Portable Photoactivated Room-Temperature Gas Sensor for On-Site Methanol Monitoring

Methanol is an essential chemical feedstock and renewable fuel, yet its high volatility and flammability necessitate intrinsically safe room-temperature detection for safe deployment. Current room-temperature methanol sensing technologies, however, suffer from inadequate sensitivity and high detection limits, hindering reliable early leakage warning. Herein, we report a photoactivated room-temperature, chemiresistive methanol sensor based on bimetallic PdPt clusters-decorated W18O49. Bimetallic PdPt clusters with tunable compositions dramatically improve the sensor receptor function via selectively increasing the adsorption of chemisorbed oxygen species and methanol molecules, as revealed by theoretical calculations. Meanwhile, ultraviolet (UV) photoactivation replaces thermal activation by promoting charge-carrier generation and surface redox reactions, while the Schottky barrier enables efficient charge-carrier separation, thereby enhancing the sensor transducer function. The enhanced sensing reaction pathway is elucidated by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) under UV irradiation. Accordingly, the sensor exhibits a more than fourfold enhancement in response, low detection limit (100 ppb), and stable operation for over 30 days in ambient air at room temperature. Finally, we integrate the sensor into a portable on-site monitoring device, providing an intrinsically safe platform for real-time methanol leakage monitoring and early warning in hazardous industrial environments.