Study On The Modification Of CuO/Fe₂O₃ Catalyst For Water Gas Shift Reaction

With the increasing serious problems of environment pollution and the energy shortage becoming prominent,it is urgently to develop kinds of green clean energies.So far,hydrogen is widely recognised as.clean energy.Water gas shift reaction is able to generate hydrogen and decrease carbon monoxide.It is applied to not only generate hydrogen energy,but also decrease the content of CO in polymer electrolyte membrane fuel cell?PEMFC?to extend the lifetime of Pt electrode.As for the rapid development of fuel cell technology in recent years,traditional water gas shift reaction catalysts are already unable to meet the demand of fuel cell,and non-noble metal load on catalysts attract scientists' attention.Compared with noble catalysts,CuO/Fe₂O₃ catalyst is with well catalytic performance,and its materials are easy to obtain and cheap in price,with abundant of reserves.Therefore,we carried on the modification research on CuO/Fe₂O₃ catalyst in this paper.Different additives?transition metal oxide ZrO₂,ZnO and main group metal oxide Al₂O₃?were used to study the catalytic performance of CuO/Fe₂O₃ catalyst in water gas shift reaction?WGSR?.We explored the relationship between structure and performance of modified CuO/Fe₂O₃ catalyst,through the powder X-ray diffraction?XRD?,N₂ adsorption,Raman spectroscopy,N₂O decomposition,temperature-programmed reduction by hydrogen?H₂-TPR?and temperature-programmed desorption by carbon dioxide?CO₂-TPD?techniques.Firstly,the catalytic performance research for water gas shift reaction was carried on CuO/Fe₂O₃ catalyst by adding different contents of ZrO₂.A series of zirconia modified copper ferrite catalysts were synthesized by fractional precipitation.It found that the introduction of ZrO₂ decreased the synergistic interaction between copper and iron species in CuFe₂O₄,and decreased the number of strong basic sites on the surface.When the zirconia content was 1%,there were more reduction copper species,more weak basic sites,and less strong basic sites on the catalyst,which were able to provide more active sites on the surface,as a result,improved the catalytic performance for WGSR.Secondly,we studied the effect of main group metal oxide Al₂O₃-modified CuO/Fe₂O₃ catalysts in the water gas shift reaction.The results indicated that the appropriate introduction of Al₂O₃ could change part of the crystal structure of CuFe₂O₄,and the tetragonal CuFe₂O₄ was transferred to cubic phase.Besides,Al₂O₃ improved the Cu dispersion and reduction copper species in the catalysts,with better reducing properties.When the content of alumina was 10%,metal Cu was with small particle size,high dispersion,and there were more weak basic sites,presenting better catalytic activity and thermal stability.Lastly,we studied the catalytic effect of ZnO on Al₂O₃-modified CuO/Fe₂O₃ catalysts.A series of CuO/Fe₂O₃-Al₂O₃-ZnO catalysts were prepared by co-precipitation method.The characterization results indicated that zinc oxide was conducive to the formation of CuFe₂O₄ crystals,at the same time,the synergistic interaction between copper and iron species was weaken,with poor reducibility.Combined with the activity test,the sample CFAZ-2.5?ZnO 2.5 wt.%?exhibited better catalytic activity.This is closely related to its uniform pore size distribution,larger amounts of pores,more weak basic sites and less strong basic sites.