Phase formation and photocatalytic properties of chalcostibite and tetrahedrite thin films derived from copper and antimony xanthates†

Metal sulfides receive great interest as solar absorber materials for photocatalysis and solar cells. Among them, copper antimony sulfide is a promising ternary metal sulfide. Copper antimony sulfide possesses four accessible phases, which have great potential in solar energy conversion and photocatalysis due to their energy levels and optical properties. However, the synthesis often requires high temperatures and prolonged reaction times. While the different phases are already well characterized, insights into their formation processes from specific precursors, which can enable targeted optimization of material properties, still remain largely unexplored. In this study, we investigated thin films of the two phases chalcostibite (CuSbS₂) and tetrahedrite (Cu₁₂Sb₄S₁₃), prepared from metal xanthate precursors. We used temperature-dependent grazing incidence X-ray scattering to analyze their thermal conversion process and crystal growth in detail. Furthermore, we evaluated their photocatalytic performance, revealing a good specific catalytic activity of 52 μmol g⁻¹ h⁻¹ for chalcostibite in methylene blue degradation. Additionally, tetrahedrite demonstrated high co-catalytic performance for hydrogen evolution in combination with mesoporous titania, achieving a specific activity exceeding 2.5 mmol g⁻¹ h⁻¹. The findings of this study provide valuable insights into the controlled synthesis of copper antimony sulfides and highlight their potential in solar-driven catalytic applications.