Separated detection of ethanol and acetone based on SnO2-ZnO gas sensor with improved humidity tolerance

Developing separated detection of ethanol and acetone for semiconductor oxides based gas sensors with relative stable gas response under different humidity is of great significance to practical application. Herein, a unique mesoporous SnO2-ZnO hierarchical structure has been prepared by a facile one-step hydrothermal method. Several characterizations for SnO2-ZnO samples have been carried out and the gas sensing properties of all gas sensors have been systematically investigated and analyzed. The results indicate that the optimal working temperature for ethanol detection will decrease from 275°C to 250°C, while the optimal working temperature for acetone detection will maintain at same temperature of 300°C with Sn2+ doping ratio increasing. For ethanol detection, 10 at% SnO2 modified ZnO gas sensor has the highest gas response, and the humidity tolerance has been obviously improved compared with those of lower Sn element doping ratios (1 at% and 5 at%) at 250°C. Moreover, the detection limit for ethanol and acetone can reach as low as 200 ppb with high SnO2 contents (10 at% and 15 at%). The improved gas sensing performance could be mainly attributed to the unique morphology of sensing material and the synergistic effect of SnO2 and ZnO.