Enhanced photoelectrochemical performance of Sb2S3/Bi2S3/Fe2O3 heterojunction via bond-induced rapid electron transfer channels

Heterostructures based on Fe2O3 have been extensively studied, but their application is limited by severe carrier recombination issues. In this work, we developed a visible-light-responsive Sb2S3/Bi2S3/Fe2O3 photoanode, whose outstanding performance stemed from the hypothesis of utilizing the similar chain-like crystal structures and matched band structures of Sb2S3 and Bi2S3 to construct rapid electron transport channels. Characterization and computational simulations revealed the formation of new chemical bonds, Fe-S-Bi and Sb-S-Bi, at the heterojunction interface, which create an internal electric field and induce band bending. Consequently, this photoanode achieved a photocurrent density of 2.91 mA & sdot;cm-2, which was 101 times higher than that of Fe2O3 and superior to other reported composite photoelectrodes of the same category. This design approach, originating from a fresh perspective, provides a new direction for constructing new types of heterostructures and offers more options for the development of high-performance photoelectric devices.