National Engineering Laboratory for VOCs Pollution Control Material & Technology, Chengdu Institute of Organic Chemistry, Chinese Academy of Science, Chengdu, 610041, China; University of Chinese Academy of Science, Beijing, 100049, China.
Key Laboratory of Catalysis Science and Technology of Chongqing Education Commission, Department of Chemical Engineering, Chongqing Technology and Business University, Chongqing, 400067, China.
Chemosphere. 2022 Mar;291(Pt 3):132890. doi: 10.1016/j.chemosphere.2021.132890. Epub 2021 Nov 18.
In order to clarify the role of oxygen vacancy (OV), five α-MnO catalysts with abundant OVs are fabricated via a novel and facile redox-precipitation approach and employed to the toluene oxidation in air. The concentration of OVs in α-MnO catalysts is regulated via the alkyl chain length of alcohols, and its correlation with catalytic performances is scientifically investigated based on various characterization technologies and density functional theory (DFT) calculation. The α-MnO-C2 catalyst exhibits excellent catalytic activity (T = 217 °C), stability, and water resistance for toluene oxidation in air. The OVs can induce the new bandgap states (BGS), which upshift the antibonding orbitals relative to the Fermi level (E), eventually favoring the formation of adsorbed active oxygen species. Furthermore, the OVs cause an increase in the amount of Mn, resulting in the elongated Mn-O bonds due to the strong Jahn-Teller effect of Mn. Therefore, the synergistic effects of OVs benefit toluene oxidation through L-H and MvK mechanisms over the prepared α-MnO-Cx catalysts. This work reveals the important role of OVs in the promotion of toluene catalytic oxidation activity and also may provide new insights for the design of high-performance VOCs oxidation elimination catalyst.
为了阐明氧空位（OV）的作用，通过一种新颖且简便的氧化还原沉淀方法制备了具有丰富 OV 的五种α-MnO 催化剂，并将其用于空气中的甲苯氧化。α-MnO 催化剂中 OV 的浓度通过醇的烷基链长度来调节，并基于各种表征技术和密度泛函理论（DFT）计算对其与催化性能的相关性进行了科学研究。α-MnO-C2 催化剂在空气中的甲苯氧化中表现出优异的催化活性（T=217°C）、稳定性和耐水性。OV 可以诱导新的带隙态（BGS），使反键轨道相对于费米能级（E）向上移动，最终有利于吸附活性氧物种的形成。此外，OV 会导致 Mn 的数量增加，由于 Mn 的强 Jahn-Teller 效应，导致 Mn-O 键伸长。因此，OV 的协同效应通过 L-H 和 MvK 机制有益于在制备的α-MnO-Cx 催化剂上进行甲苯氧化。这项工作揭示了 OV 在促进甲苯催化氧化活性方面的重要作用，也可能为设计高性能 VOCs 氧化消除催化剂提供新的思路。
