Systematic Development of Visible-Light-Responsive d ⁰ Transition-Metal Oxysulfide Photocatalysts

Heteroanionic oxysulfides have emerged as promising visible-light-responsive photocatalysts; however, the systematic development of non-Ti-based materials and the elucidation of their photocatalytic properties remain relatively unexplored. Here, we report the synthesis of two families of d0 transition-metal oxysulfides, RE3MS3O4 (RE = Sm, Y; M = Nb, Ta) and Y2M′2S3O4 (M′ = Zr, Hf), via a solid-state reaction route and demonstrate their visible-light-driven photocatalytic activity. All materials exhibit narrower band gaps (2.71–3.30 eV) than their oxide counterparts (>4.05 eV), and most of them enable hydrogen or oxygen evolution from aqueous solutions under visible-light irradiation (λ ≥ 400 nm) in the presence of sacrificial agents. Comparative evaluation reveals that Y2Zr2S3O4 outperforms the other tested materials. This superior performance can be attributed to its two-dimensional (2D) layered structure and needle-like morphology, which result in a larger surface area and a longer carrier lifetime. Furthermore, selective Rh3+ substitution at the Zr4+ site in Y2Zr2S3O4 leads to a remarkable enhancement in visible-light-driven photocatalytic activity, achieving a 7-fold increase in the hydrogen evolution rate. These findings establish d0 transition-metal oxysulfides as a versatile and tunable platform for visible-light-responsive photocatalysis and highlight the effectiveness of the heteroanionic strategy for the rational design of next-generation photocatalysts for solar-driven water splitting.