Enhanced NO<inf>2</inf>-Sensing Properties of Cu-Loaded SnO<inf>2</inf> Nanoparticles Synthesized via Precipitation and Impregnation Methods

Abstract

Herein, NO2 noxious gas sensors based on precipitation/impregnation synthesized SnO2 nanoparticles loaded with Cu2O (Cu2O–SnO2) are presented. The particle properties are characterized by nitrogen adsorption, X-ray spectroscopic, and microscopic analyses. The NO2-sensing performances in terms of sensor response, response times, selectivity, and stability are optimized by varying Cu contents. The optimal sensing film (1.0 wt%Cu–SnO2) shows a high sensor response of ≈5680–5 ppm of NO2 at a low operating temperature of 200 °C. In addition, 1.0 wt%Cu–SnO2 sensor exhibits very high NO2 selectivity against SO2, H2S, C2H5OH, H2, C2H2, C2H4, and CH4 compared with unloaded one. Therefore, the 1.0 wt%Cu–SnO2 sensor is a promising candidate for highly sensitive and selective detection of NO2.