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.