Effect of yttrium addition on water-gas shift reaction over CuO/CeO_2 catalysts

摘要

This paper presented a study on the role of yttrium addition to CuO/CeO2 catalyst for water-gas shift reaction. A single-step co-precipitation method was used for preparation of a series of yttrium doped CuO/CeO2 catalysts with yttrium content in the range of 0-5wt.%. Properties of the obtained samples were characterized and analyzed by X-ray diffraction(XRD) ,Raman spectroscopy,H2-TPR,cyclic voltammetry(CV) and the BET method. The results revealed that catalytic activity was increased with the yttrium content at first,but then decreased with the further increase of yttrium content. Herein,CuO/CeO2 catalyst doped with 2wt.% of yttrium showed the highest catalytic activity(CO conversion reaches 93.4% at 250 °C) and thermal stability for WGS reaction. The catalytic activity was correlated with the surface area,the area of peak γ of H2-TPR profile(i.e.,the reduction of surface copper oxide(crystalline forms) interacted with surface oxygen vacancies on ceria) ,and the area of peak C2 and A1(Cu0Cu2+ in cyclic voltammetry process) ,respectively. Besides,Raman spectra provided evidences for a synergistic Cu-Ovacancy interaction,and it was indicated that doping yttrium may facilitate the formation of oxygen vacancies on ceria.