Chen Qing, Ge Xing-Zu, Yu Linhui, Xiao Fang-Xing
College of Materials Science and Engineering, Fuzhou University, New Campus, Minhou, Fujian Province350108, China.
CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
Inorg Chem. 2023 Nov 27;62(47):19358-19365. doi: 10.1021/acs.inorgchem.3c03283. Epub 2023 Nov 15.
Atomically precise metal nanoclusters (NCs) demonstrate emerging potential as a new generation of photosensitizers in photoredox catalysis. However, metal NCs suffer from intrinsic poor instability, which leads to the loss of photosensitization effect and hampers their widespread applications in heterogeneous photocatalysis. Herein, we corroborate the design of a spatially directional charge transfer pathway over transition metal chalcogenide (TMC)-based heterostructures by way of a facile and efficient electrostatic self-assembly approach. Positively charged solid-state nonconjugated insulating polymer of poly(allylamine hydrochloride) (PAH) and negatively charged glutathione (GSH) capped metal NCs [Ag@(GSH)] as building blocks were controllably and highly ordered anchored on the TMC substrate. It was unveiled that owing to the appropriate energy level alignment and interface configuration, photogenerated electrons over metal NCs can directionally flow to the TMC substrate with the aid of PAH, which functions as an interfacial charge transfer mediator, and simultaneously holes migrate in the opposite direction, thereby collaboratively contributing to substantially boosted charge separation and prolonged charge lifetime. Benefiting from these merits, the thus self-assembled TMCs/PAH/metal NC heterostructure unfolds conspicuously enhanced photoactivity toward anaerobic selective photocatalytic reduction of nitroaromatics to amino derivatives under visible light irradiation. This work would significantly reinforce our fundamental understanding of the charge transfer characteristic of atomically precise metal NCs and the charge-withdrawing capability of solid insulating polymers for solar energy conversion.
原子精确的金属纳米团簇（NCs）在光氧化还原催化中作为新一代光敏剂展现出新兴潜力。然而，金属纳米团簇存在固有的稳定性差的问题，这导致光敏化效果丧失，并阻碍了它们在多相光催化中的广泛应用。在此，我们通过一种简便高效的静电自组装方法，证实了在基于过渡金属硫族化物（TMC）的异质结构上设计空间定向电荷转移途径。以带正电的聚（烯丙胺盐酸盐）（PAH）固态非共轭绝缘聚合物和带负电的谷胱甘肽（GSH）包覆的金属纳米团簇[Ag@(GSH)]为构建单元，可控且高度有序地锚定在TMC基底上。结果表明，由于合适的能级排列和界面构型，金属纳米团簇上的光生电子借助作为界面电荷转移介质的PAH定向流向TMC基底，同时空穴向相反方向迁移，从而共同显著促进电荷分离并延长电荷寿命。受益于这些优点，如此自组装的TMCs/PAH/金属NC异质结构在可见光照射下对硝基芳烃厌氧选择性光催化还原为氨基衍生物表现出明显增强的光活性。这项工作将显著加强我们对原子精确金属纳米团簇的电荷转移特性以及固体绝缘聚合物对太阳能转换的吸电能力的基本理解。
