Simple strategy for the construction of oxygen vacancies on α-MnO₂ catalyst to improve toluene catalytic oxidation

A strategy simple, safe and suitable for large scale production of α-MnO₂ catalyst with high activity in VOCs oxidation is crucial for its application. The catalytic reactivity of α-MnO₂ catalyst is largely related with its oxygen vacancy. Herein, we report effective construction of oxygen vacancies on α-MnO₂ through simply adjusting precipitation temperature of a redox precipitation process. The key role of surface oxygen vacancies in toluene oxidation and the formation of different amount and distribution of the oxygen vacancies over the α-MnO₂ catalysts were revealed by characterizations together with DFT calculations. The best catalyst (α-MnO₂-60) exhibited significantly improved catalytic activity of α-MnO₂ catalyst in toluene oxidation (T₉₀ = 203 ℃) and excellent water resistance. The richest surface oxygen vacancies of α-MnO₂-60 contributed to its best catalytic activity, despite of its relatively lower specific surface area. This work may provide a new perspective for the rational design of high efficient VOCs catalysts.