Doping Effects on the Reactivity of the MVO₅^- (M = V-Zn) Clusters in CO Oxidation Reaction

Doped metal oxide catalysts have important applications in heterogeneous catalysis, whereas the fundamental effects of doping on the reactivity of catalysts are elusive. Herein, benefiting from the study of a series of atomic clusters MVO₅^- (M = V-Zn) in catalytic CO oxidation by molecular O₂ under thermal collision conditions, the crucial effects of doping on the electronic structure and then the catalytic reactivity of MVO₅^- were successfully rationalized by using mass spectrometry and theoretical calculations. We defined the energy gap of active orbitals that are closely related to electron transfer in MVO₅^- during CO oxidation. It was discovered that such an energy gap can modulate reaction thermodynamics, whereas the orbital overlap of MVO₅^- with CO controls the kinetics. The doped clusters MVO₅^- (M = Cr-Zn) have reduced energy gaps than that in host V₂O₅^-, and doping can modify the orbital overlap of MVO₅^- (M = Cr-Zn) with CO. Only the MnVO₅^- and ZnVO₅^- clusters that have rational energy gaps and proper orbital overlap with CO are catalytically reactive.