Interfacial regulation of photoanodes for photoelectrochemical water splitting: the role of Interlayer and overlayer

Abstract

Green hydrogen stands as a pivotal component in constructing a sustainable energy system. Photoelectrochemical (PEC) water splitting has theoretically high efficiency for solar energy conversion and promises zero pollution in the hydrogen production process. However, the efficiency for industrial application and the stability of long-term operation still limit the pace of development. The design of efficient and stable photoelectrodes requires careful synergistic regulation of multiple interlayers and overlayer. This review presents the key role of interlayers or overlayer in the field of PEC water splitting, particularly in photoanode modification. Firstly, the effects of interface states on photoelectrode is emphasized, highlighting the significance of interface state passivation in minimizing surface recombination and maximizing charge separation. Subsequently, the various roles played by the interlayers and overlayer in improving the overall performance of photoanodes were classified and elaborated. These include interface states passivation to enhance charge separation efficiency, regulation of charge transport mechanisms across interlayers, construction of hole storage layers, serving as protective layers, and acting as a catalyst layers. Finally, this review points out the challenges and perspectives for future development of interlayers in PEC water splitting.