Dual Effect of Ag Doping and S Vacancy on H2 Detection for SnS2 Based Photo-Induced Gas Sensor at Room Temperature

Hydrogen (H₂) monitoring demonstrates significant practical importance for safety assurance in industrial production and daily life, driving the demand for gas sensing devices with enhanced performance and reduced power consumption. This study presented a room-temperature (RT) hydrogen sensing platform utilizing two-dimensional (2D) Ag-doped SnS₂ nanomaterials activated by light illumination. The Ag-SnS₂ nanosheets, synthesized through hydrothermal methods, exhibited exceptional H₂ detection capabilities under blue LED light activation. The synergistic interaction between silver dopants and photoactivation enabled remarkable gas sensitivity across a broad concentration range (5.0-2500 ppm), achieving rapid response/recovery times (4 s/18 s) at 2500 ppm under RT. Material characterization revealed that Ag doping induced S vacancy, enhancing oxygen adsorption, while simultaneously facilitating photo-induced hole transfer for surface hydrogen activation. The optimized sensor maintained good response stability after five-week ambient storage, demonstrating excellent operational durability. Experimental results further elucidated that Ag dopants enhancing hydrogen adsorption-activation while S vacancy improved surface oxygen affinity. This work provided fundamental insights into defect engineering strategies for developing optically modulated gas sensors, proposing a viable pathway for constructing energy-efficient environmental monitoring systems.