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

Abstract

The oxygen vacancies are significant defects that serve as reactive sites in several catalytic reactions. The CO₂ 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_0.90RE_0.10O_δ (RE = rare earth element) catalysts to boost catalytic activity of CO₂ 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_0.90Y_0.10O_δ catalyst demonstrated the greatest density of oxygen vacancies and optimal CO₂ methanation performance. The CO₂ conversion and CH₄ selectivity achieved 84.6 % and 99.8 % at 270 °C, respectively. In situ DRIFTS revealed Ni/Ce_0.90Y_0.10O_δ catalyst enhanced the formate pathway. These results can provide better guidance for CO₂ utilization technology to develop more efficient catalysts.