课题组通过沉淀法制备了一系列不同价电子结构的Mn_xO_y（Mn₃O₄、MnO₂和Mn₂O₃）催化剂并用于空气中甲苯催化氧化去除研究。在甲苯催化氧化反应中，MnO₂催化剂的本征活性（R_S，1.14×10^-9 mol·m^-2·s^-1）优于Mn₃O₄（0.54×10^-9 mol·m^-2·s^-1）和Mn₂O₃（0.45×10^-9 mol·m^-2·s^-1）催化剂。实验表征和DFT计算结果表明，Mn_xO_y催化剂Mn的d带中心可能是其催化本征活性的决定性因素。与Mn₃O₄（-1.25 eV）和Mn₂O₃（-1.59 eV）相比，MnO₂（-1.03 eV）具有更高的催化氧化活性，可归因于其更高的d带中心。较高的d带中心可以减弱表面Mn-O键的强度（k = 290.9 N/m），同时也能增强表面对气态O₂的吸附，从而增强表面晶格氧的迁移能力和吸附氧物种的量。本研究揭示了Mn基氧化物催化剂催化氧化活性与d电子结构的内在关系，可为催化氧化高性能催化剂的设计提供新的见解。

Jia Zeng (曾嘉), Sijia Song, Shuang Chen, Guizhi Zhang, Hongmei Xie, Guilin Zhou*. Comparative study of Mn oxide catalysts on toluene oxidation: The effect of Mn valence electronic structures [J]. Journal of Environmental Chemical Engineering, 2024, 12, 112780. https://doi.org/10.1016/j.jece.2024.112780

Understanding the structure-activity relationship of Mn-based oxide catalysts is of great importance for the rational development of highly performance catalysts for VOCs catalytic oxidation. However, the knowledge of the electronic structure-catalytic oxidation activity relationship over Mn-based oxide catalysts is still limited. Herein, we investigated the typical Mn_xO_y (Mn₃O₄, MnO₂, and Mn₂O₃) with different valence electronic structures by using various characterizations and DFT calculations. The MnO₂ exhibits superior intrinsic activities (R_S, 1.14×10^-9 mol·m^-2·s^-1) when compared with Mn₃O₄ (0.54×10^-9 mol·m^-2·s^-1) and Mn₂O₃ (0.45×10^-9 mol·m^-2·s^-1) for toluene catalytic oxidation. The solid experimental and DFT calculation results show that the d-band center of Mn determines the intrinsic activity. The superior catalytic oxidation activity of MnO₂ can be attributed to its higher d-band center (-1.03 eV) in comparison with that of Mn₃O₄ (-1.25 eV) and Mn₂O₃ (-1.59 eV). The higher d-band center can weaken the surface Mn-O bonds strength (k = 290.9 N/m) and strengthen the gaseous O₂ adsorption simultaneously, then enhancing the mobility of surface lattice oxygen and the amount of adsorbed oxygen species. This work firstly reveals the intrinsic relationship between catalytic oxidation activity and d electronic structure over Mn-based oxide catalysts and provides knowledge that will advance the design of high-performance catalysts for catalytic oxidation.