物理化学学报 >> 2023, Vol. 39 >> Issue (6): 2212016.doi: 10.3866/PKU.WHXB202212016

所属专题: S型光催化剂

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S-Scheme异质结光催化产氢研究进展

吴新鹤(), 陈郭强, 王娟, 李金懋, 王国宏()   

  • 收稿日期:2022-12-09 录用日期:2023-01-02 发布日期:2023-01-06
  • 通讯作者: 吴新鹤,王国宏 E-mail:wuxinhe@hbnu.edu.cn;wanggh2003@163.com

Review on S-Scheme Heterojunctions for Photocatalytic Hydrogen Evolution

Xinhe Wu(), Guoqiang Chen, Juan Wang, Jinmao Li, Guohong Wang()   

  • Received:2022-12-09 Accepted:2023-01-02 Published:2023-01-06
  • Contact: Xinhe Wu, Guohong Wang E-mail:wuxinhe@hbnu.edu.cn;wanggh2003@163.com

摘要:

随着不可再生能源的大量消耗,能源短缺成为人类社会面临的重大挑战。在众多新能源制备技术中,光催化分解水制氢技术只需丰富的太阳能作为驱动力就可以实现分解水制氢,且制氢条件温和、绿色无污染,被认为是解决当前能源短缺危机的有效技术之一。光催化制氢技术的核心是光催化剂,因此发展高效稳定的光催化剂至关重要。然而,单组分光催化剂由于空穴-电子复合速度快、氧化还原能力有限、太阳能利用效率低等原因,通常只能呈现出有限的光催化分解水制氢活性。为此,科研人员做了大量改性研究,其中常见的改性策略有元素掺杂、助催化剂修饰、构建异质结等。通常,元素掺杂、助催化剂修饰等改性手段可以在一定程度上提高光催化剂的制氢活性,但并不能有效解决单相光催化剂的缺陷,导致其改性效果受到制约。然而,在两个或多个半导体之间构建异质结可以有效解决上述单组分光催化剂的缺陷。相较于当前流行的传统II型异质结和Z-型异质结,S-型异质结的电荷转移机制更为合理,受到科学家们的广泛关注与应用。因此,本文首先对S-型异质结光催化体系的发展背景进行介绍,包括传统II型异质结、全固态Z-型异质结和液相Z-型异质结光催化系统。随后对S-型异质结光催化机理进行具体阐述,并对其机理表征方法进行了概述,包括原位XPS光谱、开尔文探针力显微镜、电子顺磁共振、选择性沉积和密度泛函理论计算。此外,本文系统总结了当前报道的S-型异质结光催化剂在分解水制氢领域中的应用及其制氢性能增强机理分析,包括g-C3N4基、金属硫化物基、TiO2基、其他氧化物基等S型异质结光催化剂。总体而言,S型异质结光催化剂由于其有效的载流子分离和增强的光氧化还原能力,通常呈现出优异的光催化制氢性能。最后,指出了S型异质结光催化剂在分解水产氢中的发展瓶颈,并展望攻克该瓶颈以进一步提高S型异质结的光催化效率,从而达到工业应用标准。

关键词: 光催化, 产氢, 异质结, S型

Abstract:

With the gradual depletion of conventional fossil fuels, serious energy shortage has become a major societal challenge. Among the numerous new energy generation technologies, photocatalytic water splitting for hydrogen production only requires abundant solar energy as the driving force and the process conditions are mild, green, and pollution-free. Thus, this technology has been proposed as an effective strategy to solve the current energy shortage crisis. The core of the photocatalytic hydrogen production technology is the photocatalyst. Therefore, it is necessary to develop efficient and stable photocatalysts. However, single-component photocatalysts usually exhibit insufficient photocatalytic H2 evolution efficiencies owing to its rapid hole-electron recombination, limited redox ability and low solar energy utilization efficiency. Therefore, various modification approaches have been designed to improve the photocatalytic H2 evolution efficiency of single-component photocatalysts, such as element doping, cocatalyst modification, heterojunction construction, etc. Generally, element doping and cocatalyst modification improve the photocatalytic hydrogen production activity but cannot effectively solve the drawbacks of single-component photocatalysts, which limits their ability to improve the photocatalytic performance. However, constructing heterojunctions between two or more semiconductors simultaneously resolves these drawbacks. Compared with currently used conventional type-Ⅱ all-solid-state Z-scheme, and liquid-phase Z-scheme heterojunctions, S-scheme heterojunctions present a more reasonable charge transfer mechanism, which is of great concern to and extensively used by several researchers. Therefore, this review firstly introduces the research background on S-scheme heterojunction photocatalytic systems, including the photocatalytic charge transfer mechanism of conventional type-Ⅱ, all-solid-state Z-scheme, and liquid-phase Z-scheme heterojunction systems. Subsequently, the photocatalytic mechanism of S-scheme heterojunctions is meticulously explained. Additionally, the corresponding characterization methods, including in situ irradiated X-ray photoelectron spectroscopy (ISIXPS), Kelvin probe force microscopy (KPFM), selective deposition, electron paramagnetic resonance (EPR), density functional theory (DFT) calculations, etc., are briefly summarized. Moreover, currently reported photocatalytic water splitting S-scheme heterojunctions and the corresponding significant enhancement in the hydrogen evolution mechanism are systematically summarized, including g-C3N4-, metal sulfide-, TiO2-, other oxide-, and other S-scheme heterojunction-based photocatalysts. Notably, S-scheme heterojunction photocatalysts typically exhibit highly improved photocatalytic H2 evolution performance owing to their effective carrier separation and enhanced photoredox capacities. Finally, the bottlenecks of developing S-scheme heterojunctions for photocatalytic H2 production are presented, which require further investigation to enhance the photocatalytic efficiency of S-scheme heterojunctions for achieving industrial application standards.

Key words: Photocatalysis, H2-evolution, Heterojunction, S-scheme