Highly sensitive room-temperature methanol detection enabled by UV-activated Pd-doped W18O49 gas sensor

The detection of flammable and explosive methanol (CH 3 OH) at room temperature remains challenging for semiconductor gas sensors, severely restricting their practical applications due to low sensitivity, high detection limit, and poor selectivity. Herein, we report a UV-activated gas sensor based on Pd-doped W 18 O 49 that exhibits high response to CH 3 OH along with rapid response/recovery times (169 s/346 s), and low detection limit (100 ppb), representing one of the best performances reported to date for room-temperature CH 3 OH sensing. The enhanced room-temperature sensing performance under UV illumination is attributed to the effective electron-transport pathway within nanowires, doping-induced energy band structure optimization, high adsorption capacity on defect-rich surface, and facilitated CH 3 OH dehydrogenation, as verified by density functional theory (DFT) calculations and comprehensive optical and electrical characterizations. To demonstrate practical application, a portable sensing and monitoring system was developed, enabling successful real-time indoor air quality assessment with an alarm function. This work provides a viable and efficient solution for room-temperature volatile organic compounds monitoring.