Construction of flower-like hierarchical Ni-doped SnO2 nanosheets and their gas sensing properties for ethanol

Abstract

Detecting ethanol is desirable in alcohol testing for safe driving. Therefore, developing an ethanol sensor with an obvious response and fast detection speed is urgent. In this work, a series of Ni-doped SnO₂ nanosheets with flower-like hierarchical morphologies have been constructed and utilized for detecting ethanol vapor. The results indicate that the sensor response (R_a/R_g) of 3 mol% Ni-doped SnO₂ is as high as 43.22 towards 100 ppm ethanol at 275 °C, about 6 times higher than that of pure SnO₂. In addition, a short response/recovery time (11 s/14 s for 100 ppm ethanol), and excellent selectivity are also determined. This improved ethanol-sensing response is ascribed to two aspects: (1) a unique open structure assembled by ultrathin nanosheets (20–25 nm), favorable for gas-diffusion and gas–solid interactions and (2) a higher number of oxygen vacancies and chemisorbed oxygen in SnO₂ after Ni-doping, contributing to the gas-sensing response. This work presents an efficient strategy combining morphology design and doped engineering for exploiting high-performance gas sensors.