A review of non-oxide semiconductors for photoelectrochemical water splitting

The process of photoelectrochemical (PEC) water splitting using semiconductor materials offers a remarkable opportunity to convert incident solar energy into chemical energy in hydrogen in a single step. This review chronicles the significant efforts made in developing non-oxide semiconductor materials to enable efficient hydrogen production using this process. We highlight some of these spectacular developments, ranging from the design of entirely new materials to innovative engineering of existing and known non-oxide semiconductors materials in terms of their morphology, composition and band structure such they can act as viable photoelectrodes. We start with a primer on fundamentals of the PEC process, followed by an overview of the materials development efforts. Then the review focuses on a key challenge in the large-scale uptake of these promising non-oxide materials, namely that of stability when in contact with harsh acidic or alkaline electrolytes. The review ends by outlining some of the next generation photoactive materials that are currently being pursued. We anticipate this review will spur on further research and development of non-oxide materials and devices, through both theoretical and experimental works. It is hoped ultimately to realize breakthrough non-oxide semiconductors that will enable improved performance, longer lifetimes and reduced production costs of hydrogen.