Abstract Despite of considerable efforts on the MnO2-based catalytic combustion, the different structural and component requirements of MnO2 for gas-phase selective oxidation and complete oxidation largely remain unknown. By comparing four types of MnO2 with different crystal structures (α, β, γ and δ), γ-MnO2 was found to be the most efficient catalyst for both aerobic selective oxidation of ethanol and CO oxidation. The structural effect of γ-MnO2 was further investigated by doping metal ions into the framework and by comparing the catalytic performance in the gas-phase aerobic oxidation of CO and ethanol. Among ten M-γ-MnO2 catalysts, Zn-γ-MnO2 showed the lowest temperature (160 °C) for achieving 90% CO conversion. The CO oxidation activity of the M-γ-MnO2 catalysts was found to be more relevant to the surface acidity-basicity than the reducibility. In contrast, surface reducibility has been demonstrated to be more crucial in the gas-phase ethanol oxidation. Cu-γ-MnO2 with higher reducibility and more oxygen vacancies of Mn2+/Mn3+ species exhibited higher catalytic activity in the selective ethanol oxidation. Cu-γ-MnO2 achieved the highest acetaldehyde yield (75%) and space-time-yield (5.4 g gcat–1 h–1) at 200 °C, which are even comparable to the results obtained by the state-of-the-art silver and gold-containing catalysts. Characterization results and kinetic studies further suggest that the CO oxidation follows the lattice oxygen-based Mars-van Krevelen mechanism, whereas both surface lattice oxygen and adsorbed oxygen species involve in the ethanol activation.

中文翻译：

---

阐明金属掺杂 γ-MnO2 上气相选择性乙醇氧化和 CO 氧化的结构-性能相关性

摘要 尽管在基于 MnO2 的催化燃烧方面做出了相当大的努力，但用于气相选择性氧化和完全氧化的 MnO2 的不同结构和组分要求在很大程度上仍然未知。通过比较具有不同晶体结构（α、β、γ 和 δ）的四种类型的 MnO2，发现 γ-MnO2 是乙醇有氧选择性氧化和 CO 氧化的最有效催化剂。通过将金属离子掺杂到骨架中并比较CO和乙醇气相好氧氧化的催化性能，进一步研究了γ-MnO2的结构效应。在十种 M-γ-MnO2 催化剂中，Zn-γ-MnO2 显示出实现 90% CO 转化率的最低温度（160 °C）。发现 M-γ-MnO2 催化剂的 CO 氧化活性与表面酸碱性比还原性更相关。相比之下，表面还原性已被证明在气相乙醇氧化中更为重要。Cu-γ-MnO2 具有更高的还原性和更多的 Mn2+/Mn3+ 物种的氧空位，在选择性乙醇氧化中表现出更高的催化活性。Cu-γ-MnO2 在 200 °C 下实现了最高的乙醛产率 (75%) 和时空产率 (5.4 g gcat-1 h-1)，这甚至可以与最新的研究结果相媲美。 -art 含银和金的催化剂。表征结果和动力学研究进一步表明，CO 氧化遵循晶格氧基 Mars-van Krevelen 机制，