Herein, combined computational and experimental studies are carried out to unravel the role of active center on C2H2 oxidation over Co3O4 catalysts. Density functional theory (DFT) studies indicate that Co2+ ions on Co3O4 (110)-A exhibit stronger reducibility than Co3+, and the oxygen species activated by Co2+ have better catalytic performance. On Co3O4 (110)-B surface, Co2+ ions represent the presence of oxygen vacancies. O2 can be adsorbed on oxygen vacancies and forms active O2- species, which can oxidize C2H2 to CO2 and H2O. Co3O4 catalysts with different Co2+ contents are prepared to experimentally verify the calculation results. The activity varies in the order of Co3O4-Sheets-reduction > Co3O4-Sheet > Co3O4-Sticks-reduction > Co3O4-Stick, which is in accordance with the trend of Co2+ contents. Further, microkinetic studies prove that the key of C2H2 oxidation is C-C dissociation. Decreasing C-C cleavage barrier will significantly enhance the overall reaction rates. Both of the computational and experimental results show that the presence of Co2+ on the surface of Co3O4 catalyst is the main contributing factor for the activity of the C2H2 oxidation. Minimal research has been reported on C2H2 oxidation. This may provide a guideline for eliminating the other volatile organic compounds over Co3O4 catalysts.

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