Pt-free MoS2 co-catalyst enables record photocurrent density in Sb2Se3 photocathodes for highly efficient solar hydrogen production†
Abstract
Antimony selenide (Sb2Se3) emerges as a potential light-absorbing material for thin film photovoltaics and photoelectrochemical (PEC) water-splitting devices, due to its earth-abundant constituents and excellent photoelectric properties. However, losses caused by corrosion and sluggish charge transfer at the semiconductor/electrolyte interface require a co-catalyst to enhance these kinetic factors. In this study, MoS2 is employed as a cost-effective, noble-metal-free catalyst to enhance the photocurrent density (Jph), half-cell solar-to-hydrogen (HC-STH) conversion efficiency and stability of Sb2Se3-based photocathodes. Optimized thermodynamic/kinetic physical vapor deposition of MoS2 substantially improves PEC performance, resulting champion Mo/Sb2Se3/CdS/MoS2 photocathode that achieves a record Jph of 31.03 mA cm−2 at 0 VRHE and the highest HC-STH efficiency of 3.08%, along with stability for over 5 hours in an acidic (pH 1) buffer solution. It is systematically revealed that MoS2 reduces the photo-corrosion effect, decreases electron–hole recombination, and provides a significant increase in charge transfer efficiency at the semiconductor/electrolyte interface. This work highlights the potential of cost-effective, high-performance Sb2Se3-based photocathodes in advancing efficient PEC devices for solar hydrogen production.