催化学报 ›› 2026, Vol. 91: 263-273.DOI: 10.1016/S1872-2067(26)65148-0

• 论文 • 上一篇    下一篇

空穴限域效应促进共价有机框架光催化分解水制过氧化氢和氢气

李增, 于明飞, 李留义*(), 于岩*()   

  1. 福州大学材料科学与工程学院生态材料先进技术重点实验室, 福建福州 350108
  • 收稿日期:2026-03-18 接受日期:2026-04-17 出版日期:2026-12-18 发布日期:2026-10-13
  • 通讯作者: *电子信箱: lyli@fzu.edu.cn (李留义),
    yuyan@fzu.edu.cn (于岩).
  • 基金资助:
    国家自然科学基金(52172188);福建省自然科学基金(2025J01471)

Hole-confining covalent organic frameworks for photosynthesis of H2O2 and H2 from pure water

Zeng Li, Mingfei Yu, Liuyi Li*(), Yan Yu*()   

  1. Key Laboratory of Eco-materials Advanced Technology, College of Materials Science and Engineering, Fuzhou University, Fuzhou 350108, Fujian, China
  • Received:2026-03-18 Accepted:2026-04-17 Online:2026-12-18 Published:2026-10-13
  • Supported by:
    National Natural Science Foundation of China(52172188);Fujian Provincial Natural Science Founda-tion of China(2025J01471)

摘要:

光催化全解水同步产氢(H2)与过氧化氢(H2O2)是实现太阳能向高附加值化学品转化的理想途径. 然而, 迟缓的水氧化动力学及严重的载流子复合极大制约了传统共价有机框架(COFs)光催化剂的能量转换效率. 为破解该瓶颈, 本文提出了一种“空穴空间限域”设计策略. 通过分子工程, 将光生空穴定向富集于特定的水氧化活性中心以提高局部氧化电位, 同时促使光生电子在骨架内高度离域. 该策略在大幅延长电荷分离寿命的同时, 最大限度地激发了位点的本征反应活性, 从而在无牺牲剂的纯水体系中实现了高效的全解水反应.
本研究以三嗪环为电子离域受体, 结合不同供电基团, 成功构筑了三种具有差异化激发态电荷分布的酰腙键链接COFs. 光电与原位光谱表征证实, 具有完美供受体结构的TFT-COF展现出最佳的电荷分离动力学. 开尔文探针力显微镜检测到93 mV的表面光电压, 显著高于其他两例同类型酰腙键COFs; 原位X-射线光电子能谱直接印证了空穴被精准限域于酰腙位点, 而电子向三嗪环发生离域; 瞬态吸收光谱显示其载流子寿命延长至318.7 ps. 密度泛函理论计算表明, 酰腙限域位点作为热力学最优的水吸附中心; Pt助催化剂的引入有效重构了后续基元反应的热力学势能面, 大幅降低了决速步的活化能. 在这种协同机制下, 光生空穴得以通过单电子路径驱动水分子氧化生成•OH, 并最终偶联为H2O2. 最终, 在可见光驱动下, TFT-COF的H2与H2O2产率分别高达311.2和278.6 μmol·g-1·h-1.
综上, 本文通过分子结构设计实现了光生空穴在空间上的选择性限域与水吸附位点的精准匹配, 协同促进了电荷分离与水氧化动力学, 在纯水中实现了高效的全解水同步产H2与H2O2, 为COF基光催化剂的设计提供了“空穴限域”新策略.

关键词: 共价有机框架, 光催化, 空穴积累, 全解水, 氢气和过氧化氢

Abstract:

Covalent organic frameworks (COFs) have emerged as promising candidates for photocatalysis, however, their efficiency in converting water into value-added chemicals is often severely constrained by sluggish water-oxidation kinetics. Herein, we demonstrate a strategy of confining photogenerated holes at specific water oxidation active sites in COFs to enhance simultaneous H2 and H2O2 co-generation from water. We designed three hydrazone-linked COFs capable of driving overall water splitting without the use of sacrificial agents. Mechanistic studies reveal that the capability to confine photogenerated holes at hydrazone linkages directly correlates with superior water-splitting activity. Specifically, the accumulation of holes at these thermodynamically preferred water-adsorption sites, coupled with electron delocalization, results in a unique spatial charge separation. This configuration not only significantly suppresses recombination to extend excited-state lifetimes but also creates hole-rich local environments that accelerate water oxidation kinetics. Consequently, the optimal COF achieves H2 and H2O2 production rates of 311.2 and 278.6 μmol·g-1·h-1, respectively. This work establishes the spatial accumulation of photogenerated holes as a pivotal, engineerable design principle for advancing COF-based photocatalytic water splitting.

Key words: Covalent organic frameworks, Photocatalysis, Hole accumulation, Overall water splitting, H2 and H2O2 production