物理化学学报 >> 2021, Vol. 37 >> Issue (6): 2010017.doi: 10.3866/PKU.WHXB202010017

所属专题: 先进光催化剂设计与制备

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用于光催化能量转换的Z-型异质结的研究进展

刘东, 陈圣韬, 李仁杰(), 彭天右()   

  • 收稿日期:2020-10-11 录用日期:2020-11-16 发布日期:2020-11-26
  • 通讯作者: 李仁杰,彭天右 E-mail:lirj@whu.edu.cn;typeng@whu.edu.cn
  • 作者简介:Dr. Renjie Li received his BS in applied chemistry in 2003 and his Ph.D. in inorganic chemistry in 2008 from Shandong University. He joined the faculty of Wuhan University in 2008 and is now an associate professor. He currently works on solar cells and photocatalysis using the functional materials, such as the phthalocyanines and porphyrins.
    Prof. Tianyou Peng received his Ph.D. degree in Chemistry from Wuhan University, China in 1998. He did a post-doc at Kyoto University, Japan with Prof. K. Hirano. He has been a full Professor at College of Chemistry and Molecular Sciences of Wuhan University since 2004. Right now, he is the Director of the Institute of Inorganic Chemistry in Wuhan University. His scientific interests are in inorganic chemistry, material chemistry, and nanomaterials including dye-sensitized solar cell and clean energy production including photocatalytic H2 production, CO2 conversion and N2 fixation.
  • 基金资助:
    国家自然科学基金(21975190);国家自然科学基金(21871215);国家自然科学基金(21631003);国家自然科学基金(21573166);深圳市科技创新委员会科技项目(JCYJ20180302153921190);江苏省自然科学基金(BK20151247);湖北省创新群体(2014CFA007)

Review of Z-Scheme Heterojunctions for Photocatalytic Energy Conversion

Dong Liu, Shengtao Chen, Renjie Li(), Tianyou Peng()   

  • Received:2020-10-11 Accepted:2020-11-16 Published:2020-11-26
  • Contact: Renjie Li,Tianyou Peng E-mail:lirj@whu.edu.cn;typeng@whu.edu.cn
  • About author:Tianyou Peng, Email: typeng@whu.edu.cn; +86-27-68752237(T.P.)
    Renjie Li, Email: lirj@whu.edu.cn ; Tel.: +86-27-68752237(R.L.)
  • Supported by:
    the Natural Science Foundation of China(21975190);the Natural Science Foundation of China(21871215);the Natural Science Foundation of China(21631003);the Natural Science Foundation of China(21573166);the Science & Technology Planning Project of Shenzhen Municipality, China(JCYJ20180302153921190);Natural Science Foundation of Jiangsu Province, China(BK20151247);the Funds for Creative Research Groups of Hubei Province, China(2014CFA007)

摘要:

受植物光合作用的启发,研究者发展了多种模拟光合作用体系用于光分解水、二氧化碳光还原和氮光固定以生产“太阳燃料”(如氢气、甲烷和氨气),以期缓解当前的能源短缺和环境污染。尽管基于人造半导体材料的光合作用是一种潜在、理想的以“太阳燃料”的化学键形式存储太阳能的方法,但是构筑能够在规模和成本方面与化石燃料竞争的生产“太阳燃料”的人工光合作用体系仍然存在巨大的挑战。因此,开发低成本的高效光催化剂对于促进人工光合作用的三种主要光催化过程(光俘获、电荷产生与分离,以及表面/界面催化反应)具有重要的意义。在已研究的各类光催化剂中,Z-型异质结复合体系不仅可以提高光俘获能力和显著抑制电荷载流子复合,而且还可通过保持光激发电子/空穴的强还原/氧化能力来促进表面/界面催化反应,因而受到广泛关注。将太阳能转化为化学能的Z-型纳米异质结的研究证明这些异质结在提高生产“太阳燃料”的光催化反应体系的整体效率方面的重要性。该综述主要介绍了Z-型异质结的发展历史和直接Z-型异质结相较于传统Ⅱ型异质结、液相Z-型和全固态Z-型异质结的优势,并阐述了两步激发Z-型光催化体系的反应机理和途径。然后,从材料组成角度重点介绍了近5年来不同类型Z-型纳米结构材料(无机,有机和无机-有机复合材料)在光催化能源转换领域的应用,以及提高Z-型纳米结构材料光催化性能的各种调控/工程策略(如扩展光谱吸收区、促进电荷转移/分离和表面化学改性等)。此外,还讨论了Z-型光催化机理的表征方法与策略(如金属负载法、牺牲试剂测试法、自由基捕集实验、原位X-射线光电子能谱、光催化还原实验、Kelvin探针力显微镜、表面光电压光谱、瞬态吸收光谱及理论计算等)及光催化性能的评价方法和标准。最后,介绍了Z-型异质结光催化体系目前面临的挑战和发展方向。我们希望该综述能为光催化体系的性能突破方向提供新的认识,并为新型Z-型光催化材料的设计和构筑提供指导。

关键词: 半导体, 光催化, Z-型异质结, 能源转化, 反应机理

Abstract:

Inspired by the photosynthesis of green plants, various artificial photosynthetic systems have been proposed to solve the energy shortage and environmental problems. Water photosplitting, carbon dioxide photoreduction, and nitrogen photofixation are the main systems that are used to produce solar fuels such as hydrogen, methane, or ammonia. Although conducting artificial photosynthesis using man-made semiconducting materials is an ideal and potential approach to obtain solar energy, constructing an efficient photosynthetic system capable of producing solar fuels at a scale and cost that can compete with fossil fuels remains challenging. Therefore, exploiting the efficient and low-cost photocatalysts is crucial for boosting the three main photocatalytic processes (light-harvesting, surface/interface catalytic reactions, and charge generation and separation) of artificial photosynthetic systems. Among the various photocatalysts developed, the Z-scheme heterojunction composite system can increase the light-harvesting ability and remarkably suppress charge carrier recombination; it can also promote surface/interface catalytic reactions by preserving the strong reductive/oxidative capacity of the photoexcited electrons/holes, and therefore, it has attracted considerable attention. The continuing progress of Z-scheme nanostructured heterojunctions, which convert solar energy into chemical energy through photocatalytic processes, has witnessed the importance of these heterojunctions in further improving the overall efficiency of photocatalytic reaction systems for producing solar fuels. This review summarizes the progress of Z-scheme heterojunctions as photocatalysts and the advantages of using the direct Z-scheme heterojunctions over the traditional type Ⅱ, all-solid-state Z-schemel, and liquid-phase Z-scheme ones. The basic principle and corresponding mechanism of the two-step excitation are illustrated. In particular, applications of various types of Z-scheme nanostructured materials (inorganic, organic, and inorganic-organic hybrid materials) in photocatalytic energy conversion and different controlling/engineering strategies (such as extending the spectral absorption region, promoting charge transfer/separation and surface chemical modification) for enhancing the photocatalytic efficiency in the last five years are highlighted. Additionally, characterization methods (such as sacrificial reagent experiment, metal loading, radical trapping testing, in situ X-ray photoelectron spectroscopy, photocatalytic reduction experiments, Kelvin probe force microscopy, surface photovoltage spectroscopy, transient absorption spectroscopy, and theoretical calculation) of the Z-scheme photocatalytic mechanism, and the assessment criteria and methods of the photocatalytic performance are discussed. Finally, the challenges associated with Z-scheme heterojunctions and the possible growing trend are presented. We believe that this review will provide a new understanding of the breakthrough direction of photocatalytic performance and provide guidance for designing and constructing novel Z-scheme photocatalysts.

Key words: Semiconductor, Photocatalysis, Z-scheme heterojunction, Energy conversion, Reaction mechanism