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 alpha-MnO2 catalyst with high activity in VOCs oxidation is crucial for its application. The catalytic reactivity of alpha-MnO2 catalyst is largely related with its oxygen vacancy. Herein, we report effective construction of oxygen vacancies on alpha-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 alpha-MnO2 catalysts were revealed by characterizations together with DFT calculations. The best catalyst (alpha-MnO2-60) exhibited significantly improved catalytic activity of alpha-MnO2 catalyst in toluene oxidation (T-90 = 203 degrees C) and excellent water resistance. The richest surface oxygen vacancies of alpha-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.

Automated summary

A strategy for large-scale production of high-activity alpha-MnO2 catalysts in VOCs oxidation is crucial. By adjusting the precipitation temperature, construction of oxygen vacancies on alpha-MnO2 has been achieved, improving its catalytic activity. The best catalyst, alpha-MnO2-60, showed significantly improved activity despite its lower specific surface area, highlighting the importance of surface oxygen vacancies in catalytic activity. This work offers insights for rational design of efficient VOCs catalysts.