Construction of surface active centers on the mesoporous Co/CeO2-δ catalysts for CO2 hydrogenation

The surface active centers, which include metal Co, surface oxygen vacancies, and Co0–CeO2-δ interface structures, can be constructed on the mesoporous Co/CeO2-δ catalysts by wet impregnation method. And the surface active centers can be regulated by the Co species dosage. The interaction between the metal Co and CeO2-δ can promote surface oxygen vacancies and Co0–CeO2-δ interface structures to be formed and be conducive to inhibit the aggregation and sintering of Co species in high temperature environment. The prepared Co/CeO2-δ catalysts have better catalytic performances for CO2 hydrogenation than the single component Co and CeO2-δ catalysts, which can be attributed to the synergistic effect between Co0 active centers, surface oxygen vacancies, and Co0–CeO2-δ interface structures. Therefore, the Co/CeO2-δ catalysts have strong adsorption and activation ability for reactant CO2 and H2 molecules to improve the CO2 hydrogenation activity. At atmospheric pressure and 400 °C, the CO2 conversion and CH4 selectivity on the Co/CeO2-δ catalyst with Co loading of 12% could reach 59.7% and 95.7%, respectively, and maintained good stability in 9 cycles for CO2 hydrogenation reaction.