Hole‐Storage Enhanced a‐Si Photocathodes for Efficient Hydrogen Production

Abstract

Ferrihydrite (Fh) has been demonstrated as an effective interfacial layer for photoanodes to achieve outstanding photoelectrochemical (PEC) performance for water oxidation reaction owing to its unique hole‐storage function. However, it is unknown whether such a hole‐storage layer can be used to construct highly efficient photocathodes for hydrogen evolution reaction (HER). In this work, we report Fh interfacial engineering of amorphous silicon photocathode (with nickel as HER cocatalyst) achieving a photocurrent density of 15.6 mA cm−2 at 0 V vs. the reversible hydrogen electrode and a half‐cell energy conversion efficiency of 4.08 % in alkaline solution, outperforming most of reported a‐Si based photocathodes including multi‐junction configurations integrated with noble metal cocatalysts in acid solution. Besides, the photocurrent density is maintained above 14 mA cm−2 for 175 min with 100 % Faradaic efficiency for HER in alkaline solution. Our results demonstrate a feasible approach to construct efficient photocathodes via the application of a hole‐storage layer.

Epitaxial Grown Sb2Se3@Sb2S3 Core–Shell Nanorod Radial–Axial Hierarchical Heterostructure with Enhanced Photoelectrochemical Water Splitting Performance

“…Inspired by ferrihydrite, FeOOH was applied to the surface of the photocathode to give it an effect similar to that of the hole-storage of ferrihydrite. Research work around ferrihydrite has shown that ferrihydrite has the function of hole-storage on both photoanode and photocathode surfaces and that electrons can selectively pass through its interface to participate in the HER reaction. − The hole-storage of ferrihydrite is closely related to the crystalline water molecules in its molecular composition and the chemical environment of Fe 3+ ions . The FeOOH can be obtained from ferrihydrite by annealing at a certain temperature such that it is possible for FeOOH to have a similar effect to hole-storage.…”

Stability of Photocathodes: A Review on Principles, Design, and Strategies

“…Subsequently, Zhang et al. demonstrated that such a HSL also can be used to construct highly efficient photocathodes for hydrogen evolution reaction (HER) [57] . The efficient and durable a‐Si/Fh/Ni photocathode was designed for solar hydrogen production in alkaline solution.…”