Recent advances in room-temperature hydrogen sulfide gas sensors: materials design, interface engineering, and sensing mechanisms
Abstract
Hydrogen sulfide (H2S) is a highly toxic, corrosive, and flammable gas generated from industrial production, petroleum refining, wastewater treatment, municipal waste, and anaerobic decomposition of organic matter. Reliable H2S monitoring is therefore essential for environmental safety, industrial process control, and human health protection. Conventional chemiresistive H2S sensors based on metal oxide semiconductors often require elevated operating temperatures, which increase power consumption and restrict device miniaturization, flexible integration, and long-term deployment. Room-temperature H2S sensors have consequently attracted increasing attention as low-power sensing platforms. This review summarizes recent progress in room-temperature H2S sensing across single-component semiconductors, composite heterojunctions, two-dimensional materials and their heterostructures, metal-organic-framework-based materials, noble-metal-sensitized systems, and photoactivated sensors. Representative preparation methods, structure-performance relationships, and key sensing parameters are compared. Particular emphasis is placed on sensing mechanisms and supporting evidence, including oxygen-adsorption-mediated conductivity modulation, H2S-induced sulfidation, interfacial barrier modulation, defect-related activation, noble-metal-mediated catalytic and electronic sensitization, photoinduced carrier and photothermal effects, and framework-mediated transduction. Humidity interference and mitigation are further discussed, together with advances in micro electromechanical system (MEMS) devices, flexible and self-powered platforms, wireless sensing, sensor arrays, electronic noses, and AI-assisted identification. Finally, challenges and future directions are highlighted, including ppb-level detection, reversibility, humidity tolerance, complex-gas selectivity, long-term stability, standardized evaluation, real-sample validation, and intelligent-system integration. This review provides a systematic framework for developing reliable, low-power, and application-oriented room-temperature H2S sensors.