Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China.
School of Civil & Environmental Engineering and Geography Science, Ningbo University, Ningbo 315211, P. R. China.
ACS Appl Mater Interfaces. 2023 Jul 5;15(26):31409-31420. doi: 10.1021/acsami.3c03831. Epub 2023 Jun 23.
Photocatalytic hydrodechlorination (HDC) is a promising method for eliminating chlorinated organic compounds (COCs) from water, but it requires catalysts with excellent water activation ability. Defect engineering is a feasible way to enhance the catalytic performance of photocatalysts by improving light adsorption, charge carrier dynamics, and surface reactions. Herein, a well-designed 0D/2D S-scheme heterojunction with favorable band structures and defective interfaces was constructed via defect tailoring on TiO quantum dots (QDs) and the interface structure. The optimized catalyst Ni-TiO/g-CN with 1% Ni doping after thermal treatment at 300 °C under nitrogen resulted in superior visible-light-driven activity in trichloroethylene (TCE) photocatalytic HDC, approximately an 18.2-fold increase as compared with g-CN. Ni doping and thermal-induced oxygen vacancies were verified to synergistically endow the catalyst with improved visible-light absorption efficiency, ameliorated charge separation and migration, and enhanced redox potential. Experimental and theoretical results showed that the synergy of multifold defects in promoting visible-light harvesting was mainly due to the characteristic multiple midgap states, in terms of different intermediate energy levels and narrowed bandgap. Furthermore, the contradicting effects of midgap states on photogenerated charge carrier dynamics were mediated by the defective S-scheme heterojunction, where the detrimental charge recombination relating to excessive defects was considerably inhibited via superior spatial charge separation and promoted surface redox reactions. The design of defect-engineered heterojunctions and the role of controlled defects in adjusting band structures provide valuable insights for creating highly efficient artificial photosystems in the visible region.
光催化加氢脱氯（HDC）是一种从水中消除含氯有机化合物（COCs）的很有前途的方法，但它需要具有优异水激活能力的催化剂。缺陷工程是通过改善光吸收、载流子动力学和表面反应来增强光催化剂催化性能的可行方法。在此，通过在 TiO 量子点（QD）上进行缺陷调谐和界面结构设计，构建了具有良好带结构和缺陷界面的 0D/2D S 型异质结。经过在氮气中 300°C 热处理后，优化后的催化剂 Ni-TiO/g-CN 中 1%的 Ni 掺杂量，在三氯乙烯（TCE）光催化 HDC 中表现出优异的可见光驱动活性，比 g-CN 提高了约 18.2 倍。Ni 掺杂和热诱导氧空位被证实协同赋予催化剂提高的可见光吸收效率、改善的电荷分离和迁移以及增强的氧化还原电势。实验和理论结果表明，多种缺陷协同促进可见光捕获的主要原因是特征的多个中间能态，具有不同的中间能级和缩小的能带隙。此外，中间态对光生载流子动力学的矛盾影响通过缺陷 S 型异质结进行了调节，其中与过多缺陷相关的有害电荷复合通过优异的空间电荷分离得到了极大抑制，并促进了表面氧化还原反应。缺陷工程异质结的设计和控制缺陷在调节能带结构方面的作用为在可见区域中构建高效人工光合作用系统提供了有价值的见解。
