Construction of g-C3N4-based photoelectrodes towards photoelectrochemical water splitting: A review

The conversion of solar energy into chemical energy via photoeletrochemical water splitting technology is a promising strategy to contribute to carbon-neutral systems. In order to rapidly promote pollution-free technology for large-scale use, the required photoelectrode materials need high efficiency, low cost and stability. Interestingly, graphitic carbon nitride (g-C3N4) has attracted much attention, due to its low cost, narrow bandgap, facile synthesis, nontoxic and high stability. These particular properties of g-C3N4 will be beneficial to the development of high-efficiency photoelectrode materials. Up to now, relatively few g-C3N4-based photoanode materials have been studied and reported, so there is a lack of a systematic analysis on g-C3N4-based photoanodes. This review focuses on the recent progress in the design and construction of g-C3N4-based photoelectrodes via the incorporation of various composite materials in the field of photoelectrochemical water splitting. These composite materials include metal oxide, metal hydroxide and metal sulfide, such as NiO, CuO, BiVO4, BiOI, Ni(OH)2, CoMn-layered double hydroxide, MoS2, ZnS, etc. Furthermore, the effects of different kinds of semiconductor promoters on enhanced photoelectrochemical water splitting performance are elucidated in detail. Finally, some challenges and perspectives of high efficiency g-C3N4-based photoelectrodes in the field of photoelectrocatalysis are also proposed.