催化学报 ›› 2025, Vol. 73: 300-310.DOI: 10.1016/S1872-2067(25)64676-6

• 论文 • 上一篇    下一篇

氢醌缓冲剂型共价有机框架用于长效光催化合成过氧化氢

舒畅, 杨小菊, 解沛璇, 杨旋(), 谭必恩(), 王笑颜()   

  1. 华中科技大学化学与化工学院, 能量转换与存储材料化学教育部重点实验室, 材料化学与服役失效湖北省重点实验室, 湖北武汉 430074
  • 收稿日期:2025-01-04 接受日期:2025-03-24 出版日期:2025-06-18 发布日期:2025-06-12
  • 通讯作者: *xuanyang@hust.edu.cn (杨旋),bien.tan@mail.hust.edu.cn (谭必恩),xiaoyan_wang@hust.edu.cn (王笑颜).
  • 作者简介:1共同第一作者.
  • 基金资助:
    国家自然科学基金(52203259);国家自然科学基金(21975086);国家自然科学基金(22204054);湖北省自然科学基金(2022CFB720);中央高校基本科研业务费(2024JYCXJJ041)

Long-term photocatalytic hydrogen peroxide production by hydroquinone-buffered covalent organic frameworks

Chang Shu, Xiaoju Yang, Peixuan Xie, Xuan Yang(), Bien Tan(), Xiaoyan Wang()   

  1. Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
  • Received:2025-01-04 Accepted:2025-03-24 Online:2025-06-18 Published:2025-06-12
  • Contact: *E-mail:xuanyang@hust.edu.cn (X. Yang),bien.tan@mail.hust.edu.cn (B. Tan),xiaoyan_wang@hust.edu.cn (X. Wang).
  • About author:1 Contributed equally to this work.
  • Supported by:
    National Natural Science Foundation of China(52203259);National Natural Science Foundation of China(21975086);National Natural Science Foundation of China(22204054);Natural Science Foundation of Hubei Province(2022CFB720);Fundamental Research Funds for the Central Universities(2024JYCXJJ041)

摘要:

光催化合成过氧化氢(H2O2)作为一种利用太阳能将水和氧气转化为H2O2的技术, 在绿色化学和能源领域具有重要应用价值. 然而, 由于光催化合成H2O2反应中涉及氧还原和水氧化两个动力学特性差异显著的半反应, 反应过程中易积累过量光生空穴, 进而引发光催化剂的氧化分解和催化效率降低, 限制了其在未来的实际应用. 因此, 如何提升光催化剂的长期稳定性是一个重大挑战.

本文利用对苯二酚/苯醌的可逆氧化还原化学特性, 通过在共价有机框架(COFs)中引入对苯二酚基团作为光生空穴的动态缓冲剂来平衡体系中累积的过量光生空穴, 避免有机光催化剂在反应中发生氧化分解. 对苯二酚具有可逆的氧化还原活性, 能够通过质子耦合电子转移机制, 捕获氧还原反应产生的过量空穴转化为苯醌, 并可通过水氧化反应还原回对苯二酚, 实现光生电荷动态平衡与催化剂保护. 所构建的氧化还原活性COF(Tz-QH-COF)展现出优异的光物理性能, 不仅具有较长的荧光寿命(0.69 ns), 并且表现出较小的激子结合能(51.8 meV). 通过羟基的引入, 也进一步增强了催化剂与氧气的相互作用, 显著提升了传质动力学. 在可见光照射下, Tz-QH-COF在纯水中的H2O2生成速率高达937 μmol L-1 h-1, 较未修饰体系提升4.6倍. 通过氧气与氮气之间“气氛切换”可实现氧化还原可逆反应循环, 材料在120 h持续光照下, 累积制备得到浓度为18.6 mmol L-1的H2O2溶液, 展现出优秀的稳定性. 且反应可稳定持续运行528 h, 其耐久性超过大多数已报道的有机光催化剂. Tz-QH-COF相对于未修饰体系还表现出优异的结构稳定性, 在长时间光反应后保持结构稳定. 原位衰减全反射表面增强红外光谱观测到在不同气氛中的氢醌与醌式结构特征峰的生成与消失, 证明了光催化H2O2生成中氧化还原对的动态循环, 密度泛函理论计算进一步证实了氢醌到醌式的可逆氧化还原转化机制. 系列控制实验结合旋转环盘电极测试证明了Tz-QH-COF的双电子两步骤的氧还原及水氧化的协同反应路径.

综上, 本文利用氢醌的可逆氧化还原特性, 平衡了光催化合成H2O2体系中过量的光生空穴, 有效解决光催化H2O2合成中半反应动力学失配导致的催化剂氧化降解难题, 实现了COFs光催化剂长效稳定制备H2O2, 为开发高效稳定光催化制备H2O2体系提供了新的思路.

关键词: 共价有机框架, 空穴缓冲剂, 可逆氧化还原化学, 氢醌-醌转化, 长效光催化过氧化氢制备

Abstract:

Photocatalytic hydrogen peroxide (H2O2) production offers a sustainable route to convert water and oxygen into H2O2 using solar energy. However, achieving long-term stability in photocatalysts remains a critical challenge due to mismatched kinetics between oxygen reduction (ORR) and water oxidation (WOR), which leads to hole accumulation and oxidative degradation. Here, we report a redox-mediated strategy to address this bottleneck by designing a hydroquinone-embedded covalent organic framework (Tz-QH-COF) that enables reversible hole buffering and kinetic balance. The hydroquinone (QH) units act as dynamic hole reservoirs, capturing excess holes during ORR and converting to benzoquinone (Q), which is regenerated to QH via WOR, thereby preventing oxidative decomposition. This reversible QH/Q cycle, directly visualized through in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy, ensures unmatched stability, achieving continuous H2O2 production for 528 h (22 d) with an accumulated yield of 18.6 mmol L-1—the highest reported duration for organic photocatalysts. Density functional theory calculations reveal that the QH units exhibit a strong oxygen adsorption energy and favorable two-electron ORR/WOR pathways with low energy barriers. The synergy between experimental and theoretical insights elucidates a redox-mediated charge-balance mechanism, advancing the design of robust photocatalysts for solar-driven H2O2 synthesis.

Key words: Covalent organic frameworks, Hole buffer, Reversible redox chemistry, Hydroquinone-quinone transformation, Long-term photocatalytic hydrogen, peroxide production