CeO2-supported Fe, Co and Ni toward CO2 hydrogenation: Tuning catalytic performance via metal-support interaction

The chemical transformation of CO2 produces carbon compounds that can be used as precursors for the production of chemicals and fuels. Here, we investigated the activity and selectivity of the transition metals (Fe, Co, and Ni) supported on CeO2 catalyst for CO2 hydrogenation at atmospheric pressure. We found that Ni/CeO2 shows the highest CO2 conversion compared with Fe/CeO2 and Co/CeO2. Besides, Co/CeO2 and Ni/CeO2 exhibit nearly 100% CH4 selectivity while Fe/CeO2 inclines to produce CO. The characterization results show that the metal-support interaction order is Fe/CeO2 > Co/CeO2 > Ni/CeO2, the weak metal-support interaction over Ni/CeO2 benefits the activation of H2 and then promotes the activity of CO2 hydrogenation. Additionally, in situ DRIFTS results demonstrate that monodentate formate species rather than bidentate formate are the active intermediates. The main route of CO2 hydrogenation to CH4 is that CO2 is firstly transformed to m-HCOO∗ and then direct hydrogenation of the m-HCOO∗ to CH4. This study provides insights into the understanding of the mechanisms of CO2 hydrogenation on CeO2 based catalysts.