A dendritic Sb2Se3/In2S3 heterojunction nanorod array photocathode decorated with a MoSx catalyst for efficient solar hydrogen evolution

Abstract

Developing cost-effective photocathodes that show desirable performance for use in commercial photoelectrochemical water splitting devices remains a fundamental and practical challenge. Sb₂Se₃ semiconductors satisfy most of the demands expected for an ideal highly efficient photocathode, including favorable cost and optoelectronic properties. Herein, we have demonstrated outstanding photoelectrodes using a noble-metal-free catalyst, namely, a MoS_x-decorated low-cost Sb₂Se₃/In₂S₃ heterojunction, as the photocathode. This enabled a maximum photocurrent density of up to −27 mA cm⁻² (0 V vs. RHE, 100 mW cm⁻², AM 1.5G filter) with a remarkable half solar-to-hydrogen conversion efficiency (STH) of 2.6%, obtained via decreasing charge recombination and accelerating charge transfer through morphological optimization of the In₂S₃ layer.