Ma Fang, Gao Tao, Sun Xiaodong, Han Chunqiu, Wang Yongye, Jiang Anqiang, Zhou Ying, Liang Guijie, Wang Huiqing, Wang Li, Jia Binbin, Huang Yingping, Huang Hongwei, Kong Xin Ying, Li Hui, Huang Niu, Ma Tianyi, Ye Liqun
College of Materials and Chemical Engineering, Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials, China Three Gorges University, Yichang, China.
Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Yichang, China.
Nat Commun. 2025 Aug 12;16(1):7432. doi: 10.1038/s41467-025-62286-9.
Covalent organic frameworks (COFs) are promising photocatalysts for HO photosynthesis, but charge carrier separation remains a critical challenge. Donor-acceptor COFs enhance charge separation, but the slow kinetics of water oxidation and oxygen reduction reactions lead to carrier accumulation, thereby decreasing efficiency. Here, we report T-C type COFs (T = trap units, C = catalytic units), demonstrating that units with keto-enol tautomerism can serve as dynamic electron/hole traps (T) to mitigate Coulomb forces. This design effectively facilitates swift charge transfer and extends carrier lifetimes, thereby enhancing reactions at the C units. Imine COFs derived from 2,4,6-trihydroxybenzaldehyde (Tp) outperform those based on 1,3,5-benzenetricarboxaldehyde due to tautomerization. The optimal Tp COF (TpBpy) achieves an HO generation rate of 37.9 μmol h⁻¹ (or 8350 μmol h⁻¹ g⁻¹) under simulated light, and a solar-to-chemical conversion efficiency of 0.038% in a flow reactor under natural sunlight. This work provides molecular design strategies and standard criteria for efficient HO photocatalysts.
共价有机框架（COFs）是用于光催化水分解的有前景的光催化剂，但电荷载流子分离仍然是一个关键挑战。供体-受体型COFs可增强电荷分离，但水氧化和氧还原反应的缓慢动力学导致载流子积累，从而降低效率。在此，我们报道了T-C型COFs（T = 捕获单元，C = 催化单元），证明具有酮-烯醇互变异构的单元可作为动态电子/空穴捕获剂（T）来减轻库仑力。这种设计有效地促进了快速电荷转移并延长了载流子寿命，从而增强了C单元处的反应。源自2,4,6-三羟基苯甲醛（Tp）的亚胺COFs由于互变异构而优于基于1,3,5-苯三甲醛的COFs。最佳的Tp COF（TpBpy）在模拟光下实现了37.9 μmol h⁻¹（或8350 μmol h⁻¹ g⁻¹）的产氢速率，在自然阳光下的流动反应器中太阳能到化学能的转换效率为0.038%。这项工作为高效光催化水分解催化剂提供了分子设计策略和标准准则。
