g-C3N4-based photoelectrodes for photoelectrochemical water splitting: a review

Abstract

Converting intermittent energies into green and storable chemical fuels (like hydrogen) is of great importance to address the global energy crisis and environmental issues. Photoelectrochemical (PEC) water splitting is a promising technology designed for this purpose, but its wide application relies significantly on the exploration of both economic and efficient electrode materials. g-C₃N₄ is a metal-free, low-cost and visible-light responsive semiconductor that shows great potential as a photoelectrode material for PEC water splitting. However, due to the inherent disadvantages of g-C₃N₄ and the difficulty in fabricating homogeneous and concrete g-C₃N₄ films, its PEC performance has encountered a bottleneck. For further attention on and breakthroughs in the development of g-C₃N₄-based photoelectrodes, this review commences with the basic principle of PEC water splitting. Then, recent progress in the strategies for improving the properties of g-C₃N₄ and the quality of g-C₃N₄ film electrodes is critically discussed, following the introduction of the basic structure of g-C₃N₄ as well as its advantages and challenges for PEC applications. Furthermore, current challenges in and future perspectives on obtaining g-C₃N₄-based electrodes for highly efficient and stable PEC water splitting are presented finally.