Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (1): 80-102.doi: 10.3866/PKU.WHXB201607293

• REVIEW • Previous Articles     Next Articles

Effective Strategies towards High-Performance Photoanodes for Photoelectrochemical Water Splitting

Wei-Tao QIU1,Yong-Chao HUANG1,Zi-Long WANG2,Shuang XIAO2,Hong-Bing JI1,*(),Ye-Xiang TONG1,*()   

  1. 1 School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, P. R. China
    2 Department of Chemistry, Hong Kong University of Science and Technology, Hong Kong 999077, P. R. China
  • Received:2016-05-30 Published:2016-12-29
  • Contact: Hong-Bing JI,Ye-Xiang TONG E-mail:jihb@mail.sysu.edu.cn;chedhx@mail.sysu.edu.cn
  • Supported by:
    the National Science Fund for Distinguished Young Scholars, China(21425627);National Natural Science Foundation of China(21461162003);National Natural Science Foundation of China(21476271);Natural Science Foundation of Guangdong Province, China(2014KTSCX004);Natural Science Foundation of Guangdong Province, China(2014A030308012)

Abstract:

Photoelectrochemical water splitting is to utilize collected photo-generated carrier for direct water cleavage for hydrogen production. It is a system combining photoconversion and energy storage since converted solar energy is stored as high energy-density hydrogen gas. According to intrinsic properties and band bending situation of a photoelectrode, hydrogen tends to be released at photocathode while oxygen at photoanode. In a tandem photoelectrochemical chemical cell, current passing through one electrode must equals that through another and electrode with lower conversion rate will limit efficiency of the whole device. Therefore, it is also of research interest to look into the common strategies for enhancing the conversion rate at photoanode. Although up to 15% of solar-to-hydrogen efficiency can be estimated according to some semiconductor for solar assisted water splitting, practical conversion ability of state-of-the-art photoanode has yet to approach that theoretical limit. Five major steps happen in a full water splitting reaction at a semiconductor surface:light harvesting with electron excitations, separated electron-hole pairs transferring to two opposite ends due to band bending, electron/hole injection through semiconductor-electrolyte interface into water, recombination process and mass transfer of products/reactants. They are closely related to different proposed parameters for solar water splitting evaluation and this review will first help to give a fast glance at those evaluation parameters and then summarize on several major adopted strategies towards high-efficiency oxygen evolution at photoanode surface. Those strategies and thereby optimized evaluation parameter are shown, in order to disclose the importance of modifying different steps for a photoanode with enhanced output.

Key words: Photoelectrochemical catalysis, Water splitting, Photoanode, Photocatalysis step, Modification strategy

MSC2000: 

  • O649