Geometric-electronic synergistic modulation in hollow CdS/high-entropy sulfide Schottky junctions for efficient photocatalytic hydrogen evolution

Severe charge recombination and inherent photocorrosion are two critical bottlenecks restricting the application of metal sulfide photocatalysts for solar-to‑hydrogen conversion. Herein, a “Geometric-Electronic Synergistic” strategy is proposed to overcome these limitations by constructing a high-entropy Schottky junction photocatalyst, where spinel-phase high-entropy sulfide (HES, CoNiCuTiVS x ) nanoparticles are anchored on hollow CdS spheres (CdS-h) via electrostatic self-assembly. Benefiting from the entropy stabilization effect, the multi-component HES maintains a high-symmetry spinel structure and exhibits superior metallic-like conductivity. Experimental characterizations combined with Density Functional Theory calculations reveal the underlying mechanism: Electronically, the HES possesses a significantly higher work function, inducing a substantial Fermi level difference upon contact with CdS. This establishes a robust Schottky junction with a strong built-in electric field, which acts as a powerful driving force for ultrafast interfacial electron extraction, thereby suppressing photocorrosion. Geometrically, the nanoscale thin-shell architecture of the hollow CdS physically shortens the bulk diffusion distance of photogenerated carriers, minimizing transport losses. Consequently, the optimized CH-20 composite achieves a remarkable hydrogen evolution rate of 11,942.23 μmol·g −1 ·h −1 under visible light, which is 3.94 and 2.55 times higher than that of pristine CdS-h and the binary Co 9 S 8 -based composite, respectively. This work not only demonstrates the superiority of high-entropy materials in modulating Schottky barriers but also provides a paradigm for designing efficient photocatalysts by integrating morphology engineering with entropy engineering.