Superior performance of α@β-MnO2 for the toluene oxidation: Active interface and oxygen vacancy

By Na Huang, Z. Qu, C. Dong, Yuanhang Qin, Xiaoxiao Duan. Applied Catalysis A : General, 2018

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Abstract The crystalline phase of manganese dioxide catalysts shows strong influence on its catalytic performance, and the construction of hierarchically nanostructured materials with active interface and oxygen vacancy is an effective approach to develop the enhanced functionality. Herein, nanosized MnO 2 catalysts with α-, β- and hierarchically α@β-crystal phases were synthesized. α@β-MnO 2 catalysts showed the excellent activity than pure MnO 2 in toluene combustion, either α-MnO 2 or β-MnO 2. The catalytic activity was strongly related with the ratio of α-MnO 2 and β-MnO 2 in α@β-MnO 2 catalyst, and α@β-MnO 2 (1:1) exhibited the highest activity for toluene oxidation and toluene can be completely oxidized to CO 2 and H 2 O at about 205 °C with a space velocity (GSHV) of 30,000 h −1 . HRTEM, Raman and XPS demonstrated that α@β-MnO 2 owned the abundant defects due to the mixed phase interfacial structure. The strong synergistic effect in α@β-MnO 2 catalyst with larger specific area enhanced and facilitated the adsorption and activation of toluene molecules and oxygen species. The mobility of oxygen species and low-temperature reducibility compared with pure MnO 2 were significantly enhanced. When the ratio of α-MnO 2 and β-MnO 2 was 1:1, α@β-MnO 2 reached the maximum biphase interface content, formed large amount of oxygen vacancy, and showed the strongest synergistic effect and activation ability for reactants. Thus it was thought that the formation of the special biphase structure of α@β-MnO 2 was beneficial to the improvement of toluene catalytic oxidation activity.

Subfields: Catalysis, Materials Chemistry, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/844608c3f2b5af7622dc96edf7e8005e44a44a8a