催化学报 ›› 2025, Vol. 73: 279-288.DOI: 10.1016/S1872-2067(25)64655-9

• 论文 • 上一篇    下一篇

共轭多孔聚合物构建单元的电子结构匹配性对光催化析氢活性的影响

何雪璐, 马雯燕(), 朱思腾, 李丹, 蒋加兴()   

  1. 江汉大学光电材料与技术学院, 柔性光电材料与技术教育部重点实验室, 湖北武汉 430056
  • 收稿日期:2024-12-25 接受日期:2025-02-11 出版日期:2025-06-18 发布日期:2025-06-12
  • 通讯作者: *电子信箱: wenyanma@jhun.edu.cn (马雯燕),jiaxing@jhun.edu.cn (蒋加兴).
  • 基金资助:
    国家自然科学基金(22175110);国家自然科学基金(22375076);湖北省自然科学基金创新群体项目(2024AFA031);武汉市重点研发计划项目(2024010802030157);江汉大学一流学科建设重大专项(2023XKZ040)

The effect of electronic structure matching between building blocks in conjugated porous polymers on photocatalytic hydrogen evolution activity

Xuelu He, Wenyan Ma(), Siteng Zhu, Dan Li, Jia-Xing Jiang()   

  1. Key Laboratory of Flexible Optoelectronic Materials and Technology (Jianghan University), Ministry of Education, School of Optoelectronic Materials & Technology, Jianghan University, Wuhan 430056, Hubei, China
  • Received:2024-12-25 Accepted:2025-02-11 Online:2025-06-18 Published:2025-06-12
  • Contact: *E-mail: wenyanma@jhun.edu.cn (W. Ma),jiaxing@jhun.edu.cn (J.-X. Jiang).
  • Supported by:
    National Natural Science Foundation of China(22175110);National Natural Science Foundation of China(22375076);Hubei Provincial Natural Science Foundation of China(2024AFA031);Key Research and Development Program of Wuhan(2024010802030157);Excellent Discipline Cultivation Project by JHUN(2023XKZ040)

摘要:

利用太阳能将水分解为氢气是一种绿色可持续的制氢技术, 共轭多孔聚合物因其延伸的共轭结构、丰富的孔隙结构以及易于功能化等特性, 受到了广泛关注. 然而, 有机聚合物光催化剂仍面临电荷分离效率低和电子-空穴复合率高等挑战, 共轭聚合物的电子结构对光催化性能影响至关重要, 而骨架内的电荷转移效率在很大程度上受到构建单元电子结构匹配性的影响.

本文以二苯并[g,p]稠二萘(DBC)为电子供体单元, 分别与具有不同电子特性的苯(B)、1,4-二甲氧基苯(BMO)和1,4-二氰基苯(BCN)构建单元结合, 设计合成了三种具有不同电子结构的有机聚合物(DBC-B, DBC-BMO和DBC-BCN)光催化剂. 紫外-可见吸收光谱、光致发光光谱、瞬态光电流响应和量子产率测试结果表明, 相对于DBC-B和DBC-BMO而言, DBC-BCN在电荷载流子的产生、分离、传输和利用等方面均显著增强. 进一步理论计算结果表明, 由于DBC的电子能级与B和BMO的电子能级相近, 它们彼此结合形成电子供体-供体(D-D)结构. 在D-D结构中, 缺乏有效的电子推拉效应, 导致DBC-B和DBC-BMO的电荷分离效率低, 限制了光催化制氢性能. 而氰基取代基通过吸电子效应显著增强了BCN的电子接受能力, 降低了其最低未占分子轨道和最高占据分子轨道能级. 当DBC与BCN配对时, 形成了供体-受体(D-A)结构. D-A结构不仅增强了光吸收能力, 还加速了光生电荷的分离与传输, 减少了电荷复合, 显著提升了光催化制氢性能. 因此, 在紫外-可见光照射下, D-A型聚合物DBC-BCN的光催化析氢速率达到了20.67 mmol h-1 g-1, 显著优于DBC-BMO (2.13 mmol h-1 g-1)和DBC-B (13.10 mmol h-1 g-1).

综上, 本研究揭示了聚合物光催化剂中电子结构合理匹配的重要性, 通过取代基工程可有效调控构建单元的电子结构, 实现了聚合物从D-D到D-A型的结构转变, 有效提升了聚合物光催化制氢性能.

关键词: 共轭多孔聚合物, 电子结构匹配性, 供体-受体, 电荷载流子分离, 产氢

Abstract:

Conjugated porous polymers have been extensively studied as photocatalysts for hydrogen generation. However, the photocatalytic efficiency is often hindered by the inefficient charge separation and rapid recombination of photo-induced charge carriers, both are strongly affected by the electronic structure of the co-monomers in polymer photocatalysts. In this study, we design three conjugated porous polymers with distinct electronic architectures by combining dibenzo[g,p]chrysene (DBC) and benzene with different substituted groups. The results demonstrate that the combination of DBC and the unsubstituted benzene forms a donor-donor (D-D) structure due to their similar energy levels, while the introduction of methoxy enhances the electron-donating ability of benzene ring, leading to a reinforced D-D structure between DBC and the methoxy-substituted benzene unit, which suppresses the charges separation. In contrast, the introduction of electron-withdrawing cyano group significantly enhances the electron receptivity of the benzene unit, leading to the formation of donor-acceptor (D-A) structure between DBC and the cyano-substituted benzene unit, promoting charges transfer and separation of light-induced electrons and holes. As a result, the D-A polymer DBC-BCN achieves an impressive hydrogen evolution rate (HER) of 20.67 mmol h-1 g-1 under UV-Vis light irradiation, outperforming the D-D polymers of DBC-BMO (2.13 mmol h-1 g-1) and DBC-B (13.10 mmol h-1 g-1). This study underscores the importance of the electronic structure matching of building blocks in polymer photocatalysts to enhance the photocatalytic activity.

Key words: Conjugated porous polymers, Electronic structure matching, Donor-acceptor, Charge carrier separation, Hydrogen production