Hierarchical NiO/ZnS nanocomposite for optimal photocatalytic performance

Hierarchical nickel oxide (NiO) has recently garnered significant interest due to its abundant unsaturated bonds, oxygen vacancies, and defect sites. These features act as reaction centers, promoting effective photocatalytic performance. However, the fast photogenerated charge recombination rate impedes its practical utilization. To tackle this problem, we deposited nanoscale ZnS on hierarchical NiO using the Pseudo-successive ionic layer adsorption and reaction process, which is a facile, vacuum-free, cost-effective, and suitable for deposition at room-temperature. The enhanced dye degradation performance can be ascribed to the precise deposition of ZnS and the notable surface structure, which together create a dynamic p-n heterojunction that effectively suppresses photogenerated charge carriers. Various techniques like UV-visible spectrometer, X-ray diffraction, photoluminescence spectroscopy, scanning electron microscopy, X-ray photoelectron spectrometer, electrochemical spectroscopy, and photocurrent were used to assess the electrical, photocatalytic, optical, and morphological properties of the p-n heterojunction. The reactive species involved in dye degradation were identified and investigated using scavenger studies, and a plausible reaction mechanism was proposed.