Xu Feiyan, He Ying, Zhang Jianjun, Liang Guijie, Liu Chengyuan, Yu Jiaguo
Laboratory of Solar Fuel, Faculty of Materials Science and Chemistry, China University of Geosciences, 68 Jincheng Street, 430078, Wuhan, P. R. China.
Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices, Hubei University of Arts and Science, 441053, Xiangyang, P. R. China.
Angew Chem Int Ed Engl. 2025 Jan 10;64(2):e202414672. doi: 10.1002/anie.202414672. Epub 2024 Nov 21.
S-scheme heterostructure photocatalysts, distinguished by unique charge-transfer pathways and exceptional catalytic redox capabilities, have found widespread applications in addressing challenging chemical processes, including the photocatalytic reduction of CO with a high reaction barrier. Nevertheless, the influence of intraband defect levels within S-scheme heterojunctions on charge separation, carrier lifetime, and surface catalytic reactions has, for the most part, been overlooked. Herein, we develop a tunable defect-level-assisted strategy to construct an electron reservoir, effectively prolonging the lifetime of charge carriers through the rapid capture and gradual release of photoelectrons within WO/InS S-scheme heterojunctions, as authenticated by femtosecond transient absorption spectroscopy and theoretical simulations. The surface photoredox mechanism, unraveled by Gibbs free energy calculations, demonstrates that oxygen-vacancy-induced defect states in WO/InS heterojunctions unlock the rate-determining HO oxidation into free oxygen molecules by forming metastable oxygen intermediates, contributing to the facilitation of HO photooxidation. This distinct role, combined with the extended carrier lifetime, results in boosted CO photoreduction with nearly 100 % CO selectivity in the absence of any photosensitizer or scavenger. Our work sheds light on the role of controllable defect levels in governing charge transfer dynamics within S-scheme heterojunctions, thereby inspiring the development of more advanced photocatalysts for artificial photosynthesis.
S型异质结构光催化剂以其独特的电荷转移途径和卓越的催化氧化还原能力而著称，在解决具有挑战性的化学过程中得到了广泛应用，包括具有高反应势垒的光催化还原CO。然而，S型异质结内带内缺陷能级对电荷分离、载流子寿命和表面催化反应的影响在很大程度上被忽视了。在此，我们开发了一种可调谐的缺陷能级辅助策略来构建一个电子库，通过在WO/InS S型异质结内快速捕获和逐步释放光电子，有效地延长了电荷载流子的寿命，这已通过飞秒瞬态吸收光谱和理论模拟得到证实。通过吉布斯自由能计算揭示的表面光氧化还原机制表明，WO/InS异质结中氧空位诱导的缺陷态通过形成亚稳氧中间体，将速率决定步骤的HO氧化为游离氧分子，有助于促进HO光氧化。这种独特的作用，结合延长的载流子寿命，在没有任何光敏剂或清除剂的情况下，实现了近100%的CO选择性，从而提高了CO光还原效率。我们的工作揭示了可控缺陷能级在调控S型异质结内电荷转移动力学中的作用，从而为开发更先进的人工光合作用光催化剂提供了启示。
