Sun Kang, Huang Yan, Sun Fusai, Wang Qingyu, Zhou Yujie, Wang Jingxue, Zhang Qun, Zheng Xusheng, Fan Fengtao, Luo Yi, Jiang Jun, Jiang Hai-Long
Hefei National Research Center for Physical Sciences at the Microscale, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, People's Republic of China.
Key Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of China, Hefei, People's Republic of China.
Nat Chem. 2024 Oct;16(10):1638-1646. doi: 10.1038/s41557-024-01599-6. Epub 2024 Aug 12.
Photocatalytic overall water splitting holds great promise for solar-to-hydrogen conversion. Maintaining charge separation is a major challenge but is key to unlocking this potential. Here we discovered a metal-organic framework (MOF) that shows suppressed charge recombination. This MOF features electronically insulated Zn nodes and two chemically equivalent, yet crystallographically independent, linkers. These linkers behave as an electron donor-acceptor pair with non-overlapping band edges. Upon photoexcitation, the MOF undergoes a dynamic excited-state structural twist, inducing orbital rearrangements that forbid radiative relaxation and thereby promote a long-lived charge-separated state. As a result, the MOF achieves visible-light photocatalytic overall water splitting, in the presence of co-catalysts, with an apparent quantum efficiency of 3.09 ± 0.32% at 365 nm and shows little activity loss in 100 h of consecutive runs. Furthermore, the dynamic excited-state structural twist is also successfully extended to other photocatalysts. This strategy for suppressing charge recombination will be applicable to diverse photochemical processes beyond overall water splitting.
光催化全水分解在太阳能制氢方面具有巨大潜力。维持电荷分离是一项重大挑战，但却是释放这一潜力的关键。在此，我们发现了一种金属有机框架（MOF），其电荷复合受到抑制。这种MOF具有电子绝缘的锌节点以及两个化学等价但晶体学上独立的连接体。这些连接体表现为具有不重叠能带边缘的电子供体 - 受体对。光激发后，该MOF经历动态的激发态结构扭曲，引发轨道重排，从而阻止辐射弛豫，进而促进长寿命的电荷分离态。结果，在助催化剂存在的情况下，该MOF实现了可见光光催化全水分解，在365 nm处的表观量子效率为3.09±0.32%，并且在连续运行100小时内几乎没有活性损失。此外，这种动态的激发态结构扭曲也成功扩展到了其他光催化剂。这种抑制电荷复合的策略将适用于全水分解之外的多种光化学过程。
