催化学报 ›› 2026, Vol. 91: 274-289.DOI: 10.1016/S1872-2067(26)65226-6

• 论文 • 上一篇    下一篇

空间分辨电荷转移机制主导的Al掺杂SrTiO3/C3N5 S-型异质结增强太阳能光催化析氢

陈啸萱a, 李康a, 姜泽文a, 郭浩田b, 徐选文b, 董鹏玉a,*()   

  1. a 盐城工学院, 材料科学与工程学院, 江苏盐城 224051
    b 盐城工学院, 化学化工学院, 江苏盐城 224051
  • 收稿日期:2026-01-26 接受日期:2026-02-10 出版日期:2026-12-18 发布日期:2026-10-13
  • 通讯作者: *电子信箱: dongpy11@ycit.edu.cn (董鹏玉).
  • 基金资助:
    国家自然科学基金(21403184);江苏省高等学校自然科学研究面上项目(22KJA430008)

Exploring the spatially resolved charge transfer mechanism in the Al-doped SrTiO3/C3N5 S-scheme heterojunction for boosted solar-driven photocatalytic hydrogen evolution

Xiaoxuan Chena, Kang Lia, Zewen Jianga, Haotian Guob, Xuanwen Xub, Pengyu Donga,*()   

  1. a School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, Jiangsu, China
    b School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng 224051, Jiangsu, China
  • Received:2026-01-26 Accepted:2026-02-10 Online:2026-12-18 Published:2026-10-13
  • About author:First author contact:

    Xiaoxuan Chen: Investigation, Data curation, Visualization, Writing-original draft; Kang Li: Data curation; Zewen Jiang: Data curation; Haotian Guo: Software, Data curation; Xuanwen Xu: Validation; Pengyu Dong: Conceptualization, Methodology, Supervision, Writing-review & editing.

  • Supported by:
    National Natural Science Foundation of China(21403184);Natural Science Foundation of Jiangsu Higher Education Institutions of China(22KJA430008)

摘要:

光催化水分解技术是利用光催化剂将太阳能直接转化为化学能(例如氢气), 该过程通过光诱导的催化反应来完成; 获得的化学能有效地克服了太阳能转换过程中常见的不稳定性和间歇性问题, 是高效开发和利用太阳能资源的重要策略. 因此, 高性能光催化剂的制备已成为当务之急.
开发高效且成本低廉的C3N5基光催化剂以实现氢气生产具有重要意义. 此外, 从纳米级精度的空间角度研究C3N5基S-型异质结中光生电荷的表面电势分布仍比较缺乏. 本文利用具有强氧化能力的Al掺杂SrTiO3(ASTO)和具有高还原能力的C3N5纳米片, 通过水热法成功合成了一种新型的ASTO/C3N5 S-型异质结. 结果表明, 多面体的ASTO颗粒与C3N5纳米片能够紧密结合, 两者之间存在清晰且明显的界面. 最优的5%-ASTO/C3N5 S-型异质结在模拟太阳光照射下表现出较高的氢气生成速率(1.87 mmol g-1 h-1), 分别比原始的C3N5和ASTO高出2.5倍和37.4倍. 采用光辅助的开尔文探针力显微镜揭示了ASTO/C3N5 S型异质结中电荷转移动力学的空间分辨特征, 在ASTO/C3N5 S-型异质结中, 光生电子聚集在还原型光催化剂C3N5表面, 导致其表面光电压(SPV)低于纯C3N5, 而空穴则聚集在氧化型光催化剂ASTO表面, 因而比纯ASTO的SPV更高. 此外, ASTO (4.66 eV)和C3N5(4.25 eV)之间较大的功函数差异(0.41 eV)促使界面电子从C3N5转移到ASTO, 引发能带弯曲并形成强大的界面电场, 因而促进了S-型电荷迁移, 即ASTO导带中的光生电子与C3N5价带中的空穴发生复合, 从而使ASTO/C3N5 S-型异质结保持高氧化还原电位. 此外, 活性自由基测量证实了5%-ASTO/C3N5异质结中•O2-和•OH信号增强, 证实了S-型机制而非II型机制, 原位X-射线光电子能谱结果也证实了这一点.
综上, 本文不仅证明了ASTO/C3N5 S-型异质结是一种性能卓越的光催化剂,而且还对空间分辨的电荷转移机制提供了直接实验依据.

关键词: 光催化析氢, S型异质结, C3N5, Al掺杂SrTiO3, 电荷转移机制

Abstract:

Developing highly efficient and low-cost C3N5-based photocatalysts for hydrogen production is of great significance. However, research on the surface potential distribution of photogenerated charges in the C3N5-based S-scheme heterojunction from a spatial perspective with nanoscale precision is still lacking. In this work, using Al-doped SrTiO3 (ASTO) with strong oxidation ability and C3N5 nanosheets with high reduction ability, a novel S-scheme heterojunction was created. The ASTO/C3N5 S-scheme heterojunction was synthesized via a hydrothermal method. It reveals that the polyhedral ASTO particles are in intimate contact with C3N5 nanosheets, with a clear and distinct interface observed between them. The optimal 5%-ASTO/C3N5 S-scheme heterojunction exhibits a high hydrogen production rate under simulated solar light, surpassing pristine C3N5 and ASTO by factors of 2.5 and 37.4, respectively. Light-assisted Kelvin-probe force microscopy was employed to uncover the spatially resolved features of the kinetics of charge transfer in the ASTO/C3N5 S-scheme heterojunction. It reveals that photogenerated electrons gather on the surface of C3N5 as a reduction photocatalyst in the heterojunction, resulting in a reduced surface photovoltage (SPV) compared to pure C3N5, whereas holes accumulate on the surface of ASTO as an oxidation photocatalyst in the heterojunction, providing higher SPV than pure ASTO. Moreover, the large work function difference (0.41 eV) between ASTO and C3N5 induces a robust interfacial electric field (IEF). This strong IEF facilitates the photogenerated electrons in ASTO’s conduction band recombine with holes in C3N5’s valence band, preserving high redox potentials. Furthermore, active free radical measurement confirms the enhanced •O2- and •OH signals for the 5%-ASTO/C3N5 heterojunction, confirming the S-scheme mechanism and excluding the type-II mechanism, which is also demonstrated by in-situ X-ray photoelectron spectroscopy. Overall, this work offers some evidence regarding the spatially resolved characteristics of the kinetics of charge transfer in the S-scheme heterojunction.

Key words: Photocatalytic hydrogen production, S-scheme heterojunction, C3N5, Al-doped SrTiO3, Charge transfer mechanism