Toward a fundamental understanding of factors affecting the function of cocatalysts in photocatalytic water splitting

Although numerous cocatalysts in photocatalytic water splitting have been studied, the fundamental understanding of factors affecting the function of cocatalysts is limited. This brief review summarizes the progress of cocatalysts in the last 3 years. The effects of intrinsic characters of cocatalysts including morphology, crystallization, and composition are first examined. The influence of interfacial coupling of cocatalysts with host photocatalysts, such as cocatalyst location, built-in electric field, and contact manner, is subsequently discussed. To confirm the active species of cocatalysts, some in situ/operando characterization techniques are finally introduced. It is expected that this brief review would provide useful information to design efficient cocatalysts for photocatalytic water splitting.