催化学报 ›› 2024, Vol. 59: 185-194.DOI: 10.1016/S1872-2067(23)64610-8

• 论文 • 上一篇    下一篇

利用电荷分离调控S型异质结光催化氧化产物选择性

谷苗莉a, 杨祎a, 程蓓a, 张留洋b,*(), 肖鹏c, 陈涛c   

  1. a武汉理工大学材料复合新技术国家重点实验室, 湖北武汉 430070
    b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
    c中国科学技术大学材料科学与工程系, 中国科学院能量转换材料重点实验室, 合肥微尺度物质科学国家实验室, 安徽合肥 230026
  • 收稿日期:2023-12-26 接受日期:2024-01-25 出版日期:2024-04-18 发布日期:2024-04-15
  • 通讯作者: *电子邮箱: zhangliuyang@cug.edu.cn (张留洋).
  • 基金资助:
    国家重点研发计划(2022YFB3803600);国家重点研发计划(2022YFE0115900);国家自然科学基金(52322214);国家自然科学基金(22278383);国家自然科学基金(22238009);国家自然科学基金(22278324);国家自然科学基金(52073223);湖北省自然科学基金(2022CFA001);湖北省自然科学基金(2023AFA088);湖北省重点科技发展计划项目(2023BAB113)

Unveiling product selectivity in S-scheme heterojunctions: Harnessing charge separation for tailored photocatalytic oxidation

Miaoli Gua, Yi Yanga, Bei Chenga, Liuyang Zhangb,*(), Peng Xiaoc, Tao Chenc   

  1. aState Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, Hubei, China
    bLaboratory of Solar Fuel, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430078, Hubei, China
    cHefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, Anhui, China
  • Received:2023-12-26 Accepted:2024-01-25 Online:2024-04-18 Published:2024-04-15
  • Contact: *E-mail: zhangliuyang@cug.edu.cn (L. Zhang).
  • Supported by:
    The National Key Research and Development Program of China(2022YFB3803600);The National Key Research and Development Program of China(2022YFE0115900);The National Natural Science Foundation of China(52322214);The National Natural Science Foundation of China(22278383);The National Natural Science Foundation of China(22238009);The National Natural Science Foundation of China(22278324);The National Natural Science Foundation of China(52073223);The National Science Foundation of Hubei Province of China(2022CFA001);The National Science Foundation of Hubei Province of China(2023AFA088);Key R&D Program Projects in Hubei Province(2023BAB113)

摘要:

半导体光催化技术为太阳能的高效利用提供了巨大的潜力. 尽管众多单一半导体材料, 如TiO2, CdS, g-C3N4等, 已被广泛制备并用于光催化反应, 但在单一光催化剂中, 光生电子和空穴常因强库仑引力作用而迅速复合, 导致光催化效率较低, 难以实现大规模产业化应用. 针对这一问题, 开发S型异质结光催化剂成为提高催化效率的有效途径之一. 该异质结不仅能实现氧化还原位点在空间上的有效分离, 同时保持了较强的氧化还原能力. 然而,目前关于空间分离对光催化氧化产物选择性的影响研究较少. 因此,深入探究S型异质结光催化剂中空间分离对产物选择性的作用机制,对于优化光催化过程、提高产物选择性具有重要意义.

本文构建了具有良好暴露活性位点的2D/2D层状BiOBr/ZnIn2S4 S型异质结(BOB/ZIS). 实验发现, 在纯ZnIn2S4体系中, 由于无法实现空间上的有效电荷分离, 氧还原反应(ORR)生成的H2O2在光生空穴的作用下进一步转化为•OH(羟基自由基), 其氧化能力超过了体系中的光生空穴, 导致2,5-呋喃二甲醛被过度氧化为经济性不高的产物呋喃二甲酸. 在BOB/ZIS异质结中, 我们实现了光生电子-空穴的有效转移和丰富的活性中心利用. ZnIn2S4价带上的电子通过ORR持续生成H2O2 (1.15 mmol∙L-1, 5 h), 而BiOBr导带上的空穴则将5-羟甲基糠醛(HMF)氧化为具有高经济价值的2,5-呋喃二甲醛(有机合成中有价值的中间体). 这一结果证实了S型异质结中光生电子-空穴的有效空间分离能够同时促进H2O2 的产生和HMF的选择性氧化为2,5-呋喃二甲醛. 这一发现不仅揭示了S型异质结在光催化反应中的优势, 还证实了其相对于传统牺牲剂的经济可行性. 原位光照X射线光电子能谱、飞秒超快瞬态吸收光谱和密度泛函理论计算均证实, 在BOB/ZIS界面之间构建了S型电荷转移机制, 加速了光生电子-空穴对的转移动力学. 此外, 通过原位傅里叶变换红外光谱研究了催化剂表面HMF氧化过程中官能团的变化, 不仅加深了对纯ZnIn2S4体系中HMF过度氧化现象的认识, 还揭示了S型异质结在选择性氧化HMF和原位生成H2O2中的独特光催化机制.

综上所述, 本文构建了2D/2D层状BiOBr/ZnIn2S4 S型异质结, 不仅实现了光生电子-空穴的有效空间分离, 还提高了产物选择性和光催化效率. 本文通过深入研究S型异质结在光催化反应中的作用机制, 为调控光催化产物提供了新的见解, 并为有机合成相关反应中S型异质结的设计提供了借鉴.

关键词: BiOBr/ZnIn2S4, S型异质结, 过氧化氢制备, 5-羟甲基糠醛选择性转化, 转化机理

Abstract:

The utilization of semiconductor-based photocatalytic technology holds immense promise for harnessing solar energy. However, the inherent issue of strong Coulombic attraction between photo-generated electrons and holes within a single photocatalyst often leads to rapid recombination, limiting efficiency. Addressing this challenge, the development of S-scheme heterojunction photocatalysts has emerged as an effective strategy. Nevertheless, the impact of this spatial separation on the photocatalytic reaction has remained largely unexplored. This study reveals that the recombination of useless charge carriers significantly influences the oxidation product. In the pristine ZnIn2S4 system, the spatially unseparated holes interact with the H2O2 generated on the surface of ZnIn2S4, all of which are converted to •OH with higher oxidation ability, causing excessive oxidation of 5-hydroxymethylfurfural (HMF). Conversely, the BiOBr/ZnIn2S4 system, effective separation of electrons and holes in space, selectively oxidizes HMF into valuable 2,5-dimethylfuran (DFF) while efficiently generating H2O2 (1.15 mmol∙L-1, 5 h). This outcome, elucidated through in-situ Fourier-transform infrared spectroscopy, density functional theory calculation, and femtosecond transient absorption spectroscopy, underscores the role of spatially separated charge carriers in influencing product selectivity within S-scheme heterojunctions. This work sheds new light on selective oxidation phenomena and underscores the significance of charge separation in S-scheme heterojunctions.

Key words: BiOBr/ZnIn2S4, S-scheme heterojunction, H2O2 production, 5-Hydroxymethylfurfural conversion, Transformation mechanism