Surface and interface design in cocatalysts for photocatalytic water splitting and CO2 reduction

Recent advances in photocatalysis highlight the important role of cocatalysts in improving the solar-to-chemical conversion efficiency for various reactions, such as water splitting and CO2 reduction reactions. Given that cocatalysts play two important roles, in charge trapping and surface reactions, the rational material design of cocatalysts would be an effective route in pursuing their maximum contribution to the performance of photocatalysts. In this review, we aim to outline the recent progress of surface and interface design in cocatalysts for photocatalytic water splitting and CO2 reduction. We first introduce the surface design of cocatalysts, which enables the enhancement of specific water splitting or CO2 reduction reactions through surface parameter (e. g., the composition, facets and phases) adjustments. We then present key parameters for designing the interface between photocatalyst and cocatalyst, which offer a set of versatile options for tuning the charge transfer to the cocatalyst. Taken together, the surface and interface of cocatalysts may have synergetic effects on the photocatalytic performance, which are discussed to provide guidance for simultaneously tailoring surface and interface parameters. Finally, we summarize the challenges and opportunities for the surface and interface design of cocatalysts for the efficient production of solar fuels.