Search results for "reforming"
showing 10 items of 18 documents
Photocatalytic solar light H2 production by aqueous glucose reforming
2018
A series of tungsten and nitrogen doped Pt-TiO2 samples were prepared with the aim to extend the TiO2 absorption to the visible light region and to enhance the separation efficiency of the photogenerated electron/hole pairs. The physicochemical features of the powders were characterized by Xray diffraction (XRD), UV/Vis reflectance spectra, specific surface area (SSA) determinations, and transmission electron microscopy (TEM) analyses. The influence of the presence of different doping agents was evaluated, under anaerobic conditions, in the aqueous photo-reforming of glucose to form H2 at ambient pressure and temperature under a halogen lamp or natural solar light irradiation. Arabinose, er…
Ni-Based Catalysts for Low Temperature Methane Steam Reforming: Recent Results on Ni-Au and Comparison with Other Bi-Metallic Systems
2013
Steam reforming of light hydrocarbons provides a promising method for hydrogen production. Ni-based catalysts are so far the best and the most commonly used catalysts for steam reforming because of their acceptably high activity and significantly lower cost in comparison with alternative precious metal-based catalysts. However, nickel catalysts are susceptible to deactivation from the deposition of carbon, even when operating at steam-to-carbon ratios predicted to be thermodynamically outside of the carbon-forming regime. Reactivity and deactivation by carbon formation can be tuned by modifying Ni surfaces with a second metal, such as Au through alloy formation. In the present review, we su…
Photocatalytic H2 evolution from aqueous solutions of oxygenated organic compounds in the presence of C3N4/reduced graphene oxide based photocatalysts
2022
Composites of C3N4/reduced graphene oxide have been used as a cheap and promising photocatalysts for triethanolamine and ethanol photo-reforming with H2 generation in aqueous solution. The rate of H2 production over the best performing photocatalysts reached 1,415 μmol·h-1·g-1 which increases up to 57,306 in the presence of 1% of Pt. The apparent quantum efficiency of the optimal material was 7 % by using both LED and natural sunlight irradiation
Photoreforming of organics in aqueous suspension of Nb2O5/C3N4 composites to obtain H2
2023
Photocatalysis based on the use of semiconductors has gained, during the recent years, increased attention as promising sustainable process for H2 and fine chemicals production, given the possibility of activating such photocatalysts by visible light radiation. The photo-reforming activity in this work has been measured under both UV-LED irradiation and natural sunlight illumination. Moreover, the presence of metallic Pt as co-catalysts has been studied. Carbon nitride (C3N4) based materials are good candidates for solar energy conversions. The choice of C3N4 and Nb2O5 arises from the fact that their heterojunction can lead to lower recombination between the photo-generated electrons and ho…
Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations
2017
Under the water-rich pre-treatment and/or reaction conditions, structure and chemistry of the monoclinic zirconia surfaces are strongly influenced by oxygen vacancies and incorporated water. Here, we report a combined first-principles and atomistic thermodynamics study on the structure and stability of selected surfaces of the monoclinic zirconia. Our results indicate that among the studied surfaces, the most stable (111) surface is the least vulnerable towards oxygen vacancies in contrast to the less stable (011) and (101) surfaces, where formation of oxygen vacancies is energetically more favorable. Furthermore, we present a vigorous, systematic screening of water incorporation onto the s…
In situ ATR-IR studies in aqueous phase reforming of hydroxyacetone on Pt/ZrO2 and Pt/AlO(OH) catalysts: The role of aldol condensation
2018
Abstract In situ Attenuated Total Reflection Infrared (ATR-IR) spectroscopy was used to study Aqueous Phase Reforming of hydroxyacetone on Pt/AlO(OH) and Pt/ZrO2 catalysts at 230 °C/ 30 bar. Formation of strongly adsorbed aldol condensation products was observed on the surface of Pt/ZrO2 and ZrO2 in contrast to Pt/AlO(OH) and AlO(OH). Peak assignments were supported by DFT calculations of the IR spectra of the condensation products in vacuum and in the presence of water. Aldol condensation of hydroxyacetone leading to compounds with high molecular weight with unsaturated bonds was suggested as a first step in coke formation. Carbonaceous deposits on the surface of the ZrO2 support are oxyge…
Overview on photoreforming of biomass aqueous solutions to generate H2 in the presence of g-C3N4 based materials
2023
Photoreforming (PR) of biomass can be considered a viable technology under mild experimental conditions to produce hydrogen with a high reaction rate using compounds from renewable resources and waste materials. The application of biomass PR gives rise to both hydrogen generation and biomass waste valorization. The process could be scaled up to obtain hydrogen under natural sunlight irradiation, and research on polymeric carbon nitride (g-C3N4)-based photocatalysts has been widely carried out in recent years. The non-metallic-based carbon nitride materials are economical and (photo)stable polymer semiconductors, and their physicochemical surface and electronic properties are optimal for obt…
Study of the synergistic interaction between nickel, gold and molybdenum in novel modified NiO/GDC cermets, possible anode materials for CH4 fueled S…
2013
Abstract The present study concerns the structural and physicochemical characterization of novel Au–Mo–NiO/GDC cermets, alongside with measurements of their carbon tolerance. This is an investigation on whether commercially available NiO/GDC powder that is modified with Au and/or Mo can yield possible electrocatalysts as anodes for CH4 fueled SOFCs. Specifically, the performed preparation methods of deposition-precipitation and deposition-coprecipitation permitted the modification of a commercial electrocatalyst and lead to cermets that exhibit different reaction kinetics for the catalytic dissociation of CH4 and different performance for CH4 steam reforming. The most interesting structural…
Researches on the Alternative Fuels Which Can Be Used to Motors
2010
The alternative fuels are substances or materials used as fuel, other than the old conventional fuels (oil, natural gases and coals). 
 The paper analyses the most important alternative fuels, such as: bio-diesel, alcohols and hydrogen, presenting at each category the main important characteristics, the advantages and disadvantages presented by them. 
 The methyl-ester which is known as bio-diesel can be used in all motors with ignition by compression, alone or mixed in any proportion with oil, with minor modifications at the injection system. Bio-diesel fuel assures the same motor power as oil does, having even a bigger cetanic number than the usual oil. After tests, it was obser…
Screening of ceria-based catalysts for internal methane reforming in low temperature SOFC
2010
Gaudillere, Cyril Vernoux, Philippe Mirodatos, Claude Caboche, Gilles Farrusseng, David 6th World Congress on Oxidation Catalysis (6WCOC) JUL 05-10, 2009 Lille, FRANCE; International audience; Ceria-based catalysts have been assessed for internal methane reforming at low temperature (400-600 C) in Solid Oxide Fuel Cell (SOFC) A combinatorial library of 15 metal (Cu Pt Ni) supported ceria was prepared using wet impregnation method The ceria-based oxides are undoped or doped with metal transition (Zr) or by rare earth (Gd or Pr) The effect of the metal the dopant and the surface area on the catalytic performances was investigated in high-throughput manner using a 16-parallel reactor The catal…