中国科学技术大学江海龙团队报道了金属有机框架中的动态结构扭曲增强了太阳能整体水分解。相关研究成果发表在2024年8月12日出版的《自然—化学》。

光催化整体水分解为太阳能到氢气的转化带来了巨大的希望。保持电荷分离是一个重大挑战，但也是释放这一潜力的关键。

该文中，研究人员发现了一种金属-有机框架（MOF），能够抑制电荷复合。这种MOF具有电子绝缘的Zn²⁺节点和两个化学上等效但晶体学上独立的连接体。这些连接体表现为具有不重叠带边的电子供体-受体对。在光激发下，MOF会经历动态的激发态结构扭曲，导致轨道重排，从而阻止辐射弛豫，促进长寿命的电荷分离态。

因此，在助催化剂的存在下，MOF实现了可见光光催化整体水分解，在365nm处的表观量子效率为3.09±0.32%，在连续运行100小时后几乎没有活性损失。此外，动态激发态结构扭曲也成功地扩展到其他光催化剂。这种抑制电荷复合的策略将适用于除整体水分解之外的各种光化学过程。

附：英文原文

Title: Dynamic structural twist in metal–organic frameworks enhances solar overall water splitting

Author: 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

Issue&Volume: 2024-08-12

Abstract: 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 Zn2+ 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 365nm and shows little activity loss in 100h 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.

DOI: 10.1038/s41557-024-01599-6

Source: https://www.nature.com/articles/s41557-024-01599-6