NO2 sensing studies of WO3 and Ag doped WO3 prepared through sol-gel route

Paper reports sensing studies of NO2 gas by WO3 (prepared through sol-gel route) and Ag doped WO3 for operating temperatures 200°C, 250°C and 300°C, for NO2 gas concentration of 0 to 100 ppm. Both pure WO3 and Ag doped WO3 show better sensitivity for the operating temperature of 200°C. WO3 and Ag doped WO3 both show increase in value of sensitivity with increasing concentration (ppm) of NO2. For concentration of 100 ppm, sensitivity for sensing element of Ag doped WO3 over WO3 increased by 25% for operating temperature 200°C. Response time of sensors depend on operating temperatures both for pure WO3 and Ag doped WO3. Least response time was obtained for operating temperature of 200°C.