Solution-processed CuSbS2 thin film: A promising earth-abundant photocathode for efficient visible-light-driven hydrogen evolution

Cost-effective photoelectrochemical water splitting requires highly efficient and inexpensive electrode materials. Herein, we report a novel earth-abundant photocathode for hydrogen evolution consisting of a CdS-modified CuSbS2 synthesized using low-cost and high-throughput solution processes. The prepared CuSbS2 thin film is homogenous over large area and exhibits desirable micrometer-sized columnar grain structure. The fabricated CuSbS2/CdS/Pt photocathode achieves a cathodic photocurrent of −4.2 mA cm−2 at 0 VRHE, an onset potential of 0.46 VRHE, and a stable cathodic photocurrent with nearly unity of Faraday efficiency for hydrogen production in neutral electrolyte under AM 1.5 G simulated sunlight illumination. In addition, the CuSbS2-based photocathode possesses a significant response to visible light with an optical absorption edge around 860 nm, so that the reported CuSbS2 photocathode offers potential for efficient use of solar radiation without resorting to expensive raw materials and fabrication techniques.