S-scheme异质结光催化剂具有独特的电荷转移路径和优异的氧化还原催化性能，在光催化还原CO₂等反应能垒比较高的反应中得到应用。但是人们对于S-scheme异质结的缺陷能级对于电荷分离、载流子寿命、表面催化反应的影响并不清楚。

有鉴于此，我院梁桂杰教授与中国地质大学余家国教授（欧洲科学院院士）联合报道开发了可调控缺陷能级的策略，构筑电子存储池，能够增强载流子寿命，改善S-scheme异质结光催化性能。研究结果发表在Angewandte Chemie International Edition, 2024:e202414672.

本文要点：

（1）通过飞秒瞬态光吸收光谱和理论计算模拟验证，能够增强WO_3-x/In₂S₃ S-scheme异质结光催化剂的光电子释放。通过计算Gibbs自由能，揭示光反应机理，说明WO_3-x/In₂S₃的氧缺陷能够形成不稳定的氧中间体打开决速步骤（H₂O氧化生成氧气分子），因此促进H₂O光化学氧化反应。

（2）通过缺陷的独特作用，增加的载流子寿命，使得在没有光敏剂或者牺牲剂的CO₂光化学还原反应实现100 %的CO选择性。这项研究展示了控制缺陷能级对于控制S-scheme异质结光催化剂的载流子动力学的重要作用，这能够促进开发更加先进的光催化剂。

Fig.1 Schematic and the concept of this study: (a) traditional S-scheme heterojunction in previous work, (b) S-scheme heterojunction with intraband defect levels in this work.

Fig.2 The pseudocolor plots and transient absorption spectra measured with 400 nm pump pulse under Ar atmosphere: (a) WO_3-x-550 in the VIS region, (b) WO_3-x/In₂S₃-550 in the VIS region, (c) WO_3-x-550 in the NIR region, and (d) WO_3-x/In₂S₃-550 in the NIR region. Normalized GSB recovery kinetics recorded at around 640 nm within 100 ps in the VIS region: (e) WO_3-x-T and (f) WO_3-x/In₂S₃-T. The inset image is the corresponding GSB kinetics at extended delay time. (h) Normalized GSB decay kinetics of WO_3-x-T recorded at around 900 nm within 100 ps in the NIR region. (i) The comparison of normalized decay kinetic curves of WO_3-x-550 and WO_3-x/In₂S₃-550 in the NIR region. Schematic illustrations of the charge transfer mechanism within WO_3-x/In₂S₃ S-scheme heterojunctions in: (g) VIS region, (j) NIR region.

https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202414672