Mn1Zr O mixed oxides with abundant oxygen vacancies for propane catalytic oxidation: Insights into the contribution of Zr doping

Developing efficient non-noble catalysts for low-temperature catalytic oxidation of light alkane is highly desirable and challenging. Herein, we developed a Mn1ZrxOy mixed oxide catalyst via a co-precipitation method, finding a significant promotional effect of Zr doping on the catalytic activity of MnO2 for propane oxidation. It is unraveled that doping Zr into MnO2 lattice can lead to higher redox ability and oxygen mobility, more oxygen vacancies and enhanced acidity, which are positively responsible for catalytic activity. The kinetic studies and in-situ DRIFTs revealed that the Zr doping does not change the reaction pathway, but facilitates the adsorption and activation of propane and oxygen molecules, thus accelerating the catalytic reaction. In addition, the density functional theory (DFT) calculations further confirmed the contribution of Zr doping in the adsorption of reactant molecules and the formation of oxygen vacancies. Among all, the Mn1Zr0.10Oy catalyst exhibits the highest catalytic activity with the lowest activation energy, and its reaction rate reaches 1.34 μmol gcat.−1 s−1 at 245 °C, 8 times more than that of pure MnO2 catalyst. Moreover, the catalyst also displays good stability and reusability even under water vapor atmosphere.