A Place in the Sun for Artificial Photosynthesis?

Artificial photosynthesis enables the possibility of generating clean, sustainable, and large-scale energy resources through water splitting and renewable chemical fuel syntheses. With several decades of research, the scientific community still encounters great academic and technological challenges to efficiently generate hydrogen from water with sunlight at large scale and low cost. Recent developments based on novel system designs have led to significant advances in the fundamental understanding of light-induced charge dynamics and related interfacial chemical reactions and efficiencies. This Review provides a thorough overview of the very recent progress in new materials and photoelectrochemical system designs, surface engineering strategies, and efficient new cocatalysts for hydrogen and oxygen evolution reactions (HER and OER) as well as advanced spectroscopic studies related to photogenerated charge dynamics and interfacial electronic structure. A focus is given on newly developed strategies to improve the rate-determining steps, as well as emerging approaches for surface modifications, surface reaction dynamics, and optimal device structure design from a charge transfer viewpoint. Finally, a promising new system is being proposed and described, derived from the overall understanding, mechanisms, and concepts reported in the literature for efficient and stable water-splitting systems.