Exploring the reaction mechanism and kinetic properties of CO2 hydrogenation to methanol on Cu/CeO2

Abstract

CO2 hydrogenation to methanol using supported Cu-based catalysts is a key reaction for promoting carbon neutrality. Nevertheless, the reaction mechanism remains debated, particularly between the HCOO pathway involving a formate intermediate and the COOH route via a carboxyl intermediate. Therefore, density functional theory (DFT) calculations are employed in exploring the mechanism of CO2 hydrogenation to methanol on Cu/CeO2(100) catalyst. The results indicate that the HCOO route is thermodynamically more favorable than the COOH route. The key intermediate in the HCOO pathway is hydroxymethoxy (H2COOH*), which dissociates to form formaldehyde (H2CO*) as an intermediate, ultimately undergoing stepwise hydrogenation to produce methanol. Additionally, microkinetic analyses reveal the rate-determining step (RDS) in the reaction network and identify the HCOO route as the primary pathway for methanol synthesis on this catalyst.