福州大学化学学院王心晨研究组揭示了二氧化钛光催化剂上氧空位增强苯氧化制苯酚的选择性。2025年2月17日出版的《德国应用化学》杂志发表了这项成果。

在此，该课题组证明了在TiO₂表面引入丰富的氧空位（OVs）有助于通过双电子还原过程而不是单电子还原过程激活O₂。这有效地抑制了·O^2-的生成，从而减少了苯酚的分解，显著提高了选择性。此外，这些OVs可以捕获电子以促进电荷分离，并作为O₂活化的吸附位点。因此，在TiO₂表面引入丰富的OVs不仅提高了苯酚收率，而且重要地提高了对苯酚的选择性。这一发现丰富了他们对OVs如何影响反应途径和产物选择性的理解，为设计和定制用于选择性有机氧化的富OVs光催化剂提供了有价值的见解。

据悉，光催化氧化苯制苯酚是一种很有前途的替代传统异丙苯工艺的方法。然而，由于超氧自由基（·O2-）的开环反应，对苯酚的选择性往往较差，这主要是由O₂的单电子还原产生的。

附：英文原文

Title: Oxygen Vacancy-Enhanced Selectivity in Aerobic Oxidation of Benzene to Phenol over TiO₂ Photocatalysts

Author: Shengyang Zhong, Dexi Yu, Yuhui Ma, Yuhong Lin, Xiaoyi Wang, Zhenzhen Yu, Meirong Huang, Yidong Hou, Masakazu Anpo, Jimmy C. Yu, Jinshui Zhang, Xinchen Wang

Issue&Volume: 2025-02-17

Abstract: Photocatalytic oxidation of benzene to phenol using molecular O₂ is a promising alternative to the traditional cumene process. However, the selectivity toward phenol is often poor due to the ring-opening reaction induced by the superoxide radical (·O^2-), which is predominantly produced from the single-electron reduction of O₂. Herein, we demonstrate that introducing abundant oxygen vacancies (OVs) on the surface of TiO₂ facilitates the activation of O₂ through a two-electron reduction process instead of a single-electron reduction. This effectively suppresses the generation of·O^2-, thereby reducing phenol decomposition and significantly enhancing the selectivity. In addition, these OVs can trap the electrons to promote chare separation and serve as the adsorption sites for O₂ activation. As a result, the introduction of abundant OVs on the surface of TiO₂ not only enhances phenol yield but also importantly improves selectivity toward phenol. This finding enriches our understanding of how OVs influence reaction pathways and product selectivity, providing valuable insights for the design and tailoring of OV-rich photocatalysts for selective organic oxygenations.

DOI: 10.1002/anie.202502823

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202502823