Tuning photocatalytic behavior of ZnS nanoparticles through multi-metal doping: Insights and advances

Multi-metal doped ZnS nanoparticles have emerged as a highly efficient class of visible-light-responsive photocatalysts for environmental remediation. Strategic co-doping with transition and main-group metals modulates the electronic structure, generates defect-mediated active sites, and enhances charge-carrier separation, thereby facilitating the formation of reactive oxygen species for the degradation of industrial dyes, pharmaceuticals, and other persistent organic pollutants. This review systematically summarizes recent advances in the synthesis, structural engineering, and photocatalytic applications of multi-metal-doped ZnS nanomaterials. Particular emphasis is placed on dopant-induced band structure modification, defect-mediated charge separation, and reactive oxygen species (ROS)-driven degradation mechanisms. The influence of dopant combinations, concentrations, and synthesis routes on photocatalytic efficiency is critically discussed, along with key challenges such as dopant-induced recombination, structural instability, and scalability. Overall, multi-metal-doped ZnS represents a versatile and tunable platform for the development of efficient and sustainable photocatalysts for wastewater treatment under solar irradiation.