| As a clean,efficient and pollution-free energy and energy carrier,hydrogen energy is the most ideal clean energy.However,at present,industrial hydrogen production is mainly through catalytic reforming of natural gas,which increases the consumption of fossil energy,while efficient and green hydrogen production can be achieved through biomass-based ethanol steam reforming technology.However,there are some key problems such as catalyst sintering,carbon deposition and excessive side reactions in ethanol steam reforming process.Aiming at these problems,this study synthesized clay-based molecular sieve using cheap and environmentally friendly attapulgite as raw material,and used it as a carrier to prepare nickel-based composite catalyst doped with different Ce-Zr content by sol-gel assisted impregnation method.Finally,various characterization methods were used to analyze the catalyst structure,catalytic performance and reaction mechanism.In addition,the effect of calcination temperature on catalytic performance was also investigated.The specific research contents and results are as follows:（1）In this paper,after hydrothermal treatment of attapulgite with hydrochloric acid,the silicon source was obtained,and clay-based molecular sieve carrier（AM）was successfully prepared by template method.XRD,N2 adsorption-desorption,HRTEM and other characterization methods were used to compare AM and commercial MCM-41 molecular sieves.The results showed that AM had the same pore structure as commercial MCM-41.（2）Ni-Ce-Zr composite catalyst（Nix Cey Zr/AM-600）doped with different Ce-Zr content was prepared by sol-gel assisted impregnation method using AM as support.The effects of Ce and Zr doping on the morphology,surface chemical state and reduction properties of the catalysts were investigated by N2 adsorption-desorption,XRD,XPS,CO2-TPD,O2-TPD,HRTEM and H2-TPR.The results show that appropriate Ce-Zr doping（2.5wt%）optimizes the electronic interaction between Ni/Ce/Zr components,and increases the concentration of metal Ni（Ni0）,oxygen vacancy（OV）and strong base site.Ni2.5Ce2.5Zr/AM-600 showed the best catalytic performance in ESR process（ethanol conversion and H2 yield of 95.0%and 64.6%,respectively）.（3）The Ni-Ce-Zr composite catalyst（Ni2.5Ce2.5Zr/AM-T）was prepared by sol-gel assisted impregnation method,and the effects of calcination temperature on the physicochemical properties of the catalyst were investigated by N2 adsorption-desorption,XRD,XPS,CO2-TPD,O2-TPD,HRTEM and H2-TPR.The results show that high calcination temperature will not only destroy the pore structure of the catalyst,but also cause the metal particles to aggregate,thus reducing the concentration of the active site on the surface of the catalyst,and eventually lead to the obvious deactivation of the catalyst after the reaction.The appropriate calcination temperature（600℃）optimized the electronic interaction between Ni/Ce/Zr components,increased the concentration of metal Ni,OV and strong base sites,and made the catalyst have the best catalytic performance and good stability in the ESR process.Figure[36]Table[13]Reference[94]... |
