催化学报 ›› 2025, Vol. 74: 250-263.DOI: 10.1016/S1872-2067(25)64664-X

• 论文 • 上一篇    下一篇

有机/无机杂化FS-COF/WO3 S型异质结电荷载流子动力学及其光催化析氢性能

张云超a,b, 潘劲康a, 倪响a,b, 莫非奇a,b, 徐远国c, 董鹏玉a,*()   

  1. a盐城工学院, 江苏省新型环保重点实验室, 江苏盐城 224051
    b盐城工学院材料科学与工程学院, 江苏盐城 224051
    c江苏大学化学化工学院, 江苏镇江 212013
  • 收稿日期:2025-01-08 接受日期:2025-02-25 出版日期:2025-07-18 发布日期:2025-07-20
  • 通讯作者: *电子信箱: dongpy11@gmail.com (董鹏玉).
  • 基金资助:
    国家自然科学基金(21403184);江苏省高等学校基础科学(自然科学)研究重大项目(22KJA430008)

Revealing the dynamics of charge carriers in organic/inorganic hybrid FS-COF/WO3 S-scheme heterojunction for boosted photocatalytic hydrogen evolution

Yunchao Zhanga,b, Jinkang Pana, Xiang Nia,b, Feiqi Moa,b, Yuanguo Xuc, Pengyu Donga,*()   

  1. aKey Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province, Yancheng Institute of Technology, Yancheng 224051, Jiangsu, China
    bKey Laboratory for Ecological-Environment Materials of Jiangsu Province, School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, Jiangsu, China
    cSchool of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China
  • Received:2025-01-08 Accepted:2025-02-25 Online:2025-07-18 Published:2025-07-20
  • Contact: *E-mail: dongpy11@gmail.com (P. Dong).
  • Supported by:
    National Natural Science Foundation of China(21403184);Natural Science Foundation of the Jiangsu Higher Education Institutions of China(22KJA430008)

摘要:

光催化技术能将太阳能转化为清洁的化学能, 被认为是解决环境污染和能源短缺问题的可行方法. 近几十年来, 开发高效的析氢光催化剂受到了广泛的关注. 然而, 无机金属氧化物光催化剂由于光学吸收利用效率有限、光生电子-空穴对分离效率低, 且缺乏足够的驱动力满足过电位需求, 限制了其在光催化析氢反应中的实际应用. 因此, 有必要开发具有可见光响应的新型有机化合物析氢光催化剂. 共价有机框架(COFs)是一类有名的可见光驱动型析氢光催化剂, 通过共价键连接有机结构单元而形成的结晶多孔聚合物. 然而, 大多数COFs表面都会发生严重的电荷载流子复合. 为了增强COFs光催化剂中电荷载流子的分离, 可以将COFs与具有适当能带结构的无机金属氧化物半导体结合起来, 形成有机/无机杂化的COFs基异质结光催化剂, 从而提高光催化析氢反应活性.

本文采用溶剂热法在具有强还原能力的砜修饰共价有机框架(FS-COF)上原位生长具有优异氧化能力的无机WO3纳米颗粒, 设计并构建了独特的有机/无机杂化S型异质结. 研究发现, FS-COF与WO3具有很好的交错能带排列. 最佳设计的FS-COF/WO3-20%(即WO3占FS-COF的质量百分数为20%)在可见光下的最大光催化析氢速率为24.7 mmol g-1 h-1, 是纯FS-COF的1.4倍. 并且FS-COF/WO3-20%样品的光催化析氢速率超过了已报道的很多COFs基异质结. 此外, 由于FS-COF/WO3的功函数不同, FS-COF/WO3异质结能够产生有利的内建电场, 因此可以更有效地实现光生电子-空穴对分离, 从而通过一个额外的界面电子转移通道, 加速光生电子从WO3向FS-COF的转移动力学过程, 该电子转移通道遵从定向S型迁移机制. 此外, 自旋捕获电子顺磁共振谱表明, 在单组分和形成的异质结上的•O2信号强度的对比验证了光诱导载流子遵从S型迁移机制而非II型迁移机制. 这保证了光激发电子保持在具有强还原能力的FS-COF的最低未占分子轨道上以参与光催化析氢反应, 从而显著提高了H2的析出速率.

总之, 本文通过原位溶剂热法将还原性FS-COF与氧化性WO3纳米颗粒杂化, 构建了具有定向内建电场的有机/无机杂化S型异质结. 该异质结具有高效的界面电子传输通道, 大大提升了光催化析氢速率. 该策略不仅为有机/无机杂化光催化剂的构建提供了新思路, 更为设计兼具强氧化还原能力与高效电荷分离特性的S型异质结体系奠定了一定理论基础, 对开发高效太阳能-氢能转换材料具有重要参考.

关键词: S型异质结, 光催化析氢, 共价有机骨架, 载流子动力学, 有机/无机杂化

Abstract:

Designing high-efficiency photocatalysts by the construction of organic/inorganic heterojunctions is considered to be an effective approach for improving photocatalytic hydrogen evolution reaction (HER) activity. This work designed and built unique S-scheme heterojunctions by in-situ growing inorganic WO3 nanoparticles with excellent oxidation ability on fused-sulfone-modified covalent organic frameworks (FS-COF) with strong reduction ability. It is found that FS-COF and WO3 have a well-matched staggered band alignment. The best-designed FS-COF/WO3-20% exhibits a maximum photocatalytic HER rate of 24.7 mmol g-1 h-1 under visible light irradiation, which is 1.4 times greater than the pure FS-COF. Moreover, photogenerated electron-hole pairs can be separated and utilized more efficiently thanks to the FS-COF/WO3 heterojunction's ability to create a favorable internal electric field resulting from the difference in work functions between FS-COF and WO3, which speeds up the transfer dynamics of photoinduced electrons from WO3 to FS-COF through an additional interfacial electron-transfer channel obeying the directional S-scheme migration mechanism. Furthermore, the S-scheme migration mechanism of photoinduced charge carriers instead of the type-II mechanism was confirmed by the signal intensity of •O2 species from spin-trapping electron paramagnetic resonance spectra over the single component and the formed heterojunction. It ensures the photoexcited electrons maintain on the lowest unoccupied molecular orbital of FS-COF with a strong reduction ability to participate in photocatalytic HER, resulting in a significantly boosted H2 evolution rate. Based on organic/inorganic coupling, this work offers a strategy for creating particular S-scheme heterojunction photocatalysts.

Key words: S-scheme heterojunction, Photocatalytic hydrogen evolution, Covalent organic frameworks, Dynamics of charge carriers, Organic/inorganic hybrid