Boosting the CO2 methanation over Ni/Ce0.90RE0.10Oδ by regulating of oxygen vacancy density

• Regulating the local microelectronic structure of catalyst by doping engineering. • Compared Ni/CeO 2 , Y element can make the catalyst produce the highest oxygen vacancy concentration and the strongest MSI effect. • Ni/Ce 0.90 Y 0.10 O δ catalyst with more oxygen vacancy sites follows formate route at lower temperature, promoting the conversion of more bicarbonate and formate. The oxygen vacancies are significant defects that serve as reactive sites in several catalytic reactions. The CO 2 methanation catalysts were facilely designed through tailoring the local electron density on oxygen vacancies by introducing different electron acceptors (Pr, La and Y). We prepared a series of Ni/Ce 0.90 RE 0.10 O δ (RE = rare earth element) catalysts to boost catalytic activity of CO 2 methanation at low temperature. It demonstrated the concentration of oxygen vacancies could be significantly regulated by doping strategy, hence altering the local microelectronic structure of catalyst and strengthening the MSI effect. The Ni/Ce 0.90 Y 0.10 O δ catalyst demonstrated the greatest density of oxygen vacancies and optimal CO 2 methanation performance. The CO 2 conversion and CH 4 selectivity achieved 84.6 % and 99.8 % at 270 °C, respectively. In situ DRIFTS revealed Ni/Ce 0.90 Y 0.10 O δ catalyst enhanced the formate pathway. These results can provide better guidance for CO 2 utilization technology to develop more efficient catalysts.