Revealing high-efficiency of toluene catalytic oxidation on rod-like Mn₃O₄@MnO₂ catalyst

Mn-based compound oxides have been considered potential alternatives for the removal of volatile organic compounds (VOCs), and further improving their catalytic performance remains a current challenge. Herein, a series of bi-component Mn₃O₄@MnO₂ catalysts are synthesized through in situ oriented topotactic growth of δ-MnO₂ on Mn₃O₄ support, where Mn₃O₄ morphologies are precisely controlled by hydrothermal temperature. Among the synthesized catalysts, rod-like Mn₃O₄@MnO₂ exhibits superior catalytic performance for toluene oxidation, with the specific reaction rate 3.71 times higher than that of octahedron-like Mn₃O₄@MnO₂ at 220 °C. In comparison with octahedron-like sample, the interaction between rod-like Mn₃O₄ and MnO₂ can weaken Mn-O bond strength, which enhances reducibility at low temperature. In addition, the generation and consumption rates of benzoate are also markedly accelerated on rod-like Mn₃O₄@MnO₂ catalyst. Furthermore, rod-like Mn₃O₄@MnO₂ exhibits good long-time reaction stability. These results provide valuable guidance for designing Mn-based bicomponent catalysts for efficient VOCs oxidation.