Su Kangrui, Zheng Lingcheng, Liu Mei, Gao Juan, Shi Zeyu, Chen Changzhao, Li Yang, He Jie, Peng Mao
School of Mechanics and Photoelectric Physics, Anhui University of Science and Technology, Huainan, 232001, P. R. China.
The First Affiliated Hospital of Anhui University of Science and Technology (Huainan First People's Hospital), Huainan, 232001, P. R. China.
Small. 2024 Dec;20(51):e2405551. doi: 10.1002/smll.202405551. Epub 2024 Oct 2.
Oxygen vacancies (OVs) are widely considered as active sites in photocatalytic reactions, yet the crucial role of OVs in S-scheme heterojunction photocatalysts requires deeper understanding. In this work, OVs at hetero-interface regulated S-scheme BiVO-OVs/g-CN photocatalysts are constructed. The Fermi-level structures of BiVO and g-CN lead to a redistribution of charges at the heterojunction interface, inducing an internal electric field at the interface, which tends to promote the recombination of photogenerated carriers at the interface. Importantly, the introduction of OVs induces defect electronic states in the BiVO bandgap, creating indirect recombination energy level that serves as crucial intermediator for photogenerated carrier recombination in the S-scheme heterojunction. As a result, the photocatalytic degradation rate on Rhodamine B (RhB) and tetracyclines (TCs) for the optimal sample is 10.7 and 11.8 times higher than the bare one, the photocatalytic hydrogen production rate is also improved to 558 µmol g h. This work shows the importance of OVs in heterostructure photocatalysis from both thermodynamic and kinetic aspects and may provide new insight into the rational design of S-scheme photocatalysts.
氧空位（OVs）被广泛认为是光催化反应中的活性位点，然而氧空位在S型异质结光催化剂中的关键作用仍需要更深入的理解。在这项工作中，构建了异质界面处氧空位调控的S型BiVO-OVs/g-CN光催化剂。BiVO和g-CN的费米能级结构导致异质结界面处电荷重新分布，在界面处诱导出内建电场，这倾向于促进界面处光生载流子的复合。重要的是，氧空位的引入在BiVO带隙中诱导出缺陷电子态，产生间接复合能级，作为S型异质结中光生载流子复合的关键中间体。结果，最佳样品对罗丹明B（RhB）和四环素（TCs）的光催化降解速率分别比纯样品高10.7倍和11.8倍，光催化产氢速率也提高到558 μmol g h。这项工作从热力学和动力学两个方面展示了氧空位在异质结构光催化中的重要性，并可能为S型光催化剂的合理设计提供新见解。
