In Situ Construction of Z-Scheme BiFeO3/Bi2S3 Heterojunction for Photoelectrochemical Detection of Hydrogen Sulfide in Wines

This study developed and validated a photoelectrochemical (PEC) platform for hydrogen sulfide (H 2 S) analysis in alcoholic beverages by electrodepositing/annealing dense BiFeO 3 films on FTO and converting them in situ into BiFeO 3 /Bi 2 S 3 heterojunctions. Phase formation and elemental redistribution were verified by XRD, SEM/EDS, and XPS; UV–vis/Tauc and Mott–Schottky supported broadened visible absorption and a direct Z-scheme alignment, while EIS revealed a markedly lowered interfacial charge-transfer resistance. Under optimized conditions, the sensor delivered a linear range of 0.1‒100 μM with an LOD of 36 nM, along with good selectivity against common anions and thiol-bearing interferents and excellent cycling photostability. In real matrices, standard additions achieved recoveries of 99.2%‒103.5% in water; beer and red wine contained 1–2 μmol·L ‒1 H 2 S with 94.5%‒106.5% recoveries. These results demonstrated that in situ chemical conversion coupled with Z-scheme interfacial engineering offers a simple, robust, and general route to rapid, sensitive, and matrix-tolerant PEC monitoring of H 2 S in complex fermented beverages.