Current scenario in ternary metal indium sulfides-based heterojunctions for photocatalytic energy and environmental applications: A review

The mounting pressure of the energy crisis and environmental pollution has led to unprecedented developments in designing new age materials with superior properties for solar and visible light energy conversion. In light of this, semiconductor photocatalysts have been recognized the most preferred materials for the generation of clean energy and advanced water treatment. With strong visible light absorption, tuneable band width, low toxicity, excellent stability, and a longer lifetime of excited charge-carriers, indium sulphide and ternary metal indium sulphides (MISs) have high potential for applicability in fields of photocatalytic water detoxification, hydrogen evolution, and energy production. To harness the advantages to the fullest and address the inherent drawbacks, numerous metal indium sulphides, nanocomposites, and heterojunctions have been developed in addition to optical and defect engineering and hybridization. In this review, various synthetic routes for improved photo-catalytic performance are discussed, followed by discussions on Z-scheme, S-scheme, and p-n heterojunctions of metal indium sulfides. The most recent advances in the design and utilisation of metal indium sulfide-based heterostructures for photocatalytic applications in environmental contaminants degradation and energy con-version are then summarised. Lastly, some future prospective and future recommendations for photocatalytic activity are discussed. Finally, the challenges, outlook, and research directions for designing superior next-generation MISs-based photocatalysts are discussed.