Cu-Cluster-Doped Monolayer MoCO (MXene) as an Electron Reservoir for Catalyzing a CO Oxidation Reaction.

The catalytic oxidation of CO on Cu-cluster-decorated pristine and defective MoCO (MXene) monolayers (Cu/p-MoCO and Cu/d-MoCO) was investigated by first-principles calculations. The stability of the designed catalysts was comprehensively demonstrated via analysis of the energies, geometry distortion, and molecular dynamics simulations at finite temperatures. The difference in the individual adsorption energies, as well as the oxidation and poisoning of Cu/p(d)-MoCO under CO and O gas atmospheres, was tested to estimate the catalytic ability. We found that Cu/d-MoCO might be a superior catalyst with good stability and reactivity for CO oxidation. The active sites of the Cu cluster acting as an electron reservoir governed its electron-donating and -accepting ability. Different adsorption configurations of O on Cu/d-MoCO also gave rise to different reaction activities. The facile rate-limiting energy barrier was attributed to the charge buffer capacity of the Cu cluster that mediates the reaction. Our results may provide clues to fabricate MXene-based materials by depositing small clusters on MXenes and exploring the advanced applications of these materials.