Effect of yttrium addition on water-gas shift reaction over CuO/CeO2 catalysts

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.