NO2 sensing performance of SnO2 hollow-sphere sensor

This work examined the possibility of using SnO2 hollow spheres mediated by carbon microspheres for the efficient detection of NO2 gas. The influences of gas concentration, operating temperature, crystallite (grain) size and structure feature on the sensing performance of the sensors based on SnO2 hollow spheres were comprehensively studied. The SnO2 hollow spheres had a mean crystallite size of 12.7, 14.1 and 22.8 nm when calcined at 450, 500 and 550 °C, respectively. It was found that the SnO2 hollow spheres calcined at 450 °C with a crystallite size of 12.7 nm were the most sensitive to NO2 gas. The sensor also had a better selectivity to NO2 than to ethanol, methanol, gasoline, acetone, CCl4 and NH3 when operated at 160 °C.