Unveiling the potential of decorating tunable morphology of bismuth sulfide nanostructures on the Bi2WO6 nanosheets for enhanced photoelectrochemical performance

In this study, we used different sulfur sources (thiourea and sodium sulfide) in the hydrothermal vulcanization to create two types of Bi₂S₃/Bi₂WO₆ composite materials with different structures. We varied the vulcanization duration to control the degree of vulcanization of the samples. The composites made with sodium sulfide displayed a mix of particles and nanosheets, while those made with thiourea showed nanowires and nanosheets. The choice of sulfur source had a significant impact on the structural characteristics of the composite material. In photoelectrochemical experiments (PEC), the vulcanization-treated Bi₂S₃/Bi₂WO₆ composites improved significantly compared to the pristine Bi₂WO₆ template. In particular, the Bi₂S₃/Bi₂WO₆ composite prepared using sodium sulfide precursor for 4 h exhibited the best photocurrent density and the lowest charge transfer interface resistance. The improved performance is attributed to the suitable defect density and a Z-scheme mechanism facilitated by the built-in electric field at the interface, which effectively separated photogenerated carriers, increasing active species and significantly improving the composites' efficiency in PEC reactions.