of the polyvinyl chloride (PVC)-vitamin C (VC)-TiO2 nano-composite film.

    Science.gov (United States)

    Yang, Changjun; Gong, Chuqing; Peng, Tianyou; Deng, Kejian; Zan, Ling

    2010-06-15

    A novel photodegradable polyvinyl chloride (PVC)-vitamin C (VC)-TiO(2) nano-composite film was prepared by embedding VC modified nano-TiO(2) photocatalyst into the commercial PVC plastic. The solid-phase photocatalytic degradation behavior of PVC-VC-TiO(2) nano-composite film under UV light irradiation was investigated and compared with those of the PVC-TiO(2) film and the pure PVC film, with the aid of UV-Vis spectroscopy, scanning electron microscopy (SEM), weight loss monitoring, and X-ray diffraction spectra (XRD). The results show that PVC-VC-TiO(2) nano-composite film has a high photocatalytic activity; the photocatalytic degradation rate of it is two times higher than that of PVC-TiO(2) film and fifteen times higher than that of pure PVC film. The optimal mass ratio of VC to TiO(2) is found to be 0.5. The mechanism of enhancing photocatalytic activity is attributed to the formation of a Ti(IV)-VC charge-transfer complex with five-member chelate ring structure and a rapid photogenerated charge separation is thus achieved. Copyright 2010 Elsevier B.V. All rights reserved.

  6. Synthesis of Ag ion-implanted TiO2 thin films for antibacterial application and photocatalytic performance.

    Science.gov (United States)

    Hou, Xinggang; Ma, Huiyan; Liu, Feng; Deng, Jianhua; Ai, Yukai; Zhao, Xinlei; Mao, Dong; Li, Dejun; Liao, Bin

    2015-12-15

    TiO2 thin films were deposited by spin coating method. Silver ions were implanted into the films using a Metal Vapor Vacuum Arc implanter. The antibacterial ability of implanted films was tested using Escherichia coli removal under fluorescent irradiation and in the dark. The concentration of E. coli was evaluated by plating technique. The photocatalytic efficiency of the implanted films was studied by degradation of methyl orange under fluorescent illumination. The surface free energy of the implanted TiO2 films was calculated by contact angle testing. Vitamin C was used as radical scavengers to explore the antibacterial mechanism of the films. The results supported the model that both generation of reactive oxygen species and release of silver ions played critical roles in the toxic effect of implanted films against E. coli. XPS experimental results demonstrated that a portion of the Ag(Ag(3+)) ions were doped into the crystalline lattice of TiO2. As demonstrated by density functional theory calculations, the impurity energy level of subtitutional Ag was responsible for enhanced absorption of visible light. Ag ion-implanted TiO2 films with excellent antibacterial efficiency against bacteria and decomposed ability against organic pollutants could be potent bactericidal surface in moist environment. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. PHOTOCATALYTIC PROPERTIES OF Cr DOPED TiO2–SiO2 NANOSTRUCTURE THIN FILM

    Directory of Open Access Journals (Sweden)

    Akbar Eshaghi

    2012-07-01

    Full Text Available Cr doped TiO2–SiO2 nanostructure thin film on glass substrates was prepared by a sol-gel dip coating method. X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS and UV-vis spectrophotometer were used to characterize the structural, chemical and optical properties of the thin film. The XRD showed that thin films contain only anatase phase. FE-SEM images illustrated that anatase average crystallite size in the pure TiO2 and Cr doped TiO2–SiO2 thin films are 15 nm and 10 nm, respectively. XPS spectra confirmed the presence of Cr3+ in the thin film. UV-vis absorption spectra indicated that absorption edge in Cr doped TiO2–SiO2 thin film shifted to the visible light region. The photocatalytic results pointed that Cr doping in TiO2–SiO2 improved decoloring rate of methyl orange in comparison to pure TiO2 thin film.

  8. Photocatalytic Anatase TiO2 Thin Films on Polymer Optical Fiber Using Atmospheric-Pressure Plasma.

    Science.gov (United States)

    Baba, Kamal; Bulou, Simon; Choquet, Patrick; Boscher, Nicolas D

    2017-04-19

    Due to the undeniable industrial advantages of low-temperature atmospheric-pressure plasma processes, such as low cost, low temperature, easy implementation, and in-line process capabilities, they have become the most promising next-generation candidate system for replacing thermal chemical vapor deposition or wet chemical processes for the deposition of functional coatings. In the work detailed in this article, photocatalytic anatase TiO 2 thin films were deposited at a low temperature on polymer optical fibers using an atmospheric-pressure plasma process. This method overcomes the challenge of forming crystalline transition metal oxide coatings on polymer substrates by using a dry and up-scalable method. The careful selection of the plasma source and the titanium precursor, i.e., titanium ethoxide with a short alkoxy group, allowed the deposition of well-adherent, dense, and crystalline TiO 2 coatings at low substrate temperature. Raman and XRD investigations showed that the addition of oxygen to the precursor's carrier gas resulted in a further increase of the film's crystallinity. Furthermore, the films deposited in the presence of oxygen exhibited a better photocatalytic activity toward methylene blue degradation assumedly due to their higher amount of photoactive {101} facets.

  9. Photocatalytic activity of ferric oxide/titanium dioxide nanocomposite films on stainless steel fabricated by anodization and ion implantation

    Science.gov (United States)

    Zhan, Wei-ting; Ni, Hong-wei; Chen, Rong-sheng; Yue, Gao; Tai, Jun-kai; Wang, Zi-yang

    2013-08-01

    A simple surface treatment was used to develop photocatalytic activity for stainless steel. AISI 304 stainless steel specimens after anodization were implanted by Ti ions at an extracting voltage of 50 kV with an implantation dose of 3 × 1015 atoms·cm-2 and then annealed in air at 450°C for 2 h. The morphology was observed by scanning electron microscopy. The microstructure was characterized by X-ray diffraction and X-ray photoelectron spectroscopy. The photocatalytic degradation of methylene blue solution was carried out under ultraviolet light. The corrosion resistance of the stainless steel was evaluated in NaCl solution (3.5 wt%) by electrochemical polarization curves. It is found that the Ti ions depth profile resembles a Gaussian distribution in the implanted layer. The nanostructured Fe2O3/TiO2 composite film exhibits a remarkable enhancement in photocatalytic activity referenced to the mechanically polished specimen and anodized specimen. Meanwhile, the annealed Ti-implanted specimen remains good corrosion resistance.

  10. Effect of post-treatment on photocatalytic oxidation activity of (111 oriented NaNbO3 film

    Directory of Open Access Journals (Sweden)

    Feng Zhang

    2015-10-01

    Full Text Available We investigate the impact of post-treatment on photocatalytic oxidation activity of (111 oriented NaNbO3 film prepared by pulse laser deposition. Some impurities such as Na2Nb4O11 and bigger particles appear in the treated samples. The activity of rhodamine B degradation with N2 purge increases with the amount of ⋅OH, the sample treated under H2/Ar(7% being the highest activity, followed by under air and untreated one; the opposite trend is observed when the system was without N2 purge.

  11. A short literature survey on iron and cobalt ion doped TiO{sub 2} thin films and photocatalytic activity of these films against fungi

    Energy Technology Data Exchange (ETDEWEB)

    Tatl Latin-Small-Letter-Dotless-I dil, Ilknur [Department of Chemistry, Faculty of Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Bacaks Latin-Small-Letter-Dotless-I z, Emin [Department of Physics, Faculty of Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Buruk, Celal Kurtulus [Department of Microbiology, Faculty of Medicine, Karadeniz Technical University, 61080 Trabzon (Turkey); Breen, Chris [Materials and Engineering Research Institution, Sheffield Hallam University, Sheffield S1 1WB (United Kingdom); Soekmen, Muenevver, E-mail: msokmen@ktu.edu.tr [Department of Chemistry, Faculty of Science, Karadeniz Technical University, 61080 Trabzon (Turkey)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Co or Fe doped TiO{sub 2} thin films were prepared by sol-gel method. Black-Right-Pointing-Pointer We obtained lower E{sub g} values for Fe-doped and Co-TiO{sub 2} thin films. Black-Right-Pointing-Pointer Doping greatly affected the size and shape of the TiO{sub 2} nanoparticles. Black-Right-Pointing-Pointer Photocatalytic killing effect of the doped TiO{sub 2} thin films on C. albicans and A. niger was significantly higher than undoped TiO{sub 2} thin film for short exposure periods. - Abstract: In this study, a short recent literature survey which concentrated on the usage of Fe{sup 3+} or Co{sup 2+} ion doped TiO{sub 2} thin films and suspensions were summarized. Additionally, a sol-gel method was used for preparation of the 2% Co or Fe doped TiO{sub 2} thin films. The surface of the prepared materials was characterised using scanning-electron microscopy (SEM) combined with energy dispersive X-ray (EDX) analysis and band gap of the films were calculated from the transmission measurements that were taken over the range of 190 and 1100 nm. The E{sub g} value was 3.40 eV for the pure TiO{sub 2}, 3.00 eV for the Fe-doped TiO{sub 2} film and 3.25 eV for Co-TiO{sub 2} thin film. Iron or cobalt doping at lower concentration produce more uniformed particles and doping greatly affected the size and shape of the TiO{sub 2} nanoparticles. Photocatalytic killing effect of the 2% Co doped TiO{sub 2} thin film on Candida albicans was significantly higher than Fe doped TiO{sub 2} thin film for short and long exposure periods. Doped thin films were more effective on Aspergillus niger for short exposure periods.

  12. Resistive switching characteristics of Pt/TaOx/HfNx structure and its performance improvement

    Directory of Open Access Journals (Sweden)

    Qigang Zhou

    2013-03-01

    Full Text Available The refractory transition metal nitride (TMN film Hafnium nitride (HfNx was successfully prepared on silicon-based substrates as bottom electrodes for resistive random access memory (RRAM cells in Pt (top/metal oxide/ HfNx (bottom sandwich structure. The reproducible resistive switching (RS characteristics of the memory cells were studied systematically for RRAM applications. The advantages of adopting HfNx instead of Pt as bottom electrode material were demonstrated, including the improvement of the low resistive state value, the RS endurance and the uniformity of RS parameters. The composition and chemical bonding states of the prepared HfNx was analyzed by X-ray photoelectron spectroscopy (XPS technique. The nitrogen content in the HfNx and the Gibbs free energy of the corresponding metal oxide formation has great influences on the RS properties. The oxygen reservoir ability and diffusion barrier effect of the HfNx play a key role in the RS performance improvement of the RRAM devices.

  13. A comprehensive aerosol spray method for the rapid photocatalytic grid area analysis of semiconductor photocatalyst thin films

    International Nuclear Information System (INIS)

    Kafizas, Andreas; Mills, Andrew; Parkin, Ivan P.

    2010-01-01

    Indicator inks, previously shown to be capable of rapidly assessing photocatalytic activity via a novel photo-reductive mechanism, were simply applied via an aerosol spray onto commercially available pieces of Activ TM self-cleaning glass. Ink layers could be applied with high evenness of spread, with as little deviation as 5% upon UV-visible spectroscopic assessment of 25 equally distributed positions over a 10 cm x 10 cm glass cut. The inks were comprised of either a resazurin (Rz) or dichloroindophenol (DCIP) redox dye with a glycerol sacrificial electron donor in an aqueous hydroxyethyl cellulose (HEC) polymer media. The photo-reduction reaction under UVA light of a single spot was monitored by UV-vis spectroscopy and digital images attained from a flat-bed scanner in tandem for both inks. The photo-reduction of Rz ink underwent a two-step kinetic process, whereby the blue redox dye was initially reduced to a pink intermediate resorufin (Rf) and subsequently reduced to a bleached form of the dye. In contrast, a simple one-step kinetic process was observed for the reduction of the light blue redox dye DCIP to its bleached intermediates. Changes in red-green-blue colour extracted from digital images of the inks were inversely proportional to the changes seen at corresponding wavelengths via UV-visible absorption spectroscopy and wholly indicative of the reaction kinetics. The photocatalytic activity areas of cuts of Activ TM glass, 10 cm x 10 cm in size, were assessed using both Rz and DCIP indicator inks evenly sprayed over the films; firstly using UVA lamp light to activate the underlying Activ TM film (1.75 mW cm -2 ) and secondly under solar conditions (2.06 ± 0.14 mW cm -2 ). The photo-reduction reactions were monitored solely by flat-bed digital scanning. Red-green-blue values of a generated 14 x 14 grid (196 positions) that covered the entire area of each film image were extracted using a custom-built program entitled RGB Extractor(C). A homogenous

  14. TiO{sub 2} films organofunctionalized with 2-aminothiazole ligand and adsorbed Pd(II) ions applied in the photocatalytic degradation of phenol in an aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Cristante, Valtair M. [Instituto de Quimica, Departamento de Quimica Analitica/UNESP, P.O. box-355, 14800-900, Araraquara, SP (Brazil); Jorge, Sonia M.A. [Instituto de Biociencias, Departamento de Quimica e Bioquimica/UNESP, P.O. box-510, 18618-000, Botucatu, SP (Brazil); Valente, Jose P.S. [Instituto de Biociencias, Departamento de Quimica e Bioquimica/UNESP, P.O. box-510, 18618-000, Botucatu, SP (Brazil); Saeki, Margarida J. [Faculdade de Ciencias de Bauru, Departamento de Quimica, P.O. box-473, 17033360, Bauru, SP, Brasil (Brazil); Florentino, Ariovaldo O. [Instituto de Biociencias, Departamento de Quimica e Bioquimica/UNESP, P.O. box-510, 18618-000, Botucatu, SP (Brazil); Padilha, Pedro M. [Instituto de Biociencias, Departamento de Quimica e Bioquimica/UNESP, P.O. box-510, 18618-000, Botucatu, SP (Brazil)]. E-mail: padilha@ibb.unesp.br

    2007-05-07

    This paper describes the preparation of thin titanium films via sol-gel route and their subsequent chemical modification by anchoring with 2-aminothiazole ligand and Pd(II) ion sorption, aiming to maximize the photocatalytic activity. The material was characterized by diffuse reflectance infrared Fourier transform spectroscopy, ultraviolet and visible spectrometry, X-ray diffractometry, and scanning electronic microscopy. The amount of palladium adsorbed on the film's surface, determined by graphite furnace atomic absorption spectrometry, showed a value of 2.69 x 10{sup 16} atoms cm{sup -2}. The photocatalytic tests indicated that the functionalization with 2-aminothiazole and the adsorption of palladium (II) were determinants in the semiconductor's enhanced photocatalytic activity.

  15. Photocatalytic Graphene-TiO2 Thin Films Fabricated by Low-Temperature Ultrasonic Vibration-Assisted Spin and Spray Coating in a Sol-Gel Process

    Directory of Open Access Journals (Sweden)

    Fatemeh Zabihi

    2017-05-01

    Full Text Available In this work, we communicate a facile and low temperature synthesis process for the fabrication of graphene-TiO2 photocatalytic composite thin films. A sol-gel chemical route is used to synthesize TiO2 from the precursor solutions and spin and spray coating are used to deposit the films. Excitation of the wet films during the casting process by ultrasonic vibration favorably influences both the sol-gel route and the deposition process, through the following mechanisms. The ultrasound energy imparted to the wet film breaks down the physical bonds of the gel phase. As a result, only a low-temperature post annealing process is required to eliminate the residues to complete the conversion of precursors to TiO2. In addition, ultrasonic vibration creates a nanoscale agitating motion or microstreaming in the liquid film that facilitates mixing of TiO2 and graphene nanosheets. The films made based on the above-mentioned ultrasonic vibration-assisted method and annealed at 150 °C contain both rutile and anatase phases of TiO2, which is the most favorable configuration for photocatalytic applications. The photoinduced and photocatalytic experiments demonstrate effective photocurrent generation and elimination of pollutants by graphene-TiO2 composite thin films fabricated via scalable spray coating and mild temperature processing, the results of which are comparable with those made using lab-scale and energy-intensive processes.

  16. Suppressing the Photocatalytic Activity of TiO2 Nanoparticles by Extremely Thin Al2O3 Films Grown by Gas-Phase Deposition at Ambient Conditions

    NARCIS (Netherlands)

    Guo, J.; Bui, H.V.; Valdesueiro Gonzalez, D.; Yuan, Shaojun; Liang, Bin; van Ommen, J.R.

    2018-01-01

    This work investigated the suppression of photocatalytic activity of titanium dioxide (TiO2) pigment powders by extremely thin aluminum oxide (Al2O3) films deposited via an atomic-layer-deposition-type process using trimethylaluminum (TMA) and H2O as precursors. The deposition was performed on

  17. Effects of Calcination Temperatures on Photocatalytic Activity of Ordered Titanate Nanoribbon/SnO2 Films Fabricated during an EPD Process

    Directory of Open Access Journals (Sweden)

    Li Zhao

    2012-01-01

    Full Text Available Ordered titanate nanoribbon (TNR/SnO2 films were fabricated by electrophoretic deposition (EPD process using hydrothermally prepared titanate nanoribbon as a precursor. The formation mechanism of ordered TNR film on the fluorine-doped SnO2 coated (FTO glass was investigated by scanning electron microscopy (SEM. The effects of calcination temperatures on the phase structure and photocatalytic activity of ordered TNR/SnO2 films were investigated and discussed. The X-ray diffraction (XRD results indicate that the phase transformation of titanate to anatase occurs at 400°C and with increasing calcination temperature, the crystallization of anatase increases. At 600°C, the nanoribbon morphology still hold and the TiO2/SnO2 film exhibits the highest photocatalytic activity due to the good crystallization, unique morphology, and efficient photogenerated charge carriers separation and transfer at the interface of TiO2 and SnO2.

  18. Photocatalytic performance of Sn-doped and undoped TiO2 nanostructured thin films under UV and vis-lights

    International Nuclear Information System (INIS)

    Arpac, E.; Sayilkan, F.; Asiltuerk, M.; Tatar, P.; Kiraz, Nadir; Sayilkan, H.

    2007-01-01

    Sn-doped and undoped nano-TiO 2 particles have been synthesized by hydrotermal process without solvent at 200 deg. C in 1 h. Nanostructure-TiO 2 based thin films have been prepared on glass substrate by spin-coating technique. The structure, surface morphology and optical properties of the thin films and the particles have been investigated by element analysis and XRD, SEM, BET and UV-vis-NIR techniques. The photocatalytic performance of the films were tested for degradation of Malachite Green dye in solution under UV and vis-lights. The results showed that (a) hydrothermally synthesized nano-TiO 2 particles are fully anatase crystalline form and are easily dispersed in water, (b) the coated surfaces have nearly super-hydrophilic properties and (c) the doping of transition metal ion efficiently improved the photocatalytic performance of the TiO 2 thin film

  19. Realizing luminescent downshifting in ZnO thin films by Ce doping with enhancement of photocatalytic activity

    Science.gov (United States)

    Narayanan, Nripasree; Deepak, N. K.

    2018-04-01

    ZnO thin films doped with Ce at different concentration were deposited on glass substrates by spray pyrolysis technique. XRD analysis revealed the phase purity and polycrystalline nature of the films with hexagonal wurtzite geometry and the composition analysis confirmed the incorporation of Ce in the ZnO lattice in the case of doped films. Crystalline quality and optical transmittance diminished while electrical conductivity enhanced with Ce doping. Ce doping resulted in a red-shift of optical energy gap due to the downshift of the conduction band minimum after merging with Ce related impurity bands formed below the conduction band in the forbidden gap. In the room temperature photoluminescence spectra, UV emission intensity of the doped films decreased while the intensity of the visible emission band increased drastically implying the degradation in crystallinity as well as the incorporation of defect levels capable of luminescence downshifting. Ce doping showed improvement in photocatalytic efficiency by effectively trapping the free carriers and then transferring for dye degradation. Thus Ce doped ZnO thin films are capable of acting as luminescent downshifters as well as efficient photocatalysts.

  20. Fabrication of SnO{sub 2}-TiO{sub 2} core-shell nanopillar-array films for enhanced photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Hsyi-En, E-mail: sean@mail.stust.edu.tw; Lin, Chun-Yuan; Hsu, Ching-Ming

    2017-02-28

    Highlights: • SnO{sub 2}-TiO{sub 2} core-shell nanopillar-arrays on ITO glass were successfully fabricated. • The 3D heterojunction solves the problem of low photocatalytic activity of TiO{sub 2} films. • SnO{sub 2} is more suitable than ITO for the core layer to separate electron-hole pairs. - Abstract: Immobilized or deposited thin film TiO{sub 2} photocatalysts are suffering from a low photocatalytic activity due to either a low photon absorption efficiency or a high carrier recombination rate. Here we demonstrate that the photocatalytic activity of TiO{sub 2} can be effectively improved by the SnO{sub 2}-TiO{sub 2} core-shell nanopillar-array structure which combines the benefits of SnO{sub 2}/TiO{sub 2} heterojunction and high reaction surface area. The SnO{sub 2}-TiO{sub 2} core-shell nanopillar-array films were fabricated using atomic layer deposition and dry etching techniques via barrier-free porous anodic alumina templates. The photocatalytic activity of the prepared films was evaluated by methylene blue (MB) bleaching under 352 nm UV light irradiation. The results show that the photocatalytic activity of TiO{sub 2} film was 45% improved by introducing a SnO{sub 2} film between TiO{sub 2} and ITO glass substrate and was 300% improved by using the SnO{sub 2}-TiO{sub 2} core-shell nanopillar-array structure. The 45% improvement by the SnO{sub 2} interlayer is attributed to the SnO{sub 2}/TiO{sub 2} heterojunction which separates the photogenerated electron-hole pairs in TiO{sub 2} for MB degradation, and the high photocatalytic activity of the SnO{sub 2}-TiO{sub 2} core-shell nanopillar-array films is attributed to the three dimensional SnO{sub 2}/TiO{sub 2} heterojunction which owns both the carrier separation ability and the high photocatalytic reaction surface area.

  1. Heterogeneous photocatalytic degradation of toluene in static environment employing thin films of nitrogen-doped nano-titanium dioxide

    Science.gov (United States)

    Kannangara, Yasun Y.; Wijesena, Ruchira; Rajapakse, R. M. G.; de Silva, K. M. Nalin

    2018-04-01

    Photocatalytic semiconductor thin films have the ability to degrade volatile organic compounds (VOCs) causing numerous health problems. The group of VOCs called "BTEX" is abundant in houses and indoor of automobiles. Anatase phase of TiO2 has a band gap of 3.2 eV and UV radiation is required for photogeneration of electrons and holes in TiO2 particles. This band gap can be decreased significantly when TiO2 is doped with nitrogen (N-TiO2). Dopants like Pd, Cd, and Ag are hazardous to human health but N-doped TiO2 can be used in indoor pollutant remediation. In this research, N-doped TiO2 nano-powder was prepared and characterized using various analytical techniques. N-TiO2 was made in sol-gel method and triethylamine (N(CH2CH3)3) was used as the N-precursor. Modified quartz cell was used to measure the photocatalytic degradation of toluene. N-doped TiO2 nano-powder was illuminated with visible light (xenon lamp 200 W, λ = 330-800 nm, intensity = 1 Sun) to cause the degradation of VOCs present in static air. Photocatalyst was coated on a thin glass plate, using the doctor-blade method, was inserted into a quartz cell containing 2.00 µL of toluene and 35 min was allowed for evaporation/condensation equilibrium and then illuminated for 2 h. Remarkably, the highest value of efficiency 85% was observed in the 1 μm thick N-TiO2 thin film. The kinetics of photocatalytic degradation of toluene by N-TiO2 and P25-TiO2 has been compared. Surface topology was studied by varying the thickness of the N-TiO2 thin films. The surface nanostructures were analysed and studied with atomic force microscopy with various thin film thicknesses.

  2. Gd, I-doped TiO2 thin films coated on solid waste material: synthesis, characterization, and photocatalytic activity under UV or visible light irradiation

    Science.gov (United States)

    Deng, Siwei; Yu, Jiang; Yang, Chun; Chang, Jiahua; Wang, Yizheng; Wang, Ping; Xie, Shiqian

    2017-10-01

    In this work, titanium dioxide thin films doped with different concentrations of gadolinium (Gd) and iodine (I) were synthesized using the sol-gel method and successfully coated on solid waste material (made in our lab) by dipping, resulting in the titanium dioxide thin-film-coated material (TiO2M). Then, the doped titanium dioxide thin films were characterized by X-ray diffraction (XRD), SEM, and UV-Vis spectroscopy; the optimum coating cycle was evaluated by removal rates of COD and ammonia nitrogen in raw wastewater and secondary effluent. Moreover, the photocatalytic activity was determined by degradation efficiency of methyl orange. The results showed that TiO2M had desirable reusability and the photocatalytic activity was attractive under ultraviolet light irradiation. Furthermore, it is found that the amount of dopant in TiO2 was a key parameter in increasing the photoactivity. 1% Gd-doped TiO2M exhibited the best photocatalytic activity for the degradation of methyl orange with the removal rate reaching 85.55%. The result was in good agreement with the observed smaller crystallite size and profitable crystal structure (anatase phase). Besides, the TiO2M (0.8% Gd-doped TiO2M, 1% Gd-doped TiO2M, 10% I-doped TiO2M, and 5% I-1% Gd-doped TiO2M) with desirable photocatalytic activity at ultraviolet light irradiation was selected for the visible light photocatalytic experiments with taking methyl orange as the target pollutants. The results showed that all of them exhibited the similar photocatalytic activity after 7 h of sunlight irradiation (around 90% removal effect). In general, this research developed a very effective and environmentally friendly photocatalyst for pollutant degradation.

  3. Fabrication of a Cu{sub 2}O/Au/TiO{sub 2} composite film for efficient photocatalytic hydrogen production from aqueous solution of methanol and glucose

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xi; Dong, Haitai; Hu, Zhe; Qi, Zhong; Li, Laisheng, E-mail: llsh@scnu.edu.cn

    2017-05-15

    Highlights: • A Cu{sub 2}O/Au/TiO{sub 2} film was synthesized successfully. • Hydrogen production of Cu{sub 2}O/Au/TiO{sub 2} film improved significantly. • The highest hydrogen production rate of the film was 125.3 mmol/h/m{sup 2}. • A Z-scheme charge transfer pathway was proposed. - Abstract: A novel Cu{sub 2}O/Au/TiO{sub 2} photocatalyst composite film was fabricated on a copper substrate for photocatalytic hydrogen production. The composite films, Cu{sub 2}O/Au/TiO{sub 2}, were stepwise synthesized by using electrochemical deposition, photodeposition, and coating methods. First, a Cu{sub 2}O film was synthesized using the electrochemical deposition method, after which Au was deposited onto the Cu{sub 2}O film through in-site photodeposition. Finally, TiO{sub 2} was coated on the surface of the Cu{sub 2}O/Au film. Its morphology and surface chemical composition was characterized by SEM, TEM, XRD and XPS. The optical characteristics (UV–Vis DRS, PL spectrum) of the films were also examined. The photocatalytic hydrogen production rate of the Cu{sub 2}O/Au/TiO{sub 2} composite film from a 20% vol. methanol solution increased to125.3 mmol/h/m{sup 2} under 300 W xenon lamp light irradiation. Compared to the TiO{sub 2} (13.5 mmol/h/m{sup 2}) film and Cu{sub 2}O/TiO{sub 2} film (83.2 mmol/h/m{sup 2}), the Cu{sub 2}O/Au/TiO{sub 2} film showed excellent photocatalytic performance for hydrogen generation. The Cu{sub 2}O/Au/TiO{sub 2} film has highly effective photocatalytic properties, which are attributed to the Z-scheme system and can not only enhance the absorption of solar light but also suppress the recombination of photogenerated electron-hole pairs. It is worth noting that by introducing Au into the interface of Cu{sub 2}O/TiO{sub 2}, the surface plasmon resonance (SPR)-induced local electric field formed at the Au site induces a Z-scheme charge transfer pathway inside the composite film (Cu{sub 2}O/Au/TiO{sub 2}), which promotes both the charge of the

  4. Superhydrophilic zinc oxide film prepared by controlling ZnO microrods growth and its attractive recyclable photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Kai, E-mail: daikai940@chnu.edu.cn [College of Physics and Electronic Information, Huaibei Normal University, Huaibei, 235000 (China); Chen, Zheng [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123 (China); Lu, Luhua, E-mail: lhlu@whut.edu.cn [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123 (China); State Key Lab of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Zhu, Guangping; Liu, Zhongliang; Liu, Qinzhuang [College of Physics and Electronic Information, Huaibei Normal University, Huaibei, 235000 (China)

    2013-07-31

    Superhydrophilic functional materials have been found to be of great value for a variety of practical applications in recent years. In this paper, zinc oxide (ZnO) microrod films have been directly synthesized on a large-area zinc substrate via a simple solution method. Morphological and structural observation and crystallinity of the grown products were carried out using scanning electron microscopy, X-ray diffraction, energy dispersive spectrometer, transmission electron microscopy, ultraviolet (UV)–vis diffuse reflectance spectroscopy and photoluminescence (PL) spectroscopy. The influence of reaction time on the size and shapes of the as-prepared ZnO samples was studied. It was found that superhydrophilic ZnO films at reaction time of 20 h were made up of uniform pure ZnO microrods with 600 nm in average diameter and 6 μm in length. Room-temperature PL spectra of the ZnO products showed a UV emission and a broad green band. Photocatalytic performance and sample stability were studied. Under UV light irradiation over 95% of methylene blue was degraded by ZnO microrod films in 4 h, ZnO microrod film can be easily separated from the solution, and no observable performance degradation was observed after 5 cycles. - Highlights: • Superhydrophilic ZnO microrod films were successfully synthesized. • ZnO microrods are single crystalline with the hexagonal wurtzite structure. • ZnO microrod films can be easily separated from the solution. • Superhydrophilic ZnO microrod films can be reused.

  5. Superhydrophilic zinc oxide film prepared by controlling ZnO microrods growth and its attractive recyclable photocatalytic performance

    International Nuclear Information System (INIS)

    Dai, Kai; Chen, Zheng; Lu, Luhua; Zhu, Guangping; Liu, Zhongliang; Liu, Qinzhuang

    2013-01-01

    Superhydrophilic functional materials have been found to be of great value for a variety of practical applications in recent years. In this paper, zinc oxide (ZnO) microrod films have been directly synthesized on a large-area zinc substrate via a simple solution method. Morphological and structural observation and crystallinity of the grown products were carried out using scanning electron microscopy, X-ray diffraction, energy dispersive spectrometer, transmission electron microscopy, ultraviolet (UV)–vis diffuse reflectance spectroscopy and photoluminescence (PL) spectroscopy. The influence of reaction time on the size and shapes of the as-prepared ZnO samples was studied. It was found that superhydrophilic ZnO films at reaction time of 20 h were made up of uniform pure ZnO microrods with 600 nm in average diameter and 6 μm in length. Room-temperature PL spectra of the ZnO products showed a UV emission and a broad green band. Photocatalytic performance and sample stability were studied. Under UV light irradiation over 95% of methylene blue was degraded by ZnO microrod films in 4 h, ZnO microrod film can be easily separated from the solution, and no observable performance degradation was observed after 5 cycles. - Highlights: • Superhydrophilic ZnO microrod films were successfully synthesized. • ZnO microrods are single crystalline with the hexagonal wurtzite structure. • ZnO microrod films can be easily separated from the solution. • Superhydrophilic ZnO microrod films can be reused

  6. Novel hydrophobic/hydrophilic patterning process by photocatalytic Ag nucleation on TiO2 thin film and electroless Cu deposition

    International Nuclear Information System (INIS)

    Nishimoto, Shunsuke; Kubo, Atsushi; Zhang, Xintong; Liu, Zhaoyue; Taneichi, Noriaki; Okui, Toshiki; Murakami, Taketoshi; Komine, Takashi; Fujishima, Akira

    2008-01-01

    A hydrophobic/super-hydrophilic pattern was prepared on a TiO 2 thin film by a new fabrication process. The process consists of five key steps: (1) photocatalytic reduction of Ag + to Ag (nucleation), (2) electroless Cu deposition, (3) oxidation of Cu to CuO, (4) deposition of a self-assembled monolayer (SAM), and (5) photocatalytic decomposition of selected areas of the SAM. A hydrophobic/super-hydrophilic pattern with 500-μm 2 hydrophilic areas was obtained in this process. It is particularly noteworthy that a UV irradiation time of only 1 s was sufficient for the nucleation step in the patterning process

  7. Effect of the KOH chemical treatment on the optical and photocatalytic properties of BiVO{sub 4} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Mirabal-Rojas, R.; Depablos-Rivera, O.; Medina, J.C. [Universidad Nacional Autonoma de Mexico, Instituto de Investigaciones en Materiales, Mexico City (Mexico); Universidad Nacional Autonoma de Mexico, Posgrado en Ciencia e Ingenieria de Materiales, Mexico City (Mexico); Thalluri, S.M. [Politecnico di Torino, Department of Applied Science and Technology (DISAT), Torino (Italy); Bizarro, M.; Perez-Alvarez, J.; Rodil, S.E. [Universidad Nacional Autonoma de Mexico, Instituto de Investigaciones en Materiales, Mexico City (Mexico); Zeinert, A. [Universite de Picardie Jules Verne, Laboratoire de Physique de la Matiere Condensee, Amiens (France)

    2016-04-15

    In this work, we present the structural, optical and photocatalytic properties of BiVO{sub 4} thin films produced by a dual-magnetron sputtering process using both Bi{sub 2}O{sub 3} (α-phase, 99.98 % purity) and V (99.9 % purity) targets under Ar/O{sub 2} atmosphere with a ratio of 18:2. The films were deposited varying the power applied to the targets to obtain stoichiometric films, and the monoclinic structure was achieved by post-deposition annealing. The dual process was chosen to better control the Bi/V ratio since Bi and V have very different sputtering yields. In particular, the influence of a chemical treatment using potassium hydroxide (KOH) on the optical properties and different dye discolorations (acid blue 113 and methyl orange) is discussed. The optical properties were studied by reflectance and transmittance spectroscopy, where the spectra were fitted to obtain the refractive index dispersion and the optical band gap of the BiVO{sub 4} as a function of the film structure, as determined by X-ray diffraction and Raman spectroscopy. (orig.)

  8. Thin-film fixed-bed reactor for solar photocatalytic inactivation of Aeromonas hydrophila: influence of water quality

    Directory of Open Access Journals (Sweden)

    Khan Sadia J

    2012-11-01

    Full Text Available Abstract Background Controlling fish disease is one of the major concerns in contemporary aquaculture. The use of antibiotics or chemical disinfection cannot provide a healthy aquaculture system without residual effects. Water quality is also important in determining the success or failure of fish production. Several solar photocatalytic reactors have been used to treat drinking water or waste water without leaving chemical residues. This study has investigated the impact of several key aspects of water quality on the inactivation of the pathogenic bacterium Aeromonas hydrophila using a pilot-scale thin-film fixed-bed reactor (TFFBR system. Results The level of inactivation of Aeromonas hydrophila ATCC 35654 was determined using a TFFBR with a photocatalytic area of 0.47 m2 under the influence of various water quality variables (pH, conductivity, turbidity and colour under high solar irradiance conditions (980–1100 W m-2, at a flow rate of 4.8 L h-1 through the reactor. Bacterial enumeration were obtained through conventional plate count using trypticase soy agar media, cultured in conventional aerobic conditions to detect healthy cells and under ROS-neutralised conditions to detect both healthy and sub-lethally injured (oxygen-sensitive cells. The results showed that turbidity has a major influence on solar photocatalytic inactivation of A. hydrophila. Humic acids appear to decrease TiO2 effectiveness under full sunlight and reduce microbial inactivation. pH in the range 7–9 and salinity both have no major effect on the extent of photoinactivation or sub-lethal injury. Conclusions This study demonstrates the effectiveness of the TFFBR in the inactivation of Aeromonas hydrophila under the influence of several water quality variables at high solar irradiance, providing an opportunity for the application of solar photocatalysis in aquaculture systems, as long as turbidity remains low.

  9. Photocatalytic Degradation of 2, 4-dichlorophenol using N-doped SnO2/TiO2 Thin Film Coated Glass Fibers

    Directory of Open Access Journals (Sweden)

    Peerawas Kongsong

    2017-07-01

    Full Text Available Photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP contaminant in water was investigated. Composite SnO2/TiO2 films N-doped to varying degrees were prepared via sol-gel method, and coated on glass fibers by dipping method. The effects of nitrogen-doping on coating morphology, physical properties, and glyphosate degradation rates were experimentally determined. Nitrogen-doping shifted absorption wavelengths and narrowed the energy band gap, enhancing photocatalytic performance. The maximum efficiency of 2,4-DCP degradation was up to 93.65% for 12 h of 40N/SnO2/TiO2 composite film. The near optimal 40N/SnO2/TiO2 composite thin film exhibited about 4 folds degradation rates relative to pure TiO2, and should perform well in water purification applications.

  10. Structural, Morphological, Optical and Photocatalytic Properties of Y, N-Doped and Codoped TiO₂ Thin Films.

    Science.gov (United States)

    Hamden, Zeineb; Conceição, David; Boufi, Sami; Vieira Ferreira, Luís Filipe; Bouattour, Soraa

    2017-05-31

    Pure TiO₂, Y-N single-doped and codoped TiO₂ powders and thin films deposited on glass beads were successfully prepared using dip-coating and sol-gel methods. The samples were analyzed using grazing angle X-ray diffraction (GXRD), Raman spectroscopy, time resolved luminescence, ground state diffuse reflectance absorption and scanning electron microscopy (SEM). According to the GXRD patterns and micro-Raman spectra, only the anatase form of TiO₂ was made evident. Ground state diffuse reflectance absorption studies showed that doping with N or codoping with N and Y led to an increase of the band gap. Laser induced luminescence analysis revealed a decrease in the recombination rate of the photogenerated holes and electrons. The photocatalytic activity of supported catalysts, toward the degradation of toluidine, revealed a meaningful enhancement upon codoping samples at a level of 2% (atomic ratio). The photocatalytic activity of the material and its reactivity can be attributed to a reduced, but significant, direct photoexcitation of the semiconductor by the halogen lamp, together with a charge-transfer-complex mechanism, or with the formation of surface oxygen vacancies by the N dopant atoms.

  11. Preparation of Transparent TiO2 Nanoporous Coating with Highly Photocatalytic Activity by Anodizing Ti Film with Loose Structure

    Directory of Open Access Journals (Sweden)

    LIANG Yin

    2016-07-01

    Full Text Available The Ti film with special structure was deposited onto glass substrate by magnetron sputtering, then via the process of electrochemical anodization and annealing, a transparent TiO2 nanoporous coating (denoted as TNP with high photocatalytic activity can be directly formed on glass substrate. The crystal structure of the TNP was detected by X-ray diffractometry (XRD and the morphology of the coating was observed by scanning electron microscopy (SEM. The transmittance, wettability and adhesion of TNP were investigated by UV-Vis spectrophotometer, contact angle meter and scratch tester respectively. Finally, the photocatalytic activity of TNP was evaluated by degradation of methylene blue solution under UV illumination. The results show that the prepared TNP coating has a nanoporous structure and only anatase can be found after annealing, the transmittance of TNP coating can reach 80% or more in visible region, with a super hydrophilic surface (contact angleC0=1×10-5mol/L can reach 94% in 2 hours and the photocatalysis reaction rate constant is 1.47h-1.

  12. Characteristics and Photocatalytic Properties of TiO2 Thin Film Prepared by Sputter Deposition and Post-N+ Ion Implantation

    Directory of Open Access Journals (Sweden)

    Haider A. Shukur

    2012-01-01

    Full Text Available TiO2 thin films of a rutile, an anatase, and a mixture type with anatase and rutile were fabricated by a magnetron sputtering method. The fabricated films were irradiated by N+ ions with several doses using the Freeman ion source. Atomic force microscopy (AFM, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, and UV-VIS spectrophotometer were employed to investigate morphology, structure, chemical state, and optical characteristics, respectively. Photocatalytic activity was evaluated by degradation of a methylene blue solution using UV and visible light. TiO2 thin films with each structure irradiated by N+ ions showed the different N concentration in the same N+ ion dose and the chemical state of XPS results suggested that an O atom in TiO2 lattice replaced by an N atom. Therefore the photocatalytic activity of TiO2 thin films was improved under visible light. The maximum photocatalytic activity of TiO2 thin films with each structure was indicated at N concentration of 2.1% for a rutile type, of 1.0% for an anatase type, and of 3.8% for a mixture type under the condition of 2.5×1015 ions/cm2 in N+ ion dose.

  13. Influence of the morphology and microstructure on the photocatalytic properties of titanium oxide films obtained by sparking anodization in H{sub 3}PO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Souza Sikora, Mariana de; Viana Rosario, Adriane [Laboratorio Interdisciplinar de Eletroquimica e Ceramica (LIEC), DQ, UFSCar, P.O. Box: 676, 13565-905, Sao Carlos (Brazil); Chaves Pereira, Ernesto, E-mail: decp@power.ufscar.b [Laboratorio Interdisciplinar de Eletroquimica e Ceramica (LIEC), DQ, UFSCar, P.O. Box: 676, 13565-905, Sao Carlos (Brazil); Paiva-Santos, Carlos O. [Laboratorio Computacional em Analises Cristalograficas e Cristalinas - LabCACC, Instituto de Quimica, UNESP, 14800-900, Araraquara, SP (Brazil)

    2011-03-30

    Research highlights: {yields} Variation of morphology and microstructure of TiO{sub 2} with applied charge. {yields} Influence of morphology on photoactivity of TiO{sub 2} films prepared by sparking anodization. {yields} Influence of crystallite size on photoactivity of TiO{sub 2} films prepared by sparking anodization. - Abstract: The aim of this paper is to investigate changes in morphology and microstructure of TiO{sub 2} films, prepared by sparking anodization of Ti in a H{sub 3}PO{sub 4} solution, by applying different formation charges. We show that although films obtained by this technique are rarely used in photocatalytic applications, the morphological and microstructural changes during sparking anodization produce TiO{sub 2} films that can be used as photocatalysts. In contrast to qualitative analysis commonly found in the literature, we used quantitative methods of analysis to quantify average pore diameter and pore density from the morphology and structural parameters from X-ray diffraction (XRD) patterns using the Rietveld refinement. The results indicated that changes in both the morphology and crystalline structure have a strong influence on the photoactivity of the films. From this investigation, we concluded that, for films prepared in early stages of anodization, the morphology had the biggest influence on photoactivity, and after applying 72C of charge, crystalline properties dominated the photocatalytic characteristics of the films.

  14. Influence of the morphology and microstructure on the photocatalytic properties of titanium oxide films obtained by sparking anodization in H3PO4

    International Nuclear Information System (INIS)

    Souza Sikora, Mariana de; Viana Rosario, Adriane; Chaves Pereira, Ernesto; Paiva-Santos, Carlos O.

    2011-01-01

    Research highlights: → Variation of morphology and microstructure of TiO 2 with applied charge. → Influence of morphology on photoactivity of TiO 2 films prepared by sparking anodization. → Influence of crystallite size on photoactivity of TiO 2 films prepared by sparking anodization. - Abstract: The aim of this paper is to investigate changes in morphology and microstructure of TiO 2 films, prepared by sparking anodization of Ti in a H 3 PO 4 solution, by applying different formation charges. We show that although films obtained by this technique are rarely used in photocatalytic applications, the morphological and microstructural changes during sparking anodization produce TiO 2 films that can be used as photocatalysts. In contrast to qualitative analysis commonly found in the literature, we used quantitative methods of analysis to quantify average pore diameter and pore density from the morphology and structural parameters from X-ray diffraction (XRD) patterns using the Rietveld refinement. The results indicated that changes in both the morphology and crystalline structure have a strong influence on the photoactivity of the films. From this investigation, we concluded that, for films prepared in early stages of anodization, the morphology had the biggest influence on photoactivity, and after applying 72C of charge, crystalline properties dominated the photocatalytic characteristics of the films.

  15. Potential for photocatalytic degradation of the potassic diclofenac using scandium and silver modified titanium dioxide thin films

    International Nuclear Information System (INIS)

    Ciola, R.A.; Oliveira, C.T.; Lopes, S.A.; Cavalheiro, A.A.

    2011-01-01

    The potential for photocatalytic degradation of the potassic diclofenac drug was investigated using titanium dioxide thin films modified with two modifier types, scandium and silver, both prepared by Sol-Gel method. It was demonstrated by UVVis spectroscopy analysis of the solutions containing the drug, under UV-A light irradiation that the degradation efficiency of the titanium dioxide photocatalyst is dependent of the semiconductor nature and that the scandium accelerates the first step of the degradation when compared to the silver. This result seems to be related to the redox potential of the electron-hole pair, once the scandium modifying sample generates a p type semiconductor that reduces the band gap. The extra holes attract more strongly the chorine ion present in diclofenac and leading to the releasing more easily. However, after the first byproducts degradation the following steps are not facilitated, making the silver modifying more advantageous. (author)

  16. One-Step Formation of WO3-Loaded TiO2 Nanotubes Composite Film for High Photocatalytic Performance

    Directory of Open Access Journals (Sweden)

    Wai Hong Lee

    2015-04-01

    Full Text Available High aspect ratio of WO3-loaded TiO2 nanotube arrays have been successfully synthesized using the electrochemical anodization method in an ethylene glycol electrolyte containing 0.5 wt% ammonium fluoride in a range of applied voltage of 10–40 V for 30 min. The novelty of this research works in the one-step formation of WO3-loaded TiO2 nanotube arrays composite film by using tungsten as the cathode material instead of the conventionally used platinum electrode. As compared with platinum, tungsten metal has lower stability, forming dissolved ions (W6+ in the electrolyte. The W6+ ions then move towards the titanium foil and form a coherent deposit on titanium foil. By controlling the oxidation rate and chemical dissolution rate of TiO2 during the electrochemical anodization, the nanotubular structure of TiO2 film could be achieved. In the present study, nanotube arrays were characterized using FESEM, EDAX, XRD, as well as Raman spectroscopy. Based on the results obtained, nanotube arrays with average pore diameter of up to 74 nm and length of 1.6 µm were produced. EDAX confirmed the presence of tungsten element within the nanotube arrays which varied in content from 1.06 at% to 3.29 at%. The photocatalytic activity of the nanotube arrays was then investigated using methyl orange degradation under TUV 96W UV-B Germicidal light irradiation. The nanotube with the highest aspect ratio, geometric surface area factor and at% of tungsten exhibited the highest photocatalytic activity due to more photo-induced electron-hole pairs generated by the larger surface area and because WO3 improves charge separation, reduces charge carrier recombination and increases charge carrier lifetime via accumulation of electrons and holes in the two different metal oxide semiconductor components.

  17. Enhanced visible-light photocatalytic activity of g-C3N4/TiO2 films.

    Science.gov (United States)

    Boonprakob, Natkritta; Wetchakun, Natda; Phanichphant, Sukon; Waxler, David; Sherrell, Peter; Nattestad, Andrew; Chen, Jun; Inceesungvorn, Burapat

    2014-03-01

    Enhanced photocatalytic degradation of methylene blue (MB) using graphitic carbon nitride/titanium dioxide (g-C3N4/TiO2) catalyst films has been demonstrated in this present work. The g-C3N4/TiO2 composites were prepared by directly heating the mixture of melamine and pre-synthesized TiO2 nanoparticles in Ar gas flow. The g-C3N4 contents in the g-C3N4/TiO2 composites were varied as 0, 20, 50 and 70 wt%. It was found that the visible-light-induced photocatalytic degradation of MB was remarkably increased upon coupling TiO2 with g-C3N4 and the best degradation performance of ~70% was obtained from 50 wt% g-C3N4 loading content. Results from UV-vis absorption study, Electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy suggest that the improved photoactivity is due to a decrease in band gap energy, an increased light absorption in visible light region and possibly an enhanced electron-hole separation efficiency as a result of effective interfacial electron transfer between TiO2 and g-C3N4 of the g-C3N4/TiO2 composite film. Based on the obtained results, the possible MB degradation mechanism is ascribed mainly to the generation of active species induced by the photogenerated electrons. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. The photocatalytic application and regeneration of anatase thin films with embedded commercial TiO{sub 2} particles deposited on glass microrods

    Energy Technology Data Exchange (ETDEWEB)

    Medina-Valtierra, Jorge [Departamento de Ingenieria Quimica y Bioquimica, Tecnologico de Aguascalientes, Av. Adolfo Lopez Mateos No. 182 Ote., Fracc. Bona Gens, Aguascalientes, Ags., 20256 (Mexico)]. E-mail: jormeval@yahoo.com; Garcia-Servin, Josafat [Departamento de Ingenieria Quimica y Bioquimica, Tecnologico de Aguascalientes, Av. Adolfo Lopez Mateos No. 182 Ote., Fracc. Bona Gens, Aguascalientes, Ags., 20256 (Mexico)]. E-mail: josgaser@yahoo.com.mx; Frausto-Reyes, Claudio [Centro de Investigaciones en Optica, A.C., Unidad Aguascalientes, Prol. Constitucion No. 607, Reserva de Loma Bonita, Aguascalientes, Ags., 20200 (Mexico)]. E-mail: cfraus@cio.mx; Calixto, Sergio [Centro de Investigaciones en Optica, A.C., Loma del Bosque No. 115, Col. Lomas del Campestre, Leon, Gto., 37150 (Mexico)]. E-mail: scalixto@cio.mx

    2006-03-15

    Anatase thin films (<200 nm in thickness) embedding Degussa P25 TiO{sub 2} were prepared by sol-gel method. TiO{sub 2}-anatase thin films were deposited on a fiberglass substrate and then ground to obtain glass microrods containing the composite films. The film structure was characterized using Raman spectroscopy, atomic absorption and UV-vis spectrophotometry, and atomic force microscopy. The photocatalytic activity of the composite films, calcined at 450 deg. C, and the regeneration of the activity under the same experimental conditions, were assessed using gas chromatography to study the photodegradation of phenol, an industrial pollutant, in water under 365 nm irradiation. The film with 15.0 wt.% of P25 TiO{sub 2} was found to be more photoactive (54 ppm of degraded phenol at 6 h of illumination) than the other ones.

  19. Suppressing the Photocatalytic Activity of TiO₂ Nanoparticles by Extremely Thin Al₂O₃ Films Grown by Gas-Phase Deposition at Ambient Conditions.

    Science.gov (United States)

    Guo, Jing; Van Bui, Hao; Valdesueiro, David; Yuan, Shaojun; Liang, Bin; van Ommen, J Ruud

    2018-01-24

    This work investigated the suppression of photocatalytic activity of titanium dioxide (TiO₂) pigment powders by extremely thin aluminum oxide (Al₂O₃) films deposited via an atomic-layer-deposition-type process using trimethylaluminum (TMA) and H₂O as precursors. The deposition was performed on multiple grams of TiO₂ powder at room temperature and atmospheric pressure in a fluidized bed reactor, resulting in the growth of uniform and conformal Al₂O₃ films with thickness control at sub-nanometer level. The as-deposited Al₂O₃ films exhibited excellent photocatalytic suppression ability. Accordingly, an Al₂O₃ layer with a thickness of 1 nm could efficiently suppress the photocatalytic activities of rutile, anatase, and P25 TiO₂ nanoparticles without affecting their bulk optical properties. In addition, the influence of high-temperature annealing on the properties of the Al₂O₃ layers was investigated, revealing the possibility of achieving porous Al₂O₃ layers. Our approach demonstrated a fast, efficient, and simple route to coating Al₂O₃ films on TiO₂ pigment powders at the multigram scale, and showed great potential for large-scale production development.

  20. Suppressing the Photocatalytic Activity of TiO2 Nanoparticles by Extremely Thin Al2O3 Films Grown by Gas-Phase Deposition at Ambient Conditions

    Directory of Open Access Journals (Sweden)

    Jing Guo

    2018-01-01

    Full Text Available This work investigated the suppression of photocatalytic activity of titanium dioxide (TiO2 pigment powders by extremely thin aluminum oxide (Al2O3 films deposited via an atomic-layer-deposition-type process using trimethylaluminum (TMA and H2O as precursors. The deposition was performed on multiple grams of TiO2 powder at room temperature and atmospheric pressure in a fluidized bed reactor, resulting in the growth of uniform and conformal Al2O3 films with thickness control at sub-nanometer level. The as-deposited Al2O3 films exhibited excellent photocatalytic suppression ability. Accordingly, an Al2O3 layer with a thickness of 1 nm could efficiently suppress the photocatalytic activities of rutile, anatase, and P25 TiO2 nanoparticles without affecting their bulk optical properties. In addition, the influence of high-temperature annealing on the properties of the Al2O3 layers was investigated, revealing the possibility of achieving porous Al2O3 layers. Our approach demonstrated a fast, efficient, and simple route to coating Al2O3 films on TiO2 pigment powders at the multigram scale, and showed great potential for large-scale production development.

  1. Results on the electrochromic and photocatalytic properties of vanadium doped tungsten oxide thin films prepared by reactive dc magnetron sputtering technique

    International Nuclear Information System (INIS)

    Karuppasamy, K Muthu; Subrahmanyam, A

    2008-01-01

    In this investigation, vanadium doped tungsten oxide (V : WO 3 ) thin films are prepared at room temperature by reactive dc magnetron sputtering employing a tungsten-vanadium 'inlay' target. In comparison with pure sputtered tungsten oxide thin films, 11% vanadium doping is observed to decrease the optical band gap, enhance the colour neutral property, decrease the coloration efficiency (from 121 to 13 cm 2 C -1 ), increase the surface work function (4.68-4.83 eV) and significantly enhance the photocatalytic efficiency in WO 3 thin films. These observations suggest that (i) vanadium creates defect levels that are responsible for optical band gap reduction, (ii) multivalent vanadium bonding with terminal oxygen in the WO 3 lattice gives rise to localized covalent bonds and thus results in an increase in the work function, and (iii) a suitable work function of V : WO 3 with ITO results in an enhancement of the photocatalytic activity. These results on electrochromic and photocatalytic properties of V : WO 3 thin films show good promise in the low maintenance window application

  2. Photocatalytic evaluation of self-assembled porous network structure of ferric oxide film fabricated by dry deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yunchan; Kim, Hyungsub; Lee, Geon-Yong; Pawar, Rajendra C.; Lee, Jai-Sung; Lee, Caroline Sunyong, E-mail: sunyonglee@hanyang.ac.kr

    2016-09-15

    Ferric oxide powder in the alpha phase (α-Fe{sub 2}O{sub 3}) was deposited on an aluminum oxide (Al{sub 2}O{sub 3}) substrate by a nanoparticle deposition system using the dry deposition method. X-ray diffraction (XRD) images confirmed that the phase of the deposited α-Fe{sub 2}O{sub 3} did not change. The deposited α-Fe{sub 2}O{sub 3} was characterized in terms of its microstructure using scanning electron microscopy (SEM). A porous network microstructure formed when small agglomerates of Fe{sub 2}O{sub 3} (SAF) were deposited. The deposition and formation mechanism of the microstructure were investigated using SEM and three-dimensional (3D) profile analysis. First, a dense coating layer formed when the film was thinner than the particle size. After that, as the film thickness increased to over 5 μm, the porous network structure formed by excavating the surface of the coating layer as it was bombarded by particles. Rhodamine B (RhB) was degraded after 6 h of exposure to the Fe{sub 2}O{sub 3} coating layer with SAF, which has good photocatalytic activity and a high porous network structure. The kinetic rate constants of the SAF and large agglomerates of Fe{sub 2}O{sub 3} (LAF) were calculated to be 0.197(h{sup −1}) and 0.128(h{sup −1}), respectively, based on the absorbance results. Using linear sweep voltammetry, we confirmed that the photoelectric effect occurred in the coating layer by measuring the resulting current under illuminated and dark conditions. - Graphical abstract: Self-assembled porous photocatalytic film fabricated by dry deposition method for water purification. - Highlights: • Different sizes of Fe{sub 2}O{sub 3} agglomerates were used to form porous network structure. • Fe{sub 2}O{sub 3} agglomerate particles were deposited using solvent-free process. • Self-assembled porous network microstructure formed better with small agglomerates of Fe{sub 2}O{sub 3}. • Fabricated porous network structure showed its potential to be used

  3. Annealing Effects on Photocatalytic Activity of Zn0.2Cd0.8S Films Prepared by Chemical Bath Deposition

    Directory of Open Access Journals (Sweden)

    Yi-Feng Chai

    2014-01-01

    Full Text Available Zn0.2Cd0.8S alloyed films were prepared on glass substrates at room temperature using chemical bath deposition method. The obtained films were annealed at temperatures ranging from 200°C to 500°C with heating rate of 5°C/min and annealed at 400°C with heating rate of 2°C/min and 10°C/min. The films were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and UV-VIS spectrophotometer. The increasing of annealing temperature increases the crystallinity and the mean grain size of Zn0.2Cd0.8S alloyed films and significantly enhances the absorption in the visible region. The efficient visible light photocatalytic activity for annealed Zn0.2Cd0.8S alloyed films is associated with the larger size grain and the higher crystallinity.

  4. Characterization of thin TiO{sub 2} films prepared by plasma enhanced chemical vapour deposition for optical and photocatalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Sobczyk-Guzenda, A., E-mail: asobczyk@p.lodz.p [Institute of Materials Science and Engineering, Technical University of Lodz, Stefanowskiego 1, 90-924 Lodz (Poland); Gazicki-Lipman, M.; Szymanowski, H.; Kowalski, J. [Institute of Materials Science and Engineering, Technical University of Lodz, Stefanowskiego 1, 90-924 Lodz (Poland); Wojciechowski, P.; Halamus, T. [Department of Molecular Physics, Technical University of Lodz, Stefanowskiego 1, 90-924 Lodz (Poland); Tracz, A. [Centre for Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz (Poland)

    2009-07-31

    Thin titanium oxide films were deposited using a radio frequency (RF) plasma enhanced chemical vapour deposition method. Their optical properties and thickness were determined by means of ultraviolet-visible absorption spectrophotometry. Films of the optical parameters very close to those of titanium dioxide have been obtained at the high RF power input. Their optical quality is high enough to allow for their use in a construction of stack interference optical filters. At the same time, these materials exhibit strong photocatalytic effects. The results of structural analysis, carried out by Raman Shift Spectroscopy, show that the coatings posses amorphous structure. However, Raman spectra of the same films subjected to thermal annealing at 450 {sup o}C disclose an appearance of a crystalline form, namely that of anatase. Surface morphology of the films has also been characterized by Atomic Force Microscopy revealing granular, broccoli-like topography of the films.

  5. Photocatalytic degradation of metronidazole and methylene blue by PVA-assisted Bi2WO6-CdS nanocomposite film under visible light irradiation

    Science.gov (United States)

    Rajendran, Ranjith; Varadharajan, Krishnakumar; Jayaraman, Venkatesan; Singaram, Boobas; Jeyaram, Jayaprakash

    2018-02-01

    The enhanced photocatalytic performance of nanocomposite is synthesized via the hydrothermal method and characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS) and photoluminescence spectroscopy (PL). Under visible light irradiation, PVA assisted Bi2WO6-CdS nanocomposite film displayed enhanced photocatalytic efficiency and inhibition of photocorrosion as compared with pure CdS, pure Bi2WO6 and Bi2WO6-CdS composite. The PVA assisted Bi2WO6-CdS composite film catalyst showed stable catalytic performance until seven successive runs with 92% of methylene blue(MB) degradation, and easy to recover after degradation of organic pollutant. PVA assisted Bi2WO6-CdS nanocomposite film has optimal band edge position for superior photocatalytic degradation. Furthermore, the trapping experiment was carried out using different scavenger for active species. Among the active species, OH· are the most responsive species which play a vital role in the degradation of metronidazole and MB.

  6. The photocatalytic degradation of methylene blue by green semiconductor films that is induced by irradiation by a light-emitting diode and visible light.

    Science.gov (United States)

    Yang, Chih-Chi; Doong, Ruey-An; Chen, Ku-Fan; Chen, Giin-Shan; Tsai, Yung-Pin

    2018-01-01

    This study develops a low-energy rotating photocatalytic contactor (LE-RPC) that has Cu-doped TiO 2 films coated on stainless-steel rotating disks, to experimentally evaluate the efficiency of the degradation and decolorization of methylene blue (MB) under irradiation from different light sources (visible 430 nm, light-emitting diode [LED] 460 nm, and LED 525 nm). The production of hydroxyl radicals is also examined. The experimental results show that the photocatalytic activity of TiO 2 that is doped with Cu 2+ is induced by illumination with visible light and an LED. More than 90% of methylene blue at a 10 mg/L concentration is degraded after illumination by visible light (430 nm) for 4 hr at 20 rpm. This study also demonstrates that the quantity of hydroxyl radicals produced is directly proportional to the light energy intensity. The greater the light energy intensity, the greater is the number of hydroxyl radicals produced. The CuO-doped anatase TiO 2 powder was successfully synthesized in this study by a sol-gel method. The catalytic abilities of the stainless-steel film were enhanced in the visible light regions. This study has successfully modified the nano-photocatalytic materials to drop band gap and has also successfully fixed the nano-photocatalytic materials on a substratum to effectively treat dye wastewater in the range of visible light. The results can be useful to the development of a low-energy rotating photocatalytic contactor for decontamination purposes.

  7. Enhanced photocatalytic activity of Ag microgrid connected TiO2 nanocrystalline films

    International Nuclear Information System (INIS)

    Pan Feng; Zhang Junying; Zhang Weiwei; Wang Tianmin; Cai Chao

    2007-01-01

    One reason for the high degree of photogenerated carrier recombination was found to be the charge accumulation caused by the uneven reaction area on the photocatalyst surface. The authors connected TiO 2 nanoparticles with conducting Ag microgrid. Obvious photocatalytic activity improvement (81%) over the pure TiO 2 was observed, which is attributed to the electron-hole pairs separation by the metal-semiconductor contact and the large specific area of metal grid, which increased the O 2 absorption and transported the electrons to the sites needed for the deoxidize reactions. This structure lowers the electron accumulation on the particles and improves the utilization ratio of the photoexcited carriers

  8. Wettability modification of graphene oxide thin film through the photocatalytic reduction

    Directory of Open Access Journals (Sweden)

    2016-06-01

    Full Text Available In this paper, the effect of photocatalytic reduction on hydrophilicity of graphene oxide nanosheets is presented. The graphene oxide nanosheets were prepared by oxidation and exfoliation of natural graphite. The prepared samples were exposed to UV irradiation in presence of TiO2 nanoparticles. Raman spectroscopy and atomic force microscopy show that roughness of the surface is increased due to increasing irradiation. Also, the hydrophilicity of samples by measuring the contact angle of micro-liter droplets of deionized water, showed that by increasing exposure time up to 8 hours the contact angle of samples in crease from about 27 degrees to about 89 degrees.

  9. Structural, morphological, gas sensing and photocatalytic characterization of MoO{sub 3} and WO{sub 3} thin films prepared by the thermal vacuum evaporation technique

    Energy Technology Data Exchange (ETDEWEB)

    Arfaoui, A., E-mail: asma17687@gmail.com [Unité de physique des dispositifs a semi-conducteurs, Faculté des sciences de Tunis, Tunis El Manar University, 2092 Tunis (Tunisia); Touihri, S.; Mhamdi, A. [Unité de physique des dispositifs a semi-conducteurs, Faculté des sciences de Tunis, Tunis El Manar University, 2092 Tunis (Tunisia); Labidi, A. [Unité de Recherche de Physique des Semiconducteurs et Capteurs, IPEST, BP 51, La Marsa, 2070 Tunis (Tunisia); Manoubi, T. [Unité de physique des dispositifs a semi-conducteurs, Faculté des sciences de Tunis, Tunis El Manar University, 2092 Tunis (Tunisia)

    2015-12-01

    Graphical abstract: - Highlights: • Outlining adequacy an original combination of several characterization means. • Structural, morphological and gas sensing properties for both MoO{sub 3} and WO{sub 3} thin films have been studied. • These films had high sensitivity to ethanol, which made them as a good candidate for the ethanol sensor. • The photocatalytic activity of MoO{sub 3} and WO{sub 3} thin films has been studied. - Abstract: Thin films of molybdenum trioxide and tungsten trioxide were deposited on glass substrates using a simplified thermal evaporation under vacuum method monitored by heat treatment in flowing oxygen at 500 °C for 1 h. The structural and morphological properties of the films were investigated using X-ray diffraction, Raman spectroscopy, atomic force microscopy and scanning electron microscopy. The X-ray diffraction analysis shows that the films of MoO{sub 3} and WO{sub 3} were well crystallized in orthorhombic and monoclinic phase respectively with the crystallites preferentially oriented toward (2 0 0) direction parallel a-axis for both samples. In literature, we have shown in previous papers that structural and surface morphology of metal thin films play an important role in the gas detection mechanism. In this article, we have studied the response evolution of MoO{sub 3} and WO{sub 3} thin films sensors ethanol versus time, working temperature and the concentration of the ethanol. It was found that these films had high sensitivity to ethanol, which made them as a good candidate for the ethanol sensor. Finally, the photocatalytic activity of the samples was evaluated with respect to the degradation reaction of a wastewater containing methylene blue (MB) under UV–visible light irradiation. The molybdenum trioxide exhibits a higher degradation rate than the tungsten trioxide thin films under similar experimental conditions.

  10. Autonomous BBOBS-NX (NX-2G) for New Era of Ocean Bottom Broadband Seismology

    Science.gov (United States)

    Shiobara, H.; Ito, A.; Sugioka, H.; Shinohara, M.

    2017-12-01

    The broadband ocean bottom seismometer (BBOBS) and its new generation system (BBOBS-NX) have been developed in Japan, and we performed several test and practical observations to create and establish a new category of the ocean floor broadband seismology, since 1999. Now, the data obtained by our BBOBS and BBOBS-NX is proved to be adequate for broadband seismic analyses. Especially, the BBOBS-NX can obtain the horizontal data comparable to land sites in longer periods (10 s -). Moreover, the BBOBST-NX is in practical evaluation for the mobile tilt observation that enables dense geodetic monitoring. The BBOBS-NX system is a powerful tool, although, it has intrinsic limitation of the ROV operation. If this system can be used without the ROV, like as the BBOBS, it should lead us a true breakthrough of ocean bottom seismology. Hereafter, the new autonomous BBOBS-NX is noted as NX-2G in short. The main problem to realize the NX-2G is a tilt of the sensor unit on landing, which exceed the acceptable limit (±8°) in about 50%. As we had no evidence at which moment and how this tilt occurred, we tried to observe it during the BBOBST-NX landing in 2015 by attaching a video camera and an acceleration logger. The result shows that the tilt on landing was determined by the final posture of the system at the penetration into the sediment, and the large oscillating tilt more than ±10° was observed in descending. The function of the NX-2G system is based on 3 stage operations as shown in the image. The glass float is aimed not only to obtain enough buoyancy to extract the sensor unit, but also to suppress the oscillating tilt of the system in descending. In Oct. 2016, we made the first in-situ test of the NX-2G system with a ROV. It was dropped from the sea surface with the video camera and the acceleration logger. The ROV was used to watch the operation of the system at the seafloor. The landing looked well and it was examined from the acceleration data. As the maximum tilt in

  11. Synthesis and characterization of ZnO nanorod films for photocatalytic disinfection of contaminated water

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Juan, E-mail: rodriguezback@gmail.co [Facultad de Ciencias, Universidad Nacional de Ingenieria, P.O. Box 31-139, Av. Tupac Amaru 210, Lima (Peru); Universidad de Tarapaca, Av. General Velasquez 1775, Arica (Chile); Paraguay-Delgado, F. [Centro de Investigacion en Materiales Avanzados S. C. Miguel de Cervantes 120, Chihuahua, Chih, CP 31109 (Mexico); National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, Canada T6G 2 M9 (Canada); Lopez, Alcides; Alarcon, Julio; Estrada, Walter [Facultad de Ciencias, Universidad Nacional de Ingenieria, P.O. Box 31-139, Av. Tupac Amaru 210, Lima (Peru)

    2010-11-01

    The growth of ZnO nanorods on a flat substrate was studied as a function of the main parameters used in their preparation and their ability to photocatalytically eliminate bacteria in water. The seed layer was obtained, by a spray pyrolysis technique, from a zinc acetate solution. Subsequently, to grow the rods, the seeds were immersed in a basic solution of zinc nitrate maintained at 90 {sup o}C. The growth parameters, thickness of the seed layer, acidity of the precursor solution used to obtain the seed layer, and the rate of crystal growth on the seed layer during the thermal bath treatment, were studied. The resulting materials were characterized morphologically by scanning electron microscopy and transmission electron microscopy (TEM); X-ray diffraction and TEM were used to study their structure and ultraviolet-visible spectroscopy to determine their absorbance. Most of the obtained materials were textured in the (002) direction perpendicular to the substrate. The rods have a hexagonal cross section between 60 and 150 nm. Using these rods, the photocatalytic degradation of Escherichia coli bacteria in water was studied; a positive influence of the surface area and crystalline growth on the degradation rate was observed.

  12. Multilayered ordered mesoporous platinum/titania composite films: does the photocatalytic activity benefit from the film thickness?

    Czech Academy of Sciences Publication Activity Database

    Ismail, A. A.; Bahnemann, D.; Rathouský, Jiří; Yarovyi, V.; Wark, M.

    2011-01-01

    Roč. 21, č. 21 (2011), s. 7802-7810 ISSN 0959-9428 Institutional research plan: CEZ:AV0Z40400503 Keywords : titanium dioxide films * TiO2 thin films * sol-gel method Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.968, year: 2011

  13. A chemical bath deposition route to facet-controlled Ag{sub 3}PO{sub 4} thin films with improved visible light photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Gunjakar, Jayavant L.; Jo, Yun Kyung; Kim, In Young; Lee, Jang Mee; Patil, Sharad B. [Department of Chemistry and Nanoscience, College of Natural Sciences, Ewha Womans University, Seoul 03760 (Korea, Republic of); Pyun, Jae-Chul [Department of Materials Science and Engineering, College of Engineering, Yonsei University, Seoul (Korea, Republic of); Hwang, Seong-Ju, E-mail: hwangsju@ewha.ac.kr [Department of Chemistry and Nanoscience, College of Natural Sciences, Ewha Womans University, Seoul 03760 (Korea, Republic of)

    2016-08-15

    A facile, economic, and reproducible chemical bath deposition (CBD) method is developed for the fabrication of facet-controlled Ag{sub 3}PO{sub 4} thin films with enhanced visible light photocatalytic activity. The fine-control of bath temperature, precursor, complexing agent, substrate, and solution pH is fairly crucial in preparing the facet-selective thin film of Ag{sub 3}PO{sub 4} nanocrystal. The change of precursor from silver nitrate to silver acetate makes possible the tailoring of the crystal shape of Ag{sub 3}PO{sub 4} from cube to rhombic dodecahedron and also the bandgap tuning of the deposited films. The control of [Ag{sup +}]/[phosphate] ratio enables to maximize the loading amount of Ag{sub 3}PO{sub 4} crystals per the unit area of the deposited film. All the fabricated Ag{sub 3}PO{sub 4} thin films show high photocatalytic activity for visible light-induced degradation of organic molecules, which can be optimized by tailoring the crystal shape of the deposited crystals. This CBD method is also useful in preparing the facet-controlled hybrid film of Ag{sub 3}PO{sub 4}–ZnO photocatalyst. The present study clearly demonstrates the usefulness of the present CBD method for fabricating facet-controlled thin films of metal oxosalt and its nanohybrid. - Highlights: • The crystal facet of Ag{sub 3}PO{sub 4} films can be tuned by chemical bath deposition. • The crystal shape of Ag{sub 3}PO{sub 4} is tailorable from cube to rhombic dodecahedron. • Facet-tuned Ag{sub 3}PO{sub 4} film shows enhanced visible light photocatalyst activity.

  14. A chemical bath deposition route to facet-controlled Ag3PO4 thin films with improved visible light photocatalytic activity

    International Nuclear Information System (INIS)

    Gunjakar, Jayavant L.; Jo, Yun Kyung; Kim, In Young; Lee, Jang Mee; Patil, Sharad B.; Pyun, Jae-Chul; Hwang, Seong-Ju

    2016-01-01

    A facile, economic, and reproducible chemical bath deposition (CBD) method is developed for the fabrication of facet-controlled Ag 3 PO 4 thin films with enhanced visible light photocatalytic activity. The fine-control of bath temperature, precursor, complexing agent, substrate, and solution pH is fairly crucial in preparing the facet-selective thin film of Ag 3 PO 4 nanocrystal. The change of precursor from silver nitrate to silver acetate makes possible the tailoring of the crystal shape of Ag 3 PO 4 from cube to rhombic dodecahedron and also the bandgap tuning of the deposited films. The control of [Ag + ]/[phosphate] ratio enables to maximize the loading amount of Ag 3 PO 4 crystals per the unit area of the deposited film. All the fabricated Ag 3 PO 4 thin films show high photocatalytic activity for visible light-induced degradation of organic molecules, which can be optimized by tailoring the crystal shape of the deposited crystals. This CBD method is also useful in preparing the facet-controlled hybrid film of Ag 3 PO 4 –ZnO photocatalyst. The present study clearly demonstrates the usefulness of the present CBD method for fabricating facet-controlled thin films of metal oxosalt and its nanohybrid. - Highlights: • The crystal facet of Ag 3 PO 4 films can be tuned by chemical bath deposition. • The crystal shape of Ag 3 PO 4 is tailorable from cube to rhombic dodecahedron. • Facet-tuned Ag 3 PO 4 film shows enhanced visible light photocatalyst activity.

  15. A comparative study of humidity sensing and photocatalytic applications of pure and nickel (Ni)-doped WO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ramkumar, S. [Bannari Amman Institute of Technology, Department of Physics, Erode, Tamilnadu (India); Rajarajan, G. [Vidhya Mandhir Institute of Technology, Department of Physics, Erode, Tamilnadu (India)

    2017-06-15

    Nanocrystalline of pristine and nickel (Ni)-doped tungsten trioxide (WO{sub 3}) thin films was deposited by chemical bath deposition method. The concentrations of Ni ions were varied from 0 to 10 wt%. In order to improve the crystallinity of the films were annealed at 600 C for 2 h in the ambient atmosphere. X-ray diffraction results reveal that the WO{sub 3} doped with nickel crystallizes in monoclinic structure and the results are in good agreement with the standard JCPDS data (card no: 83-0951). AFM micrographs reveal that average grain size of about 27-39 nm for pure and Ni-doped WO{sub 3} thin films. In addition, the band gap of the Ni-doped WO{sub 3} nanostructures is facilely tunable by controlling the Ni contents. The humidity sensor setup was fabricated and measured for pure and Ni-doped WO{sub 3} thin film sensor with various level of RH (10-90%). The Ni-doped WO{sub 3} sensor showed fast response and high sensitivity than pure WO{sub 3}. The photocatalytic activities of the films were evaluated by degradation of methyl orange, methylene blue and phenol in an aqueous solution under visible light irradiation. The photocatalytic activity of WO{sub 3} nanostructures could be remarkably enhanced by doping the Ni impurity. (orig.)

  16. Photocatalytic and photoelectrocatalytic degradation of the drug omeprazole on nanocrystalline titania films in alkaline media: Effect of applied electrical bias on degradation and transformation products.

    Science.gov (United States)

    Tantis, Iosif; Bousiakou, Leda; Frontistis, Zacharias; Mantzavinos, Dionissios; Konstantinou, Ioannis; Antonopoulou, Maria; Karikas, George-Albert; Lianos, Panagiotis

    2015-08-30

    Photocatalytic and photoelectrocatalytic degradation of the drug omeprazole has been studied in the presence of nanocrystalline titania films supported on glass slides or transparent FTO electrodes in alkaline environment. Its photocatalytic degradation rate was assessed by its UV absorbance and by HPLC, while its transformation products were analyzed by HR-LC-MS. Based on UV absorbance, omeprazole can be photocatalytically degraded at an average rate of 6.7×10(-4)min(-1) under low intensity UVA irradiation of 1.5mWcm(-2) in the presence of a nanoparticulate titania film. This corresponds to degradation of 1.4mg of omeprazole per gram of the photocatalyst per liter of solution per hour. The photodegradation rate can be accelerated in a photoelectrochemical cell by applying a forward bias. In this case, the maximum rate reached under the present conditions was 11.6×10(-4)min(-1) by applying a forward bias of +0.6V vs. Ag/AgCl. Four major transformation products were successfully identified and their profiles were followed by HR-LC-MS. The major degradation path includes the scission of the sulfoxide bridge into the corresponding pyridine and benzimidazole ring derivates and this is accompanied by the release of sulfate anions in the reaction mixture. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Noble metals nanoparticles on titanium dioxide nanostructured films and the influence of their photocatalytic activity

    International Nuclear Information System (INIS)

    Nakamura, Liana Key Okada

    2012-01-01

    Currently, nanoscience and nanotechnology are considered an emerging field and continuously breaking the barrier among various disciplines. The main focus of study involves controlling structures at molecular level, arranging the atoms in order to achieve an understanding and controlling the fundamental properties of matter. In this study, molecular changes on the basis of morphology, optical and crystalline properties of TiO 2 hin films in order to increase their photon efficiency were proposed. The TiO 2 thin films were prepared by sol gel process evaluating the influence of different acids and templates to obtain the nano structured arrangements. Then, metal nanoparticles like Au, Ag, Pd and Pt were incorporated on TiO 2 thin films. This incorporation might minimize the electron-hole recombination, so it could improve the photon efficiency. From the several routes studied, the TiO 2 thin films prepared with acetic acid showed the best performance by the reason of low agglomeration of TiO 2 grains, which favors the exposure of the photoactive sites. The presence of template in the formulation had a slightly effect on photon efficiency, possible due to the higher agglomeration of the grains on the TiO 2 thin films. The addition of Pt and Au nanoparticles on TiO 2 thin films showed superior photon efficiency. The TiO 2 thin films with hexamine and metallic nanoparticles did not show the improvement on photon efficiency except for Pt and Au nanoparticles. On these situations, the improvement on photon efficiency is might be due to a possible decrease at the electron-hole recombination's velocity. Thus, the present work demonstrates the great influence of preparation conditions on the optical, morphological properties and the photon efficiency. In the future, with greater understanding of the mechanism of this influence, the properties of TiO 2 thin films will be able tailoring depending on the application. (author)

  18. Li–N doped and codoped TiO{sub 2} thin films deposited by dip-coating: Characterization and photocatalytic activity under halogen lamp

    Energy Technology Data Exchange (ETDEWEB)

    Hamden, Z. [University of Sfax-Faculty of Science-Laboratory CI, Sfax (Tunisia); Boufi, S. [University of Sfax-Faculty of Science-LMSE, Sfax (Tunisia); Conceição, D.S.; Ferraria, A.M.; Botelho do Rego, A.M.; Ferreira, D.P.; Vieira Ferreira, L.F. [Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, IST, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Bouattour, S., E-mail: soraa.boufi@yahoo.com [University of Sfax-Faculty of Science-Laboratory CI, Sfax (Tunisia)

    2014-09-30

    Graphical abstract: - Highlights: • Li and N have a synergetic effect on photocatalytic efficiency of codoped TiO{sub 2} under halogen lamp. • (Li, N) dopants decrease the recombination rate of photogenerated e–h. • (Li, N) dopants induce an increase of the energy gap, E{sub g}. • A decrease of crystallinity of the thin films seems to occur for high loadings of co-doping. - Abstract: Li-, N-doped and codoped TiO{sub 2} powders and thin films, deposited on glass substrate using dip-coating method and Ti(OBu){sub 4} as precursor, were prepared and their structural properties were investigated using grazing angle X-ray diffraction (GXRD), Raman spectroscopy, time resolved luminescence, X-ray photoelectron spectroscopy (XPS), ground state diffuse reflectance absorption and scanning electron microscopy (SEM). Unlike the powder samples, thin films with the same composition and calcination temperature exhibited lower crystallinity degree along with the prevalence of the anatase phase. Ground state diffuse reflectance absorption studies carried on the nanopowders have shown that both the Li and N dopants led to an increase of the band gap. XPS studies revealed differences in the binding energy of N in the presence and in the absence of Li, which was explained in terms of a modification in the chemical environment of N when Li is introduced. The photocatalytic activity of the ensuing film toward the degradation of aromatic amine pollutant revealed a huge enhancement upon doping with N or codoping with N and Li. This behavior is probably provide by a charge-transfer-complex mechanism in which neither the photocatalyst nor the organic compounds absorbs visible light by itself. The improvement in the photocatalytic properties occurred simultaneously with the increase of the lifetime of the charge carriers whenever N and Li were introduced at a level 2%.

  19. Photocatalytic and photoelectrocatalytic degradation of the drug omeprazole on nanocrystalline titania films in alkaline media: Effect of applied electrical bias on degradation and transformation products

    Energy Technology Data Exchange (ETDEWEB)

    Tantis, Iosif [Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras (Greece); Bousiakou, Leda [Department of Physics and Astronomy, King Saud University, Riyadh (Saudi Arabia); Department of Automation Engineering, Technological Educational Institute of Pireaus, GR-12244 Athens (Greece); Frontistis, Zacharias; Mantzavinos, Dionissios [Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras (Greece); Konstantinou, Ioannis; Antonopoulou, Maria [Department of Environmental and Natural Resources Management, University of Patras, GR-30100 Agrinio (Greece); Karikas, George-Albert [Department of Medical Laboratories Technology, Technological Educational Institute of Athens, 12210 Athens (Greece); Lianos, Panagiotis, E-mail: lianos@upatras.gr [Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras (Greece); FORTH/ICE-HT, P.O. Box 1414, GR-26504 Patras (Greece)

    2015-08-30

    Highlights: • Photocatalytic and photoelectrocatalytic degradation of the proton pump omeprazole. • Improvement of photocatalysis rate by applying a moderate forward bias. • Highlighting of the advantages of photoelectrocatalysis in a straightforward manner. • HPLC and HR-LC–MS analysis of transformation products. - Abstract: Photocatalytic and photoelectrocatalytic degradation of the drug omeprazole has been studied in the presence of nanocrystalline titania films supported on glass slides or transparent FTO electrodes in alkaline environment. Its photocatalytic degradation rate was assessed by its UV absorbance and by HPLC, while its transformation products were analyzed by HR-LC–MS. Based on UV absorbance, omeprazole can be photocatalytically degraded at an average rate of 6.7 × 10{sup −4} min{sup −1} under low intensity UVA irradiation of 1.5 mW cm{sup −2} in the presence of a nanoparticulate titania film. This corresponds to degradation of 1.4 mg of omeprazole per gram of the photocatalyst per liter of solution per hour. The photodegradation rate can be accelerated in a photoelectrochemical cell by applying a forward bias. In this case, the maximum rate reached under the present conditions was 11.6 × 10{sup −4} min{sup −1} by applying a forward bias of +0.6 V vs. Ag/AgCl. Four major transformation products were successfully identified and their profiles were followed by HR-LC–MS. The major degradation path includes the scission of the sulfoxide bridge into the corresponding pyridine and benzimidazole ring derivates and this is accompanied by the release of sulfate anions in the reaction mixture.

  20. Photocatalytic and photoelectrocatalytic degradation of the drug omeprazole on nanocrystalline titania films in alkaline media: Effect of applied electrical bias on degradation and transformation products

    International Nuclear Information System (INIS)

    Tantis, Iosif; Bousiakou, Leda; Frontistis, Zacharias; Mantzavinos, Dionissios; Konstantinou, Ioannis; Antonopoulou, Maria; Karikas, George-Albert; Lianos, Panagiotis

    2015-01-01

    Highlights: • Photocatalytic and photoelectrocatalytic degradation of the proton pump omeprazole. • Improvement of photocatalysis rate by applying a moderate forward bias. • Highlighting of the advantages of photoelectrocatalysis in a straightforward manner. • HPLC and HR-LC–MS analysis of transformation products. - Abstract: Photocatalytic and photoelectrocatalytic degradation of the drug omeprazole has been studied in the presence of nanocrystalline titania films supported on glass slides or transparent FTO electrodes in alkaline environment. Its photocatalytic degradation rate was assessed by its UV absorbance and by HPLC, while its transformation products were analyzed by HR-LC–MS. Based on UV absorbance, omeprazole can be photocatalytically degraded at an average rate of 6.7 × 10 −4 min −1 under low intensity UVA irradiation of 1.5 mW cm −2 in the presence of a nanoparticulate titania film. This corresponds to degradation of 1.4 mg of omeprazole per gram of the photocatalyst per liter of solution per hour. The photodegradation rate can be accelerated in a photoelectrochemical cell by applying a forward bias. In this case, the maximum rate reached under the present conditions was 11.6 × 10 −4 min −1 by applying a forward bias of +0.6 V vs. Ag/AgCl. Four major transformation products were successfully identified and their profiles were followed by HR-LC–MS. The major degradation path includes the scission of the sulfoxide bridge into the corresponding pyridine and benzimidazole ring derivates and this is accompanied by the release of sulfate anions in the reaction mixture

  1. Photocatalytic activity of V doped ZnO nanoparticles thin films for the removal of 2- chlorophenol from the aquatic environment under natural sunlight exposure.

    Science.gov (United States)

    Salah, Numan; Hameed, A; Aslam, M; Babkair, Saeed S; Bahabri, F S

    2016-07-15

    Vanadium doped ZnO powders were used as precursors to deposit thin films of V(5+) incorporated ZnO nanoparticles on glass substrates by the pulsed laser deposition technique. The observed variations in Raman signals, visible region shift in the diffuse reflectance spectra along with a small shift in the (101) reflections of the X-ray diffraction (XRD) confirmed the insertion of V(5+) ions in ZnO lattice. No other additional reflection in the XRD results other than ZnO further endorsed the occupation of lattice positions by V entities rather than independent oxide formation. The asymmetric XPS peaks of Zn2p and V2p core levels confirmed the existence of both in the vicinity. The existence of minimal proportion of V(3+) along with V(5+) states varied the alteration of the oxidation states V in the synthetic route. The SEM images at various resolutions displayed the uniform distribution identical nanoparticles without the presence of additional phases in the deposited films. The SEM cross-section measurements revealed the uniform thickness of ∼90 nm of each film, whereas the surface studies of the films were performed by AFM. The as-synthesized films were tested for photocatalytic activity in sunlight illumination for the removal of 2-chlorophenol. The unique feature of the study was the estimation of the photocatalytic activity 20 ppm of 2-chlorophenol by exposing the low exposed area. The degradation of the substrate was measured by liquid phase UV-vis spectroscopy, whereas total organic carbon measurement revealed the mineralization of the substrate. The released Cl(-) ions were also measured by ion chromatography. The estimated flatband potentials and pHzpc values of the V doped materials, by Mott-Schottky analysis and zeta potential measurements respectively, were correlated with the photocatalytic activity. The kinetics of the photocatalytic degradation/mineralization process was estimated and results were correlated with the plausible mechanism. Copyright

  2. Thick film titania on glass supports for vapour phase photocatalytic degradation of toluene, acetone, and ethanol

    Czech Academy of Sciences Publication Activity Database

    Neti, R.N.; Parmar, G.R.; Bakardjieva, Snejana; Šubrt, Jan

    2010-01-01

    Roč. 163, č. 3 (2010), s. 219-229 ISSN 1385-8947 Institutional research plan: CEZ:AV0Z40320502 Keywords : titania photocatalyst * thick films * glass support Subject RIV: CA - Inorganic Chemistry Impact factor: 3.074, year: 2010

  3. Improving the Photocatalytic Performance of Mesoporous Titania Films by Modification with Gold Nanostructures

    Czech Academy of Sciences Publication Activity Database

    Bannat, I.; Wessels, K.; Oekermann, T.; Rathouský, Jiří; Bahnemann, D.; Wark, M.

    2009-01-01

    Roč. 21, č. 8 (2009), s. 1645-1653 ISSN 0897-4756 R&D Projects: GA ČR GA104/08/0435 Institutional research plan: CEZ:AV0Z40400503 Keywords : thin films * metal nanoparticles * optical properties Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.368, year: 2009

  4. Nb-doped TiO2 thin films as photocatalytic materials

    Indian Academy of Sciences (India)

    Administrator

    ) instrument was used for this purpose. The monochromatic X-ray radiation AlKα. (hν = 1486.7 eV) was the excitation source. Scanning electron microscopy (SEM) analysis was carried out to investigate the surface morphology of the films, by ...

  5. Effects of Ni doping on photocatalytic activity of TiO2 thin films ...

    Indian Academy of Sciences (India)

    Wintec

    Ni–TiO2 thin film; LPD technique; photodegradation. 1. Introduction. In the field of photocatalysis, the polycrystalline system formed by transition metal-ion-doped TiO2 has been the object of several studies (Palmisano et al 1988; Soria et al 1991; Karakitsou and Verykios 1993; Choi et al 1994;. Litter and Navio 1994, 1996).

  6. Surface Structure and Photocatalytic Activity of Nano-TiO2 Thin Film

    Science.gov (United States)

    Controlled titanium dioxide (TiO2) thin films were deposited on stainless steel surfaces using flame aerosol synthetic technique, which is a one-step coating process, that doesn’t require further calcination. Solid state characterization of the coatings was conducted by different...

  7. Simultaneous Adsorption and Photocatalytic Degradation of Malachite Green Using Electrospun P(3HB-TiO2 Nanocomposite Fibers and Films

    Directory of Open Access Journals (Sweden)

    Nanthini Sridewi

    2011-01-01

    Full Text Available This paper demonstrated the applicability of electrospun P(3HB film as a dye adsorbent agent. Malachite green (MG was used as the model dye in this study. Interestingly, the electrospun P(3HB film exhibited excellent dye adsorption capacity whereby 78% of dye was adsorbed from a 30 μM solution of MG. The film was further improvised by incorporating titanium dioxide photocatalysts to form a dual dye treatment system employing adsorption and photocatalytic degradation techniques. The resultant electrospun P(3HB-50 wt%   TiO2 was capable of completely decolorizing MG in 45 min under solar irradiation, which corresponded to 58.7%  COD removal. The fully decolorized MG solution also proved to be nontoxic against A. aegypti mosquito larvae. The reapplicability of this film was possible as it induced a decolorization rate of 98% or more at every usage for ten consequent usages. EDX analysis suggested that there were no significant changes in the concentration of titanium (Ti in the film before and after ten times of usage. The concentration of Ti in cast P(3HB-50 wt%  TiO2 film was found to decrease significantly during the repeated usage. The electrospun P(3HB-50 wt%  TiO2 film has high potency as an efficient and inexpensive yet simple method for the dye effluent decolorization, degradation, and detoxification.

  8. Electrodeposition of hierarchical ZnO/Cu{sub 2}O nanorod films for highly efficient visible-light-driven photocatalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Ren, S. T.; Fan, G. H.; Liang, M. L.; Wang, Q. [Department of Optoelectronic Science, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Zhao, G. L., E-mail: zhaoguoliang@hit.edu.cn [School of Materials and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209 (China)

    2014-02-14

    The development of high-performance visible-light-responsive photocatalytic materials has attracted widespread interest due to their potential applications in the environmental and energy industries. In this work, hierarchical ZnO nanorods films were successfully prepared on the stainless steel mesh substrates via a simple two-step seed-assisted electrodeposition route. Cu{sub 2}O nanoparticles were then electrodeposited on the surface of ZnO nanorods to form the core-shell heterostructure. The synthesized ZnO/Cu{sub 2}O nanocomposites were characterized by X-ray diffraction, field-emission scanning electron microscopy, and UV-visible spectrophotometer. Due to the branched hierarchical morphologies and core-shell structure, ZnO/Cu{sub 2}O nanomaterials show a prominent visible-light-driven photocatalytic performance under the low-intensity light irradiation (40 mW/cm{sup 2}). The influence of some experimental parameters, such as Cu{sub 2}O loading amount, ZnO morphologies, the substrate type, and the PH of the Cu{sub 2}O precursor solution on ZnO/Cu{sub 2}O photocatalytic performance was evaluated.

  9. Photocatalytic properties of different TiO2 thin films of various porosity and titania loading

    Czech Academy of Sciences Publication Activity Database

    Zita, J.; Krýsa, J.; Černigoj, U.; Lavrenčič-Štangar, U.; Jirkovský, Jaromír; Rathouský, Jiří

    2011-01-01

    Roč. 161, č. 1 (2011), s. 29-34 ISSN 0920-5861 R&D Projects: GA MŠk 1M0577; GA ČR GA104/08/0435 Institutional research plan: CEZ:AV0Z40400503 Keywords : sol-gel * titanium dioxide film * porosity Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.407, year: 2011

  10. Photocatalytic activity of hydrophobized mesoporous thin films of TiO.sub.2./sub

    Czech Academy of Sciences Publication Activity Database

    Wark, M.; Tschirch, J.; Bartels, O.; Bahnemann, D.; Rathouský, Jiří

    2005-01-01

    Roč. 84, 1-3 (2005), s. 247-253 ISSN 1387-1811 R&D Projects: GA ČR GA203/03/0824; GA ČR GA203/01/0617 Grant - others:Deutsche Forschungsgemeintschaft(DE) WA 1116/7-1; DAAD(DE) D/04/25758 Institutional research plan: CEZ:AV0Z40400503 Keywords : mesoporous TiO 2 films * hydrophobicity * photocatalysis * decomposition of dyes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.355, year: 2005

  11. Novel development of nanocrystalline kesterite Cu2ZnSnS4 thin film with high photocatalytic activity under visible light illumination

    Science.gov (United States)

    Apostolopoulou, Andigoni; Mahajan, Sandip; Sharma, Ramphal; Stathatos, Elias

    2018-01-01

    Cu2ZnSnS4 (CZTS) represents a promising p-type direct band gap semiconductor with large absorption coefficient in the visible region of solar light. In the present study, a kesterite CZTS nanocrystalline film, with high purity, was successfully synthesized via the combination of successive ionic layer adsorption and reaction (SILAR) and chemical bath deposition (CBD) technique. The morphology and structural properties of the CZTS films were characterized by FE-SEM microscopy, porosimetry in terms of Brunauer-Emmett-Teller (BET) technique, X-ray diffraction and Raman spectroscopy. The as-prepared films under mild heat treatment at 250 °C in the presence of sulfur atmosphere exhibited fine nanostructure with 35 nm average particle size, high specific surface area of 53 m2/g and 9 nm pore diameter. The photocatalytic activity of the films was examined to the degradation of Basic Blue 41 (BB-41) and Acid Orange 8 (AO-8) organic azo dyes under visible light irradiation, demonstrating 97.5% and 70% discoloration for BB-41 and AO-8 respectively. Reusability of the CZTS films was also tested proving good stability over several repetitions. The reduction of photocatalyst's efficiency after three successive repetitions didn't exceed 5.6% and 8.5% for BB-41 and AO-8 respectively.

  12. Rapid thermally annealed plasma deposited SiNx:H thin films: Application to metal-insulator-semiconductor structures with Si, In0.53Ga0.47As, and InP

    International Nuclear Information System (INIS)

    Martil, I.; Prado, A. del; San Andres, E.; Gonzalez Diaz, G.; Martinez, F.L.

    2003-01-01

    We present in this article a comprehensive study of rapid thermal annealing (RTA) effects on the physical properties of SiN x :H thin films deposited by the electron cyclotron resonance plasma method. Films of different as-deposited compositions (defined in this article as the nitrogen to silicon ratio, x=N/Si) were analyzed: from Si-rich (x=0.97) to N-rich (x=1.6) films. The evolution of the composition, bonding configuration, and paramagnetic defects with the annealing temperature are explained by means of different network bond reactions that take place depending on the as-deposited film composition. All the analyzed films release hydrogen, while Si-rich and near-stoichiometric (x=1.43) ones also lose nitrogen upon annealing. These films were used to make Al/SiN x :H/semiconductor devices with Si, In 0.53 Ga 0.47 As, and InP. After RTA treatments, the electrical properties of the three different SiN x :H/semiconductor interfaces can be explained, noting the microstructural modifications that SiN x :H experiences upon annealing

  13. High efficient photocatalytic activity from nanostructuralized photonic crystal-like p-n coaxial hetero-junction film photocatalyst of Cu3SnS4/TiO2 nanotube arrays

    Science.gov (United States)

    Li, Yan; Liu, Fang-Ting; Chang, Yin; Wang, Jian; Wang, Cheng-Wei

    2017-12-01

    Structuring the materials in the form of photonic crystals is a new strategy for photocatalytic applications. Herein, a new concept of photonic crystal-induced p-n coaxial heterojunction film photocatalyst of Cu3SnS4/TiO2 (CTS/PhC-TNAs) was well-designed and successfully fabricated by combining periodic pulse anodic oxidation and in-situ self-assembling methods Such nanostructured CTS/PhC-TNAs exhibited significantly improved photocatalytic degradation activity under simulated sunlight irradiation with methyl orange (MO) as the target pollutants. Within 120 min, 82% of the MO (10 mg/L) was photodegraded and its kinetic constant per specific surface area reached 0.05332 μmol/m2h, which is 1.6 and 12.8 times more quickly than that of PhC-TNAs and CTS, respectively. Its significantly enhanced photocatalytic activity could be mainly attributed to a joint effect of the unique photonic crystal property of PhC-TNAs and the nanostructured hollow p-n coaxial hetero-junction, which result in an increased efficiency of charge separation and transfer and also an improved spectral response capability. This photonic crystal film photocatalyst has the potential for enhancing the photocatalytic activity via further optimizing the photonic stop band of PhC-TNAs. The study presents a new means to design the kind of photonic crystal structural-induced novel photocatalysts with high photocatalytic activities in pollution treatment.

  14. Thin-film fixed-bed reactor (TFFBR for solar photocatalytic inactivation of aquaculture pathogen Aeromonas hydrophila

    Directory of Open Access Journals (Sweden)

    Khan Sadia J

    2012-01-01

    Full Text Available Abstract Background Outbreaks of infectious diseases by microbial pathogens can cause substantial losses of stock in aquaculture systems. There are several ways to eliminate these pathogens including the use of antibiotics, biocides and conventional disinfectants, but these leave undesirable chemical residues. Conversely, using sunlight for disinfection has the advantage of leaving no chemical residue and is particularly suited to countries with sunny climates. Titanium dioxide (TiO2 is a photocatalyst that increases the effectiveness of solar disinfection. In recent years, several different types of solar photocatalytic reactors coated with TiO2 have been developed for waste water and drinking water treatment. In this study a thin-film fixed-bed reactor (TFFBR, designed as a sloping flat plate reactor coated with P25 DEGUSSA TiO2, was used. Results The level of inactivation of the aquaculture pathogen Aeromonas hydrophila ATCC 35654 was determined after travelling across the TFFBR under various natural sunlight conditions (300-1200 W m-2, at 3 different flow rates (4.8, 8.4 and 16.8 L h-1. Bacterial numbers were determined by conventional plate counting using selective agar media, cultured (i under conventional aerobic conditions to detect healthy cells and (ii under conditions designed to neutralise reactive oxygen species (agar medium supplemented with the peroxide scavenger sodium pyruvate at 0.05% w/v, incubated under anaerobic conditions, to detect both healthy and sub-lethally injured (oxygen-sensitive cells. The results clearly demonstrate that high sunlight intensities (≥ 600 W m-2 and low flow rates (4.8 L h-1 provided optimum conditions for inactivation of A. hydrophila ATCC 3564, with greater overall inactivation and fewer sub-lethally injured cells than at low sunlight intensities or high flow rates. Low sunlight intensities resulted in reduced overall inactivation and greater sub-lethal injury at all flow rates. Conclusions This

  15. TiO{sub 2}/SiO{sub 2} porous composite thin films: Role of TiO{sub 2} areal loading and modification with gold nanospheres on the photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Levchuk, Irina, E-mail: irina.r.levchuk@gmail.com [Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland); Laboratoire de Chimie, ENS Lyon, CNRS, Universite Claude Bernard Lyon 1, Universite de Lyon, UMR 5182, 46 allee d’Italie, 69364 Lyon (France); Sillanpää, Mika [Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland); Guillard, Chantal [Institut de Recherches sur la Catalyse et l’Environnement, IRCELYON, CNRS—University of Lyon, 69100 (France); Gregori, Damia; Chateau, Denis; Parola, Stephane [Laboratoire de Chimie, ENS Lyon, CNRS, Universite Claude Bernard Lyon 1, Universite de Lyon, UMR 5182, 46 allee d’Italie, 69364 Lyon (France)

    2016-10-15

    Highlights: • Composite TiO{sub 2}/Au/SiO{sub 2} films were prepared by sol-gel. • Size of Au NPs was in range 5–7 nm. • Physico-chemical and photocatalytic properties of TiO{sub 2}/Au/SiO{sub 2} were tested. • After UVC treatment all coatings exhibit super-hydrophilic character. • Photocatalytic activity of thin films was associated with areal loading of TiO{sub 2}. - Abstract: The aim of the work was to study photocatalytic activity of composite TiO{sub 2}/Au/SiO{sub 2} thin films. Coatings were prepared using sol-gel technique. Physicochemical parameters of coatings were characterized using UV–vis spectrometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES), ellipsometry, tactile measurements, goniometry and diffuse reflectance measurements. The photocatalytic activity of the films was tested in batch mode using aqueous solution of formic acid. Changes of formic acid concentration were determined by means of high pressure liquid chromatography (HPLC). Increase of initial degradation rate of formic acid was detected for TiO{sub 2}/Au/SiO{sub 2} films with gold nanoparticle’s load 0.5 wt.% and 1.25 wt.%. However, deeper insights using more detailed characterization of these coatings demonstrated that the improvement of the photocatalytic activity is more probably attributed to an increase in the areal loading of TiO{sub 2}.

  16. ZnO/Cu2S/ZnO Multilayer Films: Structure Optimization and Its Detail Data for Applications on Photoelectric and Photocatalytic Properties

    Directory of Open Access Journals (Sweden)

    Zhenxing Wang

    2017-01-01

    Full Text Available Monolayer Cu2S and ZnO, and three kinds of complex films, Cu2S/ZnO, ZnO/Cu2S, and ZnO/Cu2S/ZnO, were deposited on glass substrates by means of radio frequency (RF magnetron sputtering device. The impact of the thickness of ZnO and Cu2S on the whole transmittance, conductivity, and photocatalysis was investigated. The optical and electrical properties of the multilayer were studied by optical spectrometry and four point probes. Numerical simulation of the optical transmittance of the multilayer films has been carried out in order to guide the experimental work. The comprehensive performances of the multilayers as transparent conductive coatings were compared using the figure of merit. Compared with monolithic Cu2S and ZnO films, both the optical transmission property and photocatalytic performance of complex films such as Cu2S/ZnO and ZnO/Cu2S/ZnO change significantly.

  17. Surface characterisation and photocatalytic performance of N-doped TiO2 thin films deposited onto 200 nm pore size alumina membranes by sol–gel methods

    International Nuclear Information System (INIS)

    Grilli, R.; Di Camillo, D.; Lozzi, L.; Horovitz, I.; Mamane, H.; Avisar, D.; Baker, M.A.

    2015-01-01

    Membrane filtration is employed for water treatment and wastewater reclamation purposes, but membranes alone are unable to remove pollutant molecules and certain pathogens. Photocatalytically active N-doped TiO 2 coatings have been deposited by sol–gel onto 200 nm pore size alumina membranes for water treatment applications using two different methods, via pipette droplets or spiral bar applicator. The uncoated and coated membranes were characterised by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectrometry (EDX). Both coatings showed the presence of N-doped anatase, with a surface coverage between 84 and 92%, and nitrogen concentration (predominantly interstitial) of 0.9 at.%. The spiral bar applicator deposited coatings exhibit a thicker mud-cracked surface layer with limited penetration of the porous membrane, whilst the pipette deposited coatings have mostly penetrated into the bulk of the membrane and a thinner layer is present at the surface. The photocatalytic activity (PCA), measured through the degradation of carbamazepine (CBZ), under irradiation of a solar simulator was 58.6% for the pipette coating and 63.3% for the spiral bar coating. These photocatalytically active N-doped sol–gel coated membranes offer strong potential in forming the fundamental basis of a sunlight based water treatment system. - Highlights: • Sol gel N-doped TiO 2 thin films were deposited on 200 nm pore size Al 2 O 3 membranes. • Two sol–gel methods have been compared – pipette drop and spiral bar deposition. • The coatings showed a similar microstructure and composition but different morphology. • The PCA (degradation of carbamazepine) was ∼60% for both sol–gel coatings. • The coated membranes are promising for use in a membrane based water treatment system

  18. Electrochemically Assisted Photocatalytic Degradation of Oxalic Acid on Particulate TiO2 Film in a Batch Mode Plate Photoreactor

    Czech Academy of Sciences Publication Activity Database

    Krýsa, J.; Jirkovský, Jaromír

    2002-01-01

    Roč. 32, - (2002), s. 591-596 ISSN 0021-891X R&D Projects: GA ČR GA203/99/0763 Institutional research plan: CEZ:AV0Z4040901 Keywords : degradation * electrochemical * photocatalytic Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.117, year: 2002

  19. In situ construction of g-C3N4/TiO2 heterojunction films with enhanced photocatalytic activity over magnetic-driven rotating frame

    Science.gov (United States)

    Pan, Chao; Jia, Jia; Hu, Xiaoyun; Fan, Jun; Liu, Enzhou

    2018-02-01

    Corn-shaped TiO2 nanofilms were fabricated by a glycerol-assisted hydrothermal method, and then g-C3N4 was deposited on the surface of TiO2 films using melamine as precursor under air atmosphere by an in site microwave-heating technique. The investigations indicate that microwave-heating process is a facile strategy to obtain g-C3N4 by thermal polymerization of melamine, which can achieve in situ constructing of g-C3N4/TiO2 heterojunction films with high stability. The as-prepared TiO2 films with crack and holes have visible light scattering capability, and the scattering light overlaps with the intrinsic absorption of g-C3N4, leading to an absorption plateau in the range of 400-550 nm. Besides, a magnetic-driven rotating frame was developed to enhance the mass transfer processes during the photocatalytic water splitting. The result shows that g-C3N4/TiO2 films exhibit excellent activities under simulated-sunlight irradiation, in addition to the enhanced mass transfer, the overlapped visible light absorption, stable contact and effective charge transfer between g-C3N4 and TiO2 can facilitate the hydrogen production and light utilization efficiency as well. The hydrogen production rate can reach 13.8 mmol h-1 m-2 over g-C3N4/TiO2 films prepared using 0.5 g of melamine and 16.0 cm2 of TiO2.

  20. Hydrogenated nanoporous TiO{sub 2} film on Ti−25Nb−3Mo−2Sn−3Zr alloy with enhanced photocatalytic and sterilization activities driven by visible light

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lixia; He, Fang, E-mail: fanghe_tju@tju.edu.cn; Huang, Yuan; Meng, Yuhuan; Guo, Ruisong, E-mail: rsguo@tju.edu.cn

    2016-09-05

    Anatase TiO{sub 2} film with highly-ordered nanoporous structure was successfully synthesized on Ti−25Nb−3Mo−2Sn−3Zr (TLM) alloy through a simple two-step anodization method and a subsequent hydrogenated process. The results show that the obtained TiO{sub 2} film on TLM alloy presents a thickness of 900 nm and contains numerous oxygen vacancies. Furthermore, the concentration of oxygen vacancies can be tuned by controlling the temperature of hydrogen annealing. Through the first-principles calculations, it is found that the presence of oxygen vacancy can effectively narrow the band gap of TiO{sub 2} and thus expand light absorption range of TiO{sub 2} to visible light. The sample hydrogenated at 400 °C displays good photocatalytic and photocatalytic sterilization activities, which can be ascribed to the special structure, enhanced crystallinity and oxygen vacancies content of TiO{sub 2} film. These features make the material a good candidate in practical application. - Highlights: • Well-bonded and nanoporous TiO{sub 2} film on TLM alloy was successfully prepared using a modified two-step anodization. • The content-controlled oxygen vacancies are introduced into TiO{sub 2} via hydrogen annealing. • The obtained sample displays good photocatalytic and sterilization activities under visible-light irradiation.

  1. Photophysical and photocatalytic properties of Bi{sub 2}MNbO{sub 7} (M = Al, In, Ga, Fe) thin films prepared by dip-coating

    Energy Technology Data Exchange (ETDEWEB)

    Ropero-Vega, J.L., E-mail: jlropero@ciencias.uis.edu.co [Centro de Investigaciones en Catalisis - CICAT, Universidad Industrial de Santander - UIS, Sede Guatiguara Km. 2 via El Refugio, C.P. 681011, Piedecuesta (Santander) (Colombia); Rosas-Barrera, K.L. [Grupo de Investigaciones en Minerales, Biohidrometalurgia y Ambiente - GIMBA, Universidad Industrial de Santander - UIS, Sede Guatiguara Km. 2 via El Refugio, C.P. 681011, Piedecuesta (Santander) (Colombia); Pedraza-Avella, J.A. [Centro de Investigaciones en Catalisis - CICAT, Universidad Industrial de Santander - UIS, Sede Guatiguara Km. 2 via El Refugio, C.P. 681011, Piedecuesta (Santander) (Colombia); Laverde-Catano, D.A., E-mail: dlaverde@uis.edu.co [Grupo de Investigaciones en Minerales, Biohidrometalurgia y Ambiente - GIMBA, Universidad Industrial de Santander - UIS, Sede Guatiguara Km. 2 via El Refugio, C.P. 681011, Piedecuesta (Santander) (Colombia); Pedraza-Rosas, J.E. [Grupo de Investigaciones en Minerales, Biohidrometalurgia y Ambiente - GIMBA, Universidad Industrial de Santander - UIS, Sede Guatiguara Km. 2 via El Refugio, C.P. 681011, Piedecuesta (Santander) (Colombia); Nino-Gomez, M.E. [Centro de Investigaciones en Catalisis - CICAT, Universidad Industrial de Santander - UIS, Sede Guatiguara Km. 2 via El Refugio, C.P. 681011, Piedecuesta (Santander) (Colombia)

    2010-10-25

    In this work we report the preparation and characterization of Bi{sub 2}MNbO{sub 7} (M = Al, Ga, In, Fe) transparent thin films on glass slides. The films were obtained by dip-coating using bismuth(III) acetate, niobium(V) ethoxide and the corresponding metal(III) acetylacetonate precursors. Crystal structure and elemental analysis were performed by X-ray diffraction (XRD) and energy dispersive X-ray fluorescence (EDXRF). The band-gap energy (E{sub g}) of the semiconductor films was estimated by UV-vis spectroscopy. Their photocatalytic activity was evaluated in the degradation of methyl orange (MeO) in aqueous solution. The presence of a crystalline phase in the Bi-M-Nb-O (M = Al, Ga, In, Fe) systems with pyrochlore-type structure was suggested by the diffraction peak at 2{theta} {approx} 29.01. The elemental proportion in the Bi-Ga-Nb-O film fits better to the stoichiometric ratio in Bi{sub 2}MNbO{sub 7}. The estimated E{sub g} values were: Bi{sub 2}FeNbO{sub 7} (2.47 eV) < Bi{sub 2}GaNbO{sub 7} (2.67 eV) < Bi{sub 2}AlNbO{sub 7} (2.79 eV) < Bi{sub 2}InNbO{sub 7} (3.01 eV) and the calculated kinetic parameter t{sub 1/2} were: Bi{sub 2}GaNbO{sub 7} (239 min) < Bi{sub 2}AlNbO{sub 7} (278 min) < Bi{sub 2}InNbO{sub 7} (296 min) < Bi{sub 2}FeNbO{sub 7} (319 min). These results indicate that a slight band-gap narrowing has a positive effect in the photocatalytic properties but those further than E{sub g} < 2.5 eV has a detrimental effect.

  2. Investigation of microstructure and properties of ultrathin graded ZrNx self-assembled diffusion barrier in deep nano-vias prepared by plasma ion immersion implantation

    Science.gov (United States)

    Zou, Jianxiong; Liu, Bo; Lin, Liwei; Lu, Yuanfu; Dong, Yuming; Jiao, Guohua; Ma, Fei; Li, Qiran

    2018-01-01

    Ultrathin graded ZrNx self-assembled diffusion barriers with controllable stoichiometry was prepared in Cu/p-SiOC:H interfaces by plasma immersion ion implantation (PIII) with dynamic regulation of implantation fluence. The fundamental relationship between the implantation fluence of N+ and the stoichiometry and thereby the electrical properties of the ZrNx barrier was established. The optimized fluence of a graded ZrN thin film with gradually decreased Zr valence was obtained with the best electrical performance as well. The Cu/p-SiOC:H integration is thermally stable up to 500 °C due to the synergistic effect of Cu3Ge and ZrNx layers. Accordingly, the PIII process was verified in a 100-nm-thick Cu dual-damascene interconnect, in which the ZrNx diffusion barrier of 1 nm thick was successfully self-assembled on the sidewall without barrier layer on the via bottom. In this case, the via resistance was reduced by approximately 50% in comparison with Ta/TaN barrier. Considering the results in this study, ultrathin ZrNx conformal diffusion barrier can be adopted in the sub-14 nm technology node.

  3. Photo-catalytic studies of transition metal doped titanium dioxide thin films processed by metalorganic decomposition (MOD) method

    Science.gov (United States)

    Talagala, P.; Marko, X.; Padmanabhan, K. R.; Naik, R.; Rodak, D.; Cheng, Y. T.

    2006-03-01

    We have synthesized pure and transition element (Fe, Co and V) doped Titanium oxide thin films of thickness ˜ 350 nm on sapphire, Si, and stainless steel substrates by Metalorganic Decomposition (MOD) method. The films were subsequently annealed at appropriate temperatures ( 500-750C) to obtain either anatase or the rutile phase of TiO2. Analysis of the composition of the films were performed by energy dispersive X-ray(EDAX) and Rutherford backscattering spectrometry(RBS). Ion channeling was used to identify possible epitaxial growth of the films on sapphire. Both XRD and Raman spectra of the films exhibit that the films annealed at 550C are of anatase phase, while those annealed at 700C seem to prefer a rutile structure. The water contact angle measurements of the films before and after photoactivation, demonstrate a significant reduction in the contact angle for the anatase phase. However, the variation in contact angle was observed for films exposed to UV (<10^o-30^o) and dark (25^o-50^o). Films doped with Fe show a trend towards lower contact angle than those doped with Co. Results with films doped with V will also be included.

  4. Photocatalytic reactor

    Science.gov (United States)

    Bischoff, Brian L.; Fain, Douglas E.; Stockdale, John A. D.

    1999-01-01

    A photocatalytic reactor for processing selected reactants from a fluid medium comprising at least one permeable photocatalytic membrane having a photocatalytic material. The material forms an area of chemically active sites when illuminated by light at selected wavelengths. When the fluid medium is passed through the illuminated membrane, the reactants are processed at these sites separating the processed fluid from the unprocessed fluid. A light source is provided and a light transmitting means, including an optical fiber, for transmitting light from the light source to the membrane.

  5. Potential for photocatalytic degradation of the potassic diclofenac using scandium and silver modified titanium dioxide thin films; Potencial de degradacao fotocatalitica do diclofenaco potassico utilizando filmes finos de dioxido de titanio modificado com escandio e prata

    Energy Technology Data Exchange (ETDEWEB)

    Ciola, R.A.; Oliveira, C.T.; Lopes, S.A.; Cavalheiro, A.A., E-mail: rafaelciola@hotmail.com [Universidade Estadual de Mato Grosso do Sul (UFMS), Navirai, MS (Brazil). Centro de Pesquisas Tecnologicas em Recursos Naturais

    2011-07-01

    The potential for photocatalytic degradation of the potassic diclofenac drug was investigated using titanium dioxide thin films modified with two modifier types, scandium and silver, both prepared by Sol-Gel method. It was demonstrated by UVVis spectroscopy analysis of the solutions containing the drug, under UV-A light irradiation that the degradation efficiency of the titanium dioxide photocatalyst is dependent of the semiconductor nature and that the scandium accelerates the first step of the degradation when compared to the silver. This result seems to be related to the redox potential of the electron-hole pair, once the scandium modifying sample generates a p type semiconductor that reduces the band gap. The extra holes attract more strongly the chorine ion present in diclofenac and leading to the releasing more easily. However, after the first byproducts degradation the following steps are not facilitated, making the silver modifying more advantageous. (author)

  6. Less-toxic rearrangement products of NX-toxins are formed during storage and food processing.

    Science.gov (United States)

    Varga, Elisabeth; Wiesenberger, Gerlinde; Woelflingseder, Lydia; Twaruschek, Krisztian; Hametner, Christian; Vaclaviková, Marta; Malachová, Alexandra; Marko, Doris; Berthiller, Franz; Adam, Gerhard

    2018-03-01

    A new type A trichothecene mycotoxin, NX-2, was previously reported to be produced by North American isolates of the cereal pathogen Fusarium graminearum. Here we describe the isolation and structural characterization of a rearrangement product, called NX2-M1, and related compounds with different acetylation patterns (NX3-M1 and NX4-M1). In the NX-M1 derivatives, the epoxide ring is opened, and a covalent bridge between C-10 and C-12 of the trichothecene backbone is formed. In vitro translation assays showed that NX3-M1 is less toxic for eukaryotic ribosomes than NX-3. NX3-M1 also has a greatly reduced cytotoxic potential on two tested human colon cell lines. Formation of NX3-M1 can therefore be regarded as a detoxification reaction. The related F. graminearum mycotoxin deoxynivalenol (DON), which is frequently occurring worldwide, is very stable during food processing. Testing NX-3 at different pH-values and temperature conditions, as well as under conditions that simulate the storage of infected grains and bread-making process, revealed a strongly reduced stability of NX-3 and concurrent formation of NX3-M1. Although the NX-3 formed in planta is as toxic as DON, the extensive formation of the non-toxic rearrangement product should be taken into account for risk assessment of this emerging food contaminant. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  7. Effect of SiO{sub 2} addition on photocatalytic activity, water contact angle and mechanical stability of visible light activated TiO{sub 2} thin films applied on stainless steel by a sol gel method

    Energy Technology Data Exchange (ETDEWEB)

    Momeni, Mansour [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Saghafian, Hasan, E-mail: Saghafian@iust.ac.ir [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Center of Excellence for High Strength Alloys Technology (CEHSAT), Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Golestani-Fard, Farhad [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Center of Excellence for Advanced Materials, Iran University of Science and Technology, P.O. Box 16845-195, Tehran (Iran, Islamic Republic of); Barati, Nastaran; Khanahmadi, Amirhossein [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)

    2017-01-15

    Highlights: • Adding SiO{sub 2} to N doped TiO{sub 2} films increased the band gap energy of the films. • SiO{sub 2} addition encouraged crack formation in N doped TiO{sub 2} thin films. • Addition of SiO{sub 2} weakened visible light activity and hydrophilicity of TiO{sub 2} films. • All films passed nanoscratch testing without detachment from the substrates. • Results propose using non-silica films on steel for application in visible light. - Abstract: Nanostructured N doped TiO{sub 2}/20%SiO{sub 2} thin films were developed on steel surface via sol gel method using a painting airbrush. Thin films then were calcined at various temperatures in a range of 400–600 °C. The effect of SiO{sub 2} addition on phase composition and microstructural evolution of N doped TiO{sub 2} films were studied using XRD and FESEM. Optical properties, visible light photocatalytic activity, hydrophilic behavior, and mechanical behavior of the films were also investigated by DRS, methylene blue degradation, water contact angle measurements, and nanoscratch testing. Results indicated that the band gap energy of N doped TiO{sub 2}/SiO{sub 2} was increased from 2.93 to 3.09 eV. Crack formation during calcination was also significantly promoted in the composite films. All composite films demonstrated weaker visible light photocatalytic activities and lower mechanical stability in comparison with N doped TiO{sub 2} films. Moreover, the N doped TiO{sub 2}/SiO{sub 2} film calcined at 600 °C showed undesirable hydrophilic behavior with a water contact angle of 57° after 31 h of visible light irradiation. Outcomes of the present study reveal some different results to previous reports on TiO{sub 2}/SiO{sub 2} films. In general, we believe the differences in substrate material as well as application in visible light are the main reasons for the above mentioned contradiction.

  8. Technologies for deposition of transition metal oxide thin films: application as functional layers in “Smart windows” and photocatalytic systems

    International Nuclear Information System (INIS)

    Gesheva, K; Ivanova, T; Bodurov, G; Szilágyi, I M; Justh, N; Kéri, O; Boyadjiev, S; Nagy, D; Aleksandrova, M

    2016-01-01

    “Smart windows” are envisaged for future low-energy, high-efficient architectural buildings, as well as for the car industry. By switching from coloured to fully bleached state, these windows regulate the energy of solar flux entering the interior. Functional layers in these devices are the transition metals oxides. The materials (transitional metal oxides) used in smart windows can be also applied as photoelectrodes in water splitting photocells for hydrogen production or as photocatalytic materials for self-cleaning surfaces, waste water treatment and pollution removal. Solar energy utilization is recently in the main scope of numerous world research laboratories and energy organizations, working on protection against conventional fuel exhaustion. The paper presents results from research on transition metal oxide thin films, fabricated by different methods - atomic layer deposition, atmospheric pressure chemical vapour deposition, physical vapour deposition, and wet chemical methods, suitable for flowthrough production process. The lower price of the chemical deposition processes is especially important when the method is related to large-scale glazing applications. Conclusions are derived about which processes are recently considered as most prospective, related to electrochromic materials and devices manufacturing. (paper)

  9. Field solar degradation of pesticides and emerging water contaminants mediated by polymer films containing titanium and iron oxide with synergistic heterogeneous photocatalytic activity at neutral pH.

    Science.gov (United States)

    Mazille, F; Schoettl, T; Klamerth, N; Malato, S; Pulgarin, C

    2010-05-01

    Photocatalytic degradation of phenol, nalidixic acid, mixture of pesticides, and another of emerging contaminants in water was mediated by TiO(2) and iron oxide immobilized on functionalized polyvinyl fluoride films (PVF(f)-TiO(2)-Fe oxide) in a compound parabolic collector (CPC) solar photoreactor. During degradation, little iron leaching (emergent contaminant mixture was successful for eight compounds and less efficient for six other compounds. The significant reactivity differences between tested compounds were assigned to the differences in structure namely that the presence of complexing or chelating groups enhanced the rates. PVF(f)-TiO(2)-Fe oxide photoactivity gradually increased during 20 days of experiments. X-ray photoelectron spectroscopy (XPS) measurements revealed significant changes on the catalyst surface. These analyses confirm that during photocatalysis mediated by PVF(f)-TiO(2)-Fe oxide, some iron leaching led to enlargement of the TiO(2) surface exposed to light, increasing its synergy with iron oxides and leading to enhanced pollutant degradation.

  10. Structural Analysis Using NX Nastran 9.0

    Science.gov (United States)

    Rolewicz, Benjamin M.

    2014-01-01

    NX Nastran is a powerful Finite Element Analysis (FEA) software package used to solve linear and non-linear models for structural and thermal systems. The software, which consists of both a solver and user interface, breaks down analysis into four files, each of which are important to the end results of the analysis. The software offers capabilities for a variety of types of analysis, and also contains a respectable modeling program. Over the course of ten weeks, I was trained to effectively implement NX Nastran into structural analysis and refinement for parts of two missions at NASA's Kennedy Space Center, the Restore mission and the Orion mission.

  11. N-type Cu2O Film for Photocatalytic and Photoelectrocatalytic Processes: Its stability and Inactivation of E. coli

    International Nuclear Information System (INIS)

    Xiong, Liangbin; Ng, Tsz Wai; Yu, Ying; Xia, Dehua; Yip, Ho Yin; Li, Guiying; An, Taicheng; Zhao, Huijun; Wong, Po Keung

    2015-01-01

    Highlights: • Photoelectrocatalytic inactivation of E. coli by Cu 2 O film was firstly reported. • 7 log of E. coli could be completely inactivated in 2 h by Cu 2 O with a 0.1 V bias. • Charge transfer between Cu 2 O and E. coli was monitored by electrochemical technique. • Inactivation of E. coli by electric charges of electrodes was in-depth investigated. • Stability of N-type Cu 2 O as a photocatalyst was studied for the first time. - ABSTRACT: Photoelectrocatalytic (PEC) inactivation of Escherichia coli K-12 by cuprous oxide (Cu 2 O) film irradiated by visible light is firstly reported. A complete inactivation of about 7 log of E. coli was obtained for Cu 2 O film within 6 h. The bacterial inactivation efficiency was significantly improved in a photoelectrochemical cell, in which 7 log of E. coli could be completely inactivated within 2 h by Cu 2 O film with a 0.1 V bias. Electric charge transfer between electrodes and E. coli, and electric charge inactivation towards E. coli were investigated using membrane-separated reactor combined with short circuit photocurrent technique. H 2 O 2 , hole, and toxicity of Cu 2 O film were found responsible for the inactivation of E. coli. Toxicity of copper ions (including Cu 2+ and Cu + ) leakage from Cu 2 O films was determined and the results showed that the amount of leakage copper ions was not toxic to E. coli. Finally, the Cu 2 O film was proved to be effective and reusable for PC and PEC inactivation of E. coli

  12. Plasma-Sprayed Photocatalytic Zinc Oxide Coatings

    Science.gov (United States)

    Navidpour, A. H.; Kalantari, Y.; Salehi, M.; Salimijazi, H. R.; Amirnasr, M.; Rismanchian, M.; Azarpour Siahkali, M.

    2017-04-01

    Fabrication of semiconductor coatings with photocatalytic action for photodegradation of organic pollutants is highly desirable. In this research, pure zinc oxide, which is well known for its promising photocatalytic activity, was deposited on stainless-steel plates by plasma spraying. The phase composition and microstructure of the deposited films were studied by x-ray diffraction analysis and scanning electron microscopy, respectively. Despite the low-energy conditions of the plasma spraying process, the zinc oxide coatings showed good mechanical integrity on the substrate. Their photocatalytic activity was evaluated using aqueous solution of methylene blue at concentration of 5 mg L-1. The results showed the potential of the plasma spraying technique to deposit zinc oxide coatings with photocatalytic action under ultraviolet illumination. Ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy confirmed that the plasma spraying method could deposit zinc oxide films with higher photoabsorption ability relative to the initial powder.

  13. Photocatalytic and photoelectrochemical properties of sol–gel TiO2 films of controlled thickness and porosity

    Czech Academy of Sciences Publication Activity Database

    Krýsa, J.; Baudyš, M.; Zlámal, M.; Krýsová, Hana; Morozová, Magdalena; Klusoň, Petr

    2014-01-01

    Roč. 230, JUL 2014 (2014), s. 2-7 ISSN 0920-5861 Institutional support: RVO:61388955 ; RVO:67985858 Keywords : TiO2 film * Sol-gel * Thickness Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.893, year: 2014

  14. Photocatalytic Degradation of Acid Orange 7 on TiO2 Films Prepared from Various Powder Catalysts

    Czech Academy of Sciences Publication Activity Database

    Zlámal, M.; Krýsa, J.; Jirkovský, Jaromír

    2009-01-01

    Roč. 133, 1-2 (2009), s. 160-166 ISSN 1011-372X R&D Projects: GA MŠk 1M0577 Institutional research plan: CEZ:AV0Z40400503 Keywords : titanium dioxide * immobilization * particulate film Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.021, year: 2009

  15. Evidence of Plasmonic Induced Photocatalytic Hydrogen Production on Pd/TiO2 Upon Deposition on Thin Films of Gold

    KAUST Repository

    Khan, M. A.

    2017-02-28

    H2-production from renewables using sunlight is probably the holy grail of modern science and technology. Among the many approaches for increasing reaction rates, by increasing light absorption, plasmonic materials are often invoked. Yet, most plasmonic metals on semiconductors are also good for Schottky barrier formation. In this work, we are presenting evidences of de-coupling the plasmonic from Schottky effects on photoreaction. To conduct this we have systematically changed the under-layer gold film thickness and associated particle size. On top of the thin film layer, we have deposited the exact amount of a prototypical Schottky-based photo-catalyst (Pd/TiO2). We found up to 4 times increase in the H2-production rate at a critical Au film thickness (8 nm-thick). Below this thickness, the plasmonic response is not too strong while above it, the PR decays in favor of the Drude absorption mode. The reaction requires the presence of both UV (to excite the semiconductor) and visible light (to excite Au particles) in order to obtain high hydrogen production, 800 µmol/gCatal.min (probably the highest direct hydrogen (not current) production rate reported on a performing catalyst). The enhancement origin is quantitatively traced to its computed electric field strength (EFS). Adding a dielectric (SiO2) in between the Au thin layer and the catalyst exponentially decreased the reaction rate and EFS, with increasing its thickness. This work indicates the possibility of making an active and stable photo-catalyst from fundamental concepts yet further progress on the structural (technological) front is needed to make a practical catalyst.Graphical abstract

  16. Non Isolated and Non-Inverting Cockcroft Walton Multiplier Based Hybrid 2Nx Interleaved Boost Converter For Renewable Energy Applications

    DEFF Research Database (Denmark)

    Bhaskar, Mahajan Sagar; Padamanaban, Sanjeevi Kumar; Blaabjerg, Frede

    2016-01-01

    In this paper hybrid non isolated and non-invertingCockcroft-Walton multiplier based 2Nx InterleavedBoost converter (2Nx IBC) for renewable energy applications is presented. The presented hybrid boost converter topology is derived from non-inverting Nx Multilevel Boost Converter (Nx MBC......) and inverting Nx Multilevel Boost Converter (Nx MBC). In renewable energy applications, generated voltage needs to be stepped up with high conversion ratio using a DC-DC converter at voltage levels as per the application requirement. The advantages of the presentedtopology of interleaved converter are high...

  17. What can we learn from the decay of $ N_X(1625)$ in molecule picture?

    OpenAIRE

    Liu, Xiang; Zhang, Bo

    2007-01-01

    Considering two molecular state assumptions, i.e. S-wave $\\bar{\\Lambda}-K^-$ and S-wave $\\bar{\\Sigma}^0-K^-$ molecular states, we study the possible decays of $\\bar N_X(1625)$ that include $\\bar N_X(1625)\\to K^{-}\\bar{\\Lambda}, \\pi^{0}\\bar{p}, \\eta\\bar{p}, \\pi^{-}\\bar{n}$. Our results indicate: (1) if $\\bar N_{X}(1625)$ is $\\bar{\\Lambda}-K^-$ molecular state, $K^{-}\\bar{\\Lambda}$ is the main decay modes of $\\bar N_{X}(1625)$, and the branching ratios of the rest decay modes are tiny; (2) if $...

  18. Formation of crystalline TiO2-xNx and its photocatalytic activity

    International Nuclear Information System (INIS)

    Jang, Jum Suk; Kim, Hyun Gyu; Ji, Sang Min; Bae, Sang Won; Jung, Jong Hyeon; Shon, Byung Hyun; Lee, Jae Sung

    2006-01-01

    Amorphous precursors to nitrogen-doped TiO 2 (NTP) and pure TiO 2 (ATP) powders were synthesized by hydrolytic synthesis and sol-gel method (SGM), respectively. Corresponding crystalline phases were obtained by thermally induced transformation of these amorphous powders. From FT-IR and XPS data, it was concluded that a complex containing titanium and ammonia was formed in the precipitate stage while calcination drove weakly adsorbed ammonium species off the surface, decomposed ammonia bound on surface of precipitated powder and led to substitution of nitrogen atom into the lattice of TiO 2 during the crystallization. The activation energies required for grain growth in amorphous TiO 2-x N x and TiO 2 samples were determined to be 1.6 and 1.7kJ/mol, respectively. Those required for the phase transformation from amorphous to crystalline TiO 2-x N x and TiO 2 were determined to be 129 and 142kJ/mol, respectively. A relatively low temperature was required for the phase transformation in NTP sample than in ATP sample. The fabricated N-doped TiO 2 photocatalyst absorbed the visible light showing two absorption edges; one in UV range due to titanium oxide as the main edge and the other due to nitrogen doping as a small shoulder. TiO 2-x N x photocatalyst demonstrated its photoactivity for photocurrent generation and decomposition of 2-propanol (IPA) under visible light irradiation (λ>=420nm)

  19. Preparation and characterization of WO{sub 3} nanoparticles, WO{sub 3}/TiO{sub 2} core/shell nanocomposites and PEDOT:PSS/WO{sub 3} composite thin films for photocatalytic and electrochromic applications

    Energy Technology Data Exchange (ETDEWEB)

    Boyadjiev, Stefan I., E-mail: boiajiev@gmail.com [MTA-BME Technical Analytical Chemistry Research Group, Szent Gellért tér 4, Budapest, H-1111 (Hungary); Santos, Gustavo dos Lopes; Szűcs, Júlia [Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, Szent Gellért tér 4, Budapest, H-1111 (Hungary); Szilágyi, Imre M., E-mail: imre.szilagyi@mail.bme.hu [MTA-BME Technical Analytical Chemistry Research Group, Szent Gellért tér 4, Budapest, H-1111 (Hungary); Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, Szent Gellért tér 4, Budapest, H-1111 (Hungary)

    2016-03-25

    In this study, monoclinic WO{sub 3} nanoparticles were obtained by thermal decomposition of (NH{sub 4}){sub x}WO{sub 3} in air at 600 °C. On them by atomic layer deposition (ALD) TiO{sub 2} films were deposited, and thus core/shell WO{sub 3}/TiO{sub 2} nanocomposites were prepared. We prepared composites of WO{sub 3} nanoparticles with conductive polymer as PEDOT:PSS, and deposited thin films of them on glass and ITO substrates by spin coating. The formation, morphology, composition and structure of the as-prepared pure and composite nanoparticles, as well thin films, were studied by TEM, SEM-EDX and XRD. The photocatalytic activity of both the WO{sub 3} and core/shell WO{sub 3}/TiO{sub 2} nanoparticles was studied by decomposing methyl orange in aqueous solution under UV light irradiation. Cyclic voltammetry measurements were performed on the composite PEDOT:PSS/WO{sub 3} thin films, and the coloring and bleaching states were studied.

  20. VISIBLE LIGHT INDUCED PHOTOCATALYTIC DEGRADATION OF ...

    African Journals Online (AJOL)

    a

    ABSTRACT. Photocatalytic degradation of eosin and erythrosin-B (xanthene dyes) has been carried out using anthracene semiconductor immobilized on polyethylene films. Effect of various parameters like pH, concentration of dyes, amount of semiconductor and light intensity have been studied on the rate of reaction.

  1. Properties of low-temperature passivation of silicon with ALD Al2O3 films and their PV applications

    Science.gov (United States)

    Kim, Kwang-Ho; Kim, Hyun-Jun; Jang, Pyungwoo; Jung, Chisup; Seomoon, Kyu

    2011-06-01

    Low-temperature-deposited aluminium oxide (Al2O3) thin films were grown on p-type Si substrates by the remote plasma atomic layer deposition (RPALD) technique. The RPALD technique uses an alternative trimethylaluminum precursor and oxygen radicals to obtain good interface properties for metal-insulatorsemiconductor (MIS) inversion-layer solar cell applications. Si MIS capacitors with ultra-thin Al2O3 (film thickness ranges from 1 nm to 6 nm) gate dielectric and SiNx films were fabricated at 300°C and at room temperature (RT), respectively. Low-temperature-deposited Al2O3 and SiNx films were characterized by electrical properties such as capacitance-voltage (C-V), and current-voltage (I-V). The interface state density (Dit) of the MIS capacitors with SiNx films and without SiNx films was derived from the 1 MHz frequency C-V curves. By using ultra-thin RPALD Al2O3, RT-sputtered SiNx films and a simple fabrication-processing sequence, MIS solar cells were fabricated on 1 Ω·cm to 10 Ω·cm p-Si wafers. The fabricated MIS solar cell with passivated Al2O3 and SiNx films has 8.21% efficiency.

  2. Des-γ-carboxyprothrombin (DCP and NX-DCP expressions and their relationship with clinicopathological features in hepatocellular carcinoma.

    Directory of Open Access Journals (Sweden)

    Akiko Sumi

    Full Text Available Des-γ-carboxyprothrombin (DCP has been used as a tumor marker for hepatocellular carcinoma (HCC. Recently the DCP/NX-DCP ratio, calculated by dividing DCP by NX-DCP, has been reported useful in detecting HCC. The purpose of this study is to clarify the significance of DCP and NX-DCP expression in HCC tissues.HCC and non-HCC tissue samples were obtained from 157 patients and were immunohistochemically examined for DCP and NX-DCP expression using anti-DCP antibody and anti-NX-DCP antibody. DCP and NX-DCP expression scores were calculated by multiplying staining intensity grade by percentage of stained area. Serum DCP and NX-DCP levels were determined in 89 patients. We evaluated the relationship between tumor expression, serum level, and pathomorphological findings.Intrahepatic metastasis (im was significantly more frequent in cases with high DCP expression than in cases with low DCP expression. High NX-DCP expression was associated with significantly lower histological grade, and less frequent im or portal vein invasion (vp than low NX-DCP expression. Serum DCP was correlated with DCP expression, but serum NX-DCP was not correlated with NX-DCP expression. DCP-positive (≥40 mAU/L, NX-DCP-positive (≥90 mAU/L, and DCP/NX-DCP ratio-positive (≥1.5 cases were associated with significantly larger tumor size and more frequent vp than negative cases. DCP was rarely expressed, but NX-DCP was frequently expressed in non-cancerous liver tissues. Patients with NX-DCP expression-negative tumors showed a lower survival rate than those with NX-DCP expression-positive tumors (p = 0.04, whereas the survival in serum NX-DCP-positive cases was lower than that of serum negative cases (p = 0.02.DCP and NX-DCP were produced in HCC tissues, but differed in expression level and biological properties. DCP expression, serum DCP or NX-DCP level, and DCP/NX-DCP ratio were closely related to malignant properties of HCC.

  3. Study of SiNx:Hy passivant layers for AlGaN/GaN high electron mobility transistors

    International Nuclear Information System (INIS)

    Redondo-Cubero, A.; Gago, R.; Romero, M.F.; Gonzalez-Posada, F.; Brana, A.F.; Munoz, E.; Jimenez, A.

    2008-01-01

    In this work, hydrogenated silicon nitride (SiN x :H y ) grown by chemical vapour deposition as passivant layers for high electron mobility transistors (HEMT) have been studied. The film composition and bonding structure were determined by ion beam analysis and X-ray absorption spectroscopy techniques, respectively. The effects of gas precursors (SiH 4 /N 2 and SiH 4 /NH 3 ) and film/substrate interface on the film growth have been addressed. The growth on different substrates (Si, GaN, AlGaN), and the effects of plasma pre-treatments have been studied before the growth and the film growth evolution. Results yield no significant differences in all the analysed samples. This points out the relevant role of SiHn radicals as growth precursor species and that intrinsic characteristics of the SiNx:Hy layers are not affected by the film/substrate interface. Hence, improved performance of HEMT with surface plasma pre-treatments before passivation should be related to extrinsic mechanisms (such as creation of defects in AlGaN surface, removal of the surface contamination or ion-induced roughness). (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Preparation and Photocatalytic Activity of TiO-Deposited Fabrics

    Directory of Open Access Journals (Sweden)

    Yang Xu

    2012-01-01

    Full Text Available Nanoscale titanium dioxide (TiO2 photocatalytic films were deposited on the surface of polyester nonwovens by using direct current reactive magnetron sputtering. The effects of coating thickness on the surface structures and properties of TiO2-coated fabrics were investigated by X-ray photoelectron spectroscopy (XPS, atomic force microscope (AFM, and scanning electron microscope (SEM. The photocatalytic activity of the functional nonwoven fabrics was evaluated by the degradation of methylene blue. The test results proved that the grain sizes of the sputtered clusters increased and the coating layer became more compact with the increase of film thickness, but the composition of the sputtered films did not have any significant change. At the same time, the photocatalytic activity of TiO2-coated fabrics mostly depended on the film thickness which could lead to the optimum thickness for a particular application.

  5. Visible light induced photocatalytic degradation of some xanthene dyes using immobilized anthracene

    Directory of Open Access Journals (Sweden)

    Pinki B. Punjabi

    2008-12-01

    Full Text Available Photocatalytic degradation of eosin and erythrosin-B (xanthene dyes has been carried out using anthracene semiconductor immobilized on polyethylene films. Effect of various parameters like pH, concentration of dyes, amount of semiconductor and light intensity have been studied on the rate of reaction. Various control experiments were carried out which indicated that semiconductor anthracene played a key role in photocatalytic degradation of dyes. A suitable tentative mechanism has been proposed for photocatalytic degradation of dyes.

  6. Effect of deposition parameters on the photocatalytic activity and bioactivity of TiO2 thin films deposited by vacuum arc on Ti-6Al-4V substrates.

    Science.gov (United States)

    Lilja, Mirjam; Welch, Ken; Astrand, Maria; Engqvist, Håkan; Strømme, Maria

    2012-05-01

    This article evaluates the influence of the main parameters in a cathodic arc deposition process on the microstructure of titanium dioxide thin coatings and correlates these to the photocatalytic activity (PCA) and in vitro bioactivity of the coatings. Bioactivity of all as deposited coatings was confirmed by the growth of uniform layers of hydroxyapatite (HA) after 7 days in phosphate buffered saline at 37°C. Comparison of the HA growth after 24 h indicated enhanced HA formation on coatings with small titanium dioxide grains of rutile and anatase phase. The results from the PCA studies showed that coatings containing a mixed microstructure of both anatase and rutile phases, with small grain sizes in the range of 26-30 nm and with a coating thickness of about 250 nm, exhibited enhanced activity as compared with other microstructures and higher coating thickness. The results of this study should be valuable for the development of new bioactive implant coatings with photocatalytically induced on-demand antibacterial properties. Copyright © 2012 Wiley Periodicals, Inc.

  7. Preparation and Characterization of Pure Rutile TiO2 Nanoparticles for Photocatalytic Study and Thin Films for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Huei-Siou Chen

    2011-01-01

    Full Text Available Pure rutile-phase TiO2 (r-TiO2 was synthesized by a simple one pot experiment under hydrothermal condition using titanium (IV n-butoxide as a Ti-precursor and HCl as a peptizer. The TiO2 products were characterized by XRD, TEM, ESCA, and BET surface area measurement. The r-TiO2 were rodlike in shape with average size of ∼61×32 nm at hydrothermal temperature of 220°C for 10 h. Hydrothermal treatment at longer reaction time increased the tendency of crystal growth and also decreased the BET surface area. The degradation of methylene blue was selected as a test reaction to confer the photocatalytic activity of as-obtained r-TiO2. The results showed a strong correlation between the structure evolution, particle size, and photocatalytic performance of r-TiO2. Furthermore, the r-TiO2-based solar cell was prepared for the photovoltaic characteristics study, and the best efficiency of ~3.16% was obtained.

  8. Surface passivation at low temperature of p- and n-type silicon wafers using a double layer a-Si:H/SiNx:H

    International Nuclear Information System (INIS)

    Focsa, A.; Slaoui, A.; Charifi, H.; Stoquert, J.P.; Roques, S.

    2009-01-01

    Surface passivation of bare silicon or emitter region is of great importance towards high efficiency solar cells. Nowadays, this is usually accomplished by depositing an hydrogenated amorphous silicon nitride (a-SiNx:H) layer on n + p structures that serves also as an excellent antireflection layer. On the other hand, surface passivation of p-type silicon is better assured by an hydrogenated amorphous silicon (a-Si:H) layer but suffers from optical properties. In this paper, we reported the surface passivation of p-type and n-type silicon wafers by using an a-Si:H/SiNx:H double layer formed at low temperature (50-400 deg. C) with ECR-PECVD technique. We first investigated the optical properties (refraction index, reflectance, and absorbance) and structural properties by FTIR (bonds Si-H, N-H) of the deposited films. The hydrogen content in the layers was determined by elastic recoil detection analysis (ERDA). The passivation effect was monitored by measuring the minority carrier effective lifetime vs. different parameters such as deposition temperature and amorphous silicon layer thickness. We have found that a 10-15 nm a-Si film with an 86 nm thick SiN layer provides an optimum of the minority carriers' lifetime. It increases from an initial value of about 50-70 μs for a-Si:H to about 760 and 800 μs for a-Si:H/SiNx:H on Cz-pSi and FZ-nSi, respectively, at an injection level 2 x 10 15 cm -3 . The effective surface recombination velocity, S eff , for passivated double layer on n-type FZ Si reached 11 cm/s and for FZ-pSi-14 cm/s, and for Cz-pSi-16-20 cm/s. Effect of hydrogen in the passivation process is discussed.

  9. Influence of calcination temperature on the photoelectrochemical and photocatalytic properties of porous TiO2 films electrodeposited from Ti(IV)-alkoxide solution

    Czech Academy of Sciences Publication Activity Database

    Wessels, K.; Minnermann, M.; Rathouský, Jiří; Wark, M.; Oekermann, T.

    2008-01-01

    Roč. 112, č. 39 (2008), s. 15122-15128 ISSN 1932-7447 Institutional research plan: CEZ:AV0Z40400503 Keywords : sensitized solar cells * hybrid thin films * zinc oxide films Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.396, year: 2008

  10. Photocatalytic activity of Al{sub 2}O{sub 3}-doped TiO{sub 2} thin films activated with visible light on the bacteria Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Barajas-Ledesma, E., E-mail: edgar_acuario112@hotmail.com [Instituto de Investigaciones Metalurgicas, edificio ' U' , Ciudad Universitaria, UMSNH, Morelia, Michoacan, Mexico, C.P. 58000 (Mexico); Garcia-Benjume, M.L. [Instituto de Investigaciones Metalurgicas, edificio ' U' , Ciudad Universitaria, UMSNH, Morelia, Michoacan, Mexico, C.P. 58000 (Mexico); Espitia-Cabrera, I. [Facultad de Ingenieria Quimica, edificio ' M' , Ciudad Universitaria, UMSNH, Morelia, Michoacan, Mexico, C.P. 58000 (Mexico); Bravo-Patino, A. [Centro Multidisciplinario de Estudios en Biotecnologia, Km 9.5 Carretera Morelia-Zinapecuaro, Posta Veterinaria, Morelia, Michoacan, Mexico, C.P. 58262 (Mexico); Espinoza-Beltran, F.J. [CINVESTAV-Queretaro Libramiento Norponiente 2000, Fracc. Real de Juriquilla, Santiago de Queretaro, Queretaro, Mexico, C.P. 76230 (Mexico); Mostaghimi, J. [Faculty of Applied Science and Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario, M5S 3G8 (Canada); Contreras-Garcia, M.E. [Instituto de Investigaciones Metalurgicas, edificio ' U' , Ciudad Universitaria, UMSNH, Morelia, Michoacan, Mexico, C.P. 58000 (Mexico)

    2010-10-25

    Al{sub 2}O{sub 3}-doped TiO{sub 2} thin films were prepared by combining electrophoretic deposition (EPD) with sputtering. A Corning* glass was used as a substrate, in which a titanium film was deposited by sputtering. Then, a precursor sol was prepared with Ti(n-OBu){sub 4} and Al(s-OBu){sub 3} and used as the medium for EPD. Next, the thin films were sintered and, finally, characterised by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). Several cultures of Escherichia coli, strain XL1-Blue, were prepared. Nine experiments were carried out. In three of them, an inoculum (a low amount of a product that contains bacteria) was prepared without a film; in the other six Al{sub 2}O{sub 3}-doped TiO{sub 2} film-coated glass substrates were irradiated with visible light before they were introduced in the inoculum. The SEM and EDS results showed that TiO{sub 2}-Al{sub 2}O{sub 3} films were obtained, covering all the glass substrate and with uniform size of particles forming them, and that the aluminium was distributed uniformly on the film. XRD results showed that rutile phase was obtained. By TEM, the structure of TiO{sub 2} was demonstrated. Al{sub 2}O{sub 3}-doped TiO{sub 2} thin films were successful at eliminating E. coli.

  11. Photocatalytic activity of Al2O3-doped TiO2 thin films activated with visible light on the bacteria Escherichia coli

    International Nuclear Information System (INIS)

    Barajas-Ledesma, E.; Garcia-Benjume, M.L.; Espitia-Cabrera, I.; Bravo-Patino, A.; Espinoza-Beltran, F.J.; Mostaghimi, J.; Contreras-Garcia, M.E.

    2010-01-01

    Al 2 O 3 -doped TiO 2 thin films were prepared by combining electrophoretic deposition (EPD) with sputtering. A Corning* glass was used as a substrate, in which a titanium film was deposited by sputtering. Then, a precursor sol was prepared with Ti(n-OBu) 4 and Al(s-OBu) 3 and used as the medium for EPD. Next, the thin films were sintered and, finally, characterised by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). Several cultures of Escherichia coli, strain XL1-Blue, were prepared. Nine experiments were carried out. In three of them, an inoculum (a low amount of a product that contains bacteria) was prepared without a film; in the other six Al 2 O 3 -doped TiO 2 film-coated glass substrates were irradiated with visible light before they were introduced in the inoculum. The SEM and EDS results showed that TiO 2 -Al 2 O 3 films were obtained, covering all the glass substrate and with uniform size of particles forming them, and that the aluminium was distributed uniformly on the film. XRD results showed that rutile phase was obtained. By TEM, the structure of TiO 2 was demonstrated. Al 2 O 3 -doped TiO 2 thin films were successful at eliminating E. coli.

  12. Interfacial Engineering of Nanoporous Architectures in Ga2O3 Film toward Self-Aligned Tubular Nanostructure with an Enhanced Photocatalytic Activity on Water Splitting.

    Science.gov (United States)

    Shrestha, Nabeen K; Bui, Hoa Thi; Lee, Taegweon; Noh, Yong-Young

    2018-04-17

    The present work demonstrates the formation of self-aligned nanoporous architecture of gallium oxide by anodization of gallium metal film controlled at -15 °C in aqueous electrolyte consisting of phosphoric acid. SEM examination of the anodized film reveals that by adding ethylene glycol to the electrolyte and optimizing the ratio of phosphoric acid and water, chemical etching at the oxide/electrolyte interfaces can be controlled, leading to the formation of aligned nanotubular oxide structures with closed bottom. XPS analysis confirms the chemical composition of the oxide film as Ga 2 O 3 . Further, XRD and SAED examination reveals that the as-synthesized nanotubular structure is amorphous, and can be crystallized to β-Ga 2 O 3 phase by annealing the film at 600 °C. The nanotubular structured film, when used as photoanode for photoelectrochemical splitting of water, achieved a higher photocurrent of about two folds than that of the nanoporous film, demonstrating the rewarding effect of the nanotubular structure. In addition, the work also demonstrates the formation of highly organized nonporous Ga 2 O 3 structure on a nonconducting glass substrate coated with thin film of Ga-metal, highlighting that the current approach can be extended for the formation of self-organized nanoporous Ga 2 O 3 thin film even on nonconducting flexible substrates.

  13. Digital development of products with NX9 for academical areas

    Science.gov (United States)

    Goanta, A. M.

    2015-11-01

    International competitiveness forced the manufacturing enterprises to look for new ways to accelerate the development of digital products through innovation, global alliances and strategic partnerships. In an environment of global research and development of distributed geographically, all members of the joint teams made up of companies and universities need to access updated and accurate information about products created by any of the type employed, student, teacher. Current design processes involve more complex products consisting of elements of design created by multiple teams, disciplines and suppliers using independent CAD systems. Even when using a 3D CAD mature technology, many companies fail to significantly reduce losses in the process, improve product quality or product type to ensure successful innovations to market arouse interest. These challenges require a radical rethinking of the business model, which belongs to the field of design, which must be based on digital development of products based on integrated files. Through this work, the author has proposed to provide both synthesis and transformations brought news of the integrated NX [1, 2, 3] from Siemens PLM Software 9, following a news results detailed documentary study, and personal results obtained by applying the same version, the digital and integrated development of a product type device test beams. Based on educational license received for NX 9 was made a detailed study of the innovations made by this release, and the application of some of them went to graphical modelling and getting all the documentation of a test device bearing beams. Also, were synthesized in terms of methodology, the steps to take to obtain graphical documentation. The results consist of: 3D models of all parts and assembly 3D model of the three-dimensional constraints of all component parts and not least respectively all drawings and assembly drawing. The most important consequence of the paper is the obtaining of

  14. Space modeling with SolidWorks and NX

    CERN Document Server

    Duhovnik, Jože; Drešar, Primož

    2015-01-01

    Through a series of step-by-step tutorials and numerous hands-on exercises, this book aims to equip the reader with both a good understanding of the importance of space in the abstract world of engineers and the ability to create a model of a product in virtual space – a skill essential for any designer or engineer who needs to present ideas concerning a particular product within a professional environment. The exercises progress logically from the simple to the more complex; while SolidWorks or NX is the software used, the underlying philosophy is applicable to all modeling software. In each case, the explanation covers the entire procedure from the basic idea and production capabilities through to the real model; the conversion from 3D model to 2D manufacturing drawing is also clearly explained. Topics covered include modeling of prism, axisymmetric, symmetric, and sophisticated shapes; digitization of physical models using modeling software; creation of a CAD model starting from a physical model; free fo...

  15. Simulation on Vehicle Vibration Offset of NX70 Flatcar

    Directory of Open Access Journals (Sweden)

    Han Yanhui

    2014-11-01

    Full Text Available The current rolling stock gauge for standard gauge railway is a static gauge to check the vehicle frame. The contradiction of large construction gauge and small rolling stock gauge has always existed. It is important to set down the clearance requirements in respect of physical size for the safe passage of rail vehicles. Reasonably determining the maximum vibration offset can improve the efficiency of clearance. As an example, analyze the complex vibration of NX70 flat car by simulation test on the running track. Comprehensive considering the track model, loading plan, line conditions and running speed, then SIMPACK is used to present the vehicle system dynamics simulation model. After researching simulation result, respectively determine the maximum vehicle vibration offset for railroads of Class I, Class II and Class III on the height of the center of gravity 2000 mm and 2400 mm. According to the clearance between the structure gauge and the position of maximum vibration offset, analyze the safety of vehicle operation since the center of gravity is higher than before.

  16. Optimum design of reactive sputtering parameters on the mechanical and photocatalytic properties of C-doped TiO2 films

    NARCIS (Netherlands)

    Wei, Bo; Li, H.G.; Wen, Feng; Pei, Yutao T.

    2017-01-01

    TiO2 is widely studied for its good photocatalysis activity. In this research, CO2 gas was used as carbon and oxygen source to prepare carbon-doped TiO2 (C-TiO2) films on stainless steel using reactive magnetron sputtering. In order to grasp the relationship between sputtering process,

  17. Film

    OpenAIRE

    Jones, Sarah

    2002-01-01

    This book looks at the movie industry and at the labour intensive but fascinating process of making a feature film. It examines each stage in the production of a film, from initial idea through to the final cut and screening, and highlights the main activities that take place along the way. The book not only looks at the work of prominent people in the film world, such as directors and actors, but also describes the equally important but less high profile contributions of the gaffer, best boy...

  18. Photocatalytic properties of porous titania grown by oblique angle deposition

    Science.gov (United States)

    Riley, M. J.; Williams, B.; Condon, G. Y.; Borja, J.; Lu, T. M.; Gill, W. N.; Plawsky, J. L.

    2012-04-01

    High surface area nanorods of titanium dioxide were grown by oblique angle deposition on a transparent substrate to investigate their effectiveness as photocatalytic agents for the destruction of organic contaminants in air and water. Optical transmission measurements were made that allowed for an estimation of the porosity of the film (75%-78%). Comparing transmission measurements with those from a dense anatase film showed that the penetration depth for the light into the nanorod film was 2.5 times that in a dense, anatase film. The photocatalytic degradation of indigo carmine dye on the porous films was shown to depend on film thickness and annealing conditions. The effectiveness of the film was assessed by observing the change in absorbance of the dye at 610 nm over time and quantifying the film performance using a pseudo-first-order reaction rate model. Reaction rates increased as the film thickness increased from 600 nm to 1000 nm, but leveled out or decreased at thicknesses beyond 1500 nm. A transport/reaction model was used to show that there exists an optimal geometry that maximizes the overall reaction rate and that such a geometry can be simply produced using glancing angle deposition. The nanorod films were benchmarked against nanoparticle films and were shown to perform as well as 0.73 g/L of 25-nm-diameter anatase nanoparticles with surface area of 50 m2/g.

  19. Film

    OpenAIRE

    Bould, M.

    2014-01-01

    A critical overview of critical-theoretical understandings of sf film, especially those promulgated by critics devoted to sf as a prose fiction form. It also considers adaptation, spectacle and special effects.

  20. Application of NX Siemens PLM software in educational process in preparing students of engineering branch

    Science.gov (United States)

    Sadchikova, G. M.

    2017-01-01

    This article discusses the results of the introduction of computer-aided design NX by Siemens Plm Software to the classes of a higher education institution. The necessity of application of modern information technologies in teaching students of engineering profile and selection of a software product is substantiated. The author describes stages of the software module study in relation to some specific courses, considers the features of NX software, which require the creation of standard and unified product databases. The article also gives examples of research carried out by the students with the various software modules.

  1. Visible light induced photocatalytic degradation of some xanthene ...

    African Journals Online (AJOL)

    Photocatalytic degradation of eosin and erythrosin-B (xanthene dyes) has been carried out using anthracene semiconductor immobilized on polyethylene films. Effect of various parameters like pH, concentration of dyes, amount of semiconductor and light intensity have been studied on the rate of reaction. Various control ...

  2. Flexible substrates as basis for photocatalytic reduction of carbon dioxide

    DEFF Research Database (Denmark)

    Jensen, Jacob; Mikkelsen, Mette; Krebs, Frederik C

    2011-01-01

    A photocatalytic system for converting carbon dioxide into carbon monoxide was designed and constructed. The system relies on thin films of the photocatalyst prepared at low temperature using spray coating. We formulated inks based on the well-known photocatalyst titanium dioxide and characterized...

  3. Effect of interface and bulk traps on the C-V characterization of a LPCVD-SiNx/AlGaN/GaN metal-insulator-semiconductor structure

    Science.gov (United States)

    Bao, Qilong; Huang, Sen; Wang, Xinhua; Wei, Ke; Zheng, Yingkui; Li, Yankui; Yang, Chengyue; Jiang, Haojie; Li, Junfeng; Hu, Anqi; Yang, Xuelin; Shen, Bo; Liu, Xinyu; Zhao, Chao

    2016-06-01

    Silicon nitride (SiNx) film grown by low-pressure chemical vapor deposition (LPCVD) is utilized as a gate dielectric for AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs). Trap distribution at the gate-dielectric/III-nitrides interface is characterized by a temperature-dependent ac-capacitance technique. The extracted interface state density D it decreases from 2.92 × 1013 to 1.59 × 1012 cm-2 eV-1 as the energy level depth (E C-E T) increases from 0.29 to 0.50 eV, and then levels off to E C-E T = 0.80 eV. Capacitance-mode deep level transient spectroscopy (C-DLTS) and energy band diagram simulations reveal that deep levels with E C-E T > 0. 83 eV are responsible for the dispersion of capacitances at high temperature (>125 °C) and low frequencies (<1 kHz). A high-resolution transmission electron microscope (TEM) reveals that re-oxidation of the RCA-treated AlGaN barrier surface may be responsible for the relatively high density of shallow states at the LPCVD-SiNx/III-nitride interface.

  4. Photocatalytic degradation of methylorange Using TiO2, WO3 and mixed thin films under controlled pH and H2O2.

    Science.gov (United States)

    Carcel, Radu Adrian; Andronic, Luminita; Duta, Anca

    2011-10-01

    Wastewaters resulting from textile industry sector have a different chemistry compared with most of the other wastewaters. The different dyes in excess are usually very stable and even small quantities can have a major impact to the effluent. In order to treat these wastewaters, photodegradation is a largely investigated process that can be up-scaled. Photocatalysts based on wide band gap semiconductors can be used in heterogeneous photocatalysis and mostly reported are TiO2 and WO3. Under UV irradiation they form electron-hole pairs that produce active species that can oxidize the dye molecules. The electron-hole recombination represents the main cause for low efficiencies and is limited by the use of oxidant systems like H2O2. Doctor blade technique, a reproducible, up-scalable and low cost technique was used to obtain thin films. The reference dye, used in this experiment is methylorange in solution of 0.0125 mM, corresponding to average polluted water. In order to reduce the recombination in the catalysts, H2O2 is used. Another important aspect of the dye photocatalysis process, investigated in the paper is the adsorption of the dye molecule on the photocatalyst surface, strongly depending on pH which affects the dye's structure and the surface charge. Experiments are conducted at fixed pH values: 3, and respectively 7 covering values below and over the ZPC of the photocatalysts. The results show that TiO2/WO3 films have higher efficiency then the TiO2 and WO3 films, mainly due to the surface morphology of the films. By adding H2O2, higher efficiencies are obtained, confirming that the electron-hole pair recombination is reduced. From the point of view of pH, higher efficiencies are obtained in acidic solutions and the results are comparatively discussed considering the dye's ionic/neutral structure and the photocatalyst surface charge. The efficiency was calculated using UV-VIS spectrophotometer measurements of the solution and the thin films were

  5. The Equation R[subscript n]x = b over Rhotrices

    Science.gov (United States)

    Aminu, Abdulhadi

    2010-01-01

    In this article, we consider the concept of rhotrices and present one-sided system of the form R[subscript n]x = b, where R[subscript n] is an n-dimensional rhotrix, x the unknown n-dimensional rhotrix vector and b the right-hand-side rhotrix vector.

  6. OPTIMIZATION OF THE ''PISTON RODS” TECHNOLOGY OF PROCESSING USING NX7.5 SOFTWARE

    Directory of Open Access Journals (Sweden)

    BLĂNARU Viorel

    2011-11-01

    Full Text Available This paper is to present the piston rods process of optimization using NX7.5 software. The landmark modeling has been made in 3D CAD. It has been the landmark technology of execution where they reveal aspects of the sequence of processing and technological parameters.

  7. Biological Characterizations of H5Nx Avian Influenza Viruses Embodying Different Neuraminidases

    Directory of Open Access Journals (Sweden)

    Yuandi Yu

    2017-06-01

    Full Text Available The H5 subtype virus of Highly Pathogenic Avian Influenza Virus has caused huge economic losses to the poultry industry and is a threat to human health. Until 2010, H5N1 subtype virus was the major genotype in China. Since 2011, reassortant H5N2, H5N6, and H5N8 viruses were identified in domestic poultry in China. The clade 2.3.4.4 H5N6 and H5N8 AIV has now spread to most of China. Clade 2.3.4.4 H5N6 virus has caused 17 human deaths. However, the prevalence, pathogenicity, and transmissibility of the distinct NA reassortment with H5 subtypes viruses (H5Nx is unknown. We constructed five clade 2.3.4.4 reassortant H5Nx viruses that shared the same HA and six internal gene segments. The NA gene segment was replaced with N1, N2, N6, ΔN6 (with an 11 amino acid deletion at the 58th to 68th of NA stalk region, and N8 strains, respectively. The reassortant viruses with distinct NAs of clade 2.3.4.4 H5 subtype had different degrees of fitness. All reassortant H5Nx viruses formed plaques on MDCK cell monolayers, but the ΔH5N6 grew more efficiently in mammalian and avian cells. The reassortant H5Nx viruses were more virulent in mice as compared to the H5N2 virus. The H5N6 and H5N8 reassortant viruses exhibited enhanced pathogenicity and transmissibility in chickens as compared to the H5N1 reassortant virus. We suggest that comprehensive surveillance work should be undertaken to monitor the H5Nx viruses.

  8. Noble metals nanoparticles on titanium dioxide nanostructured films and the influence of their photocatalytic activity; Atividade fotocatalitica de filmes nanoestruturados de dioxido de titanio incorporados com nanoparticulas de metais nobres

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Liana Key Okada

    2012-07-01

    Currently, nanoscience and nanotechnology are considered an emerging field and continuously breaking the barrier among various disciplines. The main focus of study involves controlling structures at molecular level, arranging the atoms in order to achieve an understanding and controlling the fundamental properties of matter. In this study, molecular changes on the basis of morphology, optical and crystalline properties of TiO{sub 2}hin films in order to increase their photon efficiency were proposed. The TiO{sub 2} thin films were prepared by sol gel process evaluating the influence of different acids and templates to obtain the nano structured arrangements. Then, metal nanoparticles like Au, Ag, Pd and Pt were incorporated on TiO{sub 2} thin films. This incorporation might minimize the electron-hole recombination, so it could improve the photon efficiency. From the several routes studied, the TiO{sub 2} thin films prepared with acetic acid showed the best performance by the reason of low agglomeration of TiO{sub 2} grains, which favors the exposure of the photoactive sites. The presence of template in the formulation had a slightly effect on photon efficiency, possible due to the higher agglomeration of the grains on the TiO{sub 2} thin films. The addition of Pt and Au nanoparticles on TiO{sub 2} thin films showed superior photon efficiency. The TiO{sub 2} thin films with hexamine and metallic nanoparticles did not show the improvement on photon efficiency except for Pt and Au nanoparticles. On these situations, the improvement on photon efficiency is might be due to a possible decrease at the electron-hole recombination's velocity. Thus, the present work demonstrates the great influence of preparation conditions on the optical, morphological properties and the photon efficiency. In the future, with greater understanding of the mechanism of this influence, the properties of TiO{sub 2} thin films will be able tailoring depending on the application. (author)

  9. Applications of Photocatalytic Disinfection

    Directory of Open Access Journals (Sweden)

    Joanne Gamage

    2010-01-01

    Full Text Available Due to the superior ability of photocatalysis to inactivate a wide range of harmful microorganisms, it is being examined as a viable alternative to traditional disinfection methods such as chlorination, which can produce harmful byproducts. Photocatalysis is a versatile and effective process that can be adapted for use in many applications for disinfection in both air and water matrices. Additionally, photocatalytic surfaces are being developed and tested for use in the context of “self-disinfecting” materials. Studies on the photocatalytic technique for disinfection demonstrate this process to have potential for widespread applications in indoor air and environmental health, biological, and medical applications, laboratory and hospital applications, pharmaceutical and food industry, plant protection applications, wastewater and effluents treatment, and drinking water disinfection. Studies on photocatalytic disinfection using a variety of techniques and test organisms are reviewed, with an emphasis on the end-use application of developed technologies and methods.

  10. Visible light induced photocatalytic degradation of some xanthene dyes using immobilized anthracene

    OpenAIRE

    Pinki B. Punjabi; Rakshit Ameta; Anil Kumar; Madhu Jain

    2008-01-01

    Photocatalytic degradation of eosin and erythrosin-B (xanthene dyes) has been carried out using anthracene semiconductor immobilized on polyethylene films. Effect of various parameters like pH, concentration of dyes, amount of semiconductor and light intensity have been studied on the rate of reaction. Various control experiments were carried out which indicated that semiconductor anthracene played a key role in photocatalytic degradation of dyes. A suitable tentative mechanism has been propo...

  11. Solvent-free, visible-light photocatalytic alcohol oxidations applying an organic photocatalyst

    Directory of Open Access Journals (Sweden)

    Martin Obst

    2016-11-01

    Full Text Available A method for the solvent-free photocatalytic conversion of solid and liquid substrates was developed, using a novel rod mill apparatus. In this setup, thin liquid films are realized which is crucial for an effective photocatalytic conversion due to the low penetration depth of light in heterogeneous systems. Several benzylic alcohols were oxidized with riboflavin tetraacetate as photocatalyst under blue light irradiation of the reaction mixture. The corresponding carbonyl compounds were obtained in moderate to good yields.

  12. Solvent-free, visible-light photocatalytic alcohol oxidations applying an organic photocatalyst

    OpenAIRE

    Obst, Martin; K?nig, Burkhard

    2016-01-01

    A method for the solvent-free photocatalytic conversion of solid and liquid substrates was developed, using a novel rod mill apparatus. In this setup, thin liquid films are realized which is crucial for an effective photocatalytic conversion due to the low penetration depth of light in heterogeneous systems. Several benzylic alcohols were oxidized with riboflavin tetraacetate as photocatalyst under blue light irradiation of the reaction mixture. The corresponding carbonyl compounds were obtai...

  13. Film

    OpenAIRE

    Balint, Ruth; Dolgopolov, Greg

    2008-01-01

    From the beginning of the twentieth century, Sydney defined cosmopolitanism and modernity in the national imagination, and central to this image was the cinema: its technology, its architecture, its stars, its marketing and the stories it circulated to its audiences about Australia and the world. Though it is difficult to define a genre of Sydney film, Sydney provided the backdrop for a host of ideas about the city, and later suburbia. Sydney came to be seen as a ‘tinsel town’ of cultural ban...

  14. SYNTHESIS, CHARACTERIZATION AND PHOTOCATALYTIC ...

    African Journals Online (AJOL)

    ABSTRACT. A Mn2O3/Al2O3/Fe2O3 nanocomposite photocatalyst was prepared by a co-precipitation method. ... KEY WORDS: Co-precipitation method, Nanocomposite, Photocatalyst, Photodegradation, Malachite green ... Heterogeneous photocatalytic oxidations performed with light irradiated semiconductors.

  15. Method of photocatalytic nanotagging

    Science.gov (United States)

    Shelnutt, John A [Tijeras, NM; Medforth, Craig J [Winters, CA; Song, Yujiang [Albuquerque, NM

    2010-04-27

    A nanotagged chemical structure comprising a chemical structure with an associated photocatalyst and a tagging nanoparticle (a nanotag) grown in proximity to the photocatalyst, and a method for making the nanotagged chemical structure. The nanoparticle is grown in proximity to the photocatalyst by using a photocatalytic reduction reaction.

  16. A comparative study of transport properties in polycrystalline and epitaxial chromium nitride films

    KAUST Repository

    Duan, X. F.

    2013-01-08

    Polycrystalline CrNx films on Si(100) and glass substrates and epitaxial CrNx films on MgO(100) substrates were fabricated by reactive sputtering with different nitrogen gas flow rates (fN2). With the increase of fN2, a lattice phase transformation from metallic Cr2N to semiconducting CrN appears in both polycrystalline and epitaxial CrNx films. At fN2= 100 sccm, the low-temperature conductance mechanism is dominated by both Mott and Efros-Shklovskii variable-range hopping in either polycrystalline or epitaxial CrN films. In all of the polycrystalline and epitaxial films, only the polycrystalline CrNx films fabricated at fN2 = 30 and 50 sccm exhibit a discontinuity in ρ(T) curves at 260-280 K, indicating that both the N-vacancy concentration and grain boundaries play important roles in the metal-insulator transition. © 2013 American Institute of Physics.

  17. Molecular Characterizations of Surface Proteins Hemagglutinin and Neuraminidase from Recent H5Nx Avian Influenza Viruses

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hua; Carney, Paul J.; Mishin, Vasiliy P.; Guo, Zhu; Chang, Jessie C.; Wentworth, David E.; Gubareva, Larisa V.; Stevens, James; Schultz-Cherry, S.

    2016-04-06

    ABSTRACT

    During 2014, a subclade 2.3.4.4 highly pathogenic avian influenza (HPAI) A(H5N8) virus caused poultry outbreaks around the world. In late 2014/early 2015, the virus was detected in wild birds in Canada and the United States, and these viruses also gave rise to reassortant progeny, composed of viral RNA segments (vRNAs) from both Eurasian and North American lineages. In particular, viruses were found with N1, N2, and N8 neuraminidase vRNAs, and these are collectively referred to as H5Nx viruses. In the United States, more than 48 million domestic birds have been affected. Here we present a detailed structural and biochemical analysis of the surface antigens of H5N1, H5N2, and H5N8 viruses in addition to those of a recent human H5N6 virus. Our results with recombinant hemagglutinin reveal that these viruses have a strict avian receptor binding preference, while recombinantly expressed neuraminidases are sensitive to FDA-approved and investigational antivirals. Although H5Nx viruses currently pose a low risk to humans, it is important to maintain surveillance of these circulating viruses and to continually assess future changes that may increase their pandemic potential.

    IMPORTANCEThe H5Nx viruses emerging in North America, Europe, and Asia pose a great public health concern. Here we report a molecular and structural study of the major surface proteins of several H5Nx influenza viruses. Our results improve the understanding of these new viruses and provide important information on their receptor preferences and susceptibilities to antivirals, which are central to pandemic risk assessment.

  18. Parametric Design on Internal Gear of Cycloid Gear Pump with NX10.0

    Science.gov (United States)

    Zhang, Enguang; Chen, Min; Deng, Baoqing

    2017-10-01

    The parametric equation of the theoretical contour curve of cycloid gear was established in this paper. Using the NX10.0 software, parametric design of cycloidal gear profile curve was carried out, and the radius of curvature with the contour curve of cycloid gear was analyzed. The consistency between the simulation results and the theoretical design results was verified by assembly analysis, and the parametric drive of the cycloidal gear was verified simultaneously.

  19. Investigation of roughing machining simulation by using visual basic programming in NX CAM system

    Science.gov (United States)

    Hafiz Mohamad, Mohamad; Nafis Osman Zahid, Muhammed

    2018-03-01

    This paper outlines a simulation study to investigate the characteristic of roughing machining simulation in 4th axis milling processes by utilizing visual basic programming in NX CAM systems. The selection and optimization of cutting orientation in rough milling operation is critical in 4th axis machining. The main purpose of roughing operation is to approximately shape the machined parts into finished form by removing the bulk of material from workpieces. In this paper, the simulations are executed by manipulating a set of different cutting orientation to generate estimated volume removed from the machine parts. The cutting orientation with high volume removal is denoted as an optimum value and chosen to execute a roughing operation. In order to run the simulation, customized software is developed to assist the routines. Operations build-up instructions in NX CAM interface are translated into programming codes via advanced tool available in the Visual Basic Studio. The codes is customized and equipped with decision making tools to run and control the simulations. It permits the integration with any independent program files to execute specific operations. This paper aims to discuss about the simulation program and identifies optimum cutting orientations for roughing processes. The output of this study will broaden up the simulation routines performed in NX CAM systems.

  20. Effect of PECVD SiNx/SiOy Nx –Si interface property on surface passivation of silicon wafer

    International Nuclear Information System (INIS)

    Jia Xiao-Jie; Zhou Chun-Lan; Zhou Su; Wang Wen-Jing; Zhu Jun-Jie

    2016-01-01

    It is studied in this paper that the electrical characteristics of the interface between SiO y N x /SiN x stack and silicon wafer affect silicon surface passivation. The effects of precursor flow ratio and deposition temperature of the SiO y N x layer on interface parameters, such as interface state density Di t and fixed charge Q f , and the surface passivation quality of silicon are observed. Capacitance–voltage measurements reveal that inserting a thin SiO y N x layer between the SiN x and the silicon wafer can suppress Q f in the film and D it at the interface. The positive Q f and D it and a high surface recombination velocity in stacks are observed to increase with the introduced oxygen and minimal hydrogen in the SiO y N x film increasing. Prepared by deposition at a low temperature and a low ratio of N 2 O/SiH 4 flow rate, the SiO y N x /SiN x stacks result in a low effective surface recombination velocity (S eff ) of 6 cm/s on a p-type 1 Ω·cm–5 Ω·cm FZ silicon wafer. The positive relationship between S eff and D it suggests that the saturation of the interface defect is the main passivation mechanism although the field-effect passivation provided by the fixed charges also make a contribution to it. (paper)

  1. Growth and characterization of TiN/SiNx multilayer thin films

    OpenAIRE

    Söderberg, Hans

    2006-01-01

    The demands from industry for higher cutting speeds, feeding rates, and reduction of the use of cooling agents during turning and milling operations are increasing. Consequently the requirements on the cutting inserts are increasing and new advanced coatings that can withstand the higher temperatures and larger loads are highly sought after. Throughout the last decade a large amount of publications regarding the Ti-Si-N system have been published. The majority of publications treat nanocompos...

  2. Influence of a-Si:H deposition power on surface passivation property and thermal stability of a-Si:H/SiNx:H stacks

    Directory of Open Access Journals (Sweden)

    Hua Li

    2012-06-01

    Full Text Available The effectiveness of hydrogenated amorphous silicon (a-Si:H layers for passivating crystalline silicon surfaces has been well documented in the literature for well over a decade. One limitation of such layers however has arisen from their inability to withstand temperatures much above their deposition temperature without significant degradation. This limitation is of importance particularly with multicrystalline silicon materials where temperatures of at least 400°C are needed for effective hydrogenation of the crystallographic defects such as grain boundaries. To address this limitation, in this work the surface passivation quality and thermal stability of a stack passivating system, combining a layer of intrinsic a-Si:H and a capping layer of silicon nitride (SiNx:H, on p-type crystalline silicon wafers is studied and optimized. In particular the sensitivity of different microwave (MW power levels for underlying a-Si:H layer deposition are examined. Both effective minority carrier lifetime (ζeff measurement and Fourier transform infrared (FTIR spectrometry were employed to study the bonding configurations, passivating quality and thermal stability of the a-Si:H/SiNx:H stacks. It is established that the higher MW power could result in increased as-deposited ζeff and implied Voc (iVoc values, indicating likely improved surface passivation quality, but that this combination degrades more quickly when exposed to prolonged thermal treatments. The more dihydride-rich film composition corresponding to the higher MW power appears to be beneficial for bond restructuring by hydrogen interchanges when exposed to short term annealing, however it also appears more susceptible to providing channels for hydrogen out-effusion which is the likely cause of the poorer thermal stability for prolonged high temperature exposure compared with stacks with underlying a-Si:H deposited with lower MW power.

  3. Photocatalytic reaction engineering

    CERN Document Server

    de Lasa, Hugo; Salaices, Miguel

    2005-01-01

    Novel photocatalytic reactorsA non-equilibrium model proposed accounts for the mass balance in the liquid and solid phasesElucidates macroscopic radiation balances and the postulation of relatively simple approaches using effective extinction coefficientsThe experimental setup used here is unique and allows safe development of research on kinetic modelingComparisons to alternative technologies reveal the potential of photocatalysisFocuses on air decontamination using Photo-CREC reactors.

  4. Manipulation of K center charge states in silicon nitride films to achieve excellent surface passivation for silicon solar cells

    Science.gov (United States)

    Sharma, Vivek; Tracy, Clarence; Schroder, Dieter; Herasimenka, Stanislau; Dauksher, William; Bowden, Stuart

    2014-02-01

    High quality surface passivation (Seff textured p- and n-type solar grade Czochralski silicon substrates by externally injecting and storing positive or negative charges (>±8 × 1012 cm-2) into a dual layer stack of Plasma Enhanced Chemical Vapor Deposition (PECVD) Silicon Nitride (SiNx)/PECVD Silicon Oxide (SiO2) films using a corona charging tool. We demonstrate long term stability and uniform charge distribution in the SiNx film by manipulating the charge on K center defects while negating the requirement of a high temperature thermal oxide step.

  5. The Effects of Oxidation Temperature on the Microstructure and Photocatalytic Activity of the TiO2 Coating

    Directory of Open Access Journals (Sweden)

    Xinxin TANG

    2017-08-01

    Full Text Available Titanium coatings were prepared on the surface of 1mm ZrO2 balls by mechanical ball mill, then the coatings were oxidized to photocatalytic TiO2 films at 400 ~ 600 °C. X-Ray Diffraction, Scanning Electron Microscope, Energy Dispersive Spectroscopy and Optical Microscope were used to analyze the microstructure and crystal form of the films. The photocatalytic activity of the samples was also evaluated. After that, the effects of oxidation temperature on the microstructure and photocatalytic activity of the films were discussed. The results show that the fabricated coatings are uneven, with average thickness of 60 μm. In the process of oxidation, oxygen is imported into the inner coatings by the gaps existed in the Ti coatings, which makes the Ti particles oxidize from surface to core, finally the films with TiO2 + Ti composite microstructure are obtained. The films oxidized at 500 °C have the best photocatalytic performance with the degradation rate of methyl orange solution 79.08 %, this owing to the existence of anatase and the TiO2+Ti composite microstructure. The result will provide theoretical basis for the fabrication of efficient photocatalytic film.DOI: http://dx.doi.org/10.5755/j01.ms.23.2.15590

  6. Silicon-based thin-film transistors with a high stability

    NARCIS (Netherlands)

    Stannowski, Bernd

    2002-01-01

    Thin-Film Transistors (TFTs) are widely applied as pixel-addressing devices in large-area electronics, such as active-matrix liquid-crystal displays (AMLCDs) or sensor arrays. Hydrogenated amorphous silicon (a-Si:H) and silicon nitride (a-SiNx:H) are generally used as the semiconductor and the

  7. A comparative study into the photocatalytic properties of thin mesoporous layers of TiO2 with controlled mesoporosity

    Czech Academy of Sciences Publication Activity Database

    Tschirch, J.; Bahnemann, D.; Wark, M.; Rathouský, Jiří

    2008-01-01

    Roč. 194, 2-3 (2008), s. 181-188 ISSN 1010-6030 R&D Projects: GA MŠk 1M0577 Institutional research plan: CEZ:AV0Z40400503 Keywords : mesoporous films * film thickness * TiO2 * dye adsorption * photocatalytic degradation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.362, year: 2008

  8. Research of Design Method for Key Parts of Automotive Interior Based on NX Software

    Science.gov (United States)

    Zhang, Enguang; Wang, Li

    2017-10-01

    Take the car door-handle as an example, propose a design method for key parts of automotive interior based on NX software, which is to do concept design for interior first, secondly, carry out framework design for the motion plan, then do structure design, shape design and topology optimization design through kinematics and dynamics analysis, and finally verify the reliability of the parts by finite element strength analysis and fatigue life analysis. This method can guarantee the unification of product data, shorten the product design life cycle, and guarantee the quality of product design.

  9. APPLICATION OF MSC ADAMS – NX NASTRAN/FEMAP INTERFACE IN STRENGTH CALCULATIONS OF TRUCK FRAMES

    Directory of Open Access Journals (Sweden)

    Adam PRZEMYK

    2016-06-01

    Full Text Available In this paper, the finite element method (FEM is used to calculate the strength of truck frames by integrating the MSC Adams software, for dynamics analysis of mechanical systems, and the NX Nastran/Femap software. At the same time, a method for reducing degrees of freedom is been developed based on the Craig–Bampton method. The interface is applied in order to calculate the strength of the frame in the selected truck, which runs on the test track. The selected model of truck can be treated as the virtual prototype that is useful in the design process.

  10. On the temperature dependence of the photoconductivity of amorphous silicon nitride (a-Si Nx: H)

    International Nuclear Information System (INIS)

    Tessler, L.R.; Alvarez, F.; Chambouleyron, I.

    1984-01-01

    Experimental results on the photoconducticity of amorphous hydrogenated silicon nitride a-SiNx: H prepared from plasma decomposition of a gaseus mixture of silane and nitrogen ([Si H 4 ]/[N 2 ] ∼ 0.33) are presented. The material is deposited in a capacitively coupled glow discharge system and nitrogen content was continuously increased by increasing the RF power dissipated in the plasma. Studies of the photocurrent as a function of temperature as a function of temperature and lig ht intensities are reported. (Author) [pt

  11. A versatile new method for synthesis and deposition of doped, visible light-activated TiO2 thin films

    DEFF Research Database (Denmark)

    In, Su-il; Kean, A.H.; Orlov, A.

    2009-01-01

    A flexible and widely applicable method allows the deposition of carbon-doped visible light-activated photocatalytic TiO2 thin films on a variety of substrates.......A flexible and widely applicable method allows the deposition of carbon-doped visible light-activated photocatalytic TiO2 thin films on a variety of substrates....

  12. Tebuconazole photocatalytic degradation kinetics

    OpenAIRE

    Prestes, Thiago de Hermann; Gibbon, Danielle de Oliveira; Lansarin, Marla Azário; Moro, Celso Camilo

    2010-01-01

    The tebuconazole photocatalytic degradation kinetics was studied in a batch reactor using TiO2 (P25-Degussa) as catalyst and a high pressure mercury lamp. The photolysis, adsorption and irradiation effects in the reaction rate were evaluated. Afterward, the suspension catalyst concentration and initial pH to the maximum reaction rate was determined. It was observed that the reaction rate can be approached by a pseudo-first order, with a maximum kinetics constant at 260 mg L-1catalyst concentr...

  13. Porphyrin-Based Photocatalytic Lithography

    Energy Technology Data Exchange (ETDEWEB)

    Bearinger, J; Stone, G; Christian, A; Dugan, L; Hiddessen, A; Wu, K J; Wu, L; Hamilton, J; Stockton, C; Hubbell, J

    2007-10-15

    Photocatalytic lithography is an emerging technique that couples light with coated mask materials in order to pattern surface chemistry. We excite porphyrins to create radical species that photocatalytically oxidize, and thereby pattern, chemistries in the local vicinity. The technique advantageously does not necessitate mass transport or specified substrates, it is fast and robust and the wavelength of light does not limit the resolution of patterned features. We have patterned proteins and cells in order to demonstrate the utility of photocatalytic lithography in life science applications.

  14. Hybrid Non-Isolated and Non Inverting Nx Interleaved DC-DC Multilevel Boost Converter for Renewable Energy Applications

    DEFF Research Database (Denmark)

    Bhaskar, Mahajan Sagar; Kulkarni, Rishi M.; Padmanaban, Sanjeevi Kumar

    2016-01-01

    In this paper hybrid non isolated/ non inverting Nx interleaved DC-DC multilevel Boost Converter for renewable energy applications is presented. The presented hybrid topology is derived from the conventional interleaved converter and the Nx Multilevel boost converter. In renewable energy...... applications, generated energy cannot be directly used at application end. In most of the cases it needs to be stepped up with DC-DC converter at operating voltage levels as per the requirement of the application. Though conventional boost converter can theoretically be used for this purpose, but obtaining...

  15. CFD Analysis of Thermal Control System Using NX Thermal and Flow

    Science.gov (United States)

    Fortier, C. R.; Harris, M. F. (Editor); McConnell, S. (Editor)

    2014-01-01

    The Thermal Control Subsystem (TCS) is a key part of the Advanced Plant Habitat (APH) for the International Space Station (ISS). The purpose of this subsystem is to provide thermal control, mainly cooling, to the other APH subsystems. One of these subsystems, the Environmental Control Subsystem (ECS), controls the temperature and humidity of the growth chamber (GC) air to optimize the growth of plants in the habitat. The TCS provides thermal control to the ECS with three cold plates, which use Thermoelectric Coolers (TECs) to heat or cool water as needed to control the air temperature in the ECS system. In order to optimize the TCS design, pressure drop and heat transfer analyses were needed. The analysis for this system was performed in Siemens NX Thermal/Flow software (Version 8.5). NX Thermal/Flow has the ability to perform 1D or 3D flow solutions. The 1D flow solver can be used to represent simple geometries, such as pipes and tubes. The 1D flow method also has the ability to simulate either fluid only or fluid and wall regions. The 3D flow solver is similar to other Computational Fluid Dynamic (CFD) software. TCS performance was analyzed using both the 1D and 3D solvers. Each method produced different results, which will be evaluated and discussed.

  16. The ML1Nx2 Phosphatidylinositol 3,5-Bisphosphate Probe Shows Poor Selectivity in Cells.

    Science.gov (United States)

    Hammond, Gerald R V; Takasuga, Shunsuke; Sasaki, Takehiko; Balla, Tamas

    2015-01-01

    Phosphatidylinositol (3,5)-bisphosphate (PtdIns(3,5)P2) is a quantitatively minor phospholipid in eukaryotic cells that plays a fundamental role in regulating endocytic membrane traffic. Despite its clear importance for cellular function and organism physiology, mechanistic details of its biology have so far not been fully elucidated. In part, this is due to a lack of experimental tools that specifically probe for PtdIns(3,5)P2 in cells to unambiguously identify its dynamics and site(s) of action. In this study, we have evaluated a recently reported PtdIns(3,5)P2 biosensor, GFP-ML1Nx2, for its veracity as such a probe. We report that, in live cells, the localization of this biosensor to sub-cellular compartments is largely independent of PtdIns(3,5)P2, as assessed after pharmacological, chemical genetic or genomic interventions that block the lipid's synthesis. We therefore conclude that it is unwise to interpret the localization of ML1Nx2 as a true and unbiased biosensor for PtdIns(3,5)P2.

  17. Photocatalytic degradation of crystal violet by thiourea-doped TiO2 ...

    African Journals Online (AJOL)

    In this study, optimisation of the photocatalytic behaviour of crystal violet (CV) by thiourea (Tu)-codoped TiO2 thin film in fixed bed photoreactor was investigated by central composite designs (CCDs). The effective variables were pH, the concentration of CV dye, flow rate and reaction time. The results of the CCD model ...

  18. A transparent Pyrex μ-reactor for combined in situ optical characterization and photocatalytic reactivity measurements

    International Nuclear Information System (INIS)

    Dionigi, F.; Hansen, O.; Nielsen, M. G.; Chorkendorff, I.; Vesborg, P. C. K.; Pedersen, T.

    2013-01-01

    A new Pyrex-based μ-reactor for photocatalytic and optical characterization experiments is presented. The reactor chamber and gas channels are microfabricated in a thin poly-silicon coated Pyrex chip that is sealed with a Pyrex lid by anodic bonding. The device is transparent to light in the UV-vis-near infrared range of wavelengths (photon energies between ∼0.4 and ∼4.1 eV). The absorbance of a photocatalytic film obtained with a light transmission measurement during a photocatalytic reaction is presented as a proof of concept of a photocatalytic reactivity measurement combined with in situ optical characterization. Diffuse reflectance measurements of highly scattering photocatalytic nanopowders in a sealed Pyrex μ-reactor are also possible using an integrating sphere as shown in this work. These experiments prove that a photocatalyst can be characterized with optical techniques after a photocatalytic reaction without removing the material from the reactor. The catalyst deposited in the cylindrical reactor chamber can be illuminated from both top and bottom sides and an example of application of top and bottom illumination is presented

  19. Solid-phase photocatalytic degradation of polystyrene plastic with goethite modified by boron under UV-vis light irradiation

    Science.gov (United States)

    Liu, Guanglong; Zhu, Duanwei; Zhou, Wenbing; Liao, Shuijiao; Cui, Jingzhen; Wu, Kang; Hamilton, David

    2010-02-01

    A novel photodegradable polyethylene-boron-goethite (PE-B-goethite) composite film was prepared by embedding the boron-doped goethite into the commercial polyethylene. The goethite catalyst was modified by boron in order to improve its photocatalytic efficiency under the ultraviolet and visible light irradiation. Solid-phase photocatalytic degradation of the PE-B-goethite composite film was carried out in an ambient air at room temperature under ultraviolet and visible light irradiation. The properties of composite films were compared with those of the pure PE films and the PE-goethite composite films through performing weight loss monitoring, scanning electron microscope (SEM) analysis, FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS). The photo-induced degradation of PE-B-goethite composite films was higher than that of the pure PE films and the PE-goethite composite films under the UV-irradiation, while there has been little change under the visible light irradiation. The weight loss of the PE-B-goethite (0.4 wt.%) composite film reached 12.6% under the UV-irradiation for 300 h. The photocatalytic degradation mechanism of the composite films was briefly discussed.

  20. Highly Pathogenic Influenza A(H5Nx) Viruses with Altered H5 Receptor-Binding Specificity

    NARCIS (Netherlands)

    Guo, Hongbo; de Vries, Erik; McBride, Ryan; Dekkers, Jojanneke; Bouwman, Kim M; Nycholat, Corwin; Verheije, M Helene; Paulson, James C; van Kuppeveld, Frank J M; de Haan, Cornelis A M

    2017-01-01

    Emergence and intercontinental spread of highly pathogenic avian influenza A(H5Nx) virus clade 2.3.4.4 is unprecedented. H5N8 and H5N2 viruses have caused major economic losses in the poultry industry in Europe and North America, and lethal human infections with H5N6 virus have occurred in Asia.

  1. Theoretical calculation of the Hall mobility of InNxAs1−x alloys when ...

    Indian Academy of Sciences (India)

    The Hall mobility of InNx As1−x semiconductor alloys is calculated by solving the ... The physical and electrical properties of GaAsN and InAsN layers growth ... method [27–29]. This equation involves various scattering mechanisms occurring in the material. In this work, the scattering mechanisms due to the acoustic phonon ...

  2. OPTIMIZATION OF TECHNOLOGY IN PROCESSING THE LANDMARK ”SUCTION CAP” WITH NX 7.5 SOFTWARE

    Directory of Open Access Journals (Sweden)

    BLANARU Viorel

    2011-06-01

    Full Text Available This paper is to present the optimization processing of the landmark suction cap with NX software 7.5. It has been done the modeling CAD of the landmark 3D. It has been projected the technology to execution CAM of the landmark where they revealed aspects of processing sequence and technological parameters.

  3. OPTIMIZATION OF THE TEHNOLOGICAL PROCESS OF THE PART ‘’CYLINDER PISTON” WITH NX 7.5 SOFTWARE

    Directory of Open Access Journals (Sweden)

    EFTIMIE Dorin

    2012-11-01

    Full Text Available This paper aims to present the optimization of processing the part “piston cylinder” with NX 7.5 software. CAD modeling is realized and analyzed with finite elements (CAE simulating deformation and maximum stretching and virtual technology manufacturing (CAM where were highlighted aspects regarding the sequence of the manufacturing operations and the technological parameters.

  4. An evidence-based review of NX1207 and its potential in the treatment of benign prostatic hyperplasia

    Directory of Open Access Journals (Sweden)

    Kunit T

    2014-07-01

    Full Text Available Thomas Kunit, Lukas LusuardiDepartment of Urology and Andrology, Paracelsus Medical University Salzburg, Salzburg, AustriaAbstract: In elderly men, benign prostatic hyperplasia is often associated with lower urinary tract symptoms, and its prevalence rises with age. Lower urinary tract symptoms can be very bothersome and lead to a decrease in health-related quality of life. Furthermore, benign prostatic hyperplasia is a progressive disease that can lead to serious complications like acute urinary retention. Medical treatment with α1-blockers or 5α-reductase inhibitors is recommended by the European Association of Urology. On the other hand, there are some new innovations such as NX1207. The aim of this review is to summarize the published data. NX1207 is a new drug that is administered by transrectal intraprostatic injection under ultrasound guidance. The substance leads to prostate volume reduction and symptomatic improvement. However, patient numbers are still low and currently treatment with NX1207 is still experimental.Keywords: BPH, NX 1207, hyperplasia, LUTS, prostate

  5. Superhydrophobic photocatalytic PTFE – Titania coatings deposited by reactive pDC magnetron sputtering from a blended powder target

    Energy Technology Data Exchange (ETDEWEB)

    Ratova, Marina, E-mail: marina_ratova@hotmail.com; Kelly, Peter J.; West, Glen T.

    2017-04-01

    The production of photocatalytic coatings with superhydrophobic properties, as opposed to the conventional hydrophilic properties, is desirable for the prevention of adhesion of contaminants to photocatalytic surfaces with subsequent deterioration of photocatalytic properties. In this work polytetrafluoroethylene (PTFE) – TiO{sub 2} composite thin films were deposited using a novel method of reactive pulsed direct current (pDC) magnetron sputtering of a blended PTFE – titanium oxide powder target. The surface characteristics and photocatalytic properties of the deposited composite coatings were studied. The as-deposited coatings were annealed at 523 K in air and analysed with Raman spectroscopy, optical profilometry and scanning electron microscopy. Hydrophobicity was assessed though measurements of water contact angles, and photocatalytic properties were studied via methylene blue dye degradation under UV irradiation. It was found that variations of gas flow and, hence, process pressures allowed deposition of samples combining superhydrophobicity with stable photocatalytic efficiency under UV light irradiation. Reversible wettability behaviour was observed with the alternation of light-dark cycles. - Highlights: • PTFE-TiO{sub 2} coatings were deposited by pDC reactive magnetron sputtering. • Blended powder target was used for coatings deposition. • Deposited coatings combined superhydrophobic and photocatalytic properties. • Under UV irradiation coatings exhibited reversible wettability.

  6. Research on Rigid Body Motion Tracing in Space based on NX MCD

    Science.gov (United States)

    Wang, Junjie; Dai, Chunxiang; Shi, Karen; Qin, Rongkang

    2018-03-01

    In the use of MCD (Mechatronics Concept Designer) which is a module belong to SIEMENS Ltd industrial design software UG (Unigraphics NX), user can define rigid body and kinematic joint to make objects move according to the existing plan in simulation. At this stage, user may have the desire to see the path of some points in the moving object intuitively. In response to this requirement, this paper will compute the pose through the transformation matrix which can be available from the solver engine, and then fit these sampling points through B-spline curve. Meanwhile, combined with the actual constraints of rigid bodies, the traditional equal interval sampling strategy was optimized. The result shown that this method could satisfy the demand and make up for the deficiency in traditional sampling method. User can still edit and model on this 3D curve. Expected result has been achieved.

  7. Photocatalytic transformation of dyes and by-products in the presence of hydrogen peroxide.

    Science.gov (United States)

    Subba Rao, K V; Subrahmanyam, M; Boule, P

    2003-08-01

    The efficiency of the photocatalytic degradation of dyes and dyeing industry pollutants on immobilized photocatalysts can be improved by addition of hydrogen peroxide, due to its photocatalytic decomposition on TiO2. Experiments were carried out with two azodyes, Acid Orange-7 (AO-7) and Tartrazine (Tart), with 3-nitrobenzenesulfonic add (3-NBSA) which is a chemical intermediate in the dye industry and with real industrial wastewaters, using a thin-film fixed bed reactor. The effect of hydrogen peroxide is only significant for concentrations higher than 5 x 10(-3) M (170 mg l(-1)).

  8. An automation of design and modelling tasks in NX Siemens environment with original software - generator module

    Science.gov (United States)

    Zbiciak, M.; Grabowik, C.; Janik, W.

    2015-11-01

    Nowadays the design constructional process is almost exclusively aided with CAD/CAE/CAM systems. It is evaluated that nearly 80% of design activities have a routine nature. These design routine tasks are highly susceptible to automation. Design automation is usually made with API tools which allow building original software responsible for adding different engineering activities. In this paper the original software worked out in order to automate engineering tasks at the stage of a product geometrical shape design is presented. The elaborated software works exclusively in NX Siemens CAD/CAM/CAE environment and was prepared in Microsoft Visual Studio with application of the .NET technology and NX SNAP library. The software functionality allows designing and modelling of spur and helicoidal involute gears. Moreover, it is possible to estimate relative manufacturing costs. With the Generator module it is possible to design and model both standard and non-standard gear wheels. The main advantage of the model generated in such a way is its better representation of an involute curve in comparison to those which are drawn in specialized standard CAD systems tools. It comes from fact that usually in CAD systems an involute curve is drawn by 3 points that respond to points located on the addendum circle, the reference diameter of a gear and the base circle respectively. In the Generator module the involute curve is drawn by 11 involute points which are located on and upper the base and the addendum circles therefore 3D gear wheels models are highly accurate. Application of the Generator module makes the modelling process very rapid so that the gear wheel modelling time is reduced to several seconds. During the conducted research the analysis of differences between standard 3 points and 11 points involutes was made. The results and conclusions drawn upon analysis are shown in details.

  9. Synthesis of TiO2-doped SiO2 composite films and its applications

    Indian Academy of Sciences (India)

    Wintec

    And special attention has been focused on the relationship between the local structure of the titanium oxide species in the TiO2-doped SiO2 composite films and the photocatalytic reactiv- ity in order to provide vital information for the design and application of such highly efficient photocatalytic systems in the degradation of ...

  10. Sculpturing patterns of plasmonic silver nanoprisms by means of photocatalytic lithography

    Science.gov (United States)

    Panzarasa, Guido; Soliveri, Guido; Marra, Gianluigi; Meda, Laura; Savoini, Alberto; Ardizzone, Silvia; Salvalaggio, Mario

    2017-04-01

    The controlled shaping of nanoparticles’ morphology is one of the pillars of nanotechnology. Here, we demonstrate that photocatalytic lithography, a technique already proved to be useful in materials science, can act as a dry etching technique for noble metal nanoparticles. Triangular silver nanoprisms are self-assembled on titanium dioxide films and photocatalytically shaped into discoidal particles upon irradiation with near-UV light. The obtained patterned surfaces show a dramatically different surface-enhanced Raman scattering response, suggesting the utility of our approach for the development of sensors. The photocatalytic nature of the particle shaping is demonstrated and a plausible mechanism drawn by performing photocatalysis in different configurations (direct and remote) and by irradiating in different solvents.

  11. Preparation of self-cleaning surfaces with a dual functionality of superhydrophobicity and photocatalytic activity

    Science.gov (United States)

    Park, Eun Ji; Yoon, Hye Soo; Kim, Dae Han; Kim, Yong Ho; Kim, Young Dok

    2014-11-01

    Thin film of polydimethylsiloxane (PDMS) was deposited on SiO2 nanoparticles by chemical vapor deposition, and SiO2 became completely hydrophobic after PDMS coating. Mixtures of TiO2 and PDMS-coated SiO2 nanoparticles with various relative ratios were prepared, and distributed on glass surfaces, and water contact angles and photocatalytic activities of these surfaces were studied. Samples consisting of TiO2 and PDMS-coated SiO2 with a ratio of 7:3 showed a highly stable superhydrophobicity under UV irradiation with a water contact angle of 165° and UV-driven photocatalytic activity for decomposition of methylene blue and phenol in aqueous solution. Our process can be exploited for fabricating self-cleaning surfaces with dual functionality of superhydrophobicity and photocatalytic activity at the same time.

  12. ZnO Film Photocatalysts

    Directory of Open Access Journals (Sweden)

    Bosi Yin

    2014-01-01

    Full Text Available We have synthesized high-quality, nanoscale ultrathin ZnO films at relatively low temperature using a facile and effective hydrothermal approach. ZnO films were characterized by scanning electron microscope (SEM, X-ray diffraction (XRD, Raman spectroscopy, photoluminescence spectra (PL, and UV-vis absorption spectroscopy. The products demonstrated 95% photodegradation efficiency with Congo red (CR after 40 min irradiation. The photocatalytic degradation experiments of methyl orange (MO and eosin red also were carried out. The results indicate that the as-obtained ZnO films might be promising candidates as the excellent photocatalysts for elimination of waste water.

  13. High-pressure synthesis and crystal structures of beta- M NX (M = Zr, Hf; X = Cl, Br, I)

    CERN Document Server

    Chen, X; Yamanaka, S

    2002-01-01

    The single crystals of six kinds of metal nitride halide, beta- M NX (M = Zr, Hf; X = Cl, Br, I), were grown in sealed Au (or Pt) tubes by the reaction of M N or M NX powders with NH sub 4 X as fluxes under high-temperature and high-pressure conditions such as 3-5 GPa at 900-1200 sup o C. The x-ray structure analysis revealed that all six kinds of compound crystallize in a rhombohedral space group R3-bar m, Z = 6. beta-ZrNCl, beta-ZrNBr, and beta-HfNCl are isotypic with SmSI, and the others isostructural with YOF.

  14. A method of computer aided design with self-generative models in NX Siemens environment

    Science.gov (United States)

    Grabowik, C.; Kalinowski, K.; Kempa, W.; Paprocka, I.

    2015-11-01

    Currently in CAD/CAE/CAM systems it is possible to create 3D design virtual models which are able to capture certain amount of knowledge. These models are especially useful in an automation of routine design tasks. These models are known as self-generative or auto generative and they can behave in an intelligent way. The main difference between the auto generative and fully parametric models consists in the auto generative models ability to self-organizing. In this case design model self-organizing means that aside from the possibility of making of automatic changes of model quantitative features these models possess knowledge how these changes should be made. Moreover they are able to change quality features according to specific knowledge. In spite of undoubted good points of self-generative models they are not so often used in design constructional process which is mainly caused by usually great complexity of these models. This complexity makes the process of self-generative time and labour consuming. It also needs a quite great investment outlays. The creation process of self-generative model consists of the three stages it is knowledge and information acquisition, model type selection and model implementation. In this paper methods of the computer aided design with self-generative models in NX Siemens CAD/CAE/CAM software are presented. There are the five methods of self-generative models preparation in NX with: parametric relations model, part families, GRIP language application, knowledge fusion and OPEN API mechanism. In the paper examples of each type of the self-generative model are presented. These methods make the constructional design process much faster. It is suggested to prepare this kind of self-generative models when there is a need of design variants creation. The conducted research on assessing the usefulness of elaborated models showed that they are highly recommended in case of routine tasks automation. But it is still difficult to distinguish

  15. Application of atmospheric solution precursor plasma spray to photocatalytic devices for small and medium industries in developing countries

    Science.gov (United States)

    Kindole, Dickson; Ando, Yasutaka

    2017-01-01

    For development of a functional film deposition process with high deposition rate, as a basic study, TiO2 films were deposited by atmospheric solution precursor plasma spray (ASPPS) process. Ethanol-diluted titanium tetraisobutoxide [TTIB: Ti(OC4H9)4] was used as a feedstock. To achieve a high plasma thermal energy at a low discharge power, N2-dominant Ar/N2 as the plasma working gas was used, for film deposition at various deposition distances. Consequently, photocatalytic TiO2 with a rutile/anatase mixture film structure was deposited evenly in this case. By conducting methylene blue decomposition and wettability tests, photocatalytic properties of the film were confirmed. When a TiO2 film was applied to photocatalytic dye-sensitized solar cells (DSSCs), the cells generated an electromotive force of 0.143V oc, which is close to those of commercial DSSCs. From these results, the ASPPS process was found to have high potential for high rate functional film deposition and was cost effective, making it suitable for developing countries.

  16. Compositional analysis of silicon oxide/silicon nitride thin films

    Directory of Open Access Journals (Sweden)

    Meziani Samir

    2016-06-01

    Full Text Available Hydrogen, amorphous silicon nitride (SiNx:H abbreviated SiNx films were grown on multicrystalline silicon (mc-Si substrate by plasma enhanced chemical vapour deposition (PECVD in parallel configuration using NH3/SiH4 gas mixtures. The mc-Si wafers were taken from the same column of Si cast ingot. After the deposition process, the layers were oxidized (thermal oxidation in dry oxygen ambient environment at 950 °C to get oxide/nitride (ON structure. Secondary ion mass spectroscopy (SIMS, Rutherford backscattering spectroscopy (RBS, Auger electron spectroscopy (AES and energy dispersive X-ray analysis (EDX were employed for analyzing quantitatively the chemical composition and stoichiometry in the oxide-nitride stacked films. The effect of annealing temperature on the chemical composition of ON structure has been investigated. Some species, O, N, Si were redistributed in this structure during the thermal oxidation of SiNx. Indeed, oxygen diffused to the nitride layer into Si2O2N during dry oxidation.

  17. Physical and photocatalytic properties of laser fabricated crystalline TiO.sub.2./sub. at low temperatures

    Czech Academy of Sciences Publication Activity Database

    Remsa, Jan; Jelínek, M.; Kocourek, T.; Mikšovský, J.; Studnička, Václav; Vorlíček, Vladimír; Sváta, V.; Vymětalová, V.

    2010-01-01

    Roč. 12, č. 3 (2010), s. 754-757 ISSN 1454-4164 Institutional research plan: CEZ:AV0Z10100522 Keywords : pulsed laser deposition * TiO 2 * contact angle * photocatalytic properties * thin films Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.412, year: 2010

  18. Recyclability of thin nylon film-supported p-CuBiS2/ n-TiO2 heterojunction-based nanocomposites for visible light photocatalytic degradation of organic dye

    Science.gov (United States)

    Abdullah, Hairus; Kuo, Dong-Hau; Lee, Jiunn-Yih; Wu, Chang-Mou

    2016-08-01

    Hybrid film photocatalysts have been prepared by embedding SiO2/TiO2/CuBiS2/Ag nanocomposite spheres into nylon films (nylon/catalyst) for controlling the leaching problem of catalyst powders during the photodegradation of acid black 1 (AB 1) dye solution. The composite catalyst with 500 nm SiO2 sphere as a support which had uniform size and shape was synthesized by the sol-gel and hydrothermal methods. The coupling between p-CuBiS2 and n-TiO2 nanoparticles showed synergetic effects to the enhancement of organic dye photodegradation under visible light irradiation. Furthermore, the Ag nanoparticles on the nanocomposites increased the surface plasmonic resonance and acted as electron trapping which is leading to better photocarrier separation. The 20, 30, and 40 mg as-prepared nanocomposite catalysts were embedded into nylon films to produce three different compositions of 120 mg nylon/catalyst hybrids. The good photodegradation property of 40 mg nylon/catalyst hybrid was tested and was found that it could degrade the 100 mL of 5 ppm dye solution, respectively, in 150, 120, 180, and 150 min in four consecutive runs under 150 W halogen light irradiation. The hybrid films did not need a washing procedure after being used and could be incessantly used after that. The good reusability of hybrid photocatalyst films is attributed to its porosity, thin thickness, tiny size of nanoparticles (less than 10 nm), and the formation of nano p- n diodes between p-CuBiS2 and n-TiO2 nanoparticles.

  19. Epidemic of wild-origin H1NX avian influenza viruses in Anhui, China.

    Science.gov (United States)

    Ge, Ye; Yao, Qiu-Cheng; Wang, Xian-Fu; Fan, Zhi-Qiang; Deng, Guo-Hua; Chai, Hong-Liang; Chen, Hua-Lan; Hua, Yu-Ping

    2017-07-03

    As the natural hosts of avian influenza viruses (AIVs), aquatic and migratory birds provide a gene pool for genetic transfer among species and across species, forming transient "genome constellations." This work describes the phylogenetic dynamics of H1NX based on the complete molecular characterization of eight genes of viruses that were collected from 2014 to 2015 in Anhui Province, China. Hemagglutination and hemagglutination inhibition tests were used to determine the hemagglutination (HA) activity of the HA subtypes. The entire genomes of the viruses were sequenced on an ABI PRISM 3500xl DNA Analyzer. The sequences were genetically analysed to study their genetic evolution using DNASTAR and MEGA 6. The pathogenic effects of the viruses were evaluated using mouse infection models. Seven strains of the H1 subtype avian influenza virus were isolated. Phylogenetic analysis indicated natural recombination of the H1 influenza viruses between the Eurasian lineage and the North American lineage. Some genes had high sequence identity with A/bean goose/Korea/220/2011(H9N2), which is a typical case involving viral reassortment between the Eurasian lineage and the North American lineage. The results of infection experiments in mice showed that the viruses could acquire the ability to multiply in mouse respiratory organs without adaptation. These findings suggest that continued surveillance of wild birds, particularly migratory birds, is important to provide early warning of possible H1 influenza epidemics and to understand the ecology of the virus.

  20. Electronic structure and magnetic anisotropy of Sm2Fe17Nx

    Science.gov (United States)

    Akai, Hisazumi; Ogura, Masako

    2014-03-01

    Electronic structure and magnetic properties of Sm2Fe17Nx are studies on the basis of the first-principles electronic structure calculation in the framework of the density functional theory within the local density and coherent potential approximations. The magnetic anisotropy of the system as a function of nitrogen concentration x is discussed by taking account not only of the crystal field effects but also of the effects of the f-electron transfer from Sm to the neighboring sites. Also discussed is the magnetic transition temperature that is estimated by mapping the system into a Heisenberg model. The results show the crystalline magnetic anisotropy changes its direction from in-plane to uniaxial ones as x increases. It takes the maximum value near x ~ 2 . 8 and then decreases slightly towards x = 3 . The mechanism for these behaviors is discussed in the light of the results of detailed calculations on the bonding properties between Sm and its neighboring N. This work was partly supported by Elements Strategy Initiative Center for Magnetic Materials Project, the Ministry of Education, Culture, Sports, Science and Technology, Japan.

  1. Thermal elastic-wave attenuation in low-dimensional SiNx bars at low temperatures

    Science.gov (United States)

    Withington, S.; Williams, E.; Goldie, D. J.; Thomas, C. N.; Schneiderman, M.

    2017-08-01

    At low temperatures, mK, the thermal flux through low-dimensional amorphous dielectric bars, 400 μm, it is known that the conductance scales as 1/L, where L is the length, but for short bars, 1 μm ultra-low-noise superconducting Transition Edge Sensors to measure the heat flux through a set of SiNx bars to establish the characteristic scale size of the ballistic to diffusive transition. For bars supporting 6 to 7 modes, we measure a thermal elastic-wave attenuation length of 20 μm. The measurement is important because it sheds light on the scattering processes, which in turn are closely related to the generation of thermal fluctuation noise. Our own interest lies in creating patterned phononic filters for controlling heat flow and thermal noise in ultra-low-noise devices, but the work will be of interest to others trying to isolate devices from their environments and studying loss mechanisms in micro-mechanical resonators.

  2. Improved resistive switching characteristics in Ni/SiNx/p++-Si devices by tuning x

    Science.gov (United States)

    Kim, Sungjun; Chang, Yao-Feng; Kim, Min-Hwi; Park, Byung-Gook

    2017-07-01

    This letter studies the effect of the negative-set on the resistive switching performances of CMOS-compatible Ni/SiNx/p++-Si resistive memory devices by simply tuning x. A Ni/SiN1.07/p++-Si device showed lower power switching (20 μW) and better endurance cycles (103) compared to a Ni/SiN0.82/p++-Si device because of the improved negative set behavior and initially lower set and reset currents. In addition, we achieved fast switching speed for set (200 ns) and reset (100 ns) processes in the Ni/SiN1.07/p++-Si device. For the Ni/SiN1.07/p++-Si device, fine adjustment of resistance values is attainable by varying the pulse amplitude and width due to the gradual reset switching characteristics. The barrier-height-dependent conduction model is proposed to explain the change in the current level with the x value.

  3. Effect of Cu2O morphology on photocatalytic hydrogen generation and chemical stability of TiO2/Cu2O composite.

    Science.gov (United States)

    Zhu, Lihong; Zhang, Junying; Chen, Ziyu; Liu, Kejia; Gao, Hong

    2013-07-01

    Improving photocatalytic activity and stability of TiO2/Cu2O composite is a challenge in generating hydrogen from water. In this paper, the TiO2 film/Cu2O microgrid composite was prepared via a microsphere lithography technique, which possesses a remarkable performance of producing H2 under UV-vis light irradiation, in comparison with pure TiO2 film, Cu2O film and TiO2 film/Cu2O film. More interesting is that in TiO2 film/Cu2O microgrid, photo-corrosion of Cu2O can be retarded. After deposition of Pt on its surface, the photocatalytic activity of TiO2/Cu2O microgrid in producing H2 is improved greatly.

  4. Superhydrophobic photocatalytic surfaces through direct incorporation of titania nanoparticles into a polymer matrix by aerosol assisted chemical vapor deposition.

    Science.gov (United States)

    Crick, Colin R; Bear, Joseph C; Kafizas, Andreas; Parkin, Ivan P

    2012-07-10

    A new class of superhydrophobic photocatalytic surfaces that are self-cleaning through light-induced photodegradation and the Lotus effect are presented. The films are formed in a single-step aerosol-assisted chemical vapor deposition (AACVD) process. The films are durable and show no degradation on continuous exposure to UV-C radiation. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Study on the electrical degradation of AlGaN/GaN MIS-HEMTs induced by residual stress of SiNx passivation

    Science.gov (United States)

    Bai, Zhiyuan; Du, Jiangfeng; Liu, Yong; Xin, Qi; Liu, Yang; Yu, Qi

    2017-07-01

    In this paper, we report a new phenomenon in C-V measurement of different gate length MIS-HEMTs, which can be associated with traps character of the AlGaN/GaN interface. The analysis of DC measurement, frequency dependent capacitance-voltage measurements and simulation show that the stress from passivation layer may induce a decrease of drain output current Ids, an increase of on-resistance, serious nonlinearity of transconductance gm, and a new peak of C-V curve. The value of the peak is reduced to zero while the gate length and measure frequency are increasing to 21 μm and 1 MHz, respectively. By using conductance method, the SiNx/GaN interface traps with energy level of EC-0.42 eV to EC-0.45 eV and density of 3.2 × 1012 ∼ 5.0 × 1012 eV-1 cm-2 is obtained after passivation. According to the experimental and simulation results, formation of the acceptor-like traps with concentration of 3 × 1011 cm-2 and energy level of EC-0.37 eV under the gate on AlGaN barrier side of AlGaN/GaN interface is the main reason for the degradation after the passivation. He is currently an Associate Professor with State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Microelectronics and Solid-State Electronics, UESTC. He is the author of over 30 peer-reviewed journal papers and more than 20 conference papers. He has also hold over 20 patents. His research interests include Gallium Nitride based high-voltage power switching devices, microwave and millimeter-wave power devices and integrated technologies. Dr. Yu was a recipient of the prestigious Award of Science and Technology of China

  6. Photocatalytic degradation of textile dyes.

    Science.gov (United States)

    Mahadwad, O K; Jasra, R V; Parikh, P A; Tayade, R J

    2010-07-01

    The photocatalytic degradation of commonly used textile dyes, namely, Reactive Black-5 (RB-5), Red (ME4BL), Golden Yellow (MERL), Blue-222, Methylene Blue, and Malachite Green, has been studied, using TiO2 (P25) as a photocatalyst. All the dye solutions could be decolorized. Kinetics of RB-5 oxidation reaction has been studied and was found to be of first order in dye concentration. Effects of different parameters such as catalyst amount, initial concentration of the dyes, and pH of solution along with biological parameters (TOC and COD) on the rate of degradation were studied. Experimental results showed that photocatalytic degradation of commonly used RB-5 was very effective at the optimum catalyst quantity of 2.5 g/L.

  7. Thermoluminescence of thin films deposited by laser ablation

    International Nuclear Information System (INIS)

    Escobar A, L.; Camps, E.; Arrieta, A.; Romero, S.; Gonzalez, P.R.; Olea M, O.; Diaz E, R.

    2003-01-01

    Materials in thin film form have received great attention in the last few years mainly because of their singular properties, which may differ significantly from their bulk attributes making them attractive for a wide variety of applications. In particular, thermoluminescence (Tl) properties of thin films have been studied recently owing to their potential applications in detection for both ionizing and non ionizing radiation. The aim of the present work is to report the synthesis and characterization of C Nx, aluminum oxide and titanium oxide thin films. Thermoluminescence response of the obtained thin films was studied after subject thin films to UV radiation (254 nm) as well as to gamma radiation (Co-60). Thermoluminescence glow curves exhibited a peak centered at 150 C for CN x whereas for titanium oxide the glow curve shows a maximum peaking at 171 C. Characterization of the physical properties of the deposited materials is presented. (Author)

  8. Chemically Assisted Photocatalytic Oxidation System

    Science.gov (United States)

    Andino, Jean; Wu, Chang-Yu; Mazyck, David; Teixeira, Arthur A.

    2009-01-01

    The chemically assisted photocatalytic oxidation system (CAPOS) has been proposed for destroying microorganisms and organic chemicals that may be suspended in the air or present on surfaces of an air-handling system that ventilates an indoor environment. The CAPOS would comprise an upstream and a downstream stage that would implement a tandem combination of two partly redundant treatments. In the upstream stage, the air stream and, optionally, surfaces of the air-handling system would be treated with ozone, which would be generated from oxygen in the air by means of an electrical discharge or ultraviolet light. In the second stage, the air laden with ozone and oxidation products from the first stage would be made to flow in contact with a silica-titania photocatalyst exposed to ultraviolet light in the presence of water vapor. Hydroxyl radicals generated by the photocatalytic action would react with both carbon containing chemicals and microorganisms to eventually produce water and carbon dioxide, and ozone from the first stage would be photocatalytically degraded to O2. The net products of the two-stage treatment would be H2O, CO2, and O2.

  9. Significance of a Noble Metal Nanolayer on the UV and Visible Light Photocatalytic Activity of Anatase TiO2 Thin Films Grown from a Scalable PECVD/PVD Approach.

    Science.gov (United States)

    Baba, Kamal; Bulou, Simon; Quesada-Gonzalez, Miguel; Bonot, Sébastien; Collard, Delphine; Boscher, Nicolas D; Choquet, Patrick

    2017-11-29

    UV and visible light photocatalytic composite Pt and Au-TiO 2 coatings have been deposited on silicon and glass substrates at low temperature using a hybrid ECWR-PECVD/MS-PVD process. Methylene blue, stearic acid, and sulfamethoxazole were used as dye, organic, and antibiotic model pollutants, respectively, to demonstrate the efficiency of these nanocomposite coatings for water decontamination or self-cleaning surfaces applications. Raman investigations revealed the formation of anatase polymorph of TiO 2 in all synthesized coatings with a shifting of the main vibrational mode peak to higher wavenumber in the case of Au-TiO 2 coating, indicating an increase number of crystalline defects within this coating. Because of the difference of the chemical potentials of each of the investigated noble metals, the sputtered metal layers exhibit different morphology. Pt sputtered atoms, with high surface adhesion, promote formation of a smooth 2D layer. On the other hand, Au sputtered atoms with higher cohesive forces promote the formation of 5-10 nm nanoparticles. As a result, the surface plasmon resonance phenomenon was observed in the Au-TiO 2 coatings. UV photoactivity of the nanocomposite coatings was enhanced 1.5-3 times and 1.3 times for methylene blue and stearic acid, respectively, thanks to the enhancement of electron trapping in the noble metal layer. This electron trapping phenomenon is higher in the Pt-TiO 2 coating because of its larger work function. On the other hand, the enhancement of the visible photoactivity was more pronounced (3 and 7 times for methylene blue and stearic acid, respectively) in the case of Au-TiO 2 thanks to the surface plasmon resonance. Finally, these nanocomposite TiO 2 coatings exhibited also a good ability for the degradation of antibiotics usually found in wastewater such as sulfamethoxazole. However, a complementary test have showed an increase of the toxicity of the liquid medium after photocatalysis, which could be due the

  10. Photocatalytic effects for the TiO2-coated phosphor materials

    International Nuclear Information System (INIS)

    Yoon, Jin-Ho; Jung, Sang-Chul; Kim, Jung-Sik

    2011-01-01

    Research highlights: → The photocatalytic behavior of the coupling of TiO 2 with phosphorescent materials. → The photobleaching of an MB aqueous solution under visible light irradiation. → The ALD TiO 2 -coated phosphor composite showed much higher photocatalytic reactivity. → The light emitted from the phosphors contributed to the photo-generation. - Abstract: This study investigated the photocatalytic behavior of the coupling of TiO 2 with phosphorescent materials. A TiO 2 thin film was deposited on CaAl 2 O 4 :Eu 2+ ,Nd 3+ phosphor particles by using atomic layer deposition (ALD), and its photocatalytic reaction was investigated by the photobleaching of an aqueous solution of methylene-blue (MB) under visible light irradiation. To clarify the mechanism of the TiO 2 -phosphorescent materials, two different samples of TiO 2 -coated phosphor and TiO 2 -Al 2 O 3 -coated phosphor particles were prepared. The photocatalytic mechanisms of the ALD TiO 2 -coated phosphor powders were different from those of the pure TiO 2 and TiO 2 -Al 2 O 3 -coated phosphor. The absorbance in a solution of the ALD TiO 2 -coated phosphor decreased much faster than that of pure TiO 2 under visible irradiation. In addition, the ALD TiO 2 -coated phosphor showed moderately higher photocatalytic degradation of MB solution than the TiO 2 -Al 2 O 3 -coated phosphor did. The TiO 2 -coated phosphorescent materials were characterized by transmission electron microscopy (TEM), Auger electron spectroscopy (AES) and X-ray photon spectroscopy (XPS).

  11. Rear-Sided Passivation by SiNx:H Dielectric Layer for Improved Si/PEDOT:PSS Hybrid Heterojunction Solar Cells.

    Science.gov (United States)

    Sun, Yiling; Gao, Pingqi; He, Jian; Zhou, Suqiong; Ying, Zhiqin; Yang, Xi; Xiang, Yong; Ye, Jichun

    2016-12-01

    Silicon/organic hybrid solar cells have recently attracted great attention because they combine the advantages of silicon (Si) and the organic cells. In this study, we added a patterned passivation layer of silicon nitride (SiNx:H) onto the rear surface of the Si substrate in a Si/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) ( PSS) hybrid solar cell, enabling an improvement of 0.6 % in the power conversion efficiency (PCE). The addition of the SiNx:H layer boosted the open circuit voltage (V oc) from 0.523 to 0.557 V, suggesting the well-passivation property of the patterned SiNx:H thin layer that was created by plasma-enhanced chemical vapor deposition and lithography processes. The passivation properties that stemmed from front PSS, rear-SiNx:H, front PSS/rear-SiNx:H, etc. are thoroughly investigated, in consideration of the process-related variations.

  12. Photoelectrocatrocatalytic hydrolysis of starch by using sprayed ZnO thin films

    Science.gov (United States)

    Sapkal, R. T.; Shinde, S. S.; Rajpure, K. Y.; Bhosale, C. H.

    2013-05-01

    Thin films of zinc oxide have been deposited onto glass/FTO substrates at optimized 400 °C by using a chemical spray pyrolysis technique. Deposited films are character photocatalytic activity by using XRD, an SEM, a UV-vis spectrophotometer, and a PEC single-cell reactor. Films are polycrystalline and have a hexagonal (wurtzite) crystal structure with c-axis (002) orientation growth perpendicular to the substrate surface. The observed direct band gap is about 3.22 eV for typical films prepared at 400 °C. The photocatalytic activity of starch with a ZnO photocatalyst has been studied by using a novel photoelectrocatalytic process.

  13. Synthesis, characterization, photocatalytic and reusability studies of ...

    Indian Academy of Sciences (India)

    Administrator

    2.2 Apparatus for photocatalytic study. Photocatalytic degradation experiment was conducted in dark using self-designed photochemical reactor at room temperature. The apparatus consisted of a cylindrical glass cell of 1 L capacity. A mercury lamp (λ = 300–400 nm) was placed in a glass tube. The lamp and tube were then.

  14. Utilization of N-X bonds in the synthesis of N-heterocycles.

    Science.gov (United States)

    Minakata, Satoshi

    2009-08-18

    Nitrogen-containing heterocycles--such as aziridines, pyrrolidines, piperidines, and oxazolines--frequently show up as substructures in natural products. In addition, some of these species show potent biological activities. Therefore, researchers would like to develop practical and convenient methods for constructing these heterocycles. Among the available methods, the transfer of N(1) units to organic molecules, especially olefins, is a versatile method for the synthesis of N-heterocycles. This Account reviews some of our recent work on the synthesis of N-heterocycles using the N-X bond. A nitrogen-halogen bond bearing an electron-withdrawing group on the nitrogen can be converted to a halonium ion. In the presence of C-C double bonds, these species produce three-membered cyclic halonium intermediates, which can be strong electrophiles and can produce stereocontrolled products. N-Halosuccinimides are representative sources of halonium ions, and the nitrogen of succinimide is rarely used in organic synthesis. If the nitrogen could act as a nucleophile, after releasing halonium ions to C-C double bonds, we expect great advances would be possible in the stereoselective functionalization of olefins. We chose N-chloro-N-sodio-p-toluenesulfonamide (chloramine-T, CT), an inexpensive and commercially available reagent, as our desired reactant. In the presence of a catalytic amount of CuCl or I(2) and AgNO(3), we achieved the direct aziridination of olefins with CT. The reaction catalyzed by I(2) could be carried out in water or silica-water as a green process. The reaction of iodoolefins with CT gave pyrrolidine derivatives under extremely mild conditions with complete stereoselectivity. We also extended the utility of the N-chloro-N-metallo reagent, which is often unstable and difficult to work with. Although CT does not react with electron-deficient olefins without a metal catalyst or an additive, we found that N-chloro-N-sodiocarbamates react with electron

  15. A (Nd, Zr(Fe, Co11.5Ti0.5Nx compound as a permanent magnet material

    Directory of Open Access Journals (Sweden)

    S. Suzuki

    2014-11-01

    Full Text Available We studied NdFe11TiNx compounds as permanent magnet materials. The (Nd0.7,Zr0.3(Fe0.75Co0.2511.5Ti0.5N0.52 powder that contained a limited amount of the α-(Fe, Co phase shows fairly good magnetic properties, such as a saturation polarization (Js of 1.68 T and an anisotropic field (Ha of 2.88 (Law of approach to saturation – 4.0 MA/m (Intersection of magnetization curves. Both properties are comparable to those of the Nd2Fe14B phase.

  16. Theoretical investigation of structural, mechanical and electronic properties of GaAs1-xNx alloys under ambient and high pressure

    Science.gov (United States)

    Li, Jian; Han, Xiuxun; Dong, Chen; Fan, Changzeng

    2017-12-01

    Using first-principles total energy calculations, we have studied the structural, mechanical and electronic properties of GaAs1-xNx ternary semiconductor alloys with the zinc-blende crystal structure over the whole nitrogen concentration range (with x from 0 to 1) within density functional theory (DFT) framework. To obtain the ideal band gap, we employ the semi-empirical approach called local density approximation plus the multi-orbital mean-field Hubbard model (LDA+U). The calculated results illustrate the varying lattice constants and band gap in GaAs1-xNx alloys as functions of the nitrogen concentration x. According to the pressure dependence of the lattice constants and volume, the higher N concentration alloy exhibits the better anti-compressibility. In addition, an increasing band gap is predicted under 20 GPa pressure for GaAs1-xNx alloys.

  17. Origin of Difference in Photocatalytic Activity of ZnO (002 Grown on a- and c-Face Sapphire

    Directory of Open Access Journals (Sweden)

    Guoqiang Li

    2014-01-01

    Full Text Available The oriented (002 ZnO films were grown on a- and c-face sapphire by pulsed laser deposition. The X-ray diffraction analysis revealed that the oriented (002 ZnO films were epitaxially grown on the substrate successfully. The sample on a-face sapphire had higher crystal quality. However, the photocatalytic activity for Rhodamine B degradation of ZnO film on c-face sapphire was higher than that on a-face sapphire. The Raman spectrum and XPS analysis suggested that the sample on a-face sapphire had higher concentration of defects. The result of the contact angle measurement revealed that the sample on c-face sapphire had higher surface energy. And the investigation of the surface conductance implied that the higher light conductance was helpful for the photocatalytic activity.

  18. Pyrrole-regulated precipitation of titania nanorods on polymer fabrics for photocatalytic degradation of trace toluene in air

    Science.gov (United States)

    Gu, Yi-Jie; Wen, Wei; Xu, Yang; Wu, Jin-Ming

    2018-03-01

    When compared with nanoparticulate counterparts, TiO2 thin films with vertically aligned one-dimensional (1D) nanostructures exhibit enhanced photocatalytic activity because of the highly accessible surface area. The perpendicular of the 1D nanostructure reduces the charge migration path and hence the carrier recombination rate, which also contributes to the photocatalytic activity. Furthermore, TiO2 thin films on flexible substrates are more suitable to degrade pollutants in either water or air because of its easy recovery and free-bending shape. In this study, flexible polyethylene fabrics were firstly coated with a sol-gel nanoparticulate TiO2 seed layer. Quasi-aligned TiO2 nanorods were then precipitated homogeneously under an atmospheric pressure and a low temperature not exceeding 80 °C, using a peroxy-titanium complex precursor with the additive of pyrrole. It is found that the density of TiO2 nanorods increased with the increasing amount of pyrrole monomers. The resultant TiO2 film on polyethylene fabrics exhibited a much reduced band gap of ca. 2.86 eV, which can be attributed to the surface oxygen deficiencies. When utilized to assist photocatalytic degradation of trace toluene in air under the UV light illumination, the TiO2 film exhibited a gradually increased photocatalytic activity upon the increasing cycles for up to six, because of the gradual removal of trace organics on the TiO2 surface. The highest photocatalytic efficiency is recorded to be 5 times that of TiO2 nanotube arrays, which are regarded as an excellent photocatalyst for air cleaning.

  19. Optical, Electrical and Photocatalytic Properties of the Ternary Semiconductors ZnxCd1-xS, CuxCd1-xS and CuxZn1-xS

    Directory of Open Access Journals (Sweden)

    Sandra Andrea Mayén-Hernández

    2014-01-01

    Full Text Available The effects of vacuum annealing at different temperatures on the optical, electrical and photocatalytic properties of polycrystalline and amorphous thin films of the ternary semiconductor alloys ZnxCd1-xS, CuxCd1-xS and CuxZn1-xS were investigated in stacks of binary semiconductors obtained by chemical bath deposition. The electrical properties were measured at room temperature using a four-contact probe in the Van der Pauw configuration. The energy band gap of the films varied from 2.30 to 2.85 eV. The photocatalytic activity of the semiconductor thin films was evaluated by the degradation of an aqueous methylene blue solution. The thin film of ZnxCd1-xS annealed under vacuum at 300°C exhibited the highest photocatalytic activity.

  20. A Photocatalytic Rotating Disc Reactor with TiO₂ Nanowire Arrays Deposited for Industrial Wastewater Treatment.

    Science.gov (United States)

    Li, Fang; Szeto, Wai; Huang, Haibao; Li, Jiantao; Leung, Dennis Y C

    2017-02-22

    A photocatalytic rotating disc reactor (PRD-reactor) with TiO₂ nanowire arrays deposited on a thin Ti plate is fabricated and tested for industrial wastewater treatment. Results indicate that the PRD-reactor shows excellent decolorization capability when tested with methyl orange (>97.5%). Advanced oxidation processes (AOP), including photocatalytic oxidation and photolytic reaction, occurred during the processing. Efficiency of the AOP increases with reduction in light absorption pathlength, which enhanced the photocatalytic reaction, as well as by increasing oxygen exposure of the wastewater thin film due to the rotating disc design. It is found that, with a small dosage of hydrogen peroxide, the mineralization efficiency of industrial biodegraded wastewater can be enhanced, with a superior mineralization of >75% total organic carbon (TOC) removal. This is due to the fact that the TiO₂ photocatalysis and hydrogen peroxide processes generate powerful oxidants (hydroxyl radicals) that can strongly improve photocatalytic oxidation efficiency. Application of this industrial wastewater treatment system is benefited from the TiO₂ nanowire arrays, which can be fabricated by a mild solvothermal method at 80 °C and under atmospheric pressure. Similar morphologies and microstructures are found for the TiO₂ nanowire arrays deposited on a large metal Ti disc, which makes the wastewater treatment process more practical and economical.

  1. Porphyrin-based Photocatalytic Nanolithography

    Energy Technology Data Exchange (ETDEWEB)

    Bearinger, J P; Stone, G; Dugan, L C; Dasher, B E; Stockton, C; Conway, J W; Kuenzler, T; Hubbell, J A

    2009-06-08

    Nanoarray fabrication is a multidisciplinary endeavor encompassing materials science, chemical engineering and biology. We form nanoarrays via a new technique, porphyrin-based photocatalytic nanolithography (PCNL). The nanoarrays, with controlled features as small as 200 nm, exhibit regularly ordered patterns and may be appropriate for (a) rapid and parallel proteomic screening of immobilized biomolecules, (b) protein-protein interactions and/or (c) biophysical and molecular biology studies involving spatially dictated ligand placement. We demonstrate protein immobilization utilizing nanoarrays fabricated via PCNL on silicon substrates, where the immobilized proteins are surrounded by a non-fouling polymer background.

  2. Highly Pathogenic Influenza A(H5Nx) Viruses with Altered H5 Receptor-Binding Specificity.

    Science.gov (United States)

    Guo, Hongbo; de Vries, Erik; McBride, Ryan; Dekkers, Jojanneke; Peng, Wenjie; Bouwman, Kim M; Nycholat, Corwin; Verheije, M Helene; Paulson, James C; van Kuppeveld, Frank J M; de Haan, Cornelis A M

    2017-02-01

    Emergence and intercontinental spread of highly pathogenic avian influenza A(H5Nx) virus clade 2.3.4.4 is unprecedented. H5N8 and H5N2 viruses have caused major economic losses in the poultry industry in Europe and North America, and lethal human infections with H5N6 virus have occurred in Asia. Knowledge of the evolution of receptor-binding specificity of these viruses, which might affect host range, is urgently needed. We report that emergence of these viruses is accompanied by a change in receptor-binding specificity. In contrast to ancestral clade 2.3.4 H5 proteins, novel clade 2.3.4.4 H5 proteins bind to fucosylated sialosides because of substitutions K222Q and S227R, which are unique for highly pathogenic influenza virus H5 proteins. North American clade 2.3.4.4 virus isolates have retained only the K222Q substitution but still bind fucosylated sialosides. Altered receptor-binding specificity of virus clade 2.3.4.4 H5 proteins might have contributed to emergence and spread of H5Nx viruses.

  3. 2D photonic crystal layer assisted thiosilicate ceramic plate with red-emitting film for high quality w -LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Wubin; Lei, Yifeng; Zhou, Jia; Zhao, Yan; Zheng, Yunhao; Xu, Man; Wang, Shulin; Shen, Fan (Wuhan)

    2017-07-05

    In this work, we have succeeded in obtaining high quality warm w-light-emitting-diodes (LEDs) by adopting hybrid two-dimensional (2D) structure of SiNx photonic crystal layer (PCL) assisted cyan-emitting ceramic-plate thiosilicate SrLa2Si2S8:Ce3+ with red-emitting film SrLiAl3N4:Eu2+ phosphor on a 430 nm blue LED chip at 350 mA. 2D SiNx PCL was capped with thiosilicate is because it can enhance the luminous efficacy and maintain the low correlated color temperature (CCT) and high color-rendering index (CRI). High luminous efficacy (82.3 lm/W), high special CRI (R9=75) as well as the low CCT (5431 K) of the optimal w-LED was obtained due to the assistances of 2D SiNx PCL and narrow-band red-emitting phosphor with the doping percentage at 10 wt%. The synthesis processes, structural analysis, optical properties and LED device performances were detailed investigated to find out the relationship between the optimum composition and good optical properties. Based on intriguing luminescence properties by the 2D SiNx PCL and red-emitting film phosphor introducing, we proclaim this method could also have high potential application in other phosphor-converted w-LEDs.

  4. Nanostructure CdS/ZnO heterojunction configuration for photocatalytic degradation of Methylene blue

    Science.gov (United States)

    Velanganni, S.; Pravinraj, S.; Immanuel, P.; Thiruneelakandan, R.

    2018-04-01

    In the present manuscript, thin films of Zinc Oxide (ZnO) have been deposited on a FTO substrate using a simple successive ionic layer adsorption and reaction (SILAR) and chemical bath deposition (CBD) method. Cadmium Sulphide (CdS) nanoparticles are sensitized over ZnO thin films using SILAR method. The synthesized nanostructured CdS/ZnO heterojunction thin films was characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), High resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), UV-Vis spectroscopy and Raman spectroscopy techniques. The band gap of CdS nanoparticles over ZnO nanostructure was found to be about 3.20 eV. The photocatalytic activities of the deposited CdS/ZnO thin films were evaluated by the degradation of methylene blue (MB) in an aqueous solution under sun light irradiation.

  5. Evaluation of photocatalytic treatment of industrial wastewater using solar energy

    International Nuclear Information System (INIS)

    Restrepo, Gloria Maria; Rios, Luis A; Marin, Juan Miguel; Montoya, Juan Felipe; Velasquez, Jorge Armando

    2008-01-01

    Wastewater of a chemical industry was treated in a photocatalytic process, using a solar photo-reactor made of glass corrugated flat plates that had been set in cascade and using Titanium Dioxide (Degussa p-25) as photocatalyst that is supported on each one of them in film form. the influence of three variables in the decontamination efficiency were studied: amount of H 2 O 2 , volume of water and amount of dispersed TiO 2 , by means of the accomplishment of fifteen experiments carried out in discontinuous operation mode by a period of 5 hours for each test. The obtained results allow establishing that the FH is a viable technology of treatment like previous stage to a biological treatment since percentage of reduction in the DQO varies between 6 and 46% and was managed to reach a biodegradable effluent in all tests

  6. Nanocrystals and Nanoclusters as Cocatalysts for Photocatalytic Water Splitting

    KAUST Repository

    Sinatra, Lutfan

    2016-12-04

    studied for the photocatalytic H2 production in order to explore the synergistic effect of the plasmonic resonance from the Au nanoparticles and pn-junction between Cu2O and TiO2. Additionally, the plasmonic effect of the Au films was also studied and utilized in order to improve the PWS. Secondly, the nanoscaling of cocatalysts was studied in order to improve the efficiency thereof and to reduce the cost of the cocatalyst materials. Moreover, it is sought to explore the quantum size effect on the properties of the cocatalyst and their effect on the photocatalytic reaction. Atomically precise Au and Ni nanoclusters were employed in these studies. Au nanoclusters were studied in relation to the cocatalysts in the photocatalytic water splitting, and Ni nanoclusters were studied in relation to the cocatalysts in the electrocatalytic water oxidation. The results of these studies will provide new insights in relation to the strategy used in order to develop efficient cocatalysts for the purpose of photocatalytic water splitting.

  7. UV-Induced Photocatalytic Cashmere Fibers

    Directory of Open Access Journals (Sweden)

    Lingyun Wang

    2017-12-01

    Full Text Available Cashmere with UV-induced photocatalytic properties is developed for the first time by applying nanocrystalline anatase TiO2 colloid that is free of inorganic acids and organic solvents via a facile low-temperature one-step sol-gel process. The coated cashmere exhibits remarkable UV-induced photodegradation of methyl orange. Furthermore, the photocatalytic nano-coating on cashmere exhibits significant stability after repetitive washing cycles without the need for chemical or physical pretreatment, where the photocatalytic activities remain almost unchanged after three washing cycles while maintaining a water contact angle above 150°. The one-step functionalization process also minimizes the impact on the peculiar intrinsic properties of cashmere. These findings indicate that cashmere combining reproducible UV-induced photocatalytic activity with stable superhydrophobicity has potential in practical applications.

  8. Photocatalytic Degradation of Organic Contaminants in Water

    Science.gov (United States)

    Photocatalytic treatment of organics, including regulated and contaminants of emerging concern, has been an important area of this field. Details are provided on the mechanism of degradation, reaction intermediates, kinetics, and nanointerfacial adsorption phenomena. The degradat...

  9. Photocatalytic Active Radiation Measurements and Use

    Science.gov (United States)

    Davis, Bruce A.; Underwood, Lauren W.

    2011-01-01

    Photocatalytic materials are being used to purify air, to kill microbes, and to keep surfaces clean. A wide variety of materials are being developed, many of which have different abilities to absorb various wavelengths of light. Material variability, combined with both spectral illumination intensity and spectral distribution variability, will produce a wide range of performance results. The proposed technology estimates photocatalytic active radiation (PcAR), a unit of radiation that normalizes the amount of light based on its spectral distribution and on the ability of the material to absorb that radiation. Photocatalytic reactions depend upon the number of electron-hole pairs generated at the photocatalytic surface. The number of electron-hole pairs produced depends on the number of photons per unit area per second striking the surface that can be absorbed and whose energy exceeds the bandgap of the photocatalytic material. A convenient parameter to describe the number of useful photons is the number of moles of photons striking the surface per unit area per second. The unit of micro-einsteins (or micromoles) of photons per m2 per sec is commonly used for photochemical and photoelectric-like phenomena. This type of parameter is used in photochemistry, such as in the conversion of light energy for photosynthesis. Photosynthetic response correlates with the number of photons rather than by energy because, in this photochemical process, each molecule is activated by the absorption of one photon. In photosynthesis, the number of photons absorbed in the 400 700 nm spectral range is estimated and is referred to as photosynthetic active radiation (PAR). PAR is defined in terms of the photosynthetic photon flux density measured in micro-einsteins of photons per m2 per sec. PcAR is an equivalent, similarly modeled parameter that has been defined for the photocatalytic processes. Two methods to measure the PcAR level are being proposed. In the first method, a calibrated

  10. TiO2 Nanotubes Supported Cu Nanoparticles for Improving Photocatalytic Degradation of Simazine under UV Illumination

    Directory of Open Access Journals (Sweden)

    Syazwan Hanani Meriam Suhaimy

    2016-10-01

    Full Text Available Nano size Copper (Cu incorporated TiO2 nanotubes was successfully synthesized via the anodic oxidation technique in ethylene glycol (EG containing 0.5 wt % NH4F and 1.6 wt % KOH for the photocatalytic degradation of Simazine (2-chloro-4, 6-diethylamino-1,3,5-triazine under Ultraviolet (UV illumination. In the present study, the influence of different loading Cu concentrations on the formation of Cu-TiO2 nanotubes film towards the photocatalytic degradation of Simazine is reported. Based on our study, it was found that the optimum Cu loading concentration was about 0.45 wt % on TiO2 nanotubes film for approximately 64% photocatalytic degradation of Simazine after 4 h under UV illumination. This finding was mainly attributed to the uniform surface covering of the Cu loaded TiO2NTs which acted as electron traps, preventing the recombination of electron hole pairs, eventually leading to higher photocatalytic activity of our photocatalyst in degrading the targeted organic pollutant, Simazine. Moreover, an increased kinetic rate of the degradation to 0.0135 h−1 was observed in the presence of Cu in TiO2NTs.

  11. Adaption of wild-bird origin H5Nx highly pathogenic avian influenza virus Clade 2.3.4.4 in vaccinated poultry

    Science.gov (United States)

    The 2014-2015 incursion of H5Nx clade 2.3.4.4 high pathogenicity avian influenza (HPAI) virus caused the largest animal health emergency in U.S. history and renewed interest in developing vaccines against these newly emergent viruses. Our previous research demonstrated several H5 vaccines with varyi...

  12. OPTIMIZATION OF MANUFACTURING TEHNOLOGY FOR “ECCENTRIC MASS” COMPONENT OF A NEW TYPE OF VIBRATORY COMPACTOR USING NX 7.5 SOFTWARE

    Directory of Open Access Journals (Sweden)

    Eftimie Dorin

    2013-11-01

    Full Text Available The paper presents the technological optimization process of the eccentric mass component using the NX 7.5 software. The new design of the vibratory compactor with variable amplitudes was modeled 3D. The manufacturing technology presents graphical aspects of operations during mechanical processing.

  13. Photocatalytic, highly hydrophilic porcelain stoneware slabs

    Science.gov (United States)

    Raimondo, M.; Guarini, G.; Zanelli, C.; Marani, F.; Fossa, L.; Dondi, M.

    2011-10-01

    Photocatalytic, highly hydrophilic industrial porcelain stoneware large slabs were realized by deposition of nanostructured TiO2 coatings. Different surface finishing and experimental conditions were considered in order to assess the industrial feasibility. Photocatalytic and wetting behaviour of functionalized slabs mainly depends on surface phase composition in terms of anatase/rutile ratio, this involving - as a key issue - the deposition of TiO2 on industrially sintered products with an additional annealing step to strengthen coatings' performances and durability.

  14. Advanced oxidation technologies : photocatalytic treatment of wastewater

    OpenAIRE

    Chen, J.

    1997-01-01

    7.1. Summary and conclusions

    The last two decennia have shown a growing interest in the photocatalytic treatment of wastewater, and more and more research has been carried out into the various aspects of photocatalysis, varying from highly fundamental aspects to practical application. However, despite all this research, there is still much to investigate. Suggested photocatalytic mechanisms, such as those for oxidation by hydroxyl radicals and for oxidation at the surface of photocata...

  15. Investigation into adsorption and photocatalytic degradation of gaseous benzene in an annular fluidized bed photocatalytic reactor.

    Science.gov (United States)

    Geng, Qijin; Tang, Shankang; Wang, Lintong; Zhang, Yunchen

    2015-01-01

    The adsorption and photocatalytic degradation of gaseous benzene were investigated considering the operating variables and kinetic mechanism using nano-titania agglomerates in an annular fluidized bed photocatalytic reactor (AFBPR) designed. The special adsorption equilibrium constant, adsorption active sites, and apparent reaction rate coefficient of benzene were determined by linear regression analysis at various gas velocities and relative humidities (RH). Based on a series of photocatalytic degradation kinetic equations, the influences of operating variables on degradation efficiency, apparent reaction rate coefficient and half-life were explored. The findings indicated that the operating variables have obviously influenced the adsorption/photocatalytic degradation and corresponding kinetic parameters. In the photocatalytic degradation process, the relationship between photocatalytic degradation efficiency and RH indicated that water molecules have a dual-function which was related to the structure characteristics of benzene. The optimal operating conditions for photocatalytic degradation of gaseous benzene in AFBPR were determined as the fluidization number at 1.9 and RH required related to benzene concentration. This investigation highlights the importance of controlling RH and benzene concentration in order to obtain the desired synergy effect in photocatalytic degradation processes.

  16. Photocatalytic polymerization induced by a transparent anatase titania aqueous sol and fabrication of polymer composites

    Directory of Open Access Journals (Sweden)

    2010-06-01

    Full Text Available The surface modification of the anatase titania nanoparticles prepared via a controlled nonhydrolytic sol-gel process is achieved by the formation of the bidentate coordination between titania and methacrylic acid (MAA molecules. The in situ photocatalytic polymerization of methyl methacrylate (MMA monomer is initiated by surface modified anatase titania nanoparticles under Xe lamp irradiation. A variety of techniques including differential scanning calorimetry (DSC, thermo-gravimetric analysis (TGA and scanning electron microscopy (SEM are employed to characterize the resulting materials. The glass transition temperatures and the thermal stabilities of polymethyl methacrylate (PMMA composite materials prepared via photocatalytic polymerization are enhanced compared with pure polymer. The partial aggregation of titania nanoparticles in PMMA composite films is derived from the surface polymerization of MMA, which makes the inorganic particles hydrophobic and drives them to the water/oil interfaces.

  17. Synthesis of nanocrystalline TiO2 thin films by liquid phase ...

    Indian Academy of Sciences (India)

    WINTEC

    films can be used as a photocatalyst to clean up organohalides, a class of compound in pesticides that pollute the ground water. Photocatalytic degradation experiments show that indanthrene golden orange dye under- goes degradation efficiently in presence of TiO2 thin films by exposing its aqueous solution to ultraviolet ...

  18. for SERS and Photocatalytic Applications

    Directory of Open Access Journals (Sweden)

    Xue Chen

    2011-01-01

    Full Text Available ZnS/Si nanocables were synthesized via a simple two-step thermal evaporation method. The shape and diameter of the ZnS/Si nanocables can be controlled by adjusting the morphologies of the ZnS nanostructures (nanowire or nanoribbon obtained in the first step and the deposition time of the Si shell in the second step, respectively. Furthermore, we obtained polycrystalline Si nanotubes with different shapes and diameters by etching away the inner ZnS core. The as-prepared Si nanotubes were employed as SERS-active substrates, which exhibited a high sensitivity for the detection of R6G. The Si nanotubes also showed effective photocatalytic activity on the decomposition of R6G under the irradiation of visible light.

  19. Capillary photoelectrode structures for photoelectrochemical and photocatalytic cells

    Science.gov (United States)

    Wang, Xudong; Li, Zhaodong; Cai, Zhiyong; Yao, Chunhua

    2017-05-02

    Photocatalytic structures having a capillary-force based electrolyte delivery system are provided. Also provided are photoelectrochemical and photocatalytic cells incorporating the structures and methods for using the cells to generate hydrogen and/or oxygen from water. The photocatalytic structures use an electrolyte-transporting strip comprising a porous network of cellulose nanofibers to transport electrolyte from a body of the electrolyte to a porous photoelectrode or a porous photocatalytic substrate via capillary force.

  20. Solar photocatalytic degradation of Aldrin

    Energy Technology Data Exchange (ETDEWEB)

    Bandala, Erick R.; Gelover, Silvia; Leal, Maria Teresa [Instituto Mexicano de Tecnologia del Agua, Paseo Cuauhnahuac 8532, Morelos 62550 Jiutepec (Mexico); Arancibia-Bulnes, Camilo; Jimenez, Antonio; Estrada, Claudio A. [Centro de Investigacion en Energia-UNAM, Privada Xochicalco S.N. A.P. 34, Morelos 62580 Temixco (Mexico)

    2002-11-15

    Photocatalytic degradation of the pesticide Aldrin dissolved in water was carried out, in one case, using concentrated solar radiation and, in another case, using non-concentrated solar radiation. In these experiments, the effects of catalyst concentration, oxidant agent concentration, and solar irradiation were tested. In experiments without irradiation, strong adsorption of the pesticide over titanium dioxide was observed in the first few minutes of contact in the presence of titanium dioxide (TiO{sub 2}). These results can be explained by means of Coulombic interactions between the catalyst surface and the pesticide molecules. During the photodegradation process, results show a residual degradation (photolysis) in both the cases, when no catalyst was added. In the case of the non-concentrated solar system, the achieved results suggest that the use of H{sub 2}O{sub 2} increased the degradation rate. For concentrated sunlight, an increase of the Aldrin concentration was observed during the first few minutes of irradiation. This can be explained as a desorption process that is triggered by a change in surface charge of the catalyst in the presence of hydrogen peroxide (H{sub 2}O{sub 2}) during irradiation. When photocatalysis was performed with TiO{sub 2} alone, no Aldrin was detected in the water solutions throughout the entire experiment. This result was unexpected; however, it might be explained by the adsorption of the pesticide on the catalyst surface and by the absence of the oxidant's effect. Three transformation products (TPs) of the degradation process were identified: dieldrin, chlordene and 12-hydroxy-dieldrin. The results presented here are in agreement with previously reported results for photocatalytic degradation of other chlorinated pesticides using lamps as radiation sources.

  1. Formation of SiNx:H by PECVD: optimization of the optical, bulk passivation and structural properties for photovoltaic applications

    International Nuclear Information System (INIS)

    Lelievre, J.F.

    2007-04-01

    The hydrogenated silicon nitride SiNx:H is widely used as antireflection coating and passivation layer in the manufacture of silicon photovoltaic cells. The aim of this work was to implement a low frequency (440 kHz) PECVD reactor and to characterize the obtained SiN layers. After having determined the parameters of the optimal deposition, the physico-chemical structure of the layers has been studied. The optical properties have been studied with the aim to improve the antireflection coating of the photovoltaic cells. The surface and bulk passivation properties, induced by the SiN layer in terms of its stoichiometry, have been analyzed and have revealed the excellent passivating efficiency of this material. At last, have been studied the formation conditions of the silicon nano-crystals in the SiN matrix. (O.M.)

  2. An initial analysis of short- and medium-range correlations potential non-Pt catalysts in CoNx

    Science.gov (United States)

    Peterson, Joe

    2010-03-01

    A potential show stopper for the development of fuel cells for the commercial automotive industry is the design of low-cost catalysts. The best catalysts are based on platinum, which is a rare and expensive noble metal. Our group has been involved in the characterization of potential materials for non-Pt catalysts. In this presentation, I will present some preliminary neutron scattering data from a nanocrystalline powder sample of CoNx. It is apparent that the diffraction data cannot be analyzed with standard Riedveld refinement, and we have to invoke pair distribution function (PDF) analysis. The PDF provides insight into short-range correlations, as it measures the probabilities of short- and mid-range interatomic distances in a material. The analysis reveals a strong incoherent scattering response, which is indicative of the presence of hydrogen in the sample. After correcting for the incoherent scattering, one obtains the normalized scattering function S(Q), whose Fourier transform yields the PDF.

  3. Delayed risk stratification system in pT1aN0/Nx DTC patients treated without radioactive iodine

    Directory of Open Access Journals (Sweden)

    Danuta Ga˛sior-Perczak

    2017-09-01

    Full Text Available Purpose: Delayed risk stratification (DRS system by Momesso and coworkers was accepted by the American Thyroid Association as a diagnostic tool for the risk stratification of unfavorable clinical outcomes and to monitor the clinical outcomes of differentiated thyroid cancer (DTC patients treated without radioactive iodine (RAI. The aim of this study was to evaluate the DRS system in patients with pT1aN0/Nx stage. Methods: The study included 304 low-risk patients after thyroidectomy (n = 202 or lobectomy (n = 102 without RAI and were treated at a single center. The median age was 50.5 years, 91.1% were women and the median follow-up was 4 years. DRS of the treatment response was performed based on medical records and according to the criteria of Momesso and coworkers. Disease course (recurrence, death and status (remission, persistent disease on December 31, 2016 were evaluated. The relationship between unfavorable outcomes and the DRS system was evaluated. Results: Response to initial therapy was excellent in 272 patients (89.5%, indeterminate in 31 (10.2% and biochemical incomplete (increased TgAb levels in one (0.3%. Two patients in the excellent response group experienced recurrence at 6 and 7 years of follow-up (after lobectomy. None of the patients with indeterminate and biochemical incomplete response developed structural disease, and none of the patients died during the follow-up. Conclusions: The DRS system was not useful for predicting the risk of unfavorable clinical outcomes and cannot be used to personalize the monitoring method of the disease in patients at pT1aN0/Nx stage who are not treated with RAI.

  4. Photocatalytic activity of porous multiwalled carbon nanotube-TiO{sub 2} composite layers for pollutant degradation

    Energy Technology Data Exchange (ETDEWEB)

    Zouzelka, Radek [J. Heyrovsky Institute of Physical Chemistry, v.i.i., Academy of Sciences of the Czech Republic, Dolejskova 3, 18223 Prague 8 (Czech Republic); Department of Physical Chemistry, University of Chemistry and Technology Prague, 16628 Prague (Czech Republic); Kusumawati, Yuly [Chimie ParisTech, PSL Research University, CNRS, Institut de Recherche de Chimie Paris (IRCP), 11 rue Pierre et Marie Curie, 75005 Paris (France); Remzova, Monika [J. Heyrovsky Institute of Physical Chemistry, v.i.i., Academy of Sciences of the Czech Republic, Dolejskova 3, 18223 Prague 8 (Czech Republic); Department of Physical Chemistry, University of Chemistry and Technology Prague, 16628 Prague (Czech Republic); Rathousky, Jiri [J. Heyrovsky Institute of Physical Chemistry, v.i.i., Academy of Sciences of the Czech Republic, Dolejskova 3, 18223 Prague 8 (Czech Republic); Pauporté, Thierry, E-mail: thierry.pauporte@chimie-paristech.fr [Chimie ParisTech, PSL Research University, CNRS, Institut de Recherche de Chimie Paris (IRCP), 11 rue Pierre et Marie Curie, 75005 Paris (France)

    2016-11-05

    Highlights: • A simple method for TiO{sub 2}/graphene nanocomposite layer preparation. • Stable coatings on glass substrate. • Mesoporous nanocomposite films with high internal surface area. • High photoactivity for 4-chlorophenol degradation. • Analysis of photocatalysis enhancement mechanism. - Abstract: TiO{sub 2} nanoparticles are suitable building blocks nanostructures for the synthesis of porous functional thin films. Here we report the preparation of films using brookite, P25 titania and anatase pristine nanoparticles and of nanocomposite layers combining anatase nanoparticles and multi-walled carbon nanotube (MWCNT) at various concentrations. The structure and phase composition of the layers were characterized by X-ray diffraction and Raman spectroscopy. Their morphology and texture properties were determined by scanning electron microscopy and krypton adsorption experiments, respectively. Additionally to a strong absorption in the UV range, the composites exhibited light absorption in the visible range as well. The photocatalytic performance of the layers was tested in the degradation of aqueous solutions of 4-chlorophenol serving as a model of an eco-persistent pollutant. Besides the determination of the decrease in the concentration of 4-chlorophenol, also the formation of intermediate degradation products, namely hydroquinone and benzoquinone, was followed. The presence of MWCNTs had a beneficial effect on the photocatalytic performance, a marked increase in the photocatalytic degradation rate constant being observed even at very low concentrations of MWCNTs. Compared to a P25 reference layer, the first order rate reaction constant increased by about 100% for the composite films containing MWCNTs at concentrations above 0.6 wt%. The key parameters for the enhancement of the photocatalytic performance are discussed. The presence of carbon nanotubes influences beneficially the degradation of 4-chlorophenol by an attack of the primarily

  5. Photo-oxidation of NO using an exterior paint--screening of various commercial titania in powder pressed and paint films.

    Science.gov (United States)

    Aguia, C; Angelo, J; Madeira, Luis M; Mendes, A

    2011-07-01

    The present work aims to evaluate the photocatalytic activity of photo-TiO(2) from various producers (Evonik, Kemira, Kronos, Millennium, Sachtleben and Tayca), in the form of powder pressed films and upon incorporation in a water-based paint, for outdoor NO abatement. The photocatalytic activity of the different samples was evaluated in terms of NO conversion and selectivity towards nitrite and nitrate ions following approximately the ISO 22197-1:2007(E) standard. The highest yields obtained for powder pressed films were achieved with VLP7000 (0.70), followed by VLP7101 (0.55) and UVLP7500 (0.55), all from Kronos. On the other hand, when incorporated in paint films, the highest yields were obtained with PC500 and PC105 from Millennium and UV100 from Sachtleben (ca. 0.15). The paint matrix plays an important role on the photocatalytic activity. In particular, the time for steady state is one or two orders of magnitude higher when the photocatalysts are incorporated in paint films in relation to the powder pressed films. The paint films were activated following the procedure recommended by the above-mentioned standard. However, the photocatalytic activity of films incorporating P25 (Evonik) was displayed only when higher power radiation and higher humidity conditions were used. This allowed for similar levels of photocatalytic activity as the other paint films. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Dual functional porous anti-reflective coatings with a photocatalytic effect based on a single layer system

    Science.gov (United States)

    Jilavi, M. H.; Mousavi, S. H.; Müller, T. S.; de Oliveira, P. W.

    2018-05-01

    Anti-reflection and photocatalytic properties are desirable for improving the optical properties of electronic devices. We describe a method of fabrication a single-layer, anti-reflective (AR) thin film with an additional photocatalytic property. The layer is deposited on glass substrates by means of a low-cost dip-coating method using a SiO2-TiO2 solution. A comparative study was undertaken to investigate the effects of TiO2 concentrations on the photocatalytic properties of the film and to determine the optimal balance between transmittance and photocatalysis. The average transmittance increases from T = 90.51% to T = 95.46 ± 0.07% for the wavelengths between 380 and 1200 nm. The structural characterization indicated the formation of thin, porous SiO2-TiO2 films with a roughness of less than 7.5 nm. The quality of the samples was evaluated by a complete test program of the mechanical, chemical and accelerated weathering stability. This results open up new possibilities for cost-effective AR coatings for the glass and solar cell industries.

  7. Preparation and characterization of Co-doped TiO2 materials for solar light induced current and photocatalytic applications

    International Nuclear Information System (INIS)

    Ganesh, Ibram; Gupta, A.K.; Kumar, P.P.; Chandra Sekhar, P.S.; Radha, K.; Padmanabham, G.; Sundararajan, G.

    2012-01-01

    Different amounts of Co-doped TiO 2 powders and thin films were prepared by following a conventional co-precipitation and sol–gel dip coating technique, respectively. The synthesized powders and thin films were subjected to thermal treatments from 400 to 800 °C and were thoroughly investigated by means of X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive analysis with X-rays, FT-infrared, FT-Raman, diffuse reflectance spectroscopy, ultraviolet–visible spectroscopy, BET surface area, zeta potential, flat band potential measurements, band-gap energy, etc. The photocatalytic ability of the powders was evaluated by methylene blue (MB) degradation studies. The thin films were characterized by photocurrent and ultraviolet–visible (UV–Vis) spectroscopy techniques. The characterization results suggest that the Co-doped TiO 2 powders synthesized in this study consist mainly anatase phase, and possess reasonably high specific surface area, low band gap energy and flat band potentials amenable to water oxidation in photoelectrochemical (PEC) cells. The photocatalytic degradation of MB over Co-doped TiO 2 powders followed the Langmuir–Hinshelwood first order reaction rate relationship. The 0.1 wt.% Co-doped TiO 2 composition provided the higher photocurrent, n-type semi-conducting behavior and higher photocatalytic activity among various Co-doped TiO 2 compositions and pure TiO 2 investigated.

  8. Airborne Microorganism Disinfection by Photocatalytic HEPA Filter

    Directory of Open Access Journals (Sweden)

    Rotruedee Chotigawin

    2010-07-01

    Full Text Available This study determined the efficacy of photocatalytic HEPA filters on microorganism disinfection in a closed-loop chamber and later applied it in an air purifier and tested its efficacy in an 8-m3 chamber and in a hospital. The photocatalytic filters were made by dip-coating a HEPA filter in a TiO2 slurry. In order to disinfect the microorganisms retained on the filter, UV-A light was irradiated onto the filter to create strong oxidative radicals which can destroy microorganisms. The findings showed that disinfection efficiency of the photocatalytic filters with high TiO2 loading was insignificantly higher than with lower loading. S. epidermidis was completely eliminated within 2 hours, while 86.8% of B. subtilis, 77.1% of A. niger, and 82.7% of P. citrinum were destroyed within 10 hours. When applying the photocatalytic filters into an air purifier in a 8-m3 chamber, it was found that as soon as the air purifier was turned on, 83.4% of S. epidermidis, 81.4% of B. subtilis, 88.5% of A. niger, and 75.8% of P. citrinum were removed from the air. In a hospital environment, the PCO air purifier efficacy was lower than that in the chamber. Besides, relative humidity, distances from the air purifier and room size were suspected to affect the efficacy of the photocatalytic filters.

  9. Photocatalytic materials and technologies for air purification.

    Science.gov (United States)

    Ren, Hangjuan; Koshy, Pramod; Chen, Wen-Fan; Qi, Shaohua; Sorrell, Charles Christopher

    2017-03-05

    Since there is increasing concern for the impact of air quality on human health, the present work surveys the materials and technologies for air purification using photocatalytic materials. The coverage includes (1) current photocatalytic materials for the decomposition of chemical contaminants and disinfection of pathogens present in air and (2) photocatalytic air purification systems that are used currently and under development. The present work focuses on five main themes. First, the mechanisms of photodegradation and photodisinfection are explained. Second, system designs for photocatalytic air purification are surveyed. Third, the photocatalytic materials used for air purification and their characteristics are considered, including both conventional and more recently developed photocatalysts. Fourth, the methods used to fabricate these materials are discussed. Fifth, the most significant coverage is devoted to materials design strategies aimed at improving the performance of photocatalysts for air purification. The review concludes with a brief consideration of promising future directions for materials research in photocatalysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Thermoluminescence of thin films deposited by laser ablation; Termoluminiscencia de peliculas delgadas depositadas por ablacion laser

    Energy Technology Data Exchange (ETDEWEB)

    Escobar A, L.; Camps, E.; Arrieta, A.; Romero, S.; Gonzalez, P.R.; Olea M, O.; Diaz E, R. [Depto. de Fisica, ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2003-07-01

    Materials in thin film form have received great attention in the last few years mainly because of their singular properties, which may differ significantly from their bulk attributes making them attractive for a wide variety of applications. In particular, thermoluminescence (Tl) properties of thin films have been studied recently owing to their potential applications in detection for both ionizing and non ionizing radiation. The aim of the present work is to report the synthesis and characterization of C Nx, aluminum oxide and titanium oxide thin films. Thermoluminescence response of the obtained thin films was studied after subject thin films to UV radiation (254 nm) as well as to gamma radiation (Co-60). Thermoluminescence glow curves exhibited a peak centered at 150 C for CN{sub x} whereas for titanium oxide the glow curve shows a maximum peaking at 171 C. Characterization of the physical properties of the deposited materials is presented. (Author)

  11. Germanium nitride and oxynitride films for surface passivation of Ge radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Maggioni, G., E-mail: maggioni@lnl.infn.it [Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Viale dell’Universita’2, I-35020 Legnaro, Padova (Italy); Carturan, S. [Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Viale dell’Universita’2, I-35020 Legnaro, Padova (Italy); Fiorese, L. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Viale dell’Universita’2, I-35020 Legnaro, Padova (Italy); Dipartimento di Ingegneria dei Materiali e delle Tecnologie Industriali, Università di Trento, Via Mesiano 77, I-38050 Povo, Trento (Italy); Pinto, N.; Caproli, F. [Scuola di Scienze e Tecnologie, Sezione di Fisica, Università di Camerino, Via Madonna delle Carceri 9, Camerino (Italy); INFN, Sezione di Perugia, Perugia (Italy); Napoli, D.R. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Viale dell’Universita’2, I-35020 Legnaro, Padova (Italy); Giarola, M.; Mariotto, G. [Dipartimento di Informatica—Università di Verona, Strada le Grazie 15, I-37134 Verona (Italy)

    2017-01-30

    Highlights: • A surface passivation method for HPGe radiation detectors is proposed. • Highly insulating GeNx- and GeOxNy-based layers are deposited at room temperature. • Deposition parameters affect composition and electrical properties of the layers. • The improved performance of a GeNx-coated HPGe diode is assessed. - Abstract: This work reports a detailed investigation of the properties of germanium nitride and oxynitride films to be applied as passivation layers to Ge radiation detectors. All the samples were deposited at room temperature by reactive RF magnetron sputtering. A strong correlation was found between the deposition parameters, such as deposition rate, substrate bias and atmosphere composition, and the oxygen and nitrogen content in the film matrix. We found that all the films were very poorly crystallized, consisting of very small Ge nitride and oxynitride nanocrystallites, and electrically insulating, with the resistivity changing from three to six orders of magnitude as a function of temperature. A preliminary test of these films as passivation layers was successfully performed by depositing a germanium nitride film on the intrinsic surface of a high-purity germanium (HPGe) diode and measuring the improved performance, in terms of leakage current, with respect to a reference passivated diode. All these interesting results allow us to envisage the application of this coating technology to the surface passivation of germanium-based radiation detectors.

  12. tavgM_2d_int_Nx: MERRA 2D IAU Diagnostic, Vertical Integrals and Budget Terms, Monthly Mean 0.667 x 0.5 degree V5.2.0 (MATMNXINT) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATMNXINT or tavgM_2d_int_Nx data product is the MERRA Data Assimilation System 2-Dimensional vertical integral that is time averaged single-level at the native...

  13. tavgU_2d_flx_Nx: MERRA 2D IAU Diagnostic, Surface Fluxes, Diurnal 0.667 x 0.5 degree V5.2.0 (MATUNXFLX) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATUNXFLX or tavgU_2d_flx_Nx data product is the MERRA Data Assimilation System 2-Dimensional surface turbulence flux diagnostic that is time averaged...

  14. tavgM_2d_slv_Nx: MERRA 2D IAU Diagnostic, Single Level Meteorology, Monthly Mean 0.667 x 0.5 degree V5.2.0 (MATMNXSLV) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATMNXSLV or tavgM_2d_slv_Nx data product is the MERRA Data Assimilation System 2-Dimensional atmospheric single-level diagnostics that is time averaged...

  15. tavgM_2d_ocn_Nx: MERRA 2D IAU Ocean Surface Diagnostic, Monthly Mean 0.667 x 0.5 degree V5.2.0 (MATMNXOCN) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATMNXOCN or tavgM_2d_ocn_Nx data product is the MERRA Data Assimilation System 2-Dimensional ocean surface single-level diagnostics that is monthly mean...

  16. tavgM_2d_ocn_Nx: MERRA 2D IAU Ocean Surface Diagnostic, Diurnal 0.667 x 0.5 degree V5.2.0 (MATUNXOCN) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATUNXOCN or tavgU_2d_ocn_Nx data product is the MERRA Data Assimilation System 2-Dimensional ocean surface single-level diagnostics that is monthly mean...

  17. tavgM_2d_flx_Nx: MERRA 2D IAU Diagnostic, Surface Fluxes, Monthly Mean 0.667 x 0.5 degree V5.2.0 (MATMNXFLX) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATMNXFLX or tavgM_2d_flx_Nx data product is the MERRA Data Assimilation System 2-Dimensional surface turbulence flux diagnostic that is time averaged...

  18. tavgM_2d_lnd_Nx: MERRA 2D IAU Diagnostic, Land Only States and Diagnostics, Monthly Mean 0.667 x 0.5 degree V5.2.0 (MATMNXLND) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATMNXLND or tavgM_2d_lnd_Nx data product is the MERRA Data Assimilation System 2-Dimensional land surface diagnostic that is time averaged single-level at the...

  19. tavgM_2d_rad_Nx: MERRA 2D IAU Diagnostic, Radiation Surface and TOA, Monthly Mean 0.667 x 0.5 degree V5.2.0 (MATMNXRAD) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATMNXRAD or tavgM_2d_rad_Nx data product is the MERRA Data Assimilation System 2-Dimensional surface and TOA radiation flux that is time averaged single-level...

  20. instM_2d_int_Nx: MERRA 2D IAU Diagnostic, Vertical Integrals and Budget Terms, Monthly Mean 0.667 x 0.5 degree V5.2.0 (MAIMNXINT) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAIMNXINT or instM_2d_int_Nx data product is the MERRA Data Assimilation System 2-Dimensional vertical integral that is time averaged single-level at the native...

  1. tavgU_2d_int_Nx: MERRA 2D IAU Diagnostic, Vertical Integrals and Budget Terms, Diurnal 0.667 x 0.5 degree V5.2.0 (MATUNXINT) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MATUNXINT or tavgU_2d_int_Nx data product is the MERRA Data Assimilation System 2-Dimensional vertical integral that is time averaged single-level at the native...

  2. instU_2d_int_Nx: MERRA 2D IAU Diagnostic, Vertical Integrals and Budget Terms, Diurnal 0.667 x 0.5 degree V5.2.0 (MAIUNXINT) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAIUNXINT or instU_2d_int_Nx data product is the MERRA Data Assimilation System 2-Dimensional vertical integral that is time averaged single-level at the native...

  3. tavg1_2d_ocn_Nx: MERRA 2D IAU Ocean Surface Diagnostic, Time Average 1-hourly 0.667 x 0.5 degree V5.2.0 (MAT1NXOCN) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAT1NXOCN or tavg1_2d_ocn_Nx data product is the MERRA Data Assimilation System 2-Dimensional ocean surface single-level diagnostics that is time averaged...

  4. tavg1_2d_flx_Nx: MERRA 2D IAU Diagnostic, Surface Fluxes, Time Average 1-hourly 0.667 x 0.5 degree V5.2.0 (MAT1NXFLX) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAT1NXFLX or tavg1_2d_flx_Nx data product is the MERRA Data Assimilation System 2-Dimensional surface turbulence flux diagnostic that is time averaged...

  5. tavg1_2d_slv_Nx: MERRA 2D IAU Diagnostic, Single Level Meteorology, Time Average 1-hourly 0.667 x 0.5 degree V5.2.0 (MAT1NXSLV) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAT1NXSLV or tavg1_2d_slv_Nx data product is the MERRA Data Assimilation System 2-Dimensional atmospheric single-level diagnostics that is time averaged...

  6. const_2d_asm_Nx: MERRA DAS 2d constants 0.667 x 0.5 degree V5.2.0 (MAC0NXASM) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAC0NXASM or const_2d_asm_Nx data product is the MERRA Data Assimilation System 2-Dimensional Constants at native resolution. MERRA, or the Modern Era...

  7. Surface passivation of n-type c-Si wafers by a-Si/SiO2/SiNx stack with <1 cm/s effective surface recombination velocity

    Science.gov (United States)

    Herasimenka, Stanislau Y.; Tracy, Clarence J.; Sharma, Vivek; Vulic, Natasa; Dauksher, William J.; Bowden, Stuart G.

    2013-10-01

    The passivation quality of an a-Si/SiO2/SiNx (aSON) stack deposited by conventional PECVD at corona charging of SiNx is presented. textured n-type Czochralski (CZ) substrates. It was shown that very good passivation can be achieved using 60 ms on 5000 Ω-cm and 20.9 ms on 1.7 Ω-cm mirror polished float zone (FZ) material passivated with aSON stacks.

  8. Integrated photocatalytic-biological reactor for accelerated phenol mineralization.

    Science.gov (United States)

    Zhang, Yongming; Wang, Lei; Rittmann, Bruce E

    2010-05-01

    An integrated photocatalytic-biological reactor (IPBR) was developed for accelerated phenol degradation and mineralization. In the IPBR, photodegradation and biodegradation occurred simultaneously, but in two separated zones: a piece of mat-glass plate coated with TiO(2) film and illuminated by UV light was connected by internal circulation to a honeycomb ceramic that was the biofilm carrier for biodegradation. This arrangement was designed to give intimate coupling of photocatalysis and biodegradation. Phenol degradation was investigated by following three protocols: photocatlysis with TiO(2) film under ultraviolet light, but no biofilm (photodegradation); biofilm biodegradation with no UV light (biodegradation); and simultaneous photodegradation and biodegradation (intimately coupled photobiodegradation). Photodegradation alone could partly degrade phenol, but was not able to achieve significant mineralization, even with an HRT of 10 h. Biodegradation alone could completely degrade phenol, but it did not mineralize the COD by more than 74%. Photobiodegradation allowed continuous rapid degradation of phenol, but it also led to more complete mineralization of phenol (up to 92%) than the other protocols. The results demonstrate that intimate coupling was achieved by protecting the biofilm from UV and free-radical inhibition. With phenol as the target compound, the main advantage of intimate coupling in the IPBR was increased mineralization, presumably because photocatalysis made soluble microbial products more rapidly biodegradable.

  9. Porphyrin-Based Nanostructures for Photocatalytic Applications

    Directory of Open Access Journals (Sweden)

    Yingzhi Chen

    2016-03-01

    Full Text Available Well-defined organic nanostructures with controllable size and morphology are increasingly exploited in optoelectronic devices. As promising building blocks, porphyrins have demonstrated great potentials in visible-light photocatalytic applications, because of their electrical, optical and catalytic properties. From this perspective, we have summarized the recent significant advances on the design and photocatalytic applications of porphyrin-based nanostructures. The rational strategies, such as texture or crystal modification and interfacial heterostructuring, are described. The applications of the porphyrin-based nanostructures in photocatalytic pollutant degradation and hydrogen evolution are presented. Finally, the ongoing challenges and opportunities for the future development of porphyrin nanostructures in high-quality nanodevices are also proposed.

  10. Photocatalytic semiconductors synthesis, characterization, and environmental applications

    CERN Document Server

    Hernández-Ramírez, Aracely

    2014-01-01

    This critical volume examines the different methods used for the synthesis of a great number of photocatalysts, including TiO2, ZnO and other modified semiconductors, as well as characterization techniques used for determining the optical, structural and morphological properties of the semiconducting materials. Additionally, the authors discuss photoelectrochemical methods for determining the light activity of the photocatalytic semiconductors by means of measurement of properties such as band gap energy, flat band potential and kinetics of hole and electron transfer. Photocatalytic Semiconductors: Synthesis, Characterization and Environmental Applications provide an overview of the semiconductor materials from first- to third-generation photocatalysts and their applications in wastewater treatment and water disinfection. The book further presents economic and toxicological aspects in the production and application of photocatalytic materials.

  11. Photocatalytic elimination of indoor air biological and chemical pollution in realistic conditions.

    Science.gov (United States)

    Sánchez, Benigno; Sánchez-Muñoz, Marta; Muñoz-Vicente, María; Cobas, Guillermo; Portela, Raquel; Suárez, Silvia; González, Aldo E; Rodríguez, Nuria; Amils, Ricardo

    2012-05-01

    The photocatalytic elimination of microorganisms from indoor air in realistic conditions and the feasibility of simultaneous elimination of chemical contaminants have been studied at laboratory scale. Transparent polymeric monoliths have been coated with sol-gel TiO(2) films and used as photocatalyst to treat real indoor air in a laboratory-scale single-step annular photocatalytic reactor. The analytical techniques used to characterize the air quality and analyze the results of the photocatalytic tests were: colony counting, microscopy and PCR with subsequent sequencing for microbial quantification and identification; automated thermal desorption coupled to gas chromatography with mass spectrometry detection for chemical analysis. The first experiments performed proved that photocatalysis based on UVA-irradiated TiO(2) for the reduction of the concentration of bacteria in the air could compete with the conventional photolytic treatment with UVC radiation, more expensive and hazardous. Simultaneously to the disinfection, the concentration of volatile organic compounds was greatly reduced, which adds value to this technology for real applications. The fungal colony number was not apparently modified. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Tuning the Photocatalytic Activity of Graphitic Carbon Nitride by Plasma-Based Surface Modification.

    Science.gov (United States)

    Ji, Xueqiang; Yuan, Xiaohong; Wu, Jiajie; Yu, Lan; Guo, Huiyun; Wang, Hannian; Zhang, Haiquan; Yu, Dongli; Zhao, Yuanchun

    2017-07-26

    In this study, we demonstrate that plasma treatment can be a facile and environmentally friendly approach to perform surface modification of graphitic carbon nitride (g-CN), leading to a remarkable modulation on its photocatalytic activity. The bulk properties of g-CN, including the particle size, structure, composition, and electronic band structures, have no changes after being treated by oxygen or nitrogen plasma; however, its surface composition and specific surface area exhibit remarkable differences corresponding to an oxygen functionalization induced by the plasma post-treatment. The introduced oxygen functional groups play a key role in reducing the recombination rate of the photoexcited charge carries. As a consequence, the oxygen-plasma-treated sample shows a much superior photocatalytic activity, which is about 4.2 times higher than that of the pristine g-CN for the degradation of rhodamine B (RhB) under visible light irradiation, while the activity of nitrogen-plasma-treated sample exhibits a slight decrease. Furthermore, both of the plasma-treated samples are found to possess impressive photocatalytic stabilities. Our results suggest that plasma treatment could be a conventional strategy to perform surface modification of g-CN in forms of both powders and thin films, which holds broad interest not only for developing g-CN-based high-performance photocatalysts but also for constructing photoelectrochemical cells and photoelectronic devices with improved energy conversion efficiencies.

  13. Self Cleaning Paint: Introduction of Photocatalytic Particles into a Paint System

    DEFF Research Database (Denmark)

    Gunnarsson, Sverrir Grimur

    The current industrial PhD work was aimed at synthesising a photocatalytic composite material which could be used to give organic wood paint films self-cleaning and anti-microbial properties. The current PhD work was done in collaboration between Dyrup A/S and Technical University of Denmark....... The paint industry constantly faces updated restriction on toxic chemicals as for instance biocides which has prompted the search for alternative strategies for increasing the durability of their products. Photocatalysts are generally known to have adverse effects on organic coatings due to the highly...

  14. Structural and Mechanical Properties of CrNx Coatings Deposited by Medium-Frequency Magnetron Sputtering with and without Ion Source Assistance

    International Nuclear Information System (INIS)

    Tian, C.X.; He, J.; Wang, H.J.; Fu, D.J.; Yang, B.

    2011-01-01

    CrNx coatings were deposited on Si (100) and WC-Co substrates by a home-made medium-frequency magnetron sputtering system with and without thermal filament ion source assistance. The structure and composition of the coatings were characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, and transmission electron microscopy. The mechanical and tribological properties were assessed by microhardness and pin-on-disc testing. The ion source-assisted system showed a deposition rate of 3.88 μm/h, much higher than the value 2.2 μm/h without ion source assistance. The CrNx coatings prepared with ion source assistance exhibited an increase in microhardness (up to 16.3 GPa) and a decrease in friction coefficient (down to 0.48) at the optimized cathode source-to-substrate distance.

  15. Improving the Microstructure and Electrical Properties of Aluminum Induced Polysilicon Thin Films Using Silicon Nitride Capping Layer

    Directory of Open Access Journals (Sweden)

    Min-Hang Weng

    2014-01-01

    Full Text Available We investigated the capping layer effect of SiNx (silicon nitride on the microstructure, electrical, and optical properties of poly-Si (polycrystalline silicon prepared by aluminum induced crystallization (AIC. The primary multilayer structure comprised Al (30 nm/SiNx (20 nm/a-Si (amorphous silicon layer (100 nm/ITO coated glass and was then annealed in a low annealing temperature of 350°C with different annealing times, 15, 30, 45, and 60 min. The crystallization properties were analyzed and verified by X-ray diffraction (XRD and Raman spectra. The grain growth was analyzed via optical microscope (OM and scanning electron microscopy (SEM. The improved electrical properties such as Hall mobility, resistivity, and dark conductivity were investigated by using Hall and current-voltage (I-V measurements. The results show that the amorphous silicon film has been effectively induced even at a low temperature of 350°C and a short annealing time of 15 min and indicate that the SiNx capping layer can improve the grain growth and reduce the metal content in the induced poly-Si film. It is found that the large grain size is over 20 μm and the carrier mobility values are over 80 cm2/V-s.

  16. Enhanced photocatalytic performance of TiO{sub 2} nanotube based heterojunction photocatalyst via the coupling of graphene and FTO

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Xiaoyou [College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Yu, Jianyuan [College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Department of Environmental and Chemical Engineering, Tangshan University, Tangshan 063000 (China); Wang, Likun; Fu, Chen; Wang, Jixia; Wang, Li [College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Zhao, Hongli, E-mail: zhaohongli@ysu.edu.cn [College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); State Key Laboratory of Metastable Materials Science and Technology, Qinhuangdao 066004 (China); Yang, Jingkai, E-mail: yangjk@ysu.edu.cn [National Defense Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

    2017-08-15

    Highlights: • The rGO-TONT composites have been deposited onto FTO. • Photocatalytic reaction rate shows 3 times greater than TONT. • Chemical interaction between rGO and TONT was analyzed. • Electron transfer process in rGO-TONT/FTO heterojunction was discussed. - Abstract: The TiO{sub 2} nanotube (TONT) based heterojunction photocatalyst was developed via the coupling of reduced graphene oxide (rGO) and SnO{sub 2}:F film (FTO). Based on the characterization of Raman analysis, XRD, SEM, TEM, XPS and ESR, the crystal phase, morphology, heterojunction interfacial interaction and the photoinduced electron chemical environment of the samples are studied. In the photodegradation of methylene blue (MB) solution under UV irradiation, the rGO-TONT/FTO heterojunction photocatalyst exhibits the improved photocatalytic reaction rate, 3 times greater than that of pure TONT. The enhanced photocatalytic mechanism was discussed by PL. The effectively separate charge in heterojunction structure of rGO-TONT/FTO is responsible for the enhanced photocatalytic activity. Wherein, the abundant oxygen vacancies at TiO{sub 2} surface and the chemically bonded interface in rGO-TONT heterojunction also contributes to the interfacial electron transfer. Besides, the introduction of rGO enhanced its optical absorption capacity.

  17. SCO-spondin derived peptide NX210 induces neuroprotection in vitro and promotes fiber regrowth and functional recovery after spinal cord injury.

    Directory of Open Access Journals (Sweden)

    Laurent Sakka

    Full Text Available In mammals, the limited regenerating potential of the central nervous system (CNS in adults contrasts with the plasticity of the embryonic and perinatal periods. SCO (subcommissural organ-spondin is a protein secreted early by the developing central nervous system, potentially involved in the development of commissural fibers. SCO-spondin stimulates neuronal differentiation and neurite growth in vitro. NX210 oligopeptide was designed from SCO-spondin's specific thrombospondin type 1 repeat (TSR sequences that support the main neurogenic properties of the molecule. The objective of this work was to assess the neuroprotective and neuroregenerative properties of NX210 in vitro and in vivo for the treatment of spinal cord injury (SCI. In vitro studies were carried out on the B104 neuroblastoma cell line demonstrating neuroprotection by the resistance to oxidative damage using hydrogen peroxide and the measure of cell viability by metabolic activity. In vivo studies were performed in two rat models of SCI: (1 a model of aspiration of dorsal funiculi followed by the insertion of a collagen tube in situ to limit collateral sprouting; white matter regeneration was assessed using neurofilament immunostaining; (2 a rat spinal cord contusion model to assess functional recovery using BBB scale and reflex testing. We demonstrate for the first time that NX210 (a provides neuroprotection to oxidative stress in the B104 neuroblastoma cells, (b stimulates axonal regrowth in longitudinally oriented neofibers in the aspiration model of SCI and (c significantly improves functional recovery in the contusive model of SCI.

  18. Study of interface barrier of SiNx/GaN interface for nitrogen-polar GaN based high electron mobility transistors

    Science.gov (United States)

    Nidhi, Rajan, Siddharth; Keller, Stacia; Wu, Feng; DenBaars, Steven P.; Speck, James S.; Mishra, Umesh K.

    2008-06-01

    The SiNx/GaN interface barrier height for N-polar GaN based metal-insulator-semiconductor high electron mobility transistors (MISHEMTs) was investigated. N-polar SiNx/GaN/AlGaN/GaN MISHEMT structures with different GaN cap thicknesses were grown by metal-organic chemical vapor deposition. The properties of the SiNx/GaN interface are of critical importance to device operation and modeling in these devices. An analytical expression for the pinch-off voltage of the HEMT was obtained, and capacitance-voltage (C-V) measurements with different Schottky metals were used to extract the barrier height. The Fermi level at the interface was found to be pinned at approximately 1 eV with respect to GaN conduction band edge, irrespective of the work function of the gate metal. Hall measurements of the two-dimensional electron gas density were found to corroborate the predicted interface barrier height. An approximate value for interface charge causing this pinning was calculated to be 4.5×1012 cm-2.

  19. Estimation of the Binding Free Energy of AC1NX476 to HIV-1 Protease Wild Type and Mutations Using Free Energy Perturbation Method.

    Science.gov (United States)

    Ngo, Son Tung; Mai, Binh Khanh; Hiep, Dinh Minh; Li, Mai Suan

    2015-10-01

    The binding mechanism of AC1NX476 to HIV-1 protease wild type and mutations was studied by the docking and molecular dynamics simulations. The binding free energy was calculated using the double-annihilation binding free energy method. It is shown that the binding affinity of AC1NX476 to wild type is higher than not only ritonavir but also darunavir, making AC1NX476 become attractive candidate for HIV treatment. Our theoretical results are in excellent agreement with the experimental data as the correlation coefficient between calculated and experimentally measured binding free energies R = 0.993. Residues Asp25-A, Asp29-A, Asp30-A, Ile47-A, Gly48-A, and Val50-A from chain A, and Asp25-B from chain B play a crucial role in the ligand binding. The mutations were found to reduce the receptor-ligand interaction by widening the binding cavity, and the binding propensity is mainly driven by the van der Waals interaction. Our finding may be useful for designing potential drugs to combat with HIV. © 2015 John Wiley & Sons A/S.

  20. Photocatalytic reduction synthesis of SrTiO3-graphene nanocomposites and their enhanced photocatalytic activity.

    Science.gov (United States)

    Xian, Tao; Yang, Hua; Di, Lijing; Ma, Jinyuan; Zhang, Haimin; Dai, Jianfeng

    2014-01-01

    SrTiO3-graphene nanocomposites were prepared via photocatalytic reduction of graphene oxide by UV light-irradiated SrTiO3 nanoparticles. Fourier transformed infrared spectroscopy analysis indicates that graphene oxide is reduced into graphene. Transmission electron microscope observation shows that SrTiO3 nanoparticles are well assembled onto graphene sheets. The photocatalytic activity of as-prepared SrTiO3-graphene composites was evaluated by the degradation of acid orange 7 (AO7) under a 254-nm UV irradiation, revealing that the composites exhibit significantly enhanced photocatalytic activity compared to the bare SrTiO3 nanoparticles. This can be explained by the fact that photogenerated electrons are captured by graphene, leading to an increased separation and availability of electrons and holes for the photocatalytic reaction. Hydroxyl (·OH) radicals were detected by the photoluminescence technique using terephthalic acid as a probe molecule and were found to be produced over the irradiated SrTiO3 nanoparticles and SrTiO3-graphene composites; especially, an enhanced yield is observed for the latter. The influence of ethanol, KI, and N2 on the photocatalytic efficiency was also investigated. Based on the experimental results, ·OH, h(+), and H2O2 are suggested to be the main active species in the photocatalytic degradation of AO7 by SrTiO3-graphene composites. 61.46. + w; 78.67.Bf; 78.66.Sq.

  1. Characterization and photocatalytic treatability of red water from Brazilian TNT industry

    Energy Technology Data Exchange (ETDEWEB)

    Ludwichk, Raquel [Department of Chemistry, Postgraduate Programme in Technology of Chemical and Biochemical Processes, Federal Technological University of Paraná, Pato Branco, PR (Brazil); Helferich, Oliver Karil; Kist, Cristiane Patrícia [Academic Department of Chemistry and Biology, Post graduation in Environmental Science and Technology Federal Technological University of Paraná, Curitiba, PR (Brazil); Lopes, Aline Chitto; Cavasotto, Thiago [Department of Chemistry, Postgraduate Programme in Technology of Chemical and Biochemical Processes, Federal Technological University of Paraná, Pato Branco, PR (Brazil); Silva, Davi Costa [Academic Department of Chemistry and Biology, Post graduation in Environmental Science and Technology Federal Technological University of Paraná, Curitiba, PR (Brazil); Barreto-Rodrigues, Marcio, E-mail: marciorodrigues@utfpr.edu.br [Department of Chemistry, Postgraduate Programme in Technology of Chemical and Biochemical Processes, Federal Technological University of Paraná, Pato Branco, PR (Brazil); Academic Department of Chemistry and Biology, Post graduation in Environmental Science and Technology Federal Technological University of Paraná, Curitiba, PR (Brazil)

    2015-08-15

    Highlights: • The red water effluent has high levels of COD, color and acute toxicity. • The compounds 2-methyl-1, 3-dinitrobenzene, 1-methyl-2, 4-dinitrobenzene and 1-methyl-3, 5-dinitrobenzene were identified. • A nanostructured TiO{sub 2}-borosilicate glass was obtained and characterized. • The photocatalytic treatment removes all color 32% of the organic matter content of the effluent. • The borosilicate-glass-TiO{sub 2} system degrades all content of identified nitroaromatic compounds. - Abstract: The current study aims to characterize and evaluate the photocatalytic treatability of the “red water” effluent from a Brazilian TNT production industry. Analyses were performed using physical, chemical, spectroscopic and chromatographic assays, which demonstrated that the effluent presented a significant pollution potential, mainly due to COD, BOD, solids and to the high concentration of nitroaromatic compounds such as 1,3,5-trinitrobenzene, 1-methyl-2,4-dinitrobenzene, 2-methyl-1,3-dinitrobenzene, 2,4,6-trinitrotoluene-3,5-dinitro-p-toluidine and 2-methyl-3,5-dinitro-benzoamine. By a modified sol-gel and a dip-coating technique, it was possible to obtain a TiO{sub 2} film on borosilicate glass substrate which functional composition and microstructure were characterized by infrared spectroscopy and scanning electron microscopy. The evaluation of the photocatalytic treatability using borosilicate-glass-TiO{sub 2} demonstrated high degradation efficiency. In this context, a reduction of 32 and 100% for COD and nitroaromatic compounds, respectively, was observed. Although the proposed photocatalytic process has found difficulties in reducing the content of organic matter and effluent color in the red water, its potential for degrading refractory chemical compounds such as the nitroaromatic ones enables it to be used as tertiary treatment.

  2. Effect of Fluorine Diffusion on Amorphous-InGaZnO-Based Thin-Film Transistors.

    Science.gov (United States)

    Jiang, Jingxin; Furuta, Mamoru

    2018-08-01

    This study investigated the effect of fluorine (F) diffusion from a fluorinated siliconnitride passivation layer (SiNX:F-Pa) into amorphous-InGaZnO-based thin-film transistors (a-IGZO TFTs). The results of thermal desorption spectroscopy and secondary ion mass spectrometry revealed that F was introduced into the SiOX etch-stopper layer (SiOX-ES) during the deposition of a SiNX:F-Pa, and did not originate from desorption of Si-F bonds; and that long annealing times enhanced F diffusion from the SiOX-ES layer to the a-IGZO channel. Improvements to the performance and threshold-voltage (Vth) negative shift of IGZO TFTs were achieved when annealing time increased from 1 h to 3 h; and capacitance-voltage results indicated that F acted as a shallow donor near the source side in a-IGZO and induced the negative Vth shift. In addition, it was found that when IGZO TFTs with SiNX:F-Pa were annealed 4 h, a low-resistance region was formed at the backchannel of the TFT, leading to a drastic negative Vth shift.

  3. Direct generation of titanium dioxide nanoparticles dispersion under supercritical conditions for photocatalytic active thermoplastic surfaces for microbiological inactivation

    International Nuclear Information System (INIS)

    Zydziak, Nicolas; Zanin, Maria-Helena Ambrosio; Trick, Iris; Hübner, Christof

    2015-01-01

    Thermoplastic poly(propylene) (PP) and acrylonitrile-butadiene-styrene (ABS) surfaces were coated with silica based films via the sol–gel process, containing titanium dioxide (TiO 2 ) as photocatalyst. TiO 2 was previously synthesized via sol–gel and treated under supercritical conditions in water dispersions. The characterization of the TiO 2 dispersions was performed via disc centrifuge to determine the particle size and via Raman spectroscopy and X-Ray Diffraction (XRD) to characterize the crystallinity of TiO 2 . The synthesized TiO 2 dispersions and commercially available TiO 2 particles were incorporated in silica based films which were synthesized under acidic or basic conditions, leading to dense or porous films respectively. The morphology of the films was characterized via Scanning Electron Microscopy (SEM). The incorporation of synthesized TiO 2 in the coating led to photocatalytically more active thermoplastic surfaces than films formulated with commercially available TiO 2 as determined via dye discoloration test. A microbiological test performed with Sarcina lutea confirmed this result and showed an inactivation factor of 6 (99.9999%) after 24 h UV irradiation, for synthesized TiO 2 incorporated in acidic formulated silica layer on ABS surfaces. - Highlights: • We report about photocatalytic layers formulated on thermoplastic surfaces. • We synthesized silica layer and TiO 2 via sol–gel and supercritical treatment. • Amorphous, crystalline and commercial dispersions were generated and characterized. • The morphology of dense and porous photocatalytic layers is observed via SEM. • Discoloration and microbiological tests correlate activity and surface morphology

  4. Synthesis, characterization and photocatalytic reactions of ...

    Indian Academy of Sciences (India)

    Mesoporous structure of phosphated titania did not collapse even after calcination at 600°C. The enhanced photocatalytic activity of the synthesized phosphate nanomaterials were evaluated through a study of the decomposition of fluorescein under UV light excitation and compared with undoped titania nanomaterial as ...

  5. Synthesis crystal structure, photoluminescence and photocatalytic ...

    Indian Academy of Sciences (India)

    photoluminescence and photocatalytic properties of 1 were also been investigated. Keywords. Zinc; 5-(pyridyl)tetrazolato (PTZ); Single-Crystal X-Ray Crystallography. 1. Introduction. In last few years tetrazole ligands have been widely used to synthesize metal–organic and H-bonded frameworks of various topologies.1–5 ...

  6. Photocatalytic Solutions Create Self-Cleaning Surfaces

    Science.gov (United States)

    2013-01-01

    A Stennis Space Center researcher investigating the effectiveness of photocatalytic materials for keeping the Center's buildings free of grime turned to a solution created by PURETi Inc. of New York City. Testing proved successful, and NASA and the company now share a Dual Use Technology partnership. PURETi's coatings keep surfaces clean and purify surrounding air, eliminating pollution, odors, and microbes.

  7. Synthesis, characterization and photocatalytic reactions of ...

    Indian Academy of Sciences (India)

    Titanium dioxide is one of the most extensively investigated photocatalyst and is the subject of extensive .... with commercial titania powder from Merck. 2.2 Characterization. X-ray diffraction patterns of the ..... Bickley R I and Navio J A 1985 Photocatalytic production of energy-rich compounds (eds) G Grassi and D O Hall ...

  8. Photocatalytic reforming of biomass for hydrogen production

    NARCIS (Netherlands)

    Ripken, R.M.; de Boer, V.J.H.W.; Gardeniers, J.G.E.; le Gac, S.

    2017-01-01

    Here, we describe a novel microfluidic device to determine the required bandgap for the photocatalytic reforming of biomass model substrates (ethylene glycol, glycerol, xylose and xylitol) in water. Furthermore, this device is applied to eventually elucidate the reaction mechanism of aqueous

  9. Photoluminescence quenching and photocatalytic enhancement of ...

    Indian Academy of Sciences (India)

    24

    The work reports the synthesis of novel Praseodymium (Pr) doped ZnO nanocrystals with excellent photocatalytic activity via modified solid state reaction route. The impacts of doping on the wurtzite hexagonal structure are analysed with X-ray diffraction (XRD) and Raman spectroscopy. The production of defect levels and ...

  10. Synthesis, characterization, photocatalytic and reusability studies of ...

    Indian Academy of Sciences (India)

    This paper presents results of a study on the structural and morphological properties of 2-mercaptoethanol (2-ME) capped ZnS nanoparticles (NPs). The photocatalytic and reusability study of the synthesized NPs to degrade dyes was also done. ZnS semiconductor NPs were synthesized via chemical precipitation route ...

  11. Photocatalytic degradation of geosmin: Reaction pathway analysis

    African Journals Online (AJOL)

    2011-07-25

    Jul 25, 2011 ... The presence of geosmin in drinking water imparts a musty odour which leads to consumer complaints. Geosmin and other unwanted organics can be treated using photocatalysis. However, the intermediates formed during the photocatalytic degra- dation process and their degradation pathways have not ...

  12. Advanced oxidation technologies : photocatalytic treatment of wastewater

    NARCIS (Netherlands)

    Chen, J.

    1997-01-01

    7.1. Summary and conclusions

    The last two decennia have shown a growing interest in the photocatalytic treatment of wastewater, and more and more research has been carried out into the various aspects of photocatalysis, varying from highly fundamental aspects to practical application.

  13. Photocatalytic reactor for organic compound removal using ...

    Indian Academy of Sciences (India)

    http://www.ias.ac.in/article/fulltext/boms/039/02/0569-0572. Keywords. Titanium dioxide; photocatalysis; methylene blue; wastewater treatment. Abstract. In this work, a photocatalytic reactor with a working volume of 13 l was fabricated of soda-lime silica glass. Commercial titanium dioxide (TiO 2 ) particles were used as the ...

  14. Photocatalytic degradation of geosmin: Reaction pathway analysis ...

    African Journals Online (AJOL)

    The presence of geosmin in drinking water imparts a musty odour which leads to consumer complaints. Geosmin and other unwanted organics can be treated using photocatalysis. However, the intermediates formed during the photocatalytic degradation process and their degradation pathways have not previously been ...

  15. Um negócio da China: o discurso do guānxì nas articulações no âmbito organizacional

    Directory of Open Access Journals (Sweden)

    Osíris Luís da Cunha Fernandes

    Full Text Available Este estudo explora o guānxì como discurso organizacional vigente na cultura de negócios nas organizações chinesas a partir da lógica da equivalência e da lógica da diferença propostas por Ernesto Laclau e Chantal Mouffe. O guānxì consiste em um relacionamento interpessoal e na criação de conhecimento colaborativo que envolve um saber tácito, orientado para o futuro, complexo que opera em contexto específico. Em uma perspectiva pós-estruturalista aplicada às organizações, utilizamos a análise de discurso como método que permite pôr em prática o papel da linguagem na condição de eixo de compreensão de processos sociais, como acontece com o guānxì. Analisamos 3 entrevistas em profundidade realizadas com chief executive officers (CEOs chineses e 32 reportagens relacionadas à prática do guānxì em organizações do setor terciário, publicadas em 2 dos maiores diários digitais da China. Com isso, nosso objetivo foi identificar a forma como esse fenômeno tem sido apropriado como discurso no âmbito organizacional a partir da lógica da equivalência e da lógica da diferença. Constatamos que as organizações chinesas utilizam o guānxì para obterem acesso preferencial a atores estratégicos que têm informações e recursos demandados nos processos negociais, com vista a obterem vantagens competitivas. Por outro lado, o sucesso dos negócios envolvendo essas organizações depende de uma identificação mútua entre seus líderes, baseada na confiança e credibilidade estabelecidas nas articulações.

  16. Growth of onion (Allium cepa L. var. "Red Arequipeña" due to fertilization NxK

    Directory of Open Access Journals (Sweden)

    Julio Estuardo Amaya Robles

    2012-03-01

    Full Text Available Whit the objective to determining the influence of increasing levels of nitrogen and potassium in the growth of onion, was carried an experiment in Pampas de San Juan, Laredo during October 2010 to January 2011. We used certified seed red onion var. "Red Arequipeña". The treatments were the combinations results of 60, 120, 180 and 240 kg N ha-1 and 40, 80 and 160 kg K2O ha-1 , used as a single dose, 80 kg P2O5 ha-1 . The experiment was designed in randomized complete block with 3x4 factorial arrangements with three replications. The results of this research to conclude that the dose of 120 kg N.ha-1 , was obtained a linear response to nitrogen ascendant of 44.9cm in height with 90 days of DDT and 14.2 mm for diameter of the false stem with 60 N.kg-1 to 104 days DDT. There were no responses to potassium in this variable. There were no responses to NxK for the number of leaves.

  17. Improvement of poly-γ-glutamic acid biosynthesis in a moving bed biofilm reactor by Bacillus subtilis NX-2.

    Science.gov (United States)

    Jiang, Yongxiang; Tang, Bao; Xu, Zongqi; Liu, Kun; Xu, Zheng; Feng, Xiaohai; Xu, Hong

    2016-10-01

    The production of poly-γ-glutamic acid (γ-PGA) by Bacillus subtilis NX-2 using a moving bed biofilm reactor (MBBR) system was tested for the first time in this study. Polypropylene TL-2 was chosen as a suitable carrier, and γ-PGA concentration of 42.7±0.86g/L and productivity of 0.59±0.06g/(Lh) were obtained in batch fermentation. After application of the strategy of dissolved oxygen (DO)-stat feeding, higher γ-PGA concentration and productivity were achieved than with glucose feedback feeding. Finally, the repeated fed-batch cultures implemented in the MBBR system showed high stability, and the maximal γ-PGA concentration and productivity of 74.2g/L and 1.24g/(Lh) were achieved, respectively. In addition, the promotion of oxygen transfer by an MBBR carrier was well explained by a computational fluid dynamics (CFD) simulation. These results suggest that an MBBR system could be applied to large-scale γ-PGA production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Transparent, well-aligned TiO(2) nanotube arrays with controllable dimensions on glass substrates for photocatalytic applications.

    Science.gov (United States)

    Tan, Lee Kheng; Kumar, Manippady K; An, Wen Wen; Gao, Han

    2010-02-01

    Transparent, well-aligned TiO(2) nanotube arrays (NTAs) with controllable dimensions are grown on glass substrates via atomic layer deposition (ALD) of TiO(2) onto free-standing porous anodic alumina (PAA) templates. Photodegradation of aqueous methylene blue (MB) solution and solid stearic acid (SA) film using TiO(2) NTAs of various wall thicknesses are investigated. The Pd functionalized TiO(2) NTAs, with a wall thickness of 15 nm and height of 200 nm, has the highest photodegradation efficiency at 76% after 4 h of UV irradiation. These functionalized NTAs are able to photodegrade MB molecules completely as no obvious demethylated byproducts are observed during the process. It also demonstrates excellent photocatalytic activity for solid contaminants such as SA film. By using the ALD technique, the nanotube wall thickness can be precisely controlled so that it is sufficiently thin to be transparent while sufficiently thick for excellent photocatalytic performances. The transparent TiO(2) NTAs on glass substrates with excellent photocatalytic properties might have potential applications in self-cleaning coating, transparent electronics, and solar cells.

  19. Facet‐Engineered Surface and Interface Design of Photocatalytic Materials

    Science.gov (United States)

    Wang, Lili; Li, Zhengquan

    2016-01-01

    The facet‐engineered surface and interface design for photocatalytic materials has been proven as a versatile approach to enhance their photocatalytic performance. This review article encompasses some recent advances in the facet engineering that has been performed to control the surface of mono‐component semiconductor systems and to design the surface and interface structures of multi‐component heterostructures toward photocatalytic applications. The review begins with some key points which should receive attention in the facet engineering on photocatalytic materials. We then discuss the synthetic approaches to achieve the facet control associated with the surface and interface design. In the following section, the facet‐engineered surface design on mono‐component photocatalytic materials is introduced, which forms a basis for the discussion on more complex systems. Subsequently, we elucidate the facet‐engineered surface and interface design of multi‐component photocatalytic materials. Finally, the existing challenges and future prospects are discussed. PMID:28105398

  20. TiO2 Solar Photocatalytic Reactor Systems: Selection of Reactor Design for Scale-up and Commercialization—Analytical Review

    Directory of Open Access Journals (Sweden)

    Yasmine Abdel-Maksoud

    2016-09-01

    Full Text Available For the last four decades, viability of photocatalytic degradation of organic compounds in water streams has been demonstrated. Different configurations for solar TiO2 photocatalytic reactors have been used, however pilot and demonstration plants are still countable. Degradation efficiency reported as a function of treatment time does not answer the question: which of these reactor configurations is the most suitable for photocatalytic process and optimum for scale-up and commercialization? Degradation efficiency expressed as a function of the reactor throughput and ease of catalyst removal from treated effluent are used for comparing performance of different reactor configurations to select the optimum for scale-up. Comparison included parabolic trough, flat plate, double skin sheet, shallow ponds, shallow tanks, thin-film fixed-bed, thin film cascade, step, compound parabolic concentrators, fountain, slurry bubble column, pebble bed and packed bed reactors. Degradation efficiency as a function of system throughput is a powerful indicator for comparing the performance of photocatalytic reactors of different types and geometries, at different development scales. Shallow ponds, shallow tanks and fountain reactors have the potential of meeting all the process requirements and a relatively high throughput are suitable for developing into continuous industrial-scale treatment units given that an efficient immobilized or supported photocatalyst is used.

  1. Nitrogen and europium doped TiO2 anodized films with applications in photocatalysis

    International Nuclear Information System (INIS)

    Chi, Choong-Soo; Choi, Jinwook; Jeong, Yongsoo; Lee, Oh Yeon; Oh, Han-Jun

    2011-01-01

    Micro-arc oxidation method is a useful process for mesoporous titanium dioxide films. In order to improve the photocatalytic activity of the TiO 2 film, N-Eu co-doped titania catalyst was synthesized by micro-arc oxidation in the H 2 SO 4 /Eu(NO 3 ) 3 mixture solution. The specific surface area and the roughness of the anodic titania film fabricated in the H 2 SO 4 /Eu(NO 3 ) 3 electrolyte, were increased compared to that of the anodic TiO 2 film prepared in H 2 SO 4 solution. The absorbance response of N-Eu titania film shows a higher adsorption onset toward visible light region, and the incorporated N and Eu ions during anodization as a dopant in the anodic TiO 2 film significantly enhanced the photocatalytic activity for dye degradation. After dye decomposition test for 3 h, dye removal rates for the anodic TiO 2 film were 60.7% and 90.1% for the N-Eu doped titania film. The improvement of the photocatalytic activity was ascribed to the synergistic effects of the surface enlargement and the new electronic state of the TiO 2 band gap by N and Eu co-doping.

  2. Nitrogen doping in atomic layer deposition grown titanium dioxide films by using ammonium hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Kaeaeriaeinen, M.-L., E-mail: marja-leena.kaariainen@lut.fi; Cameron, D.C.

    2012-12-30

    Titanium dioxide films have been created by atomic layer deposition using titanium chloride as the metal source and a solution of ammonium hydroxide in water as oxidant. Ammonium hydroxide has been used as a source of nitrogen for doping and three thickness series have been deposited at 350 Degree-Sign C. A 15 nm anatase dominated film was found to possess the highest photocatalytic activity in all film series. Furthermore almost three times better photocatalytic activity was discovered in the doped series compared to undoped films. The doped films also had lower resistivity. The results from X-ray photoemission spectroscopy showed evidence for interstitial nitrogen in the titanium dioxide structure. Besides, there was a minor red shift observable in the thickest samples. In addition the film conductivity was discovered to increase with the feeding pressure of ammonium hydroxide in the oxidant precursor. This may indicate that nitrogen doping has caused the decrease in the resistivity and therefore has an impact as an enhanced photocatalytic activity. The hot probe test showed that all the anatase or anatase dominant films were p-type and all the rutile dominant films were n-type. The best photocatalytic activity was shown by anatase-dominant films containing a small amount of rutile. It may be that p-n-junctions are formed between p-type anatase and n-type rutile which cause carrier separation and slow down the recombination rate. The combination of nitrogen doping and p-n junction formation results in superior photocatalytic performance. - Highlights: Black-Right-Pointing-Pointer We found all N-doped and undoped anatase dominating films p-type. Black-Right-Pointing-Pointer We found all N-doped and undoped rutile dominating films n-type. Black-Right-Pointing-Pointer We propose that p-n junctions are formed in anatase-rutile mixture films. Black-Right-Pointing-Pointer We found that low level N-doping has increased TiO{sub 2} conductivity. Black

  3. Visible Light Activated Photocatalytic Water Polishing System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal targets development of a LED light activated photocatalytic water polishing system that enables reduction of organic impurities (TOC and...

  4. High Performance Photocatalytic Oxidation Reactor System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Pioneer Astronautics proposes a technology program for the development of an innovative photocatalytic oxidation reactor for the removal and mineralization of...

  5. In situ SERS monitoring of photocatalytic organic decomposition using recyclable TiO{sub 2}-coated Ag nanowire arrays

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Zhi Yong [Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong (China); Liu, Xin [Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong (China); Key Lab of Advanced Transducers and Intelligent Control System of Ministry of Education, and College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan (China); Dai, Jiyan [Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong (China); Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen (China); Wu, Yucheng [College of Material Science and Engineering, Hefei University of Technology, Hefei (China); Tsang, Yuen Hong, E-mail: yuen.tsang@polyu.edu.hk [Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong (China); Lei, Dang Yuan, E-mail: dylei@polyu.edu.hk [Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong (China); Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen (China)

    2014-05-01

    Highlights: • TiO{sub 2}-coated Ag nanowire arrays (SNA) were synthesized through hydrolysis of butyl titanate on the surface of SNA. • The TiO{sub 2}-coated SNA exhibits much higher photocatalytic activity than bare TiO{sub 2} films, as demonstrated by the enhanced photodegradation rate of R6G and methyl blue molecules. • The prepared substrates serve as a high-sensitivity surface-enhanced Raman scattering (SERS) substrate for in situ monitoring of the photocatalytic decomposition reaction detecting 2,4-D molecules. • Full-wave numerical calculations reveal that the improved photocatalysis and SERS efficiencies are attributed to the largely enhanced electromagnetic near-field in the nanocomposites. - Abstract: Recently, semiconductor and noble metal complex nanomaterials have attracted ever-increasing attention because of the realization of multiple functionalities in a single entity. In this study, Ag–TiO{sub 2} core–shell nanocomposites were synthesized by hydrolysis of butyl titanate on the surface of Ag nanowires. Due to efficient electron transfer at the Ag–TiO{sub 2} interface, the as-prepared nanocomposites exhibit much higher photocatalytic activity than bare TiO{sub 2} films, as demonstrated by the enhanced photodegradation rate of R6G and methyl blue molecules. In the meanwhile, such nanocomposites serve as a high-sensitivity surface-enhanced Raman scattering (SERS) substrate for in situ monitoring of the photocatalytic decomposition reaction, and the substrate is recyclable due to its self-cleaning function. Full-wave numerical calculations reveal that the improved photocatalysis and SERS efficiencies are attributed to the largely enhanced electromagnetic near-field in the nanocomposites. Our results point out that bifunctional semiconductor-metal hybrids hold great promise for simultaneously detecting and decomposing organic pollutants in the environment.

  6. Tylosin abatement in water by photocatalytic process.

    Science.gov (United States)

    Alatrache, A; Laoufi, N A; Pons, M N; Van Deik, J; Zahraa, O

    2010-01-01

    The photocatalytic degradation of a macrolide (tylosin) has been studied using immobilized titanium dioxide as photocatalyst in a laboratory reactor under UV illumination (365 nm). The degradation of the antibiotic and of the reaction intermediary product was monitored by UV spectrophotometry and HPLC. Three photocatalysts (P25 from Degussa and PC105 and PC500 from Millennium) immobilized on glass plates were compared. A slightly better degradation was obtained with P25. Then the tylosin degradation kinetics were investigated with the P25 photocatalyst. The kinetic model of Langmuir-Hinshelwood is satisfactorily obeyed at initial time and in the course of the reaction. Adsorption and apparent rate constants were determined. These results suggest that, although an intermediary by-product was detected during the reaction, complete degradation of tylosin can be achieved, which confirms the feasibility of such a photocatalytic treatment for tylosin elimination from wastewater.

  7. Effect of metal ion dopants on photochemical properties of anatase TiO{sub 2} films synthesized by a modified sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Zhangfu [Multi-Phase Reaction Laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 10080 (China)]. E-mail: yuanzhf@home.ipe.ac.cn; Zhang Junling [Multi-Phase Reaction Laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 10080 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Li Bin [Multi-Phase Reaction Laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 10080 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Li Jianqiang [Multi-Phase Reaction Laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 10080 (China)

    2007-06-25

    Anatase TiO{sub 2} films were successfully synthesized by a modified sol-gel method wherein peroxo titanic acid solution was derived from TiCl{sub 4}/ethanol/water solution at room temperature. The as-prepared films were further surface-doped by photodeposited Fe{sub 2}O{sub 3} and Cr{sub 2}O{sub 3} to improve its physicochemical properties. The phase and structure of the films were investigated by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The physicochemical properties of the films were also measured. The results show that both hydrophilicity and photocatalytic activity of the films were remarkably improved by doping transition metal ion Fe{sup 3+}. In case of Cr{sup 3+} doped films, hydrophilicity was also significantly enhanced but photocatalytic activity for methyl orange under UV irradiation was still comparable with the undoped films.

  8. Film/NotFilm

    OpenAIRE

    Willems, Gertjan

    2016-01-01

    Although Samuel Beckett (1906-1989) showed a genuine interest in audio-visual media in his fascinating and innovative radio plays and television works, and in 1936 even wrote a letter to Sergei Eisenstein to be accepted to the famous Soviet film school VGIK, the 22-minute Film (1965) was his only venture into cinema. Beckett conceived the film, wrote the screenplay, supervised the production and, as one of the film’s crew members recalled and as the director Alan Schneider himself acknowledge...

  9. Synthesis crystal structure, photoluminescence and photocatalytic ...

    Indian Academy of Sciences (India)

    In this study the preparation and characterization of a zinc MOF which gives blue luminescence and photocatalytic activity have been described The reaction of 2cyanopyridine, Zn(NO3)2·4H2O and NaN3 yielded a new 3D Zn(II) coordination polymer {(2PTZ)2Zn}n (1), where 2PTZ=5(2pyridyl)tetrazolate via in situ [2+3] ...

  10. Mechanism of Acetyl Salicylic Acid (Aspirin) Degradation under Solar Light in Presence of a TiO2-Polymeric Film Photocatalyst

    OpenAIRE

    Debjani Mukherjee; Ajay K. Ray; Shahzad Barghi

    2016-01-01

    Application of titanium dioxide (TiO2) as a photocatalyst has presented a promising avenue for the safe photocatalytic degradation of pollutants. Increasing levels of the release of pharmaceuticals in the environment and formation of the intermediates during their degradation may impose health and environmental risks and therefore require more attention. Photocatalytic degradation of acetylsalicylic acid (aspirin) was carried out in the presence of the TiO2-filled polymeric film as a photocat...

  11. Band gap characterization of ternary BBi1-xNx (0≤x≤1) alloys using modified Becke-Johnson (mBJ) potential

    Science.gov (United States)

    Yalcin, Battal G.

    2015-04-01

    The semi-local Becke-Johnson (BJ) exchange-correlation potential and its modified form proposed by Tran and Blaha have attracted a lot of interest recently because of the surprisingly accurate band gaps they can deliver for many semiconductors and insulators (e.g., sp semiconductors, noble-gas solids, and transition-metal oxides). The structural and electronic properties of ternary alloys BBi1-xNx (0≤x≤1) in zinc-blende phase have been reported in this study. The results of the studied binary compounds (BN and BBi) and ternary alloys BBi1-xNx structures are presented by means of density functional theory. The exchange and correlation effects are taken into account by using the generalized gradient approximation (GGA) functional of Wu and Cohen (WC) which is an improved form of the most popular Perdew-Burke-Ernzerhof (PBE). For electronic properties the modified Becke-Johnson (mBJ) potential, which is more accurate than standard semi-local LDA and PBE calculations, has been chosen. Geometric optimization has been implemented before the volume optimization calculations for all the studied alloys structure. The obtained equilibrium lattice constants of the studied binary compounds are in coincidence with experimental works. And, the variation of the lattice parameter of ternary alloys BBi1-xNx almost perfectly matches with Vegard's law. The spin-orbit interaction (SOI) has been also considered for structural and electronic calculations and the results are compared to those of non-SOI calculations.

  12. Solar photocatalytic treatment of synthetic municipal wastewater.

    Science.gov (United States)

    Kositzi, M; Poulios, I; Malato, S; Caceres, J; Campos, A

    2004-03-01

    The photocatalytic organic content reduction of a selected synthetic municipal wastewater by the use of heterogeneous and homogeneous photocatalytic methods under solar irradiation has been studied at a pilot-plant scale at the Plataforma Solar de Almeria. In the case of heterogeneous photocatalysis the effect of catalysts and oxidants concentration on the decomposition degree of the wastewater was examined. By an accumulation energy of 50 kJL(-1) the synergetic effect of 0.2 gL(-1)TiO(2) P-25 with hydrogen peroxide (H(2)O(2)) and Na(2)S(2)O(8) leads to a 55% and 73% reduction of the initial organic carbon content, respectively. The photo-fenton process appears to be more efficient for this type of wastewater in comparison to the TiO(2)/oxidant system. An accumulation energy of 20 kJL(-1) leads to 80% reduction of the organic content. The presence of oxalate in the Fe(3+)/H(2)O(2) system leads to an additional improvement of the photocatalytic efficiency.

  13. Photocatalytic degradation of recalcitrant organic pollutants in water using a novel cylindrical multi-column photoreactor packed with TiO2-coated silica gel beads

    International Nuclear Information System (INIS)

    Li, Dawei; Zhu, Qi; Han, Chengjie; Yang, Yingnan; Jiang, Weizhong; Zhang, Zhenya

    2015-01-01

    Highlights: • A novel cylindrical multi-column photocatalytic reactor (CMCPR) was developed. • Methyl orange, amoxicillin and 3-chlorophenol were degraded successfully in CMCPR. • Electrical energy per order (E EO ) was used to evaluate the efficiency of CMCPR. • The CMCPR is high efficient, low-cost and easily repeatable for water purification. - Abstract: A novel cylindrical multi-column photocatalytic reactor (CMCPR) has been developed and successfully applied for the degradation of methyl orange (MO), amoxicillin (AMX) and 3-chlorophenol (3-CP) in water. Due to its higher adsorption capacity and simpler molecular structure, 3-CP compared with MO and AMX obtained the highest photodegradation (100%) and mineralization (78.1%) after 300-min photocatalytic reaction. Electrical energy consumption for photocatalytic degradation of MO, AMX and 3-CP using CMCPR was 5.79 × 10 4 , 7.31 × 10 4 and 2.52 × 10 4 kW h m −3 order −1 , respectively, which were less than one-thousand of those by reported photoreactors. The higher flow rate (15 mL min −1 ), lower initial concentration (5 mg L −1 ) and acidic condition (pH 3) were more favorable for the photocatalytic degradation of MO using CMCPR. Five repetitive operations of CMCPR achieved more than 97.0% photodegradation of MO in each cycle and gave a relative standard deviation of 0.72%. In comparison with reported slurry and thin-film photoreactors, CMCPR exhibited higher photocatalytic efficiency, lower energy consumption and better repetitive operation performance for the degradation of MO, AMX and 3-CP in water. The results demonstrated the feasibility of utilizing CMCPR for the degradation of recalcitrant organic pollutants in water

  14. Photocatalytic degradation of recalcitrant organic pollutants in water using a novel cylindrical multi-column photoreactor packed with TiO{sub 2}-coated silica gel beads

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dawei; Zhu, Qi; Han, Chengjie [Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572 (Japan); Yang, Yingnan, E-mail: yo.innan.fu@u.tsukuba.ac.jp [Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572 (Japan); Jiang, Weizhong [Key Laboratory of Agricultural Engineering in Structure and Environment, Ministry of Agriculture, China Agricultural University, Qinghua Donglu 17, Haidian, Beijing 100083 (China); Zhang, Zhenya, E-mail: zhang.zhenya.fu@u.tsukuba.ac.jp [Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572 (Japan)

    2015-03-21

    Highlights: • A novel cylindrical multi-column photocatalytic reactor (CMCPR) was developed. • Methyl orange, amoxicillin and 3-chlorophenol were degraded successfully in CMCPR. • Electrical energy per order (E{sub EO}) was used to evaluate the efficiency of CMCPR. • The CMCPR is high efficient, low-cost and easily repeatable for water purification. - Abstract: A novel cylindrical multi-column photocatalytic reactor (CMCPR) has been developed and successfully applied for the degradation of methyl orange (MO), amoxicillin (AMX) and 3-chlorophenol (3-CP) in water. Due to its higher adsorption capacity and simpler molecular structure, 3-CP compared with MO and AMX obtained the highest photodegradation (100%) and mineralization (78.1%) after 300-min photocatalytic reaction. Electrical energy consumption for photocatalytic degradation of MO, AMX and 3-CP using CMCPR was 5.79 × 10{sup 4}, 7.31 × 10{sup 4} and 2.52 × 10{sup 4} kW h m{sup −3} order{sup −1}, respectively, which were less than one-thousand of those by reported photoreactors. The higher flow rate (15 mL min{sup −1}), lower initial concentration (5 mg L{sup −1}) and acidic condition (pH 3) were more favorable for the photocatalytic degradation of MO using CMCPR. Five repetitive operations of CMCPR achieved more than 97.0% photodegradation of MO in each cycle and gave a relative standard deviation of 0.72%. In comparison with reported slurry and thin-film photoreactors, CMCPR exhibited higher photocatalytic efficiency, lower energy consumption and better repetitive operation performance for the degradation of MO, AMX and 3-CP in water. The results demonstrated the feasibility of utilizing CMCPR for the degradation of recalcitrant organic pollutants in water.

  15. Enhancement of visible light irradiation photocatalytic activity of ...

    Indian Academy of Sciences (India)

    Mohamed Abdel Salam

    2017-09-25

    Sep 25, 2017 ... Enhancement of visible light irradiation photocatalytic activity of ... The stability of the. Pt/SrTiO3 nanoparticles for the photocatalytic oxidation of cyclohexane was examined and the results revealed that the Pt/SrTiO3 nanoparticles could be used .... ticles was determined using powder X-ray diffraction (XRD),.

  16. Photocatalytic Water-Splitting Reaction from Catalytic and Kinetic Perspectives

    KAUST Repository

    Hisatomi, Takashi

    2014-10-16

    Abstract: Some particulate semiconductors loaded with nanoparticulate catalysts exhibit photocatalytic activity for the water-splitting reaction. The photocatalysis is distinct from the thermal catalysis because photocatalysis involves photophysical processes in particulate semiconductors. This review article presents a brief introduction to photocatalysis, followed by kinetic aspects of the photocatalytic water-splitting reaction.Graphical Abstract: [Figure not available: see fulltext.

  17. Thin Films

    Directory of Open Access Journals (Sweden)

    M. Benmouss

    2003-01-01

    the optical absorption are consistent with the film color changes. Finally, the optical and electrochromic properties of the films prepared by this method are compared with those of our sputtered films already studied and with other works.

  18. Synthesis of nanocrystalline TiO2 thin films by liquid phase ...

    Indian Academy of Sciences (India)

    /fulltext/boms/031/01/0043-0048 ... TiO2 thin films can be used as a photocatalyst to clean up organohalides, a class of compound in pesticides that pollute the ground water. Photocatalytic degradation experiments show that indanthrene ...

  19. Photoelectrocatrocatalytic hydrolysis of starch by using sprayed ZnO thin films

    International Nuclear Information System (INIS)

    Sapkal, R. T.; Shinde, S. S.; Rajpure, K.Y.; Bhosale, C. H.

    2013-01-01

    Thin films of zinc oxide have been deposited onto glass/FTO substrates at optimized 400 °C by using a chemical spray pyrolysis technique. Deposited films are character photocatalytic activity by using XRD, an SEM, a UV-vis spectrophotometer, and a PEC single-cell reactor. Films are polycrystalline and have a hexagonal (wurtzite) crystal structure with c-axis (002) orientation growth perpendicular to the substrate surface. The observed direct band gap is about 3.22 eV for typical films prepared at 400 °C. The photocatalytic activity of starch with a ZnO photocatalyst has been studied by using a novel photoelectrocatalytic process. (semiconductor materials)

  20. Characterization of an Amorphous Titanium Oxide Film Deposited onto a Nano-Textured Fluorination Surface

    Directory of Open Access Journals (Sweden)

    Pei-Yu Li

    2016-05-01

    Full Text Available The photocatalytic activity of an amorphous titanium oxide (a-TiOx film was modified using a two-step deposition. The fluorinated base layer with a nano-textured surface prepared by a selective fluorination etching process acted as growth seeds in the subsequent a-TiOx deposition. A nanorod-like microstructure was achievable from the resulting a-TiOx film due to the self-assembled deposition. Compared to the a-TiOx film directly deposited onto the untreated base layer, the rate constant of this fluorinate-free a-TiOx film surface for decomposing methylene blue (MB solution that was employed to assess the film’s photocatalytic activity was markedly increased from 0.0076 min−1 to 0.0267 min−1 as a mechanism for the marked increase in the specific surface area.

  1. Effect of substrate roughness and working pressure on photocatalyst of N-doped TiO{sub x} films prepared by reactive sputtering with air

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seon-Hong, E-mail: pookter@naver.com [Corporate R and D Center, Samsung SDI Co. Ltd., Yongin 446-577, Gyunggido (Korea, Republic of); Yamasue, Eiji; Okumura, Hideyuki; Ishihara, Keiichi N. [Graduate School of Energy Science, Kyoto University, Yoshida Honmachi, Sakyo, Kyoto 606-8501 (Japan)

    2015-01-01

    Highlights: • Effect of substrate roughness and working pressure on the physical properties and the photocatalytic properties of the N-doped TiO{sub x} films are investigated. • Surface roughness of glass substrate has little influence on the film properties, but significant influence on the photocatalytic ability. • Working pressure has little influence on the produced phases and the atomic bonding configurations, but significant influence on the atomic concentration of the N-doped TiO{sub x} film. • High photocatalysis of N-doped TiO{sub x} film requires the permissible range of the N doping concentration which shows the interstitial complex N doping states in TiO{sub 2}. - Abstract: N-doped TiO{sub x} films on the glass substrate were prepared by radio-frequency (RF) magnetron reactive sputtering of Ti target in a mixed gas of argon and dry air. The effect of substrate roughness and working pressure on the physical properties and the photocatalytic properties of the N-doped TiO{sub x} films was investigated. The surface roughness of glass substrate has little influence on the film properties such as produced phases, lattice parameters, introduced nitrogen contents, and atomic bonding configurations, but significant influence on the surface roughness of film resulting in the variation of the photocatalytic ability. The working pressure has little influence on the produced phases and the atomic bonding configurations, but significant influence on the atomic concentration of the N-doped TiO{sub x} film, resulting in the large variation of optical, structural, and photocatalytic properties. It is suggested that the high photocatalysis of N-doped TiO{sub x} film requires a certain range of the N doping concentration which shows the interstitial complex N doping states in TiO{sub 2}.

  2. Chapter 9 : Photocatalytic CO2 conversion to fuels by novel green photocatalytic materials

    NARCIS (Netherlands)

    Maza, W. A.; Morris, Amanda J.; Mul, Guido; Nuraje, Nurxat; Asmatulu, Ramazan; Mul, Guido

    2016-01-01

    In this chapter the necessity of solar energy storage is explained first, followed by a calculation of the photocatalytic rates necessary for practical application of artificial photosynthesis systems to achieve effective solar energy storage. Next, we introduce TiO2 as an active CO2 and H2O

  3. The structure and the photocatalytic activity of titania based nanotube and nanofiber coatings

    Energy Technology Data Exchange (ETDEWEB)

    Radtke, A., E-mail: aradtke@umk.pl [Faculty of Chemistry, Nicolaus Copernicus University, ul. Gagarina 7, 87-100 Toruń (Poland); Piszczek, P.; Topolski, A.; Lewandowska, Ż. [Faculty of Chemistry, Nicolaus Copernicus University, ul. Gagarina 7, 87-100 Toruń (Poland); Talik, E. [A. Chełkowski Institute of Physics, University of Silesia, ul. Uniwersytecka 4, 40-007 Katowice (Poland); Andersen, I. Hald; Nielsen, L. Pleth [Tribology Centre, Danish Technological Institute, Kongsvang Allé 29, 8000 Aarhus C (Denmark); Heikkilä, M.; Leskelä, M. [Centre of Excellence, Laboratory of Inorganic Chemistry, Chemistry Department, Faculty of Science, University of Helsinki, A.I. Virtasen aukio 1, FI-00014 (Finland)

    2016-04-15

    Graphical abstract: - Highlights: • The photoactivity of TNT and TNF has been quantified by two different methods. • The influence of the TNT and TNF structure on their photoactivity was studied. • The photoactivity comparison of TNT and TNF was carried out. • TNF coatings show higher photoactivity in comparison to TNT. - Abstract: The photocatalytic activity of TiO{sub 2} based nanotube (TNT) and nanofiber (TNF) coatings has been investigated, in correlation to their structure, morphology, specific surface area, acidity and the amount of surface H{sub 2}O molecules and −OH groups. Characterization of these materials was carried out using grazing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). The photocatalytic activity has been quantified by two different methods, based on the photodegradation of methylene blue (the pattern of water-soluble organic pollutant) and acetone (the pattern of volatile organic pollutant), respectively. Results of our investigations revealed that TNF coatings were significantly more active in case of both photodegradation processes in air and water, as compared to TNT, even if the specific surface area of TNF films was smaller than the adequate surface area of TNT. The microstructure of produced materials, the amount of adsorbed −OH groups and H{sub 2}O molecules located on the surface of materials, and the acidity of the surface, were the main factors which affect their photoactivity. Photocatalytic properties of tubular and porous TiO{sub 2}-based materials are the resultant of the compilation of individual factors impact and any of them cannot be neglected.

  4. First-Principle Study of the Structural, Electronic, and Optical Properties of Cubic InNxP1-x Ternary Alloys under Hydrostatic Pressure

    Science.gov (United States)

    Hattabi, I.; Abdiche, A.; Moussa, R.; Riane, R.; Hadji, K.; Soyalp, F.; Varshney, Dinesh; Syrotyuk, S. V.; Khenata, R.

    2016-09-01

    In this article, we present results of the first-principle study of the structural, electronic, and optical properties of the InN, InP binary compounds and their related ternary alloy InNxP1-x in the zinc-blend (ZB) phase within a nonrelativistic full potential linearised augmented plan wave (FP-LAPW) method using Wien2k code based on the density functional theory (DFT). Different approximations of exchange-correlation energy were used for the calculation of the lattice constant, bulk modulus, and first-order pressure derivative of the bulk modulus. Whereas the lattice constant decreases with increasing nitride composition x. Our results present a good agreement with theoretical and experimental data. The electronic band structures calculated using Tran-Blaha-modified Becke-Johnson (TB-mBJ) approach present a direct band gap semiconductor character for InNxP1-x compounds at different x values. The electronic properties were also calculated under hydrostatic pressure for (P=0.00, 5.00, 10.0, 15.0, 20.0, 25.0 GPa) where it is found that the InP compound change from direct to indirect band gap at the pressure P≥7.80 GPa. Furthermore, the pressure effect on the dielectric function and the refractive index was carried out. Results obtained in our calculations present a good agreement with available theoretical reports and experimental data.

  5. Development of Jerusalem artichoke resource for efficient one-step fermentation of poly-(γ-glutamic acid) using a novel strain Bacillus amyloliquefaciens NX-2S.

    Science.gov (United States)

    Qiu, Yibin; Sha, Yuanyuan; Zhang, Yatao; Xu, Zongqi; Li, Sha; Lei, Peng; Xu, Zheng; Feng, Xiaohai; Xu, Hong

    2017-09-01

    This study aimed to develop non-food fermentation for the cost-effective production of poly-(γ-glutamic acid) (γ-PGA) using a novel strain of Bacillus amyloliquefaciens NX-2S. The new isolate assimilated inulin more efficiently than other carbohydrates from Jerusalem artichoke, without hydrolytic treatment. To investigate the effect of inulin on γ-PGA production, the transcript levels of γ-PGA synthetase genes (pgsB, pgsC, pgsA), regulatory genes (comA, degQ, degS), and the glutamic acid biosynthesis gene (glnA) were analyzed; inulin addition upregulated these key genes. Without exogenous glutamate, strain NX-2S could produce 6.85±0.22g/L of γ-PGA during fermentation. Exogenous glutamate greatly enhances the γ-PGA yield (39.4±0.38g/L) and productivity (0.43±0.05g/L/h) in batch fermentation. Our study revealed a potential method of non-food fermentation to produce high-value products. Copyright © 2017. Published by Elsevier Ltd.

  6. Enhanced poly(γ-glutamic acid) production by H2O2-induced reactive oxygen species in the fermentation of Bacillus subtilis NX-2.

    Science.gov (United States)

    Tang, Bao; Zhang, Dan; Li, Sha; Xu, Zongqi; Feng, Xiaohai; Xu, Hong

    2016-09-01

    Effects of reactive oxygen species (ROS) on cell growth and poly(γ-glutamic acid) (γ-PGA) synthesis were studied by adding hydrogen peroxide to a medium of Bacillus subtilis NX-2. After optimizing the addition concentration and time of H 2 O 2 , a maximum concentration of 33.9 g/L γ-PGA was obtained by adding 100 µM H 2 O 2 to the medium after 24 H. This concentration was 20.6% higher than that of the control. The addition of diphenyleneiodonium chloride (ROS inhibitor) can interdict the effect of H 2 O 2 -induced ROS. Transcriptional levels of the cofactors and relevant genes were also determined under ROS stress to illustrate the possible metabolic mechanism contributing to the improve γ-PGA production. The transcriptional levels of genes belonging to the tricarboxylic acid cycle and electron transfer chain system were significantly increased by ROS, which decreased the NADH/NAD + ratio and increased the ATP levels, thereby providing more reducing power and energy for γ-PGA biosynthesis. The enhanced γ-PGA synthetic genes also directly promoted the formation of γ-PGA. This study was the first to use the ROS control strategy for γ-PGA fermentation and provided valuable information on the possible mechanism by which ROS regulated γ-PGA biosynthesis in B. subtilis NX-2. © 2015 International Union of Biochemistry and Molecular Biology, Inc.

  7. Economical production of poly(γ-glutamic acid) using untreated cane molasses and monosodium glutamate waste liquor by Bacillus subtilis NX-2.

    Science.gov (United States)

    Zhang, Dan; Feng, Xiaohai; Zhou, Zhe; Zhang, Yang; Xu, Hong

    2012-06-01

    The production of poly(γ-glutamic acid) by Bacillus subtilis NX-2 from cane molasses and monosodium glutamate waste liquor (MGWL) was studied for the first time in this work. When batch fermentation was carried out with untreated molasses, 33.6±0.37 g L(-1) PGA was obtained with a productivity of 0.46±0.006 g L(-1) h(-1). In order to minimize the substrate inhibition, fed-batch fermentation was performed with untreated or hydrolyzed molasses in 7.5 L bioreactor, giving 50.2±0.53 and 51.1±0.51 g L(-1) of PGA at 96 h, respectively. Further studies were carried out by using MGWL as another carbon source, resulting in a PGA concentration of 52.1±0.52 g L(-1) with a productivity of 0.54±0.003 g L(-1) h(-1). These results suggest that the low-cost cane molasses and MGWL can be used for the environmental-friendly and economical production of PGA by B. subtilis NX-2. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Visible light active TiO 2 films prepared by electron beam deposition of noble metals

    Science.gov (United States)

    Hou, Xing-Gang; Ma, Jun; Liu, An-Dong; Li, De-Jun; Huang, Mei-Dong; Deng, Xiang-Yun

    2010-03-01

    TiO 2 films prepared by sol-gel method were modified by electron beam deposition of noble metals (Pt, Pd, and Ag). Effects of noble metals on the chemical and surface characteristics of the films were studied using XPS, TEM and UV-Vis spectroscopy techniques. Photocatalytic activity of modified TiO 2 films was evaluated by studying the degradation of methyl orange dye solution under visible light UV irradiation. The result of TEM reveals that most of the surface area of TiO 2 is covered by tiny particles of noble metals with diameter less than 1 nm. Broad red shift of UV-Visible absorption band of modified photocatalysts was observed. The catalytic degradation of methyl orange in aqueous solutions under visible light illumination demonstrates a significant enhancement of photocatalytic activity of these films compared with the un-loaded films. The photocatalytic efficiency of modified TiO 2 films by this method is affected by the concentration of impregnating solution.

  9. Effects of swift heavy ion irradiation on structural, optical and photocatalytic properties of ZnO-CuO nanocomposites prepared by carbothermal evaporation method.

    Science.gov (United States)

    Kuriakose, Sini; Avasthi, D K; Mohapatra, Satyabrata

    2015-01-01

    ZnO-CuO nanocomposite thin films were prepared by carbothermal evaporation of ZnO and Cu, combined with annealing. The effects of 90 MeV Ni(7+) ion irradiation on the structural and optical properties of ZnO-CuO nanocomposites were studied by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV-visible absorption spectroscopy and Raman spectroscopy. XRD studies showed the presence of ZnO and CuO nanostructures in the nanocomposites. FESEM images revealed the presence of nanosheets and nanorods in the nanocomposites. The photocatalytic activity of ZnO-CuO nanocomposites was evaluated on the basis of degradation of methylene blue (MB) and methyl orange (MO) dyes under sun light irradiation and it was observed that swift heavy ion irradiation results in significant enhancement in the photocatalytic efficiency of ZnO-CuO nanocomposites towards degradation of MB and MO dyes. The possible mechanism for the enhanced photocatalytic activity of ZnO-CuO nanocomposites is proposed. We attribute the observed enhanced photocatalytic activity of ZnO-CuO nanocomposites to the combined effects of improved sun light utilization and suppression of the recombination of photogenerated charge carriers in ZnO-CuO nanocomposites.

  10. Garden-like perovskite superstructures with enhanced photocatalytic activity

    Science.gov (United States)

    Ye, Meidan; Wang, Mengye; Zheng, Dajiang; Zhang, Nan; Lin, Changjian; Lin, Zhiqun

    2014-03-01

    architectures were coexisted in the garden, including SrTiO3 flowers composed of several hollow sword-shaped petals, many sheet-shaped petals or numerous flake-shaped petals, and SrTiO3 grass consisting of a number of long blades. These SrTiO3 superstructures were simultaneously grown on fluorine-doped tin oxide (FTO) substrates. On the basis of a comprehensive study on the effects of growth time, temperature, initial concentrations of precursor, and pH, the formation of these various hierarchical architectures was attributed primarily to the dissolution of amorphous TiO2 and precipitation of perovskite crystals, followed by the Ostwald ripening process of perovskite nanocrystals and self-organization of perovskite building blocks. Interestingly, this approach can be readily extended to create other perovskite structures, including dendritic BaTiO3 and nest-like CaTiO3, as well as PbTiO3 transformed from plate-like pyrochlore Pb2Ti2O6 after post-thermal treatment. Garden-like SrTiO3 superstructures showed a superior photocatalytic performance when compared to other as-prepared semiconductors and perovskite materials (i.e., ZnO, TiO2, BaTiO3, CaTiO3 and PbTiO3), probably due to their intrinsic photocatalytic activity and special garden-like features with a coexistence of various structures that significantly facilitated the adsorption and diffusion of methyl blue (MB) molecules and oxygen species in the photochemical reaction of MB degradation. Electronic supplementary information (ESI) available: FESEM images and the XRD pattern of SrTiO3 films (effects of growth temperature, initial precursor concentration, and pH value), EDS analysis of ZnO, TiO2 and SrTiO3, the XRD pattern and PL spectra of PbTiO3, UV-vis spectra of different films, and UV photo-degradation of MB. See DOI: 10.1039/c3nr05564g

  11. PHOTOCATALYTIC EFFECT OBTAINED ON TEXTILE BY FINISHING TECHNIQUES

    Directory of Open Access Journals (Sweden)

    POPESCU Alina

    2017-05-01

    Full Text Available This study approached the experimentation of deposition by padding of commercial photocatalytic dispersion AERODISP® W 740 X with 40% solid content of TiO2 on RIPSTOP fabric, made of 100% cotton yarns Nm 70/1 and a network of polyester filament yarns 330 dtex, both in warp and weft directions. The deposition of photocatalytic dispersions on the textile material have been realised by treatment in concomitent phase of textile support with photocatalytic dispersions and with chemical substances used in fixation of TiO2 nanoparticles. As chemical substances used in fixation of TiO2 nanoparticles different crosslinking agents have been used: Itobinder AG (acrylic copolymer, Itobinder U30 NEW (polycarbonate urethane polymer and Itocoat LJ25 (urethane resin. Itocatalyst SCS and Itocatalyst A were used as catalysts. Photocatalytic activity of functionalized textile materials was evaluated by determining the photodegradation efficiency of methylene blue dye as pollutant, measuring the color difference of the irradiated samples compared with non-irradiated samples. Washing durability of the samples treated with photocatalytic dispersions was conducted qualitatively by determining the photocatalytic activity remaining on the textile fabrics after 1 washing cycle. Electron microscopy was used for viewing the distribution of TiO2 particles on the surface of textile materials treated with the photocatalytic dispersions. Ti content existing on the surface of the textile materials was performed by energy dispersive X-ray spectroscopy.

  12. Solar photocatalytic cleaning of polluted water

    International Nuclear Information System (INIS)

    Bockelmann, D.

    1994-01-01

    Alternatively to biological, physical and chemical methods of waste water cleaning, photocatalysis can be employed. In this residue-free method, titanium dioxide particles are brought into contact with polluted water as photocatalysts. Under UV irradiation at wave-lengths below 400 nm, change carriers are generated in the semiconductor particles that act so intensely oxidizing as to completely degrade almost all organic pollutants in waste water. In this process, the ultra-violet part of the solar spectrum can be harnessed to generate oxidation equivalents. Thus, solar photocatalytic waste water cleaning is excellently suited for developing countries. (BWI) [de

  13. Evaluation of Photocatalytic Active Coatings on Sintered Glass Tubes by Methylene Blue

    Directory of Open Access Journals (Sweden)

    Colin Awungacha Lekelefac

    2013-01-01

    Full Text Available A comparative study between ten different photocatalytic active coatings was done. The effectiveness and photocatalytic activity of the coatings were studied by degradation experiments of methylene blue (MB dye under UV light illumination. The reactor design consisting of sintered glass packed in a borosilicate tube placed between two planar dielectric barrier discharge lamps (Osram Planon is reported for the first time. The coatings consisted of either titania, silica, or zinc on sintered borosilicate glass. The advantage of sol-gel in catalyst preparation was exploited to combine catalyst to act as cocatalyst. TiO2-P25 widely applied in suspension systems was effectively immobilized on sintered glass support with the aid of tetraethylorthosilicate (TEOS solution which acted as support material. Results indicated that TiO2-P25+SiO2, TiO2-P25+SiO2+Pt, and TiOSO4_30,6wt% films showed highest degradation rates close to 100% after 90 min illumination with degradation rates exceeding 50% after 30 minutes. TTIP+Pt showed lowest degradation rate.

  14. Morphological influence of TiO{sub 2} nanostructures (nanozigzag, nanohelics and nanorod) on photocatalytic degradation of organic dyes

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Sadaf Bashir; Hou, Mengjing; Shuang, Shuang; Zhang, Zhengjun, E-mail: zjzhang@tsinghua.edu.cn

    2017-04-01

    Highlights: • Glancing angle deposition technique is used to fabricate various columnar nanostructures in a single step to tune physiochemical properties. • Enhanced surface area induces porosity, with dispersion of active sites at different length scales of pores. • The increase interface between nanostructures and organic dye is promising factor to enhance photocatalytic degradation. • Morphologies having high surface to volume ratio increases the number of catalytic reaction sites to facilitate organic molecules adsorption favorable for reaction kinetics. - Abstract: Hierarchical nanostructures have drawn significant attention and incredible performance in photodriven chemical conversion area due to its unique physicochemical properties. Herein, we study the morphological influence of TiO{sub 2} nanostructures on photocatalytic degradation of different organic dyes methyl blue, methyl violet and methyl orange present in industrial wastewater. Nanorod, nanohelics and nanozigzag TiO{sub 2} nanofilms were fabricated by using galancing angle deposition technique (GLAD). TiO{sub 2} nanofilms were characterized by scanning electron microscope (SEM), X-ray powder diffraction (XRD), and raman analysis. BET surface area analysis were carried out by using nitrogen adsorption desorption curves. The results show that TiO{sub 2} morphology had great influence on photocatalytic degradation of organic dyes due to difference in specific surface area and pore volume of nanostructures. The photocatalytic degradation experiments were carried out for three hours under UV–vis light irradiation. Catalysis recycling and organic dyes concentration influence were also studied. In case of high concentration of organic dyes, negligible degradation rate is observed. TiO{sub 2} nanozigzag films show better degradation performance than nanohelics and nanorod due to presence of large surface area for reaction, higher porosity with dispersion of active sites at different length

  15. tavg1_2d_rad_Nx: MERRA 2D IAU Diagnostic, Radiation Surface and TOA, Time Average 1-hourly 0.667 x 0.5 degree V5.2.0 (MAT1NXRAD) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAT1NXRAD or tavg1_2d_rad_Nx data product is the MERRA Data Assimilation System 2-Dimensional surface and TOA radiation flux that is time averaged single-level...

  16. Control of Microstructure and Magnetic Properties of FePt Thin Films with TiN-MgO Intermediate Layer.

    Science.gov (United States)

    Dong, Kai-Feng; Jin, Fang; Mo, Wen-Qin; Song, Jun-Lei; Cheng, Wei-Ming

    2018-04-01

    The effects of TiN-MgO intermediate layer on the microstructure and magnetic properties of FePt-SiNx-C films were investigated. With doping MgO into TiN, three components were formed, including titanium dioxide, titanium nitride and titanium oxynitride. This caused the decrease of the surface energy and the increase of the interface energy, and further induced the promotion of island growth of FePt, thus the improvement of the isolation and the decrease of FePt grains. On the other hand, the decrease of surface energy and the forming of some titanium dioxide with doping MgO would accompany the deterioration of epitaxial growth and thus the deterioration of the perpendicular magnetic anisotropy of FePt films in a certain degree. By optimizing the concentration of TiN and MgO, the FePt-SiNx-C films with small grain size of 5.86±1.03 nm and good perpendicular anisotropy would be obtained.

  17. Nano cobalt oxides for photocatalytic hydrogen production

    KAUST Repository

    Mangrulkar, Priti A.

    2012-07-01

    Nano structured metal oxides including TiO 2, Co 3O 4 and Fe 3O 4 have been synthesized and evaluated for their photocatalytic activity for hydrogen generation. The photocatalytic activity of nano cobalt oxide was then compared with two other nano structured metal oxides namely TiO 2 and Fe 3O 4. The synthesized nano cobalt oxide was characterized thoroughly with respect to EDX and TEM. The yield of hydrogen was observed to be 900, 2000 and 8275 mmol h -1 g -1 of photocatalyst for TiO 2, Co 3O 4 and Fe 3O 4 respectively under visible light. It was observed that the hydrogen yield in case of nano cobalt oxide was more than twice to that of TiO 2 and the hydrogen yield of nano Fe 3O 4 was nearly four times as compared to nano Co 3O 4. The influence of various operating parameters in hydrogen generation by nano cobalt oxide was then studied in detail. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  18. Solar thermal harvesting for enhanced photocatalytic reactions.

    Science.gov (United States)

    Hashemi, Seyyed Mohammad Hosseini; Choi, Jae-Woo; Psaltis, Demetri

    2014-03-21

    The Shockley-Queisser limit predicts a maximum efficiency of 30% for single junction photovoltaic (PV) cells. The rest of the solar energy is lost as heat and due to phenomena such as reflection and transmission through the PV and charge carrier recombination. In the case of photocatalysis, this maximum value is smaller since the charge carriers should be transferred to acceptor molecules rather than conductive electrodes. With this perspective, we realize that at least 70% of the solar energy is available to be converted into heat. This is specifically useful for photocatalysis, since heat can provide more kinetic energy to the reactants and increase the number of energetic collisions leading to the breakage of chemical bonds. Even in natural photosynthesis, at the most 6% of the solar spectrum is used to produce sugar and the rest of the absorbed photons are converted into heat in a process called transpiration. The role of this heating component is often overlooked; in this paper, we demonstrate a coupled system of solar thermal and photocatalytic decontamination of water by titania, the most widely used photocatalyst for various photo reactions. The enhancement of this photothermal process over solely photocatalytic water decontamination is demonstrated to be 82% at 1× sun. Our findings suggest that the combination of solar thermal energy capture with photocatalysis is a suitable strategy to utilize more of the solar spectrum and improve the overall performance.

  19. Functional photocatalytically active and scratch resistant antireflective coating based on TiO{sub 2} and SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Mazur, M., E-mail: michal.mazur@pwr.edu.pl [Wroclaw University of Technology, Faculty of Microsystem Electronics and Photonics, Janiszewskiego 11/17, 50-372 Wroclaw (Poland); Wojcieszak, D.; Kaczmarek, D.; Domaradzki, J. [Wroclaw University of Technology, Faculty of Microsystem Electronics and Photonics, Janiszewskiego 11/17, 50-372 Wroclaw (Poland); Song, S.; Gibson, D.; Placido, F. [Institute of Thin Films, Sensors & Imaging, University of the West of Scotland, Scottish Universities Physics Alliance, High Street, Paisley PA1 2BE (United Kingdom); Mazur, P. [University of Wroclaw, Institute of Experimental Physics, Max Born 9, 50-204 Wroclaw (Poland); Kalisz, M. [Motor Transport Institute, Centre for Material Testing and Mechatronics, Jagiellonska 80, 03-301 Warsaw (Poland); Poniedzialek, A. [Wroclaw University of Technology, Faculty of Microsystem Electronics and Photonics, Janiszewskiego 11/17, 50-372 Wroclaw (Poland)

    2016-09-01

    Graphical abstract: - Highlights: • Designed multilayer was deposited by microwave assisted magnetron sputtering method. • AR coating in designed wavelength range had transmittance higher than 97%. • The AR multilayer was hydrophobic and photocatalytically active. • AR coating was scratch resistant. • Deposited multilayer had higher hardness than the glass substrate. - Abstract: Antireflection (AR) multilayer coating, based on combination of five TiO{sub 2} and SiO{sub 2} thin films, was deposited by microwave assisted reactive magnetron sputtering process on microscope glass substrates. In this work X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy and wettability measurements were used to characterize the structural and surface properties of the deposited coating. These studies revealed that prepared coating was amorphous with low surface roughness. Photocatalytic properties were determined based on phenol decomposition reaction. Measurements of optical properties showed that transmittance in the visible wavelength range was increased after the deposition of AR coating as-compared to bare glass substrate. The mechanical properties were determined on the basis of nano-indentation and scratch resistance tests. Performed research has shown that deposition of an additional thin 10 nm thick TiO{sub 2} thin film top layer, the prepared AR coating was photocatalytically active, hydrophobic, scratch resistant and had increased hardness as-compared to bare glass substrate. These results indicate that prepared AR multilayer could be used also as a self-cleaning and protective coating.

  20. Oxidative esterification via photocatalytic C-H activation

    Data.gov (United States)

    U.S. Environmental Protection Agency — Direct oxidative esterification of alcohol via photocatalytic C–H activation has been developed using VO@g-C3N4 catalyst; an expeditious esterification of alcohols...

  1. Oxidative esterification via photocatalytic C-H activation

    Science.gov (United States)

    Direct oxidative esterification of alcohol via photocatalytic C-H activation has been developed using VO@g-C3N4 catalyst; an expeditious esterification of alcohols occurs under neutral conditions using visible light as the source of energy.

  2. Effects of atomic oxygen on titanium dioxide thin film

    Science.gov (United States)

    Shimosako, Naoki; Hara, Yukihiro; Shimazaki, Kazunori; Miyazaki, Eiji; Sakama, Hiroshi

    2018-05-01

    In low earth orbit (LEO), atomic oxygen (AO) has shown to cause degradation of organic materials used in spacecrafts. Similar to other metal oxides such as SiO2, Al2O3 and ITO, TiO2 has potential to protect organic materials. In this study, the anatese-type TiO2 thin films were fabricated by a sol-gel method and irradiated with AO. The properties of TiO2 were compared using mass change, scanning electron microscope (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmittance spectra and photocatalytic activity before and after AO irradiation. The results indicate that TiO2 film was hardly eroded and resistant against AO degradation. AO was shown to affects only the surface of a TiO2 film and not the bulk. Upon AO irradiation, the TiO2 films were slightly oxidized. However, these changes were very small. Photocatalytic activity of TiO2 was still maintained in spite of slight decrease upon AO irradiation, which demonstrated that TiO2 thin films are promising for elimination of contaminations outgassed from a spacecraft's materials.

  3. Preparation and Properties of Nano Dy/TiO2 Films Supported on High Silica Fiber

    Directory of Open Access Journals (Sweden)

    HUANG Feng-ping

    2017-07-01

    Full Text Available In order to improve the photocatalytic degradation performance and stability of nano TiO2, Dy doped TiO2 supported on high silica glass fiber was prepared by microwave-sol method combined with dip-coating method. The samples were analyzed by XRD,SEM,PL,EDS,XPS and other equipments for phase composition of films,surface topography, surface elements and the stability of films. And the effects of pretreatment solution and coating method on the high-silica fiber film were investigated.In addition, the photocatalytic performance of the sample has been investigated by degrading methylene blue. The results show that the catalytic stability of Dy doping TiO2 nanofilms supported on high silica glass fiber can be improved and the degradation of methyl orange can reach 94% in 30min after 5 times of coating treatment.

  4. Multi-Layered TiO2 Films towards Enhancement of Escherichia coli Inactivation

    Directory of Open Access Journals (Sweden)

    Sorachon Yoriya

    2016-09-01

    Full Text Available Crystalline TiO2 has shown its great photocatalytic properties in bacterial inactivation. This work presents a design fabrication of low-cost, layered TiO2 films assembled reactors and a study of their performance for a better understanding to elucidate the photocatalytic effect on inactivation of E. coli in water. The ability to reduce the number of bacteria in water samples for the layered TiO2 composing reactors has been investigated as a function of time, while varying the parameters of light sources, initial concentration of bacteria, and ratios of TiO2 film area and volume of water. Herein, the layered TiO2 films have been fabricated on the glass plates by thermal spray coating prior to screen printing, allowing a good adhesion of the films. Surface topology and crystallographic phase of TiO2 for the screen-printed active layer have been characterized, resulting in the ratio of anatase:rutile being 80:20. Under exposure to sunlight and a given condition employed in this study, the optimized film area:water volume of 1:2.62 has shown a significant ability to reduce the E. coli cells in water samples. The ratio of surface area of photocatalytic active base to volume of water medium is believed to play a predominant role facilitating the cells inactivation. The kinetic rate of inactivation and its behavior are also described in terms of adsorption of reaction species at different contact times.

  5. Preparation of anatase TiO{sub 2} thin films by vacuum arc plasma evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, Toshihiro [Optoelectronic Device System R and D Center, Kanazawa Institute of Technology, 7-1 Ohgigaoka, Nonoichi, Ishikawa 921-8501 (Japan)]. E-mail: tmiyata@neptune.kanazawa-it.ac.jp; Tsukada, Satoshi [Optoelectronic Device System R and D Center, Kanazawa Institute of Technology, 7-1 Ohgigaoka, Nonoichi, Ishikawa 921-8501 (Japan); Minami, Tadatsugu [Optoelectronic Device System R and D Center, Kanazawa Institute of Technology, 7-1 Ohgigaoka, Nonoichi, Ishikawa 921-8501 (Japan)

    2006-02-01

    Anatase titanium dioxide (TiO{sub 2}) thin films with high photocatalytic activity have been prepared with deposition rates as high as 16 nm/min by a newly developed vacuum arc plasma evaporation (VAPE) method using sintered TiO{sub 2} pellets as the source material. Highly transparent TiO{sub 2} thin films prepared at substrate temperatures from room temperature to 400 deg. C exhibited photocatalytic activity, regardless whether oxygen (O{sub 2}) gas was introduced during the VAPE deposition. The highest photocatalytic activity and photo-induced hydrophilicity were obtained in anatase TiO{sub 2} thin films prepared at 300 deg. C, which correlated to the best crystallinity of the films, as evidenced from X-ray diffraction. In addition, a transparent and conductive anatase TiO{sub 2} thin film with a resistivity of 2.6 x 10{sup -1} {omega} cm was prepared at a substrate temperature of 400 deg. C without the introduction of O{sub 2} gas.

  6. Photocatalytic Water Oxidation on ZnO: A Review

    Directory of Open Access Journals (Sweden)

    Sharifah Bee Abdul Hamid

    2017-03-01

    Full Text Available The investigation of the water oxidation mechanism on photocatalytic semiconductor surfaces has gained much attention for its potential to unlock the technological limitations of producing H2 from carbon-free sources, i.e., H2O. This review seeks to highlight the available scientific and fundamental understanding towards the water oxidation mechanism on ZnO surfaces, as well as present a summary on the modification strategies carried out to increase the photocatalytic response of ZnO.

  7. Preparation, characterization and photocatalytic studies of Cu , Sn ...

    Indian Academy of Sciences (India)

    K5Sb5P2O20 lattice was studied by O-N-H and XPS measurements. The photocatalytic activity of all the com- pounds was studied by degradation of methylene blue and methyl violet. The ion-substituted K5Sb5P2O20 have shown higher photocatalytic activity against both the dyes. The role of reactive intermediate species ...

  8. Triple templating of graphitic carbon nitride to enhance photocatalytic properties

    Directory of Open Access Journals (Sweden)

    Z. Yang

    2016-01-01

    Full Text Available Graphitic carbon nitride materials show some promising properties for applications such as photocatalytic water splitting. However, the conversion efficiency is still low due to factors such as a low surface area and limited light absorption. In this paper, we describe a “triple templating” approach to generating porous graphitic carbon nitride. The introduction of pores on several length-scales results in enhanced photocatalytic properties.

  9. Triple templating of graphitic carbon nitride to enhance photocatalytic properties

    OpenAIRE

    Z. Yang; A. E. Danks; J. Wang; Y. Zhang; Z. Schnepp

    2016-01-01

    Graphitic carbon nitride materials show some promising properties for applications such as photocatalytic water splitting. However, the conversion efficiency is still low due to factors such as a low surface area and limited light absorption. In this paper, we describe a “triple templating” approach to generating porous graphitic carbon nitride. The introduction of pores on several length-scales results in enhanced photocatalytic properties.

  10. Photocatalytic Degradation of Aniline Using TiO2 Nanoparticles in a Vertical Circulating Photocatalytic Reactor

    Directory of Open Access Journals (Sweden)

    F. Shahrezaei

    2012-01-01

    Full Text Available Photocatalytic degradation of aniline in the presence of titanium dioxide (TiO2 and ultraviolet (UV illumination was performed in a vertical circulating photocatalytic reactor. The effects of catalyst concentration (0–80 mg/L, initial pH (2–12, temperature (293–323 K, and irradiation time (0–120 min on aniline photodegradation were investigated in order to obtain the optimum operational conditions. The results reveal that the aniline degradation efficiency can be effectively improved by increasing pH from 2 to 12 and temperature from 313 to 323 K. Besides, the effect of temperature on aniline photo degradation was found to be unremarkable in the range of 293–313 K. The optimum catalyst concentration was about 60 mg/L. The Langmuir Hinshelwood kinetic model could successfully elucidate the effects of the catalyst concentration, pH, and temperature on the rate of heterogeneous photooxidation of aniline. The data obtained by applying the Langmuir Hinshelwood treatment are consistent with the available kinetic parameters. The activated energy for the photocatalytic degradation of aniline is 20.337 kj/mol. The possibility of the reactor use in the treatment of a real petroleum refinery wastewater was also investigated. The results of the experiments indicated that it can therefore be potentially applied for the treatment of wastewater contaminated by different organic pollutants.

  11. SiO $ _2 $/TiO $ _2 $ multi-layered thin films with self-cleaning and ...

    Indian Academy of Sciences (India)

    Self-cleaning, high transmittance glazing was obtained by cold spray deposition for glazings. The thin films contain TiO 2 , SiO 2 and Au nanoparticles in different structures which allow for tailoring the optical, hydrophilic and photocatalytic properties. The crystallinity, morphology and surface energy were correlated with the ...

  12. Photocatalysis of composite film PDMS-PMN-PT@TiO2 greatly improved via spatial electric field

    Science.gov (United States)

    Dai, Baoying; Zhang, Ling; Huang, Hengming; Lu, Chunhua; Kou, Jiahui; Xu, Zhongzi

    2017-05-01

    Efficient charge separation is quite significant to obtain high photocatalytic performance. In this work, piezoelectric-based composite photocatalyst film PDMS-PMN-PT@TiO2 possessing high recoverability was prepared. The spatial electric field of PMN-PT was introduced into photocatalyst system by ultrasonic wave vibration to accelerate charge separation. Compared with magnetic stirring, ultrasonic wave vibration greatly improved the photocatalytic degradation efficiency of rhodamine B (RhB) over PDMS-PMN-PT@TiO2 film by about 55%. A possible improvement mechanism that spatial electric field promotes charge separation was presented herein. The piezoelectric potential output demonstrated the piezoelectricity of composite film. The durability experiments of PDMS-PMN-PT@TiO2 film indicated its great stability over several runs.

  13. Versatile Gap Mode Plasmon under ATR Geometry towards Single Molecule Raman, Laser Trapping and Photocatalytic Reactions.

    Science.gov (United States)

    Futamata, Masayuki; Akai, Keitaro; Iida, Chiaki; Akiba, Natsumi

    2017-01-01

    We have investigated various aspects of a gap mode plasmon to establish it as an analytical tool. First, markedly large (10 7 - 10 9 ) enhancement factors for the Raman scattering intensity from a thiophenol (TP) monolayer sandwiched by Ag films on a prism and silver nanoparticles (AgNPs) were obtained under attenuated total reflection (ATR) geometry. Second, AgNPs with a radius of ∼20 nm were optically trapped and immobilized on TP-covered Ag films under a gap mode resonance with extremely weak laser power density of ∼1 μW/μm 2 at 532 nm. The observed optical trapping and immobilization were theoretically rationalized using a dipole-dipole coupling and van der Waals interaction between AgNPs and Ag films. Third, p-alkyl TP molecules such as p-methyl TP, p-ethyl TP, p-isopropyl TP, and p-tertiary butyl TP were photocatalytically oxidized into p-carboxyl TP, whereas o- and m-methyl TP did not show such reactions.

  14. The Semiclassical distorted wave (SCDW) model for multistep direct processes in (p,px) and (p, nx) reactions at intermediate energies: formalism and application

    CERN Document Server

    Kawai, M; Watanabe, Y

    2002-01-01

    The semi-classical distorted wave (SCDW) model for (p,p sup ' x) and (p,nx) reactions at intermediate energies is presented. Simple closed forms with no free adjustable parameter are derived for inclusive double differential cross sections and spin observables. The formulae allow simple intuitive physical interpretations. Applications of the model to analyses of experimental data at 120 to 400 MeV on target nuclei sup 1 sup 2 C, sup 4 sup 0 Ca and sup 9 sup 0 Zr are discussed. Calculations include up to three-step processes with realistic effective nucleon-nucleon interactions modified in the nuclear medium. Good over all agreement with the data is obtained including absolute magnitude of the cross sections. Through the analysis the role of multistep processes is revealed and the possibility of extracting information on nucleon-nucleon interaction in the nuclear medium becomes clear

  15. Activation of glassy carbon electrodes by photocatalytic pretreatment

    Energy Technology Data Exchange (ETDEWEB)

    Dumanli, Onur [Department of Chemistry, Faculty of Science and Art, Ondokuz Mayis University, Kurupelit, 55139 Samsun (Turkey); Onar, A. Nur [Department of Chemistry, Faculty of Science and Art, Ondokuz Mayis University, Kurupelit, 55139 Samsun (Turkey)], E-mail: nonar@omu.edu.tr

    2009-11-01

    This paper describes a simple and rapid photocatalytic pretreatment procedure that removes contaminants from glassy carbon (GC) surfaces. The effectiveness of TiO{sub 2} mediated photocatalytic pretreatment procedure was compared to commonly used alumina polishing procedure. Cyclic voltammetric and chronocoulometric measurements were carried out to assess the changes in electrode reactivity by using four redox systems. Electrochemical measurements obtained on photocatalytically treated GC electrodes showed a more active surface relative to polished GC. In cyclic voltammograms of epinephrine, Fe(CN){sub 6}{sup 3-/4-} and ferrocene redox systems, higher oxidation and reduction currents were observed. The heterogeneous electron transfer rate constants (k{sup o}) were calculated for Fe(CN){sub 6}{sup 3-/4-} and ferrocene which were greater for photocatalytic pretreatment. Chronocoulometry was performed in order to find the amount of adsorbed methylene blue onto the electrode and was calculated as 0.34 pmol cm{sup -2} for photocatalytically pretreated GC. The proposed photocatalytic GC electrode cleansing and activating pretreatment procedure was more effective than classical alumina polishing.

  16. Photocatalytic Water Treatment by Titanium Dioxide: Recent Updates

    Directory of Open Access Journals (Sweden)

    Manoj A. Lazar

    2012-12-01

    Full Text Available Photocatalytic water treatment using nanocrystalline titanium dioxide (NTO is a well-known advanced oxidation process (AOP for environmental remediation. With the in situ generation of electron-hole pairs upon irradiation with light, NTO can mineralize a wide range of organic compounds into harmless end products such as carbon dioxide, water, and inorganic ions. Photocatalytic degradation kinetics of pollutants by NTO is a topic of debate and the mostly reporting Langmuir-Hinshelwood kinetics must accompanied with proper experimental evidences. Different NTO morphologies or surface treatments on NTO can increase the photocatalytic efficiency in degradation reactions. Wisely designed photocatalytic reactors can decrease energy consumption or can avoid post-separation stages in photocatalytic water treatment processes. Doping NTO with metals or non-metals can reduce the band gap of the doped catalyst, enabling light absorption in the visible region. Coupling NTO photocatalysis with other water-treatment technologies can be more beneficial, especially in large-scale treatments. This review describes recent developments in the field of photocatalytic water treatment using NTO.

  17. Suppressing Structural Colors of Photocatalytic Optical Coatings on Glass: The Critical Role of SiO2.

    Science.gov (United States)

    Li, Ronghua; Boudot, Mickael; Boissière, Cédric; Grosso, David; Faustini, Marco

    2017-04-26

    The appearance of structural colors on coated-glass is a critical esthetical drawback toward industrialization of photocatalytic coatings on windows for architecture or automobile. Herein we describe a rational approach to suppress the structural color of mesoporous TiO 2 -based coatings preserving photoactivity and mechanical stiffness. Addition of SiO 2 as third component is discussed. Ti x Si (1-x) O 2 mesoporous coatings were fabricated by one-step liquid deposition process through the evaporation induced self-assembling and characterized by GI-SAXS, GI-WAXS, electron microscopies, and in situ Environmental Ellipsometry Porosimetry. Guided by optical simulation, we investigated the critical role of SiO 2 on the optical responses of the films but also on the structural, mechanical, and photocatalytic properties, important requirements to go toward real applications. We demonstrate that adding SiO 2 to porous TiO 2 allows tuning and suppression of structural colors through refractive index matching and up to 160% increase in mechanical stiffening of the films. This study leads us to demonstrate an example of "invisible" coating, in which the light reflection is angle- and thickness-independent, and exhibiting high porosity, mechanical stiffness, and photoactivity.

  18. Investigation of E. coli bacteria inactivation by photocatalytic activity of TiO2 coated expanded polystyrene foam

    Science.gov (United States)

    Varnagiris, S.; Sakalauskaite, S.; Tuckute, S.; Lelis, M.; Daugelavicius, R.; Milcius, D.

    2017-03-01

    Photocatalytic properties of anatase and other TiO2 polymorphs are widely researched and applied in practical application. In current study TiO2 films on the plasma pre-treated expanded polystyrene (EPS) foam were deposited using magnetron sputtering technique. Main properties of the films were characterised using combination of XRD, XPS and SEM techniques. Photocatalytic properties of the observed crystalline anatase phase were tested by investigating bleaching of the methylene blue (MB) aqueous solution and by testing Escherichia coli (E. coli) viability after incubation under UV-B irradiation. E. coli viability experiments indicated that there are two mechanisms of E. coli bacteria inactivation. UV irradiation alone causes rapid damage to the outer membrane of E. coli bacteria. The second mechanism of E. coli inactivation is invoked only with synergistic combination of TiO2 and UV. Acting as photocatalyst TiO2 generates active radicals who initiate the chain peroxidation of organic molecules and within 45 min reduce E. coli bacteria viability by nearly 90%.

  19. Silver Nanoparticles Influence on Photocatalytic Activity of Hybrid Materials Based on TiO2 P25

    Directory of Open Access Journals (Sweden)

    Tomkouani Kodom

    2015-01-01

    Full Text Available The aim of the present study consists in the obtaining of a hybrid material film, obtained using TiO2 P25 and silver nanoparticles (AgNPs. The film manufacturing process involved realization of physical mixtures of TiO2 P25 and AgNPs dispersions. The size distribution of the AgNPs proved to be a key factor determining the photodegradation activity of the materials measured using methyl orange. The best result was 33% degradation of methyl orange (MO after 150 min. The second approach was the generation of AgNPs on the surface of TiO2 P25. The obtained hybrid material presents photocatalytic activity of 45% MO degradation after 150 min. The developed materials were characterized by UV-VIS, SEM, and DLS analyses.

  20. Fabrication of Cu2O nanoplates growing on the CuCl matrix and its photocatalytic activity.

    Science.gov (United States)

    Yang, Hui; Liu, Zhi-Hong

    2011-06-01

    Novel Cu2O-CuCl composite thin film constructed by Cu2O nanoplates growing on the CuCI matrix was prepared under facile hydrothermal conditions at 120 degrees C. The phases and morphologies of the as-prepared products were characterized by energy dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The result indicated that the thickness of Cu2O nanoplates was about 100 nm. Furthermore, the photocatalytic activity of the prepared Cu2O-CuCl composite thin film for the degradation of methyl orange was investigated by UV-vis spectrophotometer, demonstrating that it possessed the higher activity.

  1. Analysis of the prognostic factors for low rectal cancer with the pT1-2NxM0 stage after abdominoperineal resection.

    Science.gov (United States)

    Zhang, Xing-mao; Ma, Chao; Sun, Da-yong; Wang, Zheng; Zhou, Zhi-xiang

    2015-01-01

    This study was designed to explore the factors influencing local recurrence and survival for low rectal cancer with pT1-2NxM0 stage after an abdominoperineal resection (APR). Data of 429 patients confirmed to have pT1-2NxM0 after APR were reviewed. The recurrence rate in patients with intraoperative perforation, less than 12 lymph nodes (LNs) harvested, T2 staging, and positive circumferential resection margin (CRM) was 25.1, 19.9, 9.5, and 26.1% compared with 6.9, 7.0, 0, and 5.8% in patients with no perforation, 12 or more LNs harvested, T1, and negative CRM. The 5-year survival rate in patients with age of at least 70, perforation, less than 12 LNs harvested, T2, and positive CRM was 71.1, 60.8, 58.8, 69.9, and 46.0%, but 73.4, 73.5, 73.8, 89.4, and 75.0% in patients with age less than 70, no perforation, 12 or more LNs harvested, T1, and negative CRM. Meanwhile, patients with N0, N1, and N2 had a survival rate of 90.7, 69.9, and 63.9%. Multivariate analysis showed that perforation (PCRM status (P=0.002) were associated with local recurrence, whereas age of the patients (P=0.023), N staging (PCRM status (P=0.004) were associated with survival. APR was affected by patients' age, operation performer, perforation, number of LNs harvested, T staging, N staging, differentiation, and CRM status. Perforation, number of LNs harvested, T staging, differentiation, and CRM status were independent factors for recurrence; meanwhile, age of the patients, N staging, differentiation, and CRM status were independent factors influencing survival.

  2. Nuclear films

    International Nuclear Information System (INIS)

    Malone, Peter.

    1985-01-01

    This booklet is a resource for the study of feature films that highlight the theme of nuclear war. It provides basic credits and brief indication of the theme, treatment, quality and particular notable aspects; and a series of questions raised by the film. Seventy feature films and thirty documentaries are examined

  3. Effect of TiO2 photocatalytic activity in a HDPE-based food packaging on the structural and microbiological stability of a short-ripened cheese.

    Science.gov (United States)

    Gumiero, Matteo; Peressini, Donatella; Pizzariello, Andrea; Sensidoni, Alessandro; Iacumin, Lucilla; Comi, Giuseppe; Toniolo, Rosanna

    2013-06-01

    A high density polyethylene (HDPE)/calcium carbonate (CaCO(3)) film containing TiO(2) was prepared via blown film extrusion process. The photocatalytic properties of this film were evaluated by voltammetric, UV-Vis spectrophotometric and gas chromatographic measurements following the decomposition rate of suitably selected molecular probes, such as 4-hydroxybenzoic acid and methylene blue. The film containing 1% w/w of TiO(2) displayed a profitable and reproducible photoinduced degradation activity towards target organic compounds. The effect of packaging photocatalytic activity on the structural and microbiological stability of a short-ripened cheese was studied. Cheese structure was assessed by dynamic, small deformation rheological tests. A container consisting of a multilayer material, where the layer brought in contact with the food, made from the HDPE+CaCO(3)+TiO(2) composite matrix, was able to provide a greater maintenance of the original cheese structure than a rigid container currently used, mainly due to the inhibition of lactic acid bacteria and coliforms. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Porous Photocatalytic Membrane Microreactor (P2M2): A new reactor concept for photochemistry

    NARCIS (Netherlands)

    Aran, H.C.; Salamon, David; Rijnaarts, Timon; Rijnaarts, T.; Mul, Guido; Wessling, Matthias; Lammertink, Rob G.H.

    2011-01-01

    In this study, a new membrane microreactor concept for multiphase photocatalytic reactions is demonstrated. Microfabrication, photocatalyst immobilization and surface modification steps were performed to develop a Porous Photocatalytic Membrane Microreactor (P2M2). This concept benefits from a

  5. Synthesis and characterization of Cu-doped TiO2 thin films produced by the inert gas condensation technique

    Science.gov (United States)

    Ahmed, H. A.; Abu-Eishah, S. I.; Ayesh, A. I.; Mahmoud, S. T.

    2017-07-01

    The bandgap of thin films Cu-doped TiO2 nanoclusters prepared using the inert gas condensation (IGC) technique have been investigated at various Cu contents. The samples were characterized using XRD, SEM/EDS and UV-visible spectrophotometer. It was found that doping of TiO2 thin film nanoclusters with Cu enhance its optical activity and shift it to the visible region; which makes it useful in photocatalytic applications.

  6. Photocatalytic and biocidal activities of novel coating systems of mesoporous and dense TiO{sub 2}-anatase containing silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Roldán, María V. [Laboratorio de Materiales Cerámicos, FCEIA-UNR, IFIR-CONICET, Pellegrini 250, Rosario S2000BTP (Argentina); Oña, Paula de [Laboratorio de Microbiología Molecular, FCByF-UNR-CONICET, Suipacha 531, Rosario S2002LRK (Argentina); Castro, Yolanda; Durán, Alicia [Instituto de Cerámica y Vidrio (CSIC), Campus de Cantoblanco, 28049, Madrid (Spain); Faccendini, Pablo; Lagier, Claudia [IQUIR-UNR-CONICET, Suipacha 531, Rosario S2002LRK (Argentina); Grau, Roberto, E-mail: robertograu@fulbrightmail.org [Laboratorio de Microbiología Molecular, FCByF-UNR-CONICET, Suipacha 531, Rosario S2002LRK (Argentina); Pellegri, Nora S., E-mail: pellegri@fceia.unr.edu.ar [Laboratorio de Materiales Cerámicos, FCEIA-UNR, IFIR-CONICET, Pellegrini 250, Rosario S2000BTP (Argentina)

    2014-10-01

    included in this article show that the architecture of the films may tune photocatalytic and bactericidal properties. - Highlights: • Photocatalytic and bactericide coatings were obtained by sol–gel. • Photocatalytic and bactericide properties were improved by Ag nanoparticles doping. • Photocatalysis was enhanced by indirect influence of Ag NPs on the catalytic process. • Bactericide efficacy was increased by Ag{sup +} ions release. • Manipulation of the composite architecture allows tuning the properties.

  7. Electrochromism and photocatalysis in dendrite structured Ti:WO3 thin films grown by sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Karuppasamy, A., E-mail: karuppasamy@psnacet.edu.in

    2015-12-30

    Graphical abstract: - Highlights: • Dendrite structured Ti doped WO{sub 3} (WTO) thin films are grown by co-sputtering. • Sputtering condition influences structure and surface morphology of WTO films. • Titanium doping and annealing lead to dendritic surface structures in WTO films. • Structural, optical, electrochromic and photocatalytic properties of WTO films. • Enhanced electrochromism and photocatalysis in dendrite structured WTO thin films. - Abstract: Titanium doped tungsten oxide (Ti:WO{sub 3}) thin films with dendrite surface structures were grown by co-sputtering titanium and tungsten in Ar + O{sub 2} atmosphere. Ti:WO{sub 3} thin films were deposited at oxygen flow rates corresponding to pressures in the range 1.0 × 10{sup −3}–5.0 × 10{sup −3} mbar. Argon flow rate and sputtering power densities for titanium (2 W/cm{sup 2}) and tungsten (3 W/cm{sup 2}) were kept constant. Ti:WO{sub 3} films deposited at an oxygen pressure of 5 × 10{sup −3} mbar are found to be better electrochromic and photocatalytic. They have high optical modulation (80% at λ = 550 nm), coloration efficiency (60 cm{sup 2}/C at λ = 550 nm), electron/ion storage and removal capacity (Qc: −22.01 mC/cm{sup 2}, Qa: 17.72 mC/cm{sup 2}), reversibility (80%) and methylene blue decomposition rate (−1.38 μmol/l d). The combined effects of titanium doping, dendrite surface structures and porosity leads to significant enhancement in the electrochromic and photocatalytic properties of Ti:WO{sub 3} films.

  8. Electrochromism and photocatalysis in dendrite structured Ti:WO3 thin films grown by sputtering

    International Nuclear Information System (INIS)

    Karuppasamy, A.

    2015-01-01

    Graphical abstract: - Highlights: • Dendrite structured Ti doped WO 3 (WTO) thin films are grown by co-sputtering. • Sputtering condition influences structure and surface morphology of WTO films. • Titanium doping and annealing lead to dendritic surface structures in WTO films. • Structural, optical, electrochromic and photocatalytic properties of WTO films. • Enhanced electrochromism and photocatalysis in dendrite structured WTO thin films. - Abstract: Titanium doped tungsten oxide (Ti:WO 3 ) thin films with dendrite surface structures were grown by co-sputtering titanium and tungsten in Ar + O 2 atmosphere. Ti:WO 3 thin films were deposited at oxygen flow rates corresponding to pressures in the range 1.0 × 10 −3 –5.0 × 10 −3 mbar. Argon flow rate and sputtering power densities for titanium (2 W/cm 2 ) and tungsten (3 W/cm 2 ) were kept constant. Ti:WO 3 films deposited at an oxygen pressure of 5 × 10 −3 mbar are found to be better electrochromic and photocatalytic. They have high optical modulation (80% at λ = 550 nm), coloration efficiency (60 cm 2 /C at λ = 550 nm), electron/ion storage and removal capacity (Qc: −22.01 mC/cm 2 , Qa: 17.72 mC/cm 2 ), reversibility (80%) and methylene blue decomposition rate (−1.38 μmol/l d). The combined effects of titanium doping, dendrite surface structures and porosity leads to significant enhancement in the electrochromic and photocatalytic properties of Ti:WO 3 films.

  9. Improvement of methane production from waste activated sludge by on-site photocatalytic pretreatment in a photocatalytic anaerobic fermenter.

    Science.gov (United States)

    Liu, Chunguang; Shi, Wansheng; Li, Huifang; Lei, Zhongfang; He, Leilei; Zhang, Zhenya

    2014-03-01

    This paper reports a new technology that using on-site TiO2-photocatalytic pretreatment in the anaerobic digestion of waste activated sludge (WAS) can enhance WAS degradation and methane production in a novel photocatalytic anaerobic fermenter. The fermenter consists of a photocatalytic unit and a digestion unit. The photocatalytic unit can constantly supply soluble organics and has less negative effect on the activity of methanogens at the optimal photocatalytic time of 4h per day. After anaerobic digestion for 35days, 1266.7ml/l-sludge of methane, 67.4% of volatile solid (VS) reduction and 60.5% of total chemical oxygen demand (TCOD) removal were achieved in the photocatalytic anaerobic fermenter, compared with 923.2ml/l-sludge of methane, 48.9% of VS reduction and 43.5% TCOD removal in the control fermenter. The results indicate that timely utilization of solubilized organics by methanogens could avoid further mineralization by TiO2-photocatalysis, which not only improves methane production but also enhances WAS degradation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Photocatalytic degradation of Phenol Red using complexes of some transition metals and hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    SAVITRI LODHA

    2008-06-01

    Full Text Available The photocatalytic degradation of Phenol Red was investigated using thiocyanate complexes of iron, copper, cobalt and hydrogen peroxide. The rate of photocatalytic degradation of the dye was followed spectrophotometrically. The effect of the variation of different parameters, such as pH, concentration of the complexes and dye, amount of H2O2 and light intensity on the rate of photocatalytic degradation was also studied. A tentative mechanism for the photocatalytic degradation of Phenol Red is proposed.

  11. Photocatalytic Treatment of a Synthetic Wastewater

    Science.gov (United States)

    Yerkinova, Azat; Balbayeva, Gaukhar; Inglezakis, Vassilis J.; Poulopoulos, Stavros G.

    2018-01-01

    This work aimed at investigating the photocatalytic treatment of a synthetic wastewater using UV light (254 nm, 6 W), TiO2 catalyst and H2O2 in a batch recycle annular photoreactor. The total volume of the solution was 250 mL while the irradiated volume in the annular photoreactor with 55.8 mL. Each experiment lasted 120 min and samples were sent for Total Carbon and HPLC analysis. The stock wastewater had initial total carbon 1118 mg L-1. The effect of the presence of phenol in the wastewater on total carbon (TC) removal was also studied. It was shown that the photocatalytic treatment was effective only when initial TC was decreased to 32 mg L-1, whereas the optimum TiO2 concentration was 0.5 g L-1, leading to a TC removal up to 56%. For the same initial carbon load, the optimum H2O2 concentration was found to be 67 mg L-1 resulting in 55% TC removal. Combining, however, TiO2 and H2O2 did not lead to better performance, as 51% TC removal was observed. In contrast, when initial carbon in the wastewater was partially substituted by phenol, the combination of catalyst and hydrogen peroxide was beneficial. Specifically, when 10 ppm of phenol were added keeping the same initial TC concentration, UV/TiO2 treatment resulted in 46% TC removal and 98% phenol conversion, whereas using additionally H2O2 led to 100% phenol conversion after 45 minutes and 81% TC removal.

  12. The influence of photocatalytic interior paints on indoor air quality

    Science.gov (United States)

    Auvinen, Joonas; Wirtanen, Leif

    2008-06-01

    A clean indoor air is important for the well-being and health of people. Lately, new photocatalytic paints have been launched on the market, which are claimed to have air-purifying effects. Photocatalysis initiates radical reactions. Radicals are formed when a photocatalyst (e.g. TiO2) is subjected to radiation. Typical radicals are the hydroxyl radical (radOH) and the superoxide radical (radO2-). Radicals cause chain reactions, which degrade and decompose organic compounds. The end products of these chain reactions are water and carbon dioxide, if the reactions are fully completed (mineralization). If mineralization does not take place, then a great number of side products can be formed, whose properties are not well understood. The side products of photocatalytic reactions can be permanent and stabile. The decomposition of indoor air impurities on the surface of photocatalytic paints is not obvious. The ability of photocatalytic indoor paints to reduce chemical indoor air impurities is the key issue of this study. Six different paints with different binder systems, such as lime, polyorganic siloxane, silica sol-gel and organic binders, were examined. The experiments were divided into three topics: degradation of an organic binder, photocatalytic decomposition of formaldehyde, and a volatile organic compound (VOC) mixture consisting of five different indoor air VOCs. All tests were carried out in an environmental test chamber under dynamic conditions. The test results indicate that many indoor pollutants are generated under normal- and UVA-light. Typical compounds formed include formaldehyde, acetone, acetaldehyde, etc. A clear decrease of formaldehyde or the VOC mixture concentration was not observed. All possibly generated compounds could not be collected or analyzed in this research project, but the measurements show that photocatalytic reactions do not generate only carbon dioxide and water. Photocatalytic decomposition of indoor air impurities can, however

  13. inst1_2d_int_Nx: MERRA 2D IAU Diagnostic, Vertical Integrals and Budget Terms, Time Average 1-hourly 0.667 x 0.5 degree V5.2.0 (MAI1NXINT) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAI1NXINT or inst1_2d_int_Nx data product is the MERRA Data Assimilation System 2-Dimensional vertical integral that is Instantaneous single-level at the native...

  14. Comparative study of photoinduced wettability conversion between [PW{sub 12}O{sub 40}]{sup 3−}/brookite and [SiW{sub 12}O{sub 40}]{sup 4−}/brookite hybrid films

    Energy Technology Data Exchange (ETDEWEB)

    Pruethiarenun, Kunchaya; Isobe, Toshihiro; Matsushita, Sachiko [Department of Metallurgy and Ceramic Science, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); Ye, Jinhua [Environmental Remediation Materials Unit, Environment and Energy Materials Division, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Nakajima, Akira, E-mail: anakajim@ceram.titech.ac.jp [Department of Metallurgy and Ceramic Science, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2014-04-01

    Two tungsten-based Keggin-type heteropolyacids (PW{sub 12}: ([PW{sub 12}O{sub 40}]{sup 3−}) and SiW{sub 12}: ([SiW{sub 12}O{sub 40}]{sup 4−})) were hybridized with brookite-type TiO{sub 2}. Then photocatalytic decomposition activity, photoinduced hydrophilicity, and sustainability of the hydrophilicity in the dark were evaluated using gaseous 2-propanol (IPA) decomposition and sessile drop method. The obtained films were transparent in the visible wavelength range. Both hybrid films exhibited higher photocatalytic decomposition activity and had higher photoinduced hydrophilicizing rates than pure brookite films under UV illumination. The PW{sub 12}/TiO{sub 2} film exhibited better photocatalytic performance than the SiW{sub 12}/TiO{sub 2} film did. Atmosphere dependence, XPS analysis, and electrochemical experiments indicated the cause of these two films' different levels of sustainability of hydrophilicity to be differences in their electron storage capability. Results show that the electron scavenger capability and reoxidation efficiency of the heteropolyacid are key factors affecting the overall performance of wettability conversion of this hybrid film system before and after UV illumination. - Highlights: • Transparent PW{sub 12}/brookite(TTP) and SiW{sub 12}/brookite(TTS) films were prepared. • Both films exhibited better photocatalytic performance than pure brookite film. • The TTP film exhibited more sustainable hydrophilicity than the TTS film did. • Reoxidation efficiency of HPAs is a key factor for wettability conversion.

  15. Thin film nano-photocatalyts with low band gap energy for gas phase degradation of p-xylene: TiO2 doped Cr, UiO66-NH2 and LaBO3 (B  =  Fe, Mn, and Co)

    Science.gov (United States)

    Loc Luu, Cam; Thuy Van Nguyen, Thi; Nguyen, Tri; Nguyen, Phung Anh; Hoang, Tien Cuong; Ha, Cam Anh

    2018-03-01

    By dip-coating technique the thin films of nano-photocatalysts TiO2, Cr-doped TiO2, LaBO3 perovskites (B  =  Fe, Mn, and Co) prepared by sol-gel method, and UiO66-NH2 prepared by a solvothermal were obtained and employed for gas phase degradation of p-xylene. Physicochemical characteristics of the catalysts were examined by the methods of BET, SEM, TEM, XRD, FT-IR, TGA, Raman and UV–vis spectroscopies. The thickness of film was determined by a Veeco-American Dektek 6M instrument. The activity of catalysts was evaluated in deep photooxidation of p-xylene in a microflow reactor at room temperature with the radiation sources of a UV (λ  =  365 nm) and LED lamps (λ  =  400–510 nm). The obtained results showed that TiO2 and TiO2 doped Cr thin films was featured by an anatase phase with nanoparticles of 10–100 nm. Doping TiO2 with 0.1%mol Cr2O3 led to reduce band gap energy from 3.01 down to 1.99 eV and extend the spectrum of photon absorption to the visible region (λ  =  622 nm). LaBO3 perovkite thin films were also featured by a crystal phase with average particle nanosize of 8–40 nm, a BET surface area of 17.6–32.7 m2 g‑1 and band gap energy of 1.87–2.20 eV. UiO66-NH2 was obtained in the ball shape of 100–200 nm, a BET surface area of 576 m2 g‑1 and a band gap energy of 2.83 eV. The low band gap energy nano-photocatalysts based on Cr-doped TiO2 and LaBO3 perovskites exhibited highly stable and active for photo-degradation of p-xylene in the gas phase under radiation of UV–vis light. Perovskite LaFeO3 and Cr–TiO2 thin films were the best photocatalysts with a decomposition yield being reached up to 1.70 g p-xylene/g cat.

  16. Demens Film

    DEFF Research Database (Denmark)

    Jensen, Anders Møller

    2012-01-01

    Vi vil skabe film til mennesker med demens – ikke film om demens sygdommen eller beretninger om livet og hverdagen med en kronisk lidelse. Filmene skal medvirke til at frembringe en behagelig stemning omkring og hos mennesker med demens, så hverdagen bliver så tryg som mulig. Filmene skal samtidig...... var at afgrænse og prioritere projektet, samt komme med anbefalinger omkring hvad der er vigtigt, i forbindelse med produktion af film målrettet mennesker med demens. Resultat af ekspertgruppen sammenfattes i denne rapport. Projektet gennemføres som et samarbejde mellem Retrospect Film...

  17. Visible-light active thin-film WO3 photocatalyst with controlled high-rate deposition by low-damage reactive-gas-flow sputtering

    Directory of Open Access Journals (Sweden)

    Nobuto Oka

    2015-10-01

    Full Text Available A process based on reactive gas flow sputtering (GFS for depositing visible-light active photocatalytic WO3 films at high deposition rates and with high film quality was successfully demonstrated. The deposition rate for this process was over 10 times higher than that achieved by the conventional sputtering process and the process was highly stable. Furthermore, Pt nanoparticle-loaded WO3 films deposited by the GFS process exhibited much higher photocatalytic activity than those deposited by conventional sputtering, where the photocatalytic activity was evaluated by the extent of decomposition of CH3CHO under visible light irradiation. The decomposition time for 60 ppm of CH3CHO was 7.5 times more rapid on the films deposited by the GFS process than on the films deposited by the conventional process. During GFS deposition, there are no high-energy particles bombarding the growing film surface, whereas the bombardment of the surface with high-energy particles is a key feature of conventional sputtering. Hence, the WO3 films deposited by GFS should be of higher quality, with fewer structural defects, which would lead to a decrease in the number of centers for electron-hole recombination and to the efficient use of photogenerated holes for the decomposition of CH3CHO.

  18. Quantum dots in photocatalytic applications: efficiently enhancing visible light photocatalytic activity by integrating CdO quantum dots as sensitizers.

    Science.gov (United States)

    Reshak, A H

    2017-09-20

    The amalgamation of a wide optical band gap photocatalyst with visible-light-active CdO quantum dots (QDs) as sensitizers is one of the most efficient ways to improve photocatalytic performance under visible light irradiation. The photocatalytic performance of cadmium benzoate ((Cd(C 7 H 5 O 2 ) 2 ) 3 (CH 3 CN) 1 ) is comprehensively investigated. The estimated optical band gap of cadmium benzoate is 2.64 eV and the EPc and EPv are about -0.09 V (vs. NHE) and +2.55 V (vs. NHE), respectively, which implies that cadmium benzoate possesses a high negative reduction potential of excited electrons due to its higher conduction band position, and hence, the locations of the conduction band minimum and the valence band maximum meet the redox capacity. Thus, this composite photocatalyst exhibits superior activity in visible-light-driven photocatalytic H 2 evolution. We found that introducing the QDs enhance the photocatalytic performance towards the visible light region. The electronic band structure shows high k-dispersion bands around the Fermi level, which implies low effective masses, and hence, the high mobility carriers favor the enhancement of the charge transfer process. The mobility of the photogenerated carriers significantly influences the photocatalytic efficiency and the higher photogenerated carriers' mobility enhances the photocatalytic performance. Moreover, the result shows a great effective mass difference between electrons (e - ) and holes (h + ), which can facilitate the e - and h + migration and separation, and finally improve the photocatalytic performance. The large mobility difference is useful for the separation of e - and h + , the reduction of the e - and h + recombination rate, and the improvement of the photocatalytic activity. Thus, cadmium benzoate exhibits rapid generation of e - -h + pairs with photoexcitation and a high negative reduction potential of excited electrons due to its higher CB position. Based on these results one can conclude

  19. Effective Charge Carrier Utilization in Photocatalytic Conversions.

    Science.gov (United States)

    Zhang, Peng; Wang, Tuo; Chang, Xiaoxia; Gong, Jinlong

    2016-05-17

    Continuous efforts have been devoted to searching for sustainable energy resources to alleviate the upcoming energy crises. Among various types of new energy resources, solar energy has been considered as one of the most promising choices, since it is clean, sustainable, and safe. Moreover, solar energy is the most abundant renewable energy, with a total power of 173 000 terawatts striking Earth continuously. Conversion of solar energy into chemical energy, which could potentially provide continuous and flexible energy supplies, has been investigated extensively. However, the conversion efficiency is still relatively low since complicated physical, electrical, and chemical processes are involved. Therefore, carefully designed photocatalysts with a wide absorption range of solar illumination, a high conductivity for charge carriers, a small number of recombination centers, and fast surface reaction kinetics are required to achieve a high activity. This Account describes our recent efforts to enhance the utilization of charge carriers for semiconductor photocatalysts toward efficient solar-to-chemical energy conversion. During photocatalytic reactions, photogenerated electrons and holes are involved in complex processes to convert solar energy into chemical energy. The initial step is the generation of charge carriers in semiconductor photocatalysts, which could be enhanced by extending the light absorption range. Integration of plasmonic materials and introduction of self-dopants have been proved to be effective methods to improve the light absorption ability of photocatalysts to produce larger amounts of photogenerated charge carriers. Subsequently, the photogenerated electrons and holes migrate to the surface. Therefore, acceleration of the transport process can result in enhanced solar energy conversion efficiency. Different strategies such as morphology control and conductivity improvement have been demonstrated to achieve this goal. Fine-tuning of the

  20. Physics properties of TiO{sub 2} films produced by dip-coating technique; Propriedades fisicas de filmes de TiO{sub 2} produzidos pela tecnica de dip-coating

    Energy Technology Data Exchange (ETDEWEB)

    Teloeken, A.C.; Alves, A.K.; Berutti, F.A.; Tabarelli, A.; Bergmann, C.P., E-mail: acteloeken@hotmail.com [Universidade Federal do Rio Grande do Sul (UFRGS),RS (Brazil). Laboratorio de Materiais Ceramicos; Regonini, D.; Graule, T.; Clemens, F. [Swiss Federal Laboratories for Materials Testing and Research, Laboratory of High Performance Ceramics (Switzerland)

    2014-07-01

    The use of titanium dioxide (TiO{sub 2}) as a photocatalyst to produce hydrogen has been of great interest because of their chemical stability, low cost and non-toxicity. TiO{sub 2} occurs in three different crystal forms: rutile, anatase and brokita. Among these, the anatase phase generally exhibits the best photocatalytic behavior, while the rutile phase is the most stable. Among the various techniques of deposition, dip-coating technique produces films with good photocatalytic properties, using simple and inexpensive equipment. In this work TiO{sub 2} films were obtained by dip-coating. The films were characterized using X-ray diffraction, scanning electron microscopy, profilometry, contact angle measurements and photocurrent. The microstructure and physical properties were evaluated in relation of the temperature and the addition of an additive. (author)

  1. Piezoelectric Response Evaluation of ZnO Thin Film Prepared by RF Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Cheng Da-Long

    2017-01-01

    Full Text Available The most important parameter of piezoelectric materials is piezoelectric coefficient (d33. In this study, the piezoelectric ZnO thin films were deposited on the SiNx/Si substrate. The 4 inches substrate is diced into 8 cm× 8 cm piece. During the deposition process, a zinc target (99.999 wt% of 2 inches diameter was used. The vertical distance between the target and the substrate holder was fixed at 5 cm. The piezoelectric response of zinc oxide (ZnO thin films were obtained by using a direct measurement system. The system adopts a mini impact tip to generate an impulsive force and read out the piezoelectric signals immediately. Experimentally, a servo motor is used to produce a fixed quantity of force, for giving an impact against to the piezoelectric film. The ZnO thin films were deposited using the reactive radio frequency (RF magnetron sputtering method. The electric charges should be generated because of the material’s extrusion. This phenomenon was investigated through the oscilloscope by one shot trigger. It was apparent that all ZnO films exhibit piezoelectric responses evaluated by our measurement system, however, its exhibit a significant discrepancy. The piezoelectric responses of ZnO thin film at various deposition positions were measured and the crystal structures of the sputtering pressure were also discussed. The crystalline characteristics of ZnO thin films are investigated through the XRD and SEM. The results show the ZnO thin film exhibits good crystalline pattern and surface morphology with controlled sputtering condition. The ZnO thin films sputtered using 2 inches target present various piezoelectric responses. With the exactly related position, a best piezoelectric response of ZnO thin film can be achieved.

  2. Modyfication of photocatalytic properties of titanium dioxide by mechanochemical method

    Directory of Open Access Journals (Sweden)

    Dulian Piotr

    2016-09-01

    Full Text Available The paper presents a simple way to improve the photocatalytic properties of titanium dioxide using mechanochemical method. The TiO2 (Anatase powders was subjected to high-energy ball milling in dry environment and in methanol. It has been shown that it is possible to induce the phase transformation from Anatase to Rutile and produce a material with a higher photocatalytic activity in the UV light. Physicochemical characteristics of the products were based on the following methods and techniques: X-ray powder diffraction (XRD, IR and UV-Vis (DR spectroscopy, measurements of specific surface area (BET. The photocatalytic activity of the powders was measured in the decomposition reaction of methyl orange in water.

  3. Tantalum nitride for photocatalytic water splitting: concept and applications

    Directory of Open Access Journals (Sweden)

    Ela Nurlaela

    2016-10-01

    Full Text Available Abstract Along with many other solar energy conversion processes, research on photocatalytic water splitting to generate hydrogen and oxygen has experienced rapid major development over the past years. Developing an efficient visible-light-responsive photocatalyst has been one of the targets of such research efforts. In this regard, nitride materials, particularly Ta3N5, have been the subject of investigation due to their promising properties. This review focuses on the fundamental parameters involved in the photocatalytic processes targeting overall water splitting using Ta3N5 as a model photocatalyst. The discussion primarily focuses on relevant parameters that are involved in photon absorption, exciton separation, carrier diffusion, carrier transport, catalytic efficiency, and mass transfer of the reactants. An overview of collaborative experimental and theoretical approaches to achieve efficient photocatalytic water splitting using Ta3N5 is discussed.

  4. Tantalum nitride for photocatalytic water splitting: concept and applications

    KAUST Repository

    Nurlaela, Ela

    2016-10-12

    Along with many other solar energy conversion processes, research on photocatalytic water splitting to generate hydrogen and oxygen has experienced rapid major development over the past years. Developing an efficient visible-light-responsive photocatalyst has been one of the targets of such research efforts. In this regard, nitride materials, particularly Ta3N5, have been the subject of investigation due to their promising properties. This review focuses on the fundamental parameters involved in the photocatalytic processes targeting overall water splitting using Ta3N5 as a model photocatalyst. The discussion primarily focuses on relevant parameters that are involved in photon absorption, exciton separation, carrier diffusion, carrier transport, catalytic efficiency, and mass transfer of the reactants. An overview of collaborative experimental and theoretical approaches to achieve efficient photocatalytic water splitting using Ta3N5 is discussed.

  5. Characterizing Nanoparticles Reactivity: Structure-Photocatalytic Activity Relationship

    International Nuclear Information System (INIS)

    Piella, J; Bastús, N G; Casals, E; Puntes, V

    2013-01-01

    Nanoparticles are reactive, and their final interactions with the surrounding media are ultimately determined by their reactivity, which in turns depends on the nanoparticles morphology, surface chemistry and environment in which they are embedded. One simple and informative approach for the study of the reactivity of nanoparticles is the determination of their photocatalytic activity. In the present work, we briefly summarize the importance of different parameters such as the size, shape and agglomeration state on the photocatalytic activity of colloidal inorganic nanoparticles. The study of the use of nanoparticles as photocatalyts is relevant not only for its potential applications in environmental remediation issues but also it can provide relevant information about the role of these parameters at the nanoscale.

  6. Application of artificial neural networks for prediction of photocatalytic reactor.

    Science.gov (United States)

    Delnavaz, Mohammad

    2015-02-01

    In this paper, forecasting of kinetic constant and efficiency of photocatalytic process of TiO2 nano powder immobilized on light expanded clay aggregates (LECA) was investigated. Synthetic phenolic wastewater, which is toxic and not easily biodegradable, was selected as the pollutant. The efficiency of the process in various operation conditions, including initial phenol concentration, pH, TiO2 concentration, retention time, and UV lamp intensity, was then measured. The TiO2 nano powder was immobilized on LECA using slurry and sol-gel methods. Kinetics of photocatalytic reactions has been proposed to follow the Langmuir-Hinshelwood model in different initial phenol concentration and pH. Several steps of training and testing of the models were used to determine the appropriate architecture of the artificial neural network models (ANNs). The ANN-based models were found to provide an efficient and robust tool in predicting photocatalytic reactor efficiency and kinetic constant for treating phenolic compounds.

  7. Synthesis of Neutral SiO/TiO Hydrosol and Its Application as Antireflective Self-Cleaning Thin Film

    Directory of Open Access Journals (Sweden)

    Chiahung Huang

    2012-01-01

    Full Text Available A neutral SiO2/TiO2 composite hydrosol was prepared by a coprecipitation-peptization method using titanium tetrachloride and silicon dioxide hydrosol as precursors. It is not only an antireflective self-cleaning coating material but also an environmental-benign material. Even heated at 700°C for 5 minutes in the tempering process, the as-prepared SiO2/TiO2 thin film still demonstrated antireflection and photocatalytic self-cleaning effect. The SiO2/TiO2 thin film increased near 2% of transmittance; however, the TiO2 thin film decreased 5% of transmittance at least. In addition to antireflection, the SiO2/TiO2 thin film decomposed the surface coated oleic acid under ultraviolet light and showed superhydrophilicity under dark for two days. The SiO2/TiO2 thin film also showed good photocatalytic degradation of methylene blue. With these antireflection, persistent superhydrophilicity, and photocatalytic self-cleaning effects, this prepared neutral SiO2/TiO2 hydrosol would be a good coating material for tempered glass and other building materials.

  8. Effect of photocatalytic oxidation technology on GaN CMP

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jie, E-mail: jie-wang11@mails.tsinghua.edu.cn; Wang, Tongqing, E-mail: wtq@mail.tsinghua.edu.cn; Pan, Guoshun, E-mail: pangs@mail.tsinghua.edu.cn; Lu, Xinchun, E-mail: xclu@mail.tsinghua.edu.cn

    2016-01-15

    Graphical abstract: - Highlights: • Photocatalytic oxidation technology was introduced to GaN CMP for the first time and proves to be more efficient than before. • XPS analysis reveals the planarization process by different N-type semiconductor particles. • Analyzing the effect of pH on photocatalytic oxidation in GaN CMP. • Proposing the photocatalytic oxidation model to reveal the removal mechanism. - Abstract: GaN is so hard and so chemically inert that it is difficult to obtain a high material removal rate (MRR) in the chemical mechanical polishing (CMP) process. This paper discusses the application of photocatalytic oxidation technology in GaN planarization. Three N-type semiconductor particles (TiO{sub 2}, SnO{sub 2}, and Fe{sub 2}O{sub 3}) are used as catalysts and added to the H{sub 2}O{sub 2}–SiO{sub 2}-based slurry. By optical excitation, highly reactive photoinduced holes are produced on the surface of the particles, which can oxidize OH{sup −} and H{sub 2}O absorbed on the surface of the catalysts; therefore, more OH* will be generated. As a result, GaN MRRs in an H{sub 2}O{sub 2}–SiO{sub 2}-based polishing system combined with catalysts are improved significantly, especially when using TiO{sub 2}, the MRR of which is 122 nm/h. The X-ray photoelectron spectroscopy (XPS) analysis shows the variation trend of chemical composition on the GaN surface after polishing, revealing the planarization process. Besides, the effect of pH on photocatalytic oxidation combined with TiO{sub 2} is analyzed deeply. Furthermore, the physical model of GaN CMP combined with photocatalytic oxidation technology is proposed to describe the removal mechanism of GaN.

  9. Photocatalytic CO₂ Reduction by Mesoporous Polymeric Carbon Nitride Photocatalysts.

    Science.gov (United States)

    Tasbihi, Minoo; Acharjya, Amitava; Thomas, Arne; Reli, Martin; AmbroŽová, Nela; Kočcí, Kamila; Schomäcker, Reinhard

    2018-08-01

    In this paper, a sol-gel derived mesoporous polymeric carbon nitride has been investigated as a photocatalyst for CO2 photocatalytic reduction. Noble-metal Pt nanoparticles were deposited on carbon nitride (sg-CN) in order to investigate the performance of both Pt-sg-CN and sg-CN for photocatalytic CO2 reduction. Physicochemical properties of prepared nanocomposites were comprehensively characterized by using powder XRD, N2 physisorption, UV-Vis DRS, ICP-AES, FTIR, solid-state NMR, SEM, TEM and photoelectrochemical measurements. Compared with pure sg-CN, the resulting Pt-loaded sg-CN (Pt-sg-CN) exhibited significant improvement on the CO2 photocatalytic reduction to CH4 in the presence of water vapor at ambient condition under UV irradiation. 1.5 wt.% Pt-loaded sg-CN (Pt-sg-CN) photocatalyst formed the highest methane yield of 13.9 μmol/gcat. after 18 h of light irradiation, which was almost 2 times and 32 times improvement in comparison to pure sg-CN and commercial TiO2 Evonik P25, respectively. The substantial photocatalytic activity of Pt-sg-CN photocatalyst for the yield product of the CO2 photocatalytic reduction was attributed to the efficient interfacial transfer of photogenerated electrons from sg-CN to Pt due to the lower Fermi level of Pt in the Pt-sg-CN hybrid heterojunctions as also evidenced by photo-electrochemical measurements. This resulted in the reduction of electron-hole pairs recombination for effective spatial charge separation, consequently increasing the photocatalytic efficiency.

  10. Asymmetric photoelectric property of transparent TiO2 nanotube films loaded with Au nanoparticles

    International Nuclear Information System (INIS)

    Wang, Hui; Liang, Wei; Liu, Yiming; Zhang, Wanggang; Zhou, Diaoyu; Wen, Jing

    2016-01-01

    Highlights: • Highly transparent films of TiO 2 nanotube arrays were directly fabricated on FTO glasses. • Semitransparent TNT-Au composite films were obtained and exhibited excellent photoelectrocatalytic ability. • Back-side of TNT-Au composite films was firstly irradiated and tested to compare with front-side of films. - Abstract: Semitransparent composite films of Au loaded TiO 2 nanotubes (TNT-Au) were prepared by sputtering Au nanoparticles on highly transparent TiO 2 nanotubes films, which were fabricated directly on FTO glasses by anodizing the Ti film sputtered on the FTO glasses. Compared with pure TNT films, the prepared TNT-Au films possessed excellent absorption ability and high photocurrent response and improved photocatalytic activity under visible-light irradiation. It could be concluded that Au nanoparticles played important roles in improving the photoelectrochemical performance of TNT-Au films. Moreover, in this work, both sides of TNT-Au films were researched and compared owing to theirs semitransparency. It was firstly found that the photoelectric activity of TNT-Au composite films with back-side illumination was obviously superior to front-side illumination.

  11. Into films

    DEFF Research Database (Denmark)

    Tan, Ed S.; Doicaru, Miruna M.; Hakemulder, Frank

    2017-01-01

    Most film viewers know the experience of being deeply absorbed in the story of a popular film. It seems that at such moments they lose awareness of watching a movie. And yet it is highly unlikely that they completely ignore the fact that they watch a narrative and technological construction...

  12. Photocatalytic degradation of synthetic dye under sunlight

    Directory of Open Access Journals (Sweden)

    Mijin Dušan

    2007-01-01

    Full Text Available Synthetic dyes are widely used in the textile industry. Dye pollutants from the textile industry are an important source of environmental contamination. The majority of these dyes are toxic, mostly non-biodegradable and also resistant to decomposition by physico-chemical methods. Among new oxidation methods or "advanced oxidation processes", heterogeneous photocatalysis appears as an emerging destructive technology leading to the total mineralization of many organic pollutants. CI Basic Yellow 28 (BY28, commonly used as a textile dye, could be photocatalytically degraded using TiU2 as catalyst under sunlight. The effect of some parameters such as the initial catalyst concentration, initial dye concentration, initial NaCl and Na2CO3 concentrations, pH, H2O2 and type of catalyst on the degradation rate of BY28 was examined in details. The presence of NaCl and Na2CO3 led to inhibition of the photodegradation process. The highest photodegradation rate was observed at high pH, while the rate was the lowest at low pH. Increase of the initial H2O2 concentration increased the initial BY28 photodegradation efficiency. ZnO was a better catalyst than TiO2 at low dye concentrations.

  13. Novel Solar Photocatalytic Reactor for Wastewater Treatment

    Science.gov (United States)

    Sutisna; Rokhmat, M.; Wibowo, E.; Murniati, R.; Khairurrijal; Abdullah, M.

    2017-07-01

    A new solar photocatalytic reactor (photoreactor) using TiO2 nanoparticles coated onto plastic granules has been designed. Catalyst granules are placed into the cavity of a reactor panel made of glass. A pump is used to circulate wastewater in the photoreactor. Methylene blue (MB) dissolved in water was chosen as the wastewater model. The performance of the photoreactor was evaluated based on changes in MB concentration with respect to time. The photoreactor showed a good performance by degrading 10 L of MB solution up to 96.54% after 48 h of solar irradiation. The photoreactor was scaled up by enlarging the panel area to twice its original size. The increase in the surface area of the reactor panel and therefore of the mass of catalyst granules and reactor volume led to a three-fold increase of the photodegradation rate. In addition, the MB degradation kinetics were also studied. Data analysis confirmed the applicability of the pseudo-first-order Langmuir-Hinshelwood model. The proposed photoreactor has great potential for use in large-scale wastewater treatment.

  14. Controlling the magnetic anisotropy in epitaxial Y3F e5O12 films by manganese doping

    Science.gov (United States)

    Wang, C. T.; Liang, X. F.; Zhang, Y.; Liang, X.; Zhu, Y. P.; Qin, J.; Gao, Y.; Peng, B.; Sun, N. X.; Bi, L.

    2017-12-01

    Controlling the magnetic anisotropy in epitaxial Y3F e5O12 (YIG) thin films is critical for magnonic and photonic device applications. In this paper, we report the crystal structure, magnetic properties, and magnetic anisotropy of epitaxial Y3(F e5 -xM nx ) O12 (Mn:YIG) thin films grown on G d3G a5O12 (111) (GGG) substrates by pulsed-laser deposition. Mn doping is observed to strongly enhance the magnetoelastic coefficient of YIG thin films, which leads to large tunability of the thin film magnetic anisotropy by lattice strain. With increasing Mn concentration from x =0 to x =1.25 , a continuous increase of out-of-plane magnetic anisotropy ranging from -644.4 Oe to 1337.5 Oe is observed. In particular, a perpendicular magnetic anisotropy (PMA) is achieved in Mn:YIG thin films with a high Mn concentration of x =1.12 . Ferromagnetic resonance (FMR) measurements show low FMR linewidths of 3.4 Oe to 129 Oe at 9.5 GHz in Mn:YIG thin films. Our paper demonstrates manganese doping as an effective way to enhance the magnetoelastic anisotropy of YIG thin films by strain, which is useful for magnonic and magneto-optical device applications.

  15. Understanding Mechanism of Photocatalytic Microbial Decontamination of Environmental Wastewater

    Directory of Open Access Journals (Sweden)

    Chhabilal Regmi

    2018-02-01

    Full Text Available Several photocatalytic nanoparticles are synthesized and studied for potential application for the degradation of organic and biological wastes. Although these materials degrade organic compounds by advance oxidation process, the exact mechanisms of microbial decontamination remains partially known. Understanding the real mechanisms of these materials for microbial cell death and growth inhibition helps to fabricate more efficient semiconductor photocatalyst for large-scale decontamination of environmental wastewater or industries and hospitals/biomedical labs generating highly pathogenic bacteria and toxic molecules containing liquid waste by designing a reactor. Recent studies on microbial decontamination by photocatalytic nanoparticles and their possible mechanisms of action is highlighted with examples in this mini review.

  16. Photocatalytic reduction of CO₂: from molecules to semiconductors.

    Science.gov (United States)

    Yui, Tatsuto; Tamaki, Yusuke; Sekizawa, Keita; Ishitani, Osamu

    2011-01-01

    We are facing three serious problems related to fossil resources, i.e., shortage of energy, shortage of carbon resources, and the global worming problem. Development of practical systems for converting CO₂ to useful chemicals using solar light, i.e., photocatalytic CO₂ reduction systems, should be one of the best solutions for these problems. In this article, we review photocatalytic CO₂ reduction systems, which are classified in two categories: (1) homogeneous reaction systems mainly using transition metal complexes, and (2) heterogeneous systems mainly using inorganic semiconductor as a light absorber.

  17. Study and optimization of an annular photocatalytic slurry reactor.

    Science.gov (United States)

    Camera-Roda, Giovanni; Santarelli, Francesco; Panico, Mauro

    2009-05-01

    The experimental results obtained for the photocatalytic degradation of a model organic dye in an annular slurry reactor are analyzed with the aid of a mathematical model. The model is used also to study the effects on the performances of many operative conditions: flow rate, photocatalyst concentration, power of the lamp, size of the photocatalytic particles, dimensions of the reactor. The investigation demonstrates that the rate of the process is often limited by the radiant energy transfer and that some simple rules can be followed in order to optimize different yields and the observed rate of reaction.

  18. Photocatalytic degradation of bisphenol A in aqueous media: A review.

    Science.gov (United States)

    Reddy, P Venkata Laxma; Kim, Ki-Hyun; Kavitha, Beluri; Kumar, Vanish; Raza, Nadeem; Kalagara, Sudhakar

    2018-05-01

    Bisphenol A (BPA) is known to be an emerging pollutant in various environmental compartments. Human exposure to BPA occurs widely because it is commonly used as the raw material in a variety of industrial processes (e.g., the preparation of epoxy and polycarbonate resins). In this review, a brief survey was carried out to cover a range of photocatalytic materials (e.g., titania, zinc, silver, carbon, and bismuth) and their modified forms as an effective means to treat water systems contaminated with BPA. The overall efficiency and limitations of these catalysts are described for the photocatalytic treatment of BPA. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Photoelectrocatalytic Degradation of Sodium Oxalate by TiO2/Ti Thin Film Electrode

    Directory of Open Access Journals (Sweden)

    Chen-Yu Chang

    2012-01-01

    Full Text Available The photocatalytically active TiO2 thin film was deposited on the titanium substrate plate by chemical vapor deposition (CVD method, and the photoelectrocatalytic degradation of sodium oxalate was investigated by TiO2 thin film reactor prepared in this study with additional electric potential at 365 nm irradiation. The batch system was chosen in this experiment, and the controlled parameters were pH, different supporting electrolytes, applied additional potential, and different electrolyte solutions that were examined and discussed. The experimental results revealed that the additional applied potential in photocatalytic reaction could prohibit recombination of electron/hole pairs, but the photoelectrocatalytic effect was decreased when the applied electric potential was over 0.25 V. Among the electrolyte solutions added, sodium sulfate improved the photoelectrocatalytic effect most significantly. At last, the better photoelectrocatalytic degradation of sodium oxalate occurred at pH 3 when comparing the pH influence.

  20. Crecimiento de cebolla (Allium cepa L. var. “Roja Arequipeña” en función de la fertilización NxK

    Directory of Open Access Journals (Sweden)

    Julio Estuardo Amaya Robles

    2012-01-01

    Full Text Available Con el objetivo de determinar la influencia de niveles crecientes de nitrógeno y potasio en el crecimiento de cebolla, se condujo un experimento en Pampas de San Juan, Laredo, durante los meses de octubre del 2010 a enero del 2011. Se utilizó semilla certificada de cebolla roja var. “Roja Arequipeña”. Los tratamientos resultaron de las combinaciones de 60, 120, 180 y 240 kg de N ha - 1 y de 40, 80 y 160 kg de K 2 O ha - 1 ; utilizándose como dosis única; 80 kg de P 2 O 5 ha - 1 . El experimento fue instalado en diseño de Bloques Completos al Azar, con arreglo factorial 3x4, con tres repeticiones. Los resultados de la investigación realizada permiten concluir que con la do sis de 120 kg de N.ha - 1 se obtuvo una respuesta lineal ascendente al nitrógeno con 44.9cm de altura a los 90 días DDT y de 14.2 mm para diámetro del falso tallo con la dosis de 60 kg de N.ha - 1 a los 104 días DDT sin respuestas al potasio en esta variable de estudio. No hubo respuestas a NxK, para el número de hojas.

  1. Elastic Properties and the Band Gap of AlNxP1-x Semiconductor Alloy: A Comparative Study of Various Ab Initio Approaches

    Directory of Open Access Journals (Sweden)

    M. P. Polak

    2016-01-01

    Full Text Available Structural and elastic properties of AlNxP1-x, a novel semiconductor alloy, are studied from the first principles in both zinc-blende and wurtzite structures. Performances of the finite difference (FD method and the density functional perturbation theory (DFPT are tested and compared. Both of these methods are applied to two different approaches of alloy simulation, a supercell of 16 and 32 atoms (for zinc-blende and wurtzite structures, resp. and the alchemical mixing (AM method, where the pseudopotentials are mixed in an appropriate way to form an alloy. All elastic properties, including the elastic tensors, elastic moduli, Poisson’s ratio, B/G, and relaxation coefficient, as well as lattice parameters are calculated using all said methods. Conclusions about the use of the approaches investigated in this paper and about their performance are drawn. In addition, in both crystal structures, the band gap is studied in the whole composition range using the MBJLDA functional. The band gap bowings are unusually high, which confirms earlier reports.

  2. Investigation of the spin-lattice coupling in M n3G a1 -xS nxN antiperovskites

    Science.gov (United States)

    Shi, Kewen; Sun, Ying; Colin, Claire V.; Wang, Lei; Yan, Jun; Deng, Sihao; Lu, Huiqing; Zhao, Wenjun; Kazunari, Yamaura; Bordet, Pierre; Wang, Cong

    2018-02-01

    The magnetovolume effects (MVEs) of M n3G a1 -xS nxN antiperovskite compounds have been investigated by means of neutron powder diffraction. Increasing the Sn-doping content at the Ga site leads to the broadening of the magnetic phase transition temperature range and the thermal expansion behavior changes from negative to positive. We establish the relationship between the square of the ordered magnetic moment m2 and the volume variation Δ ωm for the antiferromagnetic phase (Γ5 g magnetic structure with rhombohedral symmetry R 3 ¯m ). The temperature variations of Δ ωm(T ) , m2(T ) and the magnetoelastic coupling constant C (T ) are also quantitatively analyzed according to the itinerant-electron theory. Moreover, the increase of the phonon contribution to the thermal expansion induced by Sn doping and the corresponding decrease of dm/dT are revealed to be the key parameters for tuning the MVEs. Our results allow elucidating and quantifying the mechanism of the spin-lattice coupling and can be used to design magnetic functional materials with controlled thermal expansion behaviors for specific applications.

  3. Ultrasonic-promoted rapid preparation of PVC/TiO2-BSA nanocomposites: Characterization and photocatalytic degradation of methylene blue.

    Science.gov (United States)

    Mallakpour, Shadpour; Shamsaddinimotlagh, Sima

    2018-03-01

    In the present project in order to prevent agglomeration and better dispersion of TiO 2 nanoparticles (NPs) in the poly(vinyl chloride) (PVC) matrix, initially, the surface of TiO 2 NPs was covered by bovine serum albumin protein (BSA) via sonication method. Then, the TiO 2 -BSA powders were embedded into the PVC matrix using ultrasonic irradiations. With mechanical and magnetic stirring homogenous mixture was not obtained. So sonication process was very essential and vital. Physical, chemical and structural properties of the samples were investigated with various tools. Morphology studies showed the well distribution of spherical TiO 2 NPs in the PVC matrix. TGA analysis showed that nanocomposites (NCs) have higher thermal stability than the pristine polymer. The photocatalytic activity tests by destroying the methylene blue dye on the pristine TiO 2 NPs, TiO 2 -BSA NPs and PVC/TiO 2 -BSA NC 6 wt% were examined. The results showed that the photocatalytic activity of TiO 2 NPs was reduced in the presence of BSA and PVC. It can be concluded that the TiO 2 -BSA NPs and PVC/TiO 2 -BSA NC 6 wt% have UV shielding properties and can protect film from degradation by UV. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Preparation and Characterization of Ni-Doped TiO2 Materials for Photocurrent and Photocatalytic Applications

    Directory of Open Access Journals (Sweden)

    Ibram Ganesh

    2012-01-01

    Full Text Available Different amounts of Ni-doped TiO2 (Ni=0.1 to 10% powders and thin films were prepared by following a conventional coprecipitation and sol-gel dip coating techniques, respectively, at 400 to 800°C, and were thoroughly characterized by means of XRD, FT-IR, FT-Raman, DRS, UV-visible, BET surface area, zeta potential, flat band potential, and photocurrent measurement techniques. Photocatalytic abilities of Ni-doped TiO2 powders were evaluated by means of methylene blue (MB degradation reaction under simulated solar light. Characterization results suggest that as a dopant, Ni stabilizes TiO2 in the form of anatase phase, reduces its bandgap energy, and adjusts its flat band potentials such that this material can be employed for photoelectrochemical (PEC oxidation of water reaction. The photocatalytic activity and photocurrent ability of TiO2 have been enhanced by doping of Ni in TiO2. The kinetic studies revealed that the MB degradation reaction follows the Langmuir-Hinshelwood first-order reaction relationship.

  5. Praseodymium - A Competent Dopant for Luminescent Downshifting and Photocatalysis in ZnO Thin Films

    Science.gov (United States)

    Narayanan, Nripasree; Deepak, N. K.

    2018-05-01

    Highly transparent and conducting Zinc oxide (ZnO) thin films doped with Praseodymium (Pr) were deposited on glass substrates by using the spray pyrolysis method. The X-ray diffraction (XRD) analysis revealed the polycrystallinity of the deposited films with a hexagonal wurtzite structure, whereas the energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the incorporation of Pr in the films. The optical energy gap decreased by Pr doping due to the merging of the conduction band with the impurity bands formed within the forbidden gap. The room temperature photoluminescence spectra of the Pr-doped film showed enhancement of visible emission, suggesting efficient luminescent downshifting. The photocatalytic activity of the Pr-doped films is higher than that of undoped films due to the effective suppression of the rapid recombination of the photo-generated electron-hole pairs. The impurity levels formed within the forbidden gap act as efficient luminescent centers and electron traps, which lead to luminescent downshifting and enhanced photocatalytic activity.

  6. Photoelectrocatalytic Degradation of Organic Pollutants in Aqueous Solution Using a Pt-TiO2 Film

    Directory of Open Access Journals (Sweden)

    Chun He

    2009-01-01

    Full Text Available A series of Pt-TiO2 films with nanocrystaline structure was prepared by a procedure of photodeposition and subsequent dip-coating. The Pt-TiO2 films were characterized by X-ray diffraction, scanning electronic microscope, electrochemical characterization to examine the surface structure, chemical composition, and the photoelectrochemical properties. The photocatalytic activity of the Pt-TiO2 films was evaluated in the photocatalytic (PC and photoelectrocatalytic (PEC degradation of formic acid in aqueous solution. Compared with a TiO2 film, the efficiency of formic acid degradation using the Pt-TiO2 films was significantly higher in both the PC and PEC processes. The enhancement is attributed to the action of Pt deposits on the TiO2 surface, which play a key role by attracting conduction band photoelectrons. In the PEC process, the anodic bias externally applied on the illuminated Pt-TiO2 films can further drive away the accumulated photoelectrons from the metal deposits and promote a process of interfacial charge transfer.

  7. Demens Film

    DEFF Research Database (Denmark)

    Ridder, Hanne Mette Ochsner

    2012-01-01

    I forbindelse med opstarten af Demens Film projektet har der været nedsat en ekspertgruppe, som er kommet med en række anbefalinger omkring film til mennesker med demens. Anbefalingerne skal bruges i de næste faser af projektet. Deltagerne i ekspertgruppen var sammensat af en bred gruppe...... fagpersoner inde for forskellige fagområder. Læs mere om gruppens anbefalinger og sammensætning af ekspertgruppen i den kort rapport som er offentlig tilgængelig. Læs Ekspertgruppe anbefalingerne til Demens Film projekt....

  8. Self-organized nickel nanoparticles on nanostructured silicon substrate intermediated by a titanium oxynitride (TiNxOy interface

    Directory of Open Access Journals (Sweden)

    M. Morales

    2018-01-01

    Full Text Available In this work we report an experimental approach by combining in situ sequential top-down and bottom-up processes to induce the organization of nanosized nickel particles. The top-down process consists in xenon ion bombardment of a crystalline silicon substrate to generate a pattern, followed by depositing a ∼15 nm titanium oxynitride thin film to act as a metallic diffusion barrier. Then, metallic nanoparticles are deposited by argon ion sputtering a pure nickel target, and the sample is annealed to promote the organization of the nickel nanoparticles (a bottom-up process. According to the experimental results, the surface pattern and the substrate biaxial surface strain are the driving forces behind the alignment and organization of the nickel nanoparticles. Moreover, the ratio between the F of metallic atoms arriving at the substrate relative to its surface diffusion mobility determines the nucleation regime of the nickel nanoparticles. These features are presented and discussed considering the existing technical literature on the subject.

  9. Self-organized nickel nanoparticles on nanostructured silicon substrate intermediated by a titanium oxynitride (TiNxOy) interface

    Science.gov (United States)

    Morales, M.; Droppa, R., Jr.; de Mello, S. R. S.; Figueroa, C. A.; Zanatta, A. R.; Alvarez, F.

    2018-01-01

    In this work we report an experimental approach by combining in situ sequential top-down and bottom-up processes to induce the organization of nanosized nickel particles. The top-down process consists in xenon ion bombardment of a crystalline silicon substrate to generate a pattern, followed by depositing a ˜15 nm titanium oxynitride thin film to act as a metallic diffusion barrier. Then, metallic nanoparticles are deposited by argon ion sputtering a pure nickel target, and the sample is annealed to promote the organization of the nickel nanoparticles (a bottom-up process). According to the experimental results, the surface pattern and the substrate biaxial surface strain are the driving forces behind the alignment and organization of the nickel nanoparticles. Moreover, the ratio between the F of metallic atoms arriving at the substrate relative to its surface diffusion mobility determines the nucleation regime of the nickel nanoparticles. These features are presented and discussed considering the existing technical literature on the subject.

  10. Multifunctional Ceramic Nanostructure Thin Films Prepared by Solution Processing

    Science.gov (United States)

    Shim, Jong Hyun

    Oxide semiconductor coatings have been studied for the development of their nanostructures that can be tailored for multifunctional surface properties. We employed solution processing methods such as chemical bath deposition and hydrothermal process to deposit TiO2 and ZnO thin film nanostructures on various substrates including transparent conductive oxides (TCOs), polymers (polycarbonate, Teflon), and metals (stainless steels, Ti). In particular, low dimensional nanostructures (1D, 2D) were tailored by different solution process conditions. Especially, the 1D TiO2 nanorod structure were shown to grow via a non-classical crystallization way. The performances of vertically aligned TiO2 (rutile) nanorod thin films were evaluated for its use as a photoanode in dye sensitized solar cell (DSSC) and as a photocatalytic surface for organic dye degradation. In addition, densely packed 2-dimensional rutile nanoblade structure was examined for a high-k dielectric layer. And the vertically aligned ZnO nanorod thin films were grown as photocatalytic coatings and antimicrobial surfaces. The latter aspect resulted from the strong photocatalytic behavior, as well as the nanoshape effects. To control the nano- and microstructures of TiO2 and ZnO through process parameters, we used the degree of 'supersaturation' that was calculated from aqueous thermodynamics. When the thermodynamics data were not available, it was obtained through experimental measurements. In an effort to maximize the photo-responsive capacity, the hybrid structures consisting of TiO2/ZnO and ZnO/P3HT[Poly(3-hexylthiophene-2,5-diyl)] were investigated for further enhancement of the photoanode properties and photocurrent generation, respectively. This work shows that highly multifunctional oxide surface properties can be made possible through the developments of low-temperature, solution-grown nanostructures with precise process controls.

  11. Pulsed laser deposition of anatase thin films on textile substrates

    Energy Technology Data Exchange (ETDEWEB)

    Krämer, André; Kunz, Clemens; Gräf, Stephan; Müller, Frank A.

    2015-10-30

    Highlights: • Anatase thin films were grown on carbon fibre fabrics by pulsed laser deposition. • A novel Q-switched CO{sub 2} laser was utilised as radiation source. • Coated fibres exhibit photocatalytic activity and are resistant against bending. - Abstract: Pulsed laser deposition (PLD) is a highly versatile tool to prepare functional thin film coatings. In our study we utilised a Q-switched CO{sub 2} laser with a pulse duration τ ≈ 300 ns, a laser wavelength λ = 10.59 μm, a repetition frequency f{sub rep} = 800 Hz and a peak power P{sub peak} = 15 kW to deposit crystalline anatase thin films on carbon fibre fabrics. For this purpose, preparatory experiments were performed on silicon substrates to optimise the anatase deposition conditions including the influence of different substrate temperatures and oxygen partial pressures. Processing parameters were then transferred to deposit anatase on carbon fibres. Scanning electron microscopy, X-ray diffraction analyses, Raman spectroscopy and tactile profilometry were used to characterise the samples and to reveal the formation of phase pure anatase without the occurrence of a secondary rutile phase. Methanol conversion test were used to prove the photocatalytic activity of the coated carbon fibres.

  12. High-Quality Fe-doped TiO2 films with Superior Visible-Light Performance

    DEFF Research Database (Denmark)

    Su, Ren; Bechstein, Ralf; Kibsgaard, Jakob

    2012-01-01

    We report on high-quality polycrystalline Fe-doped TiO2 (Fe–TiO2) porous films synthesized via one-step electrochemical oxidation. We demonstrate that delicate properties such as the impurity concentration and the microstructure that strongly influence the performance of the material...... for photovoltaic and photocatalysis applications can be controlled by adjusting the electrolyte composition. Compared to Fe-doped TiO2 films prepared with traditional phosphate- or silicate-based electrolytes, our newly synthesised Fe–TiO2 films contain solely Fe dopants, which results in excellent photocatalytic...... and photovoltaic performance under visible light irradiation....

  13. Photocatalytic conversion of methane to methanol

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, C.E.; Noceti, R.P.; D`Este, J.R. [Pittsburgh Energy Technology Center, PA (United States)

    1995-12-31

    A long-term goal of our research group is the exploration of novel pathways for the direct oxidation of methane to liquid fuels, chemicals, and intermediates. The use of three relatively abundant and inexpensive reactants, light, water, and methane, to produce methanol is attractive. The products of reaction, methanol and hydrogen, are both commercially desirable, methanol being used as is or converted to a variety of other chemicals, and the hydrogen could be utilized in petroleum and/or chemical manufacturing. Methane is produced as a by-product of coal gasification. Depending upon reactor design and operating conditions, up to 18% of total gasifier product may be methane. In addition, there are vast proven reserves of geologic methane in the world. Unfortunately, a large fraction of these reserves are in regions where there is little local demand for methane and it is not economically feasible to transport it to a market. There is a global research effort under way in academia, industry, and government to find methods to convert methane to useful, more readily transportable and storable materials. Methanol, the initial product of methane oxidation, is a desirable product of conversion because it retains much of the original energy of the methane while satisfying transportation and storage requirements. Investigation of direct conversion of methane to transportation fuels has been an ongoing effort at PETC for over 10 years. One of the current areas of research is the conversion of methane to methanol, under mild conditions, using light, water, and a semiconductor photocatalyst. The use of three relatively abundant and inexpensive reactants, light, water, and methane, to produce methanol, is attractive. Research in the laboratory is directed toward applying the techniques developed for the photocatalytic splitting of the water and the photochemical conversion of methane.

  14. Nonthermal plasma assisted photocatalytic oxidation of dilute benzene

    Indian Academy of Sciences (India)

    mation of atomic oxygen; whereas ultraviolet light induced photocatalytic oxidation may be taking place with. TiO2 modified systems. Water vapour improved the selectivity to total oxidation. Keywords. Nonthermal plasma; sintered metal fibres; photocatalysis; ozone decomposition;. VOC abatement. 1. Introduction. Advanced ...

  15. Preparation, characterization and photocatalytic activity of TiO2 ...

    Indian Academy of Sciences (India)

    FT–IR, UV-Vis-NIR, XRD, SEM and TEM techniques were used to characterize the PANI/TiO2 core-shell nanocomposite. Photocatalytic activity of PANI/TiO2 nanocomposite was investigated under both UV and visible light irradiations and compared with unmodified TiO2 nanoparticles. Results indicated deposition of PANI ...

  16. Facile fabrication of highly flexible graphene paper for photocatalytic ...

    Indian Academy of Sciences (India)

    Administrator

    gold nano-catalytic systems because of their aggregation and tiny size for .... out of plane vibrations attributed to the presence of struc- ... during the photocatalytic oxidation were determined by. HPLC analysis. As shown in figure 5b, the relative reten- tion times (RRT) of chromatographic peak of pure 4-AP and 4-NP are ...

  17. Photocatalytic degradation of rhodamine B dye using hydrothermally ...

    Indian Academy of Sciences (India)

    The photocatalytic behaviour of the prepared ZnO was tested through the degradation of RB. The disappearance of organic molecules follows first-order kinetics. The effect of various parameters such as initial dye concentration, catalyst loading, pH of the medium, temperature of the dye solution, on the photo degradation of ...

  18. Visible light photocatalytic properties of novel molybdenum treated ...

    Indian Academy of Sciences (India)

    It was found that the photocatalytic degradation of a methylene blue solution could be attributed to the combined effects caused by the photo-degradation of titania, the electron assistance of carbon nanotube network, and the enhancement of molybdenum. The proposed redox mechanism of the photodegradation of ...

  19. Efficacy of photocatalytic HEPA filter on microorganism removal.

    Science.gov (United States)

    Chuaybamroong, P; Chotigawin, R; Supothina, S; Sribenjalux, P; Larpkiattaworn, S; Wu, C-Y

    2010-06-01

    This study assessed the application of photocatalytic oxidation (PCO) to the high efficiency particulate air (HEPA) filter for disinfection of airborne microorganisms. Experiments were conducted at two TiO2 loadings (1870 +/- 169 and 3140 +/- 67 mg/m(2)) on the HEPA filter irradiated with UV-A at the intensity of 0.85 +/- 0.18 or 4.85 +/- 0.09 mW/cm(2) under two relative humidity conditions (45 +/- 5% and 75 +/- 5%). Inactivation and penetration of four microorganisms were tested, including Aspergillus niger, Penicillium citrinum, Staphylococcus epidermidis, and Bacillus subtilis. It was found that microorganisms retained on a photocatalytic filter were inactivated around 60-80% and even 100% for S. epidermidis when the PCO reactions occurred. Lower penetration was also found from the photocatalytic filter for all airborne microorganisms. High humidity decreased photocatalysis efficacy. Increasing TiO2 loading or irradiance intensity did not substantially affect its disinfection capability. The high efficiency particulate air filter is used widely to remove particulates and microorganisms from the air stream. However, the filter may become a source of microbes if those retained microorganisms proliferate and re-entrain back into the filtered air. This study demonstrates that such a problem can be handled effectively by using photocatalytic reactions to inactivate those confined microorganisms. A 60-100% microbe reduction can be achieved for a wide variety of microorganisms to provide better indoor air quality for hospitals, offices, and domestic applications.

  20. Structural, magnetic and photocatalytic characterization of Bi1 ...

    Indian Academy of Sciences (India)

    47

    The UV–Vis absorption spectra were recorded on a Shimadzu UV-Vis-52550 spectrophotometer with the wavelength range of 200–700 nm. Photocatalytic activity of the synthesized Bi1-xLaxFeO3 nanoparticles was evaluated by the degradation of methylene blue (MB) in aqueous solution under visible light radiation.

  1. TiO₂-Based Photocatalytic Geopolymers for Nitric Oxide Degradation.

    Science.gov (United States)

    Strini, Alberto; Roviello, Giuseppina; Ricciotti, Laura; Ferone, Claudio; Messina, Francesco; Schiavi, Luca; Corsaro, Davide; Cioffi, Raffaele

    2016-06-24

    This study presents an experimental overview for the development of photocatalytic materials based on geopolymer binders as catalyst support matrices. Particularly, geopolymer matrices obtained from different solid precursors (fly ash and metakaolin), composite systems (siloxane-hybrid, foamed hybrid), and curing temperatures (room temperature and 60 °C) were investigated for the same photocatalyst content (i.e., 3% TiO₂ by weight of paste). The geopolymer matrices were previously designed for different applications, ranging from insulating (foam) to structural materials. The photocatalytic activity was evaluated as NO degradation in air, and the results were compared with an ordinary Portland cement reference. The studied matrices demonstrated highly variable photocatalytic performance depending on both matrix constituents and the curing temperature, with promising activity revealed by the geopolymers based on fly ash and metakaolin. Furthermore, microstructural features and titania dispersion in the matrices were assessed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) analyses. Particularly, EDS analyses of sample sections indicated segregation effects of titania in the surface layer, with consequent enhancement or depletion of the catalyst concentration in the active sample region, suggesting non-negligible transport phenomena during the curing process. The described results demonstrated that geopolymer binders can be interesting catalyst support matrices for the development of photocatalytic materials and indicated a large potential for the exploitation of their peculiar features.

  2. Preparation, characterization and photocatalytic activity of TiO2 ...

    Indian Academy of Sciences (India)

    , but it suffers from dissolution and photocatalytic degradation of the dyes (Min et al 2007). Conducting polymers with extended π-conjugated electron system and good environmental stability act as stable photo-sensitizer to sensitize TiO2 by ...

  3. Characterization and photocatalytic activity of Barkin-Ladi ilmenite ...

    African Journals Online (AJOL)

    Photocatalysis is an advanced oxidation process that can be carried out at room temperature under atmospheric pressure using atmospheric oxygen as the oxidant and the sun as the source of energy. This work focuses on the composition and photocatalytic activity of the raw and calcined samples of ilmenite ore obtained ...

  4. Structural, magnetic and photocatalytic characterization of Bi1 ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 40; Issue 1. Structural, magnetic and photocatalytic characterization of Bi 1 − x La x FeO 3 nanoparticles synthesized by thermal decomposition method. S M MASOUDPANAH S M MIRKAZEMI R BAGHERIYEH F JABBARI F BAYAT. Volume 40 Issue 1 February 2017 pp ...

  5. Understanding metal–organic frameworks for photocatalytic solar fuel production

    NARCIS (Netherlands)

    Garcia Santaclara, J.; Kapteijn, F.; Gascon Sabate, J.; van der Veen, M.A.

    The fascinating chemical and physical properties of MOFs have recently stimulated exploration of their application for photocatalysis. Despite the intense research effort, the efficiency of most photocatalytic MOFs for solar fuel generation is still very modest. In this highlight we analyse the

  6. Wirelessly powered ultraviolet light emitting diodes for photocatalytic oxidation

    NARCIS (Netherlands)

    Kuipers, J.; Bruning, H.; Yntema, D.R.; Rijnaarts, H.H.M.

    2015-01-01

    A method is presented to distribute small scale light sources in a photocatalytic slurry reactor. The goal of distributing the light sources is to increase photon transfer efficiency, and thereby increasing the reaction rate, compared to using one single light source. The light sources used in this

  7. [Detoxification of textile industry effluents by photocatalytic treatment].

    Science.gov (United States)

    Gebrati, L; Idrissi, L Loukili; Mountassir, Y; Nejmeddine, A

    2010-05-01

    In Morocco the textile industry, representing 31% of all Moroccan industries, is accompanied by high water consumption and important wastewater discharges rejected without any treatment. The focus of this study was to characterize the effluent from the textile industry, to test separately the effect of UV light and TiO2 catalyst and to determine the optimum conditions (pH, concentration and reaction time) in photocatalytic treatment to reduce chemical oxygen demand (COD) and colour. The biodegradability of the effluent was also studied using a toxicity test before and after treatment. After 90 min of reaction time at pH 4 and with 1.5 g F' of TiO2 catalyst, the photocatalytic treatment reached a global removal rate of 53% for COD and 89% for discoloration of the effluent. The relation BOD5/COD increased from around 0 to 0.3. The effluent became accessible to a biological treatment. The toxicity was studied by the Daphnia magna test over 24 hours. The results have shown the important toxicity of these effluents, which are rich in organic matter and other chemical compounds. After treatment by photocatalytic oxidation, the CI50 24 increased from 3.8% to 22.8%. This reduction of toxicity is related to the reduction of COD (53%) and colour (89%). Photocatalytic treatment has been shown to have an environmental benefit and, in combination with a secondary biological treatment, can be important for a significant reduction in the pollution of textile effluents.

  8. Enhanced photocatalytic properties in well-ordered mesoporous WO3

    KAUST Repository

    Li, Li

    2010-01-01

    We used polyisoprene-block-ethyleneoxide copolymers as structure-directing agents to synthesise well-ordered and highly-crystalline mesoporous WO 3 architectures that possess improved photocatalytic properties due to enhanced dye-adsorption in absence of diffusion limitation. © 2010 The Royal Society of Chemistry.

  9. Nonthermal plasma assisted photocatalytic oxidation of dilute benzene

    Indian Academy of Sciences (India)

    to utilize the UV light for photocatalytic decomposition of chlorinated VOCs.23. Benzene, a commonly used industrial solvent, whose abatement under dilute concentrations (<1000 ppm) may not be economical by conventional techniques. The present study was aimed at the total oxidation of dilute benzene in a DBD reactor.

  10. NOx photocatalytic degradation employing concrete pavement containing titanium dioxide

    NARCIS (Netherlands)

    Ballari, M.M.; Hunger, Martin; Hüsken, Götz; Brouwers, Jos

    2010-01-01

    In the present work the degradation of nitrogen oxides (NOx) by concrete paving stones containing TiO2 to be applied in road construction is studied. A kinetic model is proposed to describe the photocatalytic reaction of NOx (combining the degradation of NO and the appearance and disappearance of

  11. Transition metal oxide loaded MCM catalysts for photocatalytic ...

    Indian Academy of Sciences (India)

    Although several semiconductor mate- rials have been tested for the photocatalytic degrada- tion of dyes and other organic effluents, studies on TiO2 have always remained the primary focus.1 Several mod- ifications of TiO2 have also been carried out in order to enhance the quantum efficiency of the associated.

  12. Transition metal oxide loaded MCM catalysts for photocatalytic ...

    Indian Academy of Sciences (India)

    Nanoporous, high surface area compounds were obtained after calcination of the compounds. The catalysts were characterized by SEM, XRD, XPS, UV-vis and BET surface area analysis. The catalysts showed high activity for the photocatalytic degradation of both anionic and cationic dyes. The degradation of the dyes was ...

  13. Preparation, characterization and photocatalytic studies of Cu 2, Sn ...

    Indian Academy of Sciences (India)

    The precursor and substituted compounds were characterized by powder X-ray diffraction, FT-IR, SEM-EDS and UV-Vis diffuse reflectance spectra. Nitrogen substitution into K5Sb5P2O20 lattice was studied by O-N-H and XPS measurements. The photocatalytic activity of all the compounds was studied by degradation of ...

  14. Effect of metal ion doping on the photocatalytic activity of ...

    Indian Academy of Sciences (India)

    The activity can be enhanced by the increasing of concentration of the doped metal ions. TiAlPO-5 (4, 8, 12 atom % of Ti) showed the highest photocatalytic activity among all the compounds and its activity was compared to that of Degussa P25 (TiO2). The activity of photocatalysts was correlated with the diffuse reflectance ...

  15. Solar photocatalytic generation of hydrogen under ultraviolet-visible ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 33; Issue 1. Solar photocatalytic generation of hydrogen under ultraviolet-visible light irradiation on (CdS/ZnS)/Ag2S + (RuO2/TiO2) photocatalysts. R Priya S Kanmani. Catalysis Volume 33 Issue 1 February 2010 pp 85-88 ...

  16. Solar or UVA-Visible Photocatalytic Ozonation of Water Contaminants.

    Science.gov (United States)

    Beltrán, Fernando J; Rey, Ana

    2017-07-14

    An incipient advanced oxidation process, solar photocatalytic ozonation (SPO), is reviewed in this paper with the aim of clarifying the importance of this process as a more sustainable water technology to remove priority or emerging contaminants from water. The synergism between ozonation and photocatalytic oxidation is well known to increase the oxidation rate of water contaminants, but this has mainly been studied in photocatalytic ozonation systems with lamps of different radiation wavelength, especially of ultraviolet nature (UVC, UVB, UVA). Nowadays, process sustainability is critical in environmental technologies including water treatment and reuse; the application of SPO systems falls into this category, and contributes to saving energy and water. In this review, we summarized works published on photocatalytic ozonation where the radiation source is the Sun or simulated solar light, specifically, lamps emitting radiation to cover the UVA and visible light spectra. The main aspects of the review include photoreactors used and radiation sources applied, synthesis and characterization of catalysts applied, influence of main process variables (ozone, catalyst, and pollutant concentrations, light intensity), type of water, biodegradability and ecotoxicity, mechanism and kinetics, and finally catalyst activity and stability.

  17. INTEGRATION OF PHOTOCATALYTIC OXIDATION WITH AIR STRIPPING OF CONTAMINATED AQUIFERS

    Science.gov (United States)

    Bench scale laboratory studies and pilot scale studies in a simulated field-test situation were performed to evaluate the integration of gas-solid ultaviolet (UV) photocatalytic oxidation (PCO) downstream if an air stripper unit as a technology for cost-effectively treating water...

  18. Plant Leachate Nutrient Recovery with Biological, Thermal, and Photocatalytic Pretreatments

    Science.gov (United States)

    Wong, Les

    2015-01-01

    Plants are ideal for long term space travel: provide essential resources - oxygen, water, food; Water-soaked plants expel soluble nutrients in a leachate solution - toxins and wastes are also expelled and inhibit growth; biological, thermal, photocatalytic coupled with an acid digestion treatment will hopefully maximize recovery and remove wastes

  19. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  20. Tailoring the wettability of nanocrystalline TiO 2 films

    Science.gov (United States)

    Liang, Qiyu; Chen, Yan; Fan, Yuzun; Hu, Yong; Wu, Yuedong; Zhao, Ziqiang; Meng, Qingbo

    2012-01-01

    The water contact angle (WCA) of nanocrystalline TiO2 films was adjusted by fluoroalkylsilane (FAS) modification and photocatalytic lithography. FAS modification made the surface hydrophobic with the WCA up to ∼156°, while ultraviolet (UV) irradiation changed surface to hydrophilic with the WCA down to ∼0°. Both the hydrophobicity and hydrophilicity were enhanced by surface roughness. The wettability can be tailored by varying the concentration of FAS solution and soaking time, as well as the UV light intensity and irradiation time. Additionally, with the help of photomasks, hydrophobic-hydrophilic micropatterns can be fabricated and manifested via area-selective deposition of polystyrene particles.