Cu/CeO₂ Catalyst for Water-Gas Shift Reaction: Effect of CeO₂ Pretreatment

CuO/CeO₂ is a kind of promising catalysts for the water-gas shift (WGS) reaction. Efforts were put in to improve its performance through modification of CeO₂ support. In this study, portions of CeO₂ prepared by a co-precipitation method were separately annealed at 300 °C in air, under vacuum and with H₂ , and were used as supports for the fabrication of CuO/CeO₂ catalysts. The physicochemical properties of the catalysts were characterized by X-ray diffraction, N₂ -physisorption, inductively coupled plasma, Raman spectroscopy, CO₂ temperature-programmed desorption, and H₂ temperature-programmed reduction techniques. The relation between catalytic performances and physicochemical properties of the CuO/CeO₂ catalysts were discussed. Among the three catalysts, the one with CuO supported on H₂ -reduced CeO₂ shows the highest catalytic activity, mainly due to strong CuO-CeO₂ synergetic interaction and high concentration of Frenkel-type oxygen vacancies. The superior catalytic activities can also be attributed to the Cu⁰ crystals of small size and the oxygen vacancies in non-stoichiometric CeO_2-x .