Controllable synthesis of Ag-WO3 core-shell nanospheres for light-enhanced gas sensors

•Ag-WO3 core-shell nanospheres (CSNSs) were prepared via a sonochemical method.•The sensor based on Ag-WO3 CSNSs dramatically improve the sensor performance with respect to alcohol vapor.•Light illumination was found to boost the sensor performance effectively.•The improved sensor performance was attributed to the LSPR effect.

Ag-WO3 core-shell nanospheres (CSNSs) are fabricated for gas sensor applications. It is found that the sensor based on Ag-WO3 CSNSs dramatically improve the sensor performance towards alcohol vapor, with significantly lower optimum working temperature (260 °C) and superior detection limit (0.20 ppm) comparing to pure WO3 hollow nanospheres (HNSs). The Ag-WO3 sensor displays an ultrahigh sensitivity under visible light illumination. When illuminated under a 150 W xenon arc light source, the response is increased from 62 to 160, the optimum working temperature is reduced from 260 to 190 °C, and the detection limit is improved from 0.20 to 0.032 ppm. This work may offer an attractive strategy to improve sensitivity of light-enhanced plasmonic metal-oxide based gas sensors.