Acta Physico-Chimica Sinica ›› 2020, Vol. 36 ›› Issue (3): 1905068.doi: 10.3866/PKU.WHXB201905068

Special Issue: 光催化剂

• Review • Previous Articles     Next Articles

Recent Progress in Photocatalytic Hydrogen Evolution

Jinbo Pan1,Sheng Shen1,Wei Zhou1,Jie Tang1,Hongzhi Ding1,Jinbo Wang1,Lang Chen1,Chak-Tong Au1,Shuang-Feng Yin2,*()   

  1. 1 College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Provincial Hunan Key Laboratory for Cost-effective Utilization of Fossil Fuel Aimed at Reducing Carbon-dioxide Emissions, Hunan University, Changsha 410082, P. R. China
    2 College of Chemistry and Chemical Engineering, Hunan Institute of Engineering, Xiangtan 411104, Hunan Province, P. R. China
  • Received:2019-05-21 Accepted:2019-07-08 Published:2019-07-11
  • Contact: Shuang-Feng Yin E-mail:sf_yin@hnu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21725602);the National Natural Science Foundation of China(21476065);the National Natural Science Foundation of China(21671062);the National Natural Science Foundation of China(21776064);the Innovative Research Groups of Hunan Province(2019JJ10001);Hunan Provincial Innovation Foundation for Postgraduate(CX2018B193)

Abstract:

The photocatalytic hydrogen evolution reaction (PHER) has gained much attention as a promising strategy for the generation of clean energy. As opposed to conventional hydrogen evolution strategies (steam methane reforming, electrocatalytic hydrogen evolution, etc.), the PHER is an environmentally friendly and sustainable method for converting solar energy into H2 energy. However, the PHER remains unsuitable for industrial applications because of efficiency losses in three critical steps: light absorption, carrier separation, and surface reaction. In the past four decades, the processes responsible for these efficiency losses have been extensively studied. First, light absorption is the principal factor deciding the performance of most photocatalysts, and it is closely related to band-gap structure of photocatalysts. However, most of the existing photocatalysts have a wide bandgap, indicating a narrow light absorption range, which restricts the photocatalytic efficiency. Therefore, searching for novel semiconductors with a narrow bandgap and broadening the light absorption range of known photocatalysts is an important research direction. Second, only the photogenerated electrons and holes that migrate to the photocatalyst surface can participate in the reaction with H2O, whereas most of the photogenerated electrons and holes readily recombine with one another in the bulk phase of the photocatalysts. Hence, tremendous effort has been undertaken to shorten the charge transfer distance and enhance the electric conductivity of photocatalysts for improving the separation and transfer efficiency of photogenerated carriers. Third, the surface redox reaction is also an important process. Because water oxidation is a four-electron process, sluggish O2 evolution is the bottleneck in photocatalytic water splitting. The unreacted holes can easily recombine with electrons. Sacrificial agents are widely used in most catalytic systems to suppress charge carrier recombination by scavenging the photogenerated holes. Moreover, the low H2 evolution efficiency of most photocatalysts has encouraged researchers to introduce highly active sites on the photocatalyst surface. Based on the abovementioned three steps, multifarious strategies have been applied to modulate the physicochemical properties of semiconductor photocatalysts with the aim of improving the light absorption efficiency, suppressing carrier recombination, and accelerating the kinetics of surface reactions. The strategies include defect generation, localized surface plasmon resonance (LSPR), element doping, heterojunction fabrication, and cocatalyst loading. An in-depth study of these strategies provides guidance for the design of efficient photocatalysts. In this review, we focus on the mechanism and application of these strategies for optimizing light absorption, carrier separation and transport, and surface reactions. Furthermore, we provide a critical view on the promising trends toward the construction of advanced catalysts for H2 evolution.

Key words: Photocatalysis, Hydrogen evolution, Light absorption, Carriers separation, Surface reaction

MSC2000: 

  • O643