A Stable and Efficient Photocathode Using an Sb₂S₃ Absorber in a Near-Neutral Electrolyte for Water Splitting

Antimony sulfide (Sb2S3) is a one-dimensional semiconductor stacking (Sb4S6)n ribbons with van der Waals force, which shows anisotropic features along different orientations. Controlling the grain orientation is an efficient strategy to enhance the PEC performance of Sb2S3 photocathodes. Here, we successfully fabricated a photocathode employing Sb2S3 as an absorber material with [hk1] orientation, which is suitable for sufficiently harvesting sunlight and efficient solar energy conversion. After sequentially depositing n-type CdS as a buffer layer, TiO2, and Pt, the completed Sb2S3-based photocathode yielded a record-high photocurrent density of −6.0 mA cm–2 at 0 V versus RHE in a near-neutral electrolyte (pH = 6.0) and an onset potential of +0.5 VRHE. In the stability testing, it could maintain ∼92% of the initial photocurrent density of 5.3 mA cm–2 after the continuous illumination of 60 min. Our experimental investigation confirmed that Sb2S3 is indeed a promising light-absorbing material for water splitting, which will promote further developments of Sb2S3-based photocathodes.