The design of efficient devices for the photoelectrochemical (PEC) water splitting for solar-to-hydrogen (STH) processes has gained much attention because of the fossil fuels crisis. In PEC water splitting, solar energy is converted to a chemical fuel for storage. From the viewpoint of economics and large-scale application, semiconductor photoelectrodes with high stability and efficiency are required. However, although numerous materials have been discovered, challenges remain for their commercialization. Among the enormous number of investigated materials, layered transition metal dichalcogenide (TMD)-based photoelectrodes show attractive performance in PEC devices owing to their suitable narrow bandgaps, high absorption capacity, and fast carrier transport properties. A comprehensive review of TMDs photoelectrodes for STH processes would help advance research in this expanding research area. This review covers the physicochemical features and latest progress in various layered-structure TMD-based photoelectrodes, especially MoS2, as well as various approaches to improve the PEC performance and stability by coupling with active carbon materials, including graphene, CNTs, and conductive carbon. Finally, we discuss the prospects and potential applications for STH processes. This review paper gives insights into the fundamental concepts and the role of active chemical species during the STH conversion processes and their influence in enhancing PEC water splitting performance.
Thermodynamically Stable Synthesis of Large-Scale and Highly Crystalline Transition Metal Dichalcogenide Monolayers and their Unipolar n-n Heterojunction Devices