Coral-like Sb2Se3/SnS2 photocathode co-optimized by bilayer Sb2Se3 structure and hole-storage layer for photoelectrochemical water splitting

Achieving high light absorption efficiency and low photogenerated carrier recombination rates is critical in the production of H2 by photoelectrochemical water splitting. Antimony selenide (Sb2Se3) has recently received much attention due to its favorable optoelectronic properties, low cost and unique nanorod structure. Herein, we constructed coral-like Sb2Se3/SnS2 heterojunction by introducing SnS2 with a nanosheet structure, which contributes to enhanced light absorption and provides more reaction sites. On this basis, synergistic optimization is carried out by the bilayer Sb2Se3 structure and ferrihydrite (Fh) to effectively inhibit charge recombination at the interface and facilitate electron transport. Compared to monolayer Sb2Se3 (1.54%), the IPCE value of bilayer Sb2Se3/SnS2/Fh can reach 20.56% (735 nm). The prepared bilayer Sb2Se3/SnS2/Fh has a maximum photocurrent density of approximately − 1.0 mA cm−2 at 0 VRHE, continuous testing for 1 h compared to monolayer Sb2Se3 still maintains more than 4 times improvement. This work provides a basis for the development of high efficiency and low cost Sb2Se3-based optoelectronic devices. © 2022 Elsevier B.V.