Metal organic frameworks derived metal oxides prepared by oxygen vacancy engineering with the enhanced catalytic activity for toluene oxidation

Herein, MnOx catalysts were prepared by in situ pyrolysis of Mn metal organic frameworks (Mn-MOF). The Mn-5TA with proper doping of tartaric acid (Mn-MOF/ tartaric acid mass ratio of 5), exhibited superior catalytic activity and stability towards catalytic removal of toluene under simulated real-exhaust conditions. Mn3+ and oxygen vacancies were beneficial for toluene degradation, whereas Mn3+ can generate oxygen vacancies to maintain charge conservation and then responsible for toluene adsorption and generation of intermediates. In addition, the oxygen vacancies were explored by EPR, Raman and O2-TPD. Compared with other catalysts, Mn-5TA has higher oxygen vacancy contents. Meanwhile, in-situ DRIFTS also indicated that oxygen vacancies could play a key role in the adsorption-oxidation process of toluene. Therefore, the present study provides a simple method to introduce and control the content of oxygen vacancies, and the obtained results provide a new strategy for the rational design of efficient catalytic materials for the elimination of volatile organic compounds.