Cu₃-Cluster-Doped Monolayer Mo₂CO₂ (MXene) as an Electron Reservoir for Catalyzing a CO Oxidation Reaction

The catalytic oxidation of CO on Cu₃-cluster-decorated pristine and defective Mo₂CO₂ (MXene) monolayers (Cu₃/p-Mo₂CO₂ and Cu₃/d-Mo₂CO₂) 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 Cu₃/p(d)-Mo₂CO₂ under CO and O₂ gas atmospheres, was tested to estimate the catalytic ability. We found that Cu₃/d-Mo₂CO₂ might be a superior catalyst with good stability and reactivity for CO oxidation. The active sites of the Cu₃ cluster acting as an electron reservoir governed its electron-donating and -accepting ability. Different adsorption configurations of O₂ on Cu₃/d-Mo₂CO₂ also gave rise to different reaction activities. The facile rate-limiting energy barrier was attributed to the charge buffer capacity of the Cu₃ 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.