催化学报 ›› 2026, Vol. 85: 333-345.DOI: 10.1016/S1872-2067(26)64949-2

• 论文 • 上一篇    下一篇

二维/二维g-C3N4/WO3 S型异质结中的超快电子转移及其高效光催化产H2O2机理

李萍a, 韦良a, 夏伟b, 袁成成c, 艾陈斌c, 李猛a()   

  1. a 南宁师范大学广西天然高分子化学与物理重点实验室, 广西南宁 530001
    b 茅台学院资源与环境学院, 贵州仁怀 564507
    c 中国地质大学(武汉)材料与化学学院, 太阳燃料实验室, 湖北武汉 430078
  • 收稿日期:2025-10-06 接受日期:2025-11-09 出版日期:2026-06-18 发布日期:2026-05-18
  • 通讯作者: *电子信箱: limeng_2016@126.com (李猛).
  • 基金资助:
    国家自然科学基金(42207386);广西自然科学基金(2025GXNSFBA069543);茅台学院酒产业研究院专项课题(MTXYJCY002)

Ultrafast electron transfer in 2D/2D g-C3N4/WO3 S-scheme heterojunctions for enhanced H2O2 production

Ping Lia, Liang Weia, Wei Xiab, Chengcheng Yuanc, Chenbin Aic, Meng Lia()   

  1. a Guangxi Key Laboratory of Natural Polymer Chemistry and Physics, Nanning Normal University, Nanning 530001, Guangxi, China
    b School of Resources and Environment Engineering, Moutai Institute, Renhuai 564507, Guizhou, China
    c Laboratory of Solar Fuel, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430078, Hubei, China
  • Received:2025-10-06 Accepted:2025-11-09 Online:2026-06-18 Published:2026-05-18
  • Contact: *E-mail: limeng_2016@126.com (M. Li).
  • Supported by:
    National Natural Science Foundation of China(42207386);Natural Science Foundation of Guangxi Autonomous Region(2025GXNSFBA069543);Special Project of the Liquor Industry Research Center of Moutai Institute(MTXYJCY002)

摘要:

过氧化氢(H2O2)作为重要的化工原料和环保产品, 在化学合成、环境治理和能量存储等领域具有重要应用. 传统的蒽醌氧化工艺在H2O2制备中存在能耗高、依赖化石资源、污染严重等问题. 因此, 开发绿色、高效的H2O2合成方法已成为当今科学研究的重要课题. 光催化制H2O2通过氧还原反应(ORR)或水氧化反应(WOR)在常温常压下进行, 利用太阳能驱动, 发展具有可持续性. 然而, 当前光催化过程面临光生电子-空穴复合快、竞争性副反应多等严峻挑战. 因此, 设计具有强氧化还原能力和高效电荷分离性能的光催化剂是实现高效产H2O2的关键.

本文采用创新的异质结设计策略, 通过原位水热生长法制备了二维/二维g-C3N4/WO3 S型异质结光催化剂. 该设计充分利用g-C3N4还原能力强与WO3价氧化能力强的特点, 构建了一个具有原子级紧密界面的S型异质结体系. 在该异质结中, 内建电场的建立可以驱使光生电荷按照S型机制定向转移, 实现低能量载流子在界面处的有效复合, 同时保留高能量电子和空穴, 使其分别用于高效的O2还原和乙醇氧化反应. 系统的表征手段证实了S型异质结的形成. X-射线衍射、红外光谱和透射电镜等表征证实了g-C3N4与WO3紧密结合, 并保留各自的层状结构与晶相. 光学与电化学分析表明, g-C3N4和WO3之间形成了典型的S型能带结构, 且载流子复合显著抑制, 分离与转移效率大幅提高. 原位X-射线光电子能谱分析表明, 在暗条件及照射下探测到C 1s, N 1s与W 4f, O 1s峰的相反偏移, 证实了界面内建电场的形成以及光激发下WO3中的光生电子转移至g-C3N4; 开尔文探针力显微镜清晰显示了光照前后催化剂表面电势分布, 证实了光生电子从WO3向g-C3N4转移; 密度泛函理论计算证实了异质结界面处0.47 e从g-C3N4迁移至WO3建立内建电场. 飞秒瞬态吸收光谱直接捕捉界面电子转移过程, g-C3N4/WO3复合物中WO3导带电子在约46.1 ps内与g-C3N4价带空穴的界面复合. 优化的CW15异质结样品在光照射下表现出优异的H2O2生成性能, 产率达到2571.6 μmol g-1 h-1, 分别是纯g-C3N4和WO3的2.8倍和63.5倍, 光催化循环实验证明CW15异质结具有优异的化学和结构稳定性. 自由基捕获实验、电子顺磁共振和原位漫反射傅里叶变换红外光谱研究揭示了反应机理: O2通过单电子逐步氧还原过程(O2 + e- → ·O2-, 2H+ + ·O2- + e- → H2O2)生成H2O2, 而乙醇作为空穴牺牲剂被逐步氧化.

综上, 本研究成功构建了二维/二维g-C3N4/WO3 S型异质结, 并揭示了其超快电子转移与高效H2O2生成机制, 对进一步设计高效光催化氧还原体系具有指导意义. 该策略未来可推广到其他光响应半导体组合, 为清洁能源转化与绿色化学提供可扩展的材料体系.

关键词: g-C3N4, WO3, S型异质结, 产H2O2, 氧还原反应

Abstract:

The increasing demand for sustainable and environmentally friendly hydrogen peroxide (H2O2) production has necessitated the development of efficient photocatalytic strategies. A two-dimensional (2D)/2D graphitic carbon nitride (g-C3N4)/WO3 S-scheme heterojunction was synthesized in this study via in situ growth, yielding an atomically intimate interface that promotes ultrafast interfacial charge transfer. Comprehensive spectroscopy, photoelectrochemistry, Kelvin probe force microscopy, and density functional theory investigations confirmed the S-scheme charge-transfer mechanism. This system, driven by an internal electric field, promotes the spatial separation of photoexcited charge carriers and maintains robust redox abilities. Femtosecond transient absorption spectroscopy revealed ultrafast interfacial charge transfer from WO3 to g-C3N4. The optimized heterostructure exhibited considerably photocatalytic activity, achieving a 2571.6 μmol g−1 h−1 H2O2 production rate, representing 2.8- and 63.5-fold improvements over g-C3N4 and WO3, respectively. Electron paramagnetic resonance and in situ diffuse reflectance infrared Fourier-transform spectroscopy were used to elucidate the oxygen reduction reaction mechanism, indicating that ethanol undergoes sequential oxidation, whereas photogenerated electrons reduce O2 to produce H2O2 through a sequential single-electron process. This study offers significant mechanistic insights into the carrier dynamics within 2D S-scheme heterojunctions and presents a scalable and efficient route for green H2O2 synthesis.

Key words: g-C3N4, WO3, S-scheme heterojunction, H2O2 production, Oxygen reduction reaction