One-step hydrothermal synthesis of uniform Ag-doped SnO2 nanoparticles for highly sensitive ethanol sensing

Noble metal doping is considered to be an efficient way to promote the gas sensing performances of metal oxide semiconductor nanomaterials. In this study, uniform silver (Ag)-doped tin dioxide (SnO2) nanoparticles were successfully synthesized through a facile one-step hydrothermal route. The diameter of Ag/SnO2 nanoparticles is less than 10 nm. Compared with pure SnO2-based sensor, the Ag/SnO2-based sensors are found to effectively improve their sensitivity and selectivity to ethanol. In particular, the 6% Ag/SnO2-based sensor displays a high response (Ra/Rg = 135) to 50 ppm ethanol at 180 °C. The enhancement of ethanol sensing properties of the 6% Ag/SnO2 sample due to the small size of SnO2 and catalytic sensitization effect of Ag, as well as the Schottky barrier forms between SnO2 and Ag. These results suggest that the Ag-doped SnO2 nanoparticles acting as a promising functional composite material have potential application for ethanol sensors.