Zn-Passivated CsPbBr3@MoS2 Heterostructuresfor Efficient Photocatalytic Hydrogen Evolution in Acidic AqueousMedia

Abstract Lead-halide perovskite nanocrystals (PNCs) are highly attractive photocatalysts because they combine strong visible light absorption with favorable carrier transport, yet their use in the hydrogen evolution reaction (HER) remains severely limited by poor stability in aqueous and H+ containing media. Here, we report an interfacial design that addresses this limitation by growing CsPbBr3 nanocrystals (NCs) in situ on few-layer MoS2 to form acidic aqueous-stable heterostructures for photocatalytic hydrogen evolution. In this architecture, MoS2 serves both as a hydrogen-evolution cocatalyst and as an ultrathin scaffold that protects the PNCs while preserving interfacial charge-transfer pathways. We further refine the heterointerface through surface-localized Zn incorporation, which passivates halide-related trap sites and accelerates electron transfer from CsPbBr3 to MoS2 without perturbing the intrinsic band-edge structure of the PNCs. Structural, spectroscopic, and photoelectrochemical analyses collectively show that the improved performance arises from cooperative control of interfacial architecture, carrier extraction, and surface recombination. The optimized Zn incorporated CsPbBr3 within MoS2 heterostructure (CsPbBr3_Zn@MoS2) delivers a hydrogen evolution rate of 430 μmol g–1 h–1 in aqueous 1% HBr under 1.5 sun white-light illumination, with stable activity maintained up to 40 h. As one of the earliest demonstrations of the aqueous-phase HER using CsPbBr3-based PNCs and among the highest activities reported in this emerging area, this work establishes that in situ cocatalyst integration and surface passivation can render intrinsically fragile PNCs compatible with demanding acidic aqueous catalytic conditions.