Insights on advanced substrates for controllable fabrication of photoanodes toward efficient and stable photoelectrochemical water splitting

Abstract

Conversion of solar energy into H2 by photoelectrochemical (PEC) water splitting is recognized as an ideal way to address the growing energy crisis and environmental issues. In a typical PEC cell, the construction of photoanodes is crucial to guarantee the high efficiency and stability of PEC reactions, which fundamentally rely on rationally designed semiconductors (as the active materials) and substrates (as the current collectors). In this review work, we start with a brief introduction of the roles of substrates in the PEC process. Then, we provide a systematic overview of representative strategies for the controlled fabrication of photoanodes on rationally designed substrates, including conductive glass, metal, sapphire, silicon, silicon carbide, and flexible substrates. Finally, some prospects concerning the challenges and research directions in this area are proposed.

Zirconium Oxynitride Thin Films for Photoelectrochemical Water Splitting

“…Although electrical contact optimization is beyond the scope of the present work, integration of electron-selective contacts or interfacial TCOs for improved majority carrier extraction may provide a viable route to improving PEC performance characteristics. A recent review on the substrate choice for photoanodes can be found in Hou et al 42 To further investigate the stabilities of all samples, CA measurements were performed under constant illumination and an applied bias of 1.23 V vs RHE (Figure S7). Although these measurements confirm that the oxynitride films are more stable than the pure nitride films, all samples undergo degradation under sustained operation.…”

Recent advances on three-dimensional ordered macroporous metal oxide-based photoelectrodes for photoelectrochemical water splitting

“…In addition, using a suitable conductive scaffold and/or a hole transport layer in a photoanode can further enhance the charge transport and separation efficiency. 40,41 The introduction of oxygen vacancies in metal oxides is also effective in improving the PEC performance. 42 In addition to the mentioned approaches, decoration of metal oxides with functional materials like organic polymers and metal-organic frameworks (MOFs) can equally facilitate the charge transport and separation.…”

Dual Active Site Mediated Photocatalytic H2 Evolution through Water Splitting Using CeO2/PPy/BFO Double Heterojunction Catalyst

“…A significant number of new generation photocatalysts, including graphitic carbon nitrides, conjugated polymers, metal–organic frameworks (MOFs), covalent organic frameworks (COFs), boron nitride-based and MXene, etc. have also emerged. − Specifically, polypyrrole (PPy) nanostructures possess a narrow bandgap, which enables higher visible light harvesting, and extensive π-cloud delocalization renders higher electrical conductivity that facilitates greater charge separation and transfer, which makes them ideal for photocatalytic water splitting. − …”