Hydrophobic sulfur vacancy rich MoS(2) encapsulation of lead-free halide perovskites for aqueous catalysis.

Halide perovskites are promising for aqueous pollutant remediation but are hindered by rapid degradation in water. Here, we engineer hydrophobically encapsulated CsSnBr-MoS (CSB-MS) heterojunctions, in which sulfur-vacancy-rich MoS nanosheets conformally wrap CsSnBr (CSB) nanocrystals to form a robust - interface that simultaneously blocks moisture ingress and enables efficient interfacial charge transfer. Sulfur vacancies promote defect-assisted charge separation and suppress Sn oxidation, leading to significantly enhanced aqueous stability. The optimized hybrid achieves 98% methylene blue and 94% levofloxacin degradation, with apparent photon efficiencies of 35.5% and 25.5%, respectively, and shows further enhancement under photo-electrocatalytic conditions. A type-II band alignment prolongs carrier lifetimes (∼70%) and reduces reaction barriers, while post-catalysis analyses confirm structural integrity after repeated cycles. These results establish a versatile interfacial design strategy for stabilizing lead-free perovskites, advancing their application in sustainable water treatment.