Construction of oxygen vacancies in δ-MnO2 for promoting low-temperature toluene oxidation

Oxygen vacancy engineering is a proven method to promote catalytic performance. In this paper, a series of alkaline earth metal-doped layered MnO2 catalysts were prepared to modulate the oxygen vacancies in MnO2 and applied to catalytic oxidation of toluene at low-temperature. Various characterizations and DFT calculations show that the alkaline earth metals enter the MnO2 lattice, leading to the distortion of the lattice and the formation of oxygen vacancies, which eventually lead to the activation of the lattice oxygen. Ba-doped MnO2 shows the highest content of oxygen vacancies and the highest lattice oxygen activity, thus exhibiting the best low-temperature catalytic performance for toluene (T90 = 182 °C). This work provides an innovative approach for the construction of oxygen vacancies on high-performance catalysts for toluene oxidation.