Oriented construction of defective metal sulfides and their application in gas–solid reactions for pollutant detection and purification

Abstract

Metal sulfides, benefiting from their unique electronic structure and tunable active sites, are widely applied in gas–solid reactions in fields such as gas adsorption, sensing and energy conversion. As one of the core strategies to modulate the physicochemical properties of metal sulfides, defect engineering has shown great potential to enhance the gas–solid reaction performance in recent years. In this review, the construction methods and characterization techniques of defective metal sulfides were systematically summarized, and the influence of defect structures on gas–solid reactions was deeply discussed. From the perspective of intrinsic material properties, the introduction of defects not only exposes more active sites in metal sulfides for participation in reactions but also effectively modulates the electronic structure, narrows the bandgap, optimizes the band structure, and enhances charge transport efficiency, thereby improving the material's intrinsic reaction activity. From the perspective of reaction processes, defects can optimize the adsorption capacity for reactant gases, accelerate reaction rates, effectively lower reaction energy barriers, and regulate reaction pathways, ultimately enhancing the reaction selectivity. The current applications of defect engineering of metal sulfides in NH₃ and NO₂ sensing, CO₂ conversion and Hg⁰ removal are further summarized, and the potentiation mechanism of defect structures was elucidated. Finally, further prospects are proposed for the controllable synthesis, precise characterization and industrial application challenges of defects, providing a reference for the design of high-performance defect-type metal sulfides.