High-Performance Formaldehyde Gas Sensor Based on Cu-Doped Sn3O4 Hierarchical Nanoflowers

Gas sensors with high response, low operating temperature and superior selectivity are highly desired for monitoring toxic gases in the environment. Herein, a formaldehyde (HCHO) gas sensor with outstanding sensing properties is proposed based on Cu-doped Sn
₃
O
₄
hierarchical nanoflowers that are synthesized via a facile hydrothermal method. The Cu-doped Sn
₃
O
₄
gas sensors exhibit conspicuously improved sensing performance to HCHO compared with the pure Sn
₃
O
₄
gas sensor at a relatively low operating temperature of 160 °C. Specifically, the gas sensor based on the 4 wt% Cu-doped Sn
₃
O
₄
composite exhibits a high response up to 53 toward 100 ppm HCHO, a fast response time of 5 s, and low detection limit of 1 ppm. In addition, the prepared Cu-doped Sn
₃
O
₄
gas sensor possesses conspicuous advantages comprising a good selectivity, perfect reproducibility and excellent long-time stability. The sensing mechanism of the proposed gas sensor is explained by the electron depletion theory, and the possible reasons for the improvement of sensing properties by Cu doping are also discussed. It's strongly believed that the Cu-doped Sn
₃
O
₄
sensor has a practical application in HCHO detection.