Surface oxygen vacancy-dependent molecular oxygen activation for propane combustion over a -MnO2

Oxygen vacancies (O-V), as the sites of molecular oxygen adsorption and activation, play an important role in the catalytic combustion process of volatile organic compounds (VOCs). Revealing the relationship between O-V concentration and molecular oxygen activation behavior is of significance to construct the efficient catalysts. Herein, a-MnO2 with different O-V concentrations was prepared to investigate the molecular oxygen activation for C3H8 combustion. It is disclosed that the enhanced O-V concentration in a-MnO2 induced the reconfiguration of surface metal atoms, resulting in the transformation of oxygen activation configuration from end-on mode to side-on mode. Oxygen molecules in side-on mode possessed more localized electron density and weaker coordination bond strength with surrounding Mn atoms, which were more favorable to adsorb C3H8 molecules and activate C-H bond for the improved combustion performance. This work provides a new understanding to reveal that the increased O-V concentration contributes to more efficient VOCs combustion.