Effect of Preparation Method and Calcination Temperature on Low-Temperature CO Oxidation over Co3O4/CeO2Catalysts

Co3O4/CeO2 mixed oxides were prepared by coprecipitation–oxidation, homogeneous precipitation, and complexation–combustion methods. The catalysts were used to catalyze low-temperature CO oxidation under dry and humid conditions. The Co3O4/CeO2 catalyst that was prepared by the coprecipitation–oxidation method followed by calcination at 538 K exhibited excellent activity and good resistance to water vapor poisoning. Remarkably, CO conversion of 99% was achieved at a temperature as low as 196 K and was maintained for more than 400 min under dry condition. When the reaction was carried out at 298 K, CO conversion of 94% was obtained after running the reaction for 2400 min. Even when 3.1% steam was added, CO conversion of 79% could be maintained after 2400 min time-on-stream at 383 K. It is suggested that the strong interaction between Co3O4 and CeO2 is closely related to the preparation route and calcination temperature and plays a crucial role in the CO oxidation over the Co3O4/CeO2 catalysts.