Transition metal sulfides: From design strategies to environmental and energy-related applications

Over the preceding years, there has been a notable rise in scientific inquiry focused on nanocrystals composed of transition metal sulfides (TMSs) materials. This heightened interest stems from their potential applications in environmental conservancy and the advancement of renewable energy solutions. This is largely attributed to the plentiful availability of materials with readily adjustable electronic-optical, physical, and chemical characteristics. TMSs represent semiconducting compounds wherein sulfur functions as the anion coordinated with a metal cation. These compounds can exhibit mono-, bi-, or multiple forms of metal ions. The extensive range of TMSs materials offers a distinctive framework for generating a myriad of potential materials showcasing diverse chemical, physical, and electronic phenomena, along with innovative serviceable characteristics and applications. Unlocking the complete potential of these captivating materials necessitates the development of scalable techniques for fabricating cost-effective TMSs, heterostructures, and high-quality hybrids. This inclusive review delineates methodologies for the precise fabrication of TMSs, followed by an examination of the recent morphologies of TMSs nanocrystals achieved through various material fabrication techniques. This study highlights the notable contribution of various metal-sulfide-based nano-photocatalysts in efficiently degrading toxic organic pollutants, antibiotics, and dyes. Additionally, a detailed exploration of their role in water splitting for hydrogen fuel has been presented by specifying different charge transfer mechanisms in nanocomposites containing TMSs nanocrystals. Furthermore, TMSs-based electrodes for electrocatalytic and photoelectrocatalytic water splitting, carbon dioxide reduction, energy storage, and supercapacitance have been chartered in detail to cope with energy crises. Finally, some shortcomings of TMSs-based semiconductors are discussed from a future perspective in this review article. We hope this review article presents new directions for pollutant degradation, energy generation, and storage to reduce the impacts of global warming.