Synthesis of rGO-SnO2 nanocomposites using GO as an alkali-resistant substrate for high-performance detection of NO2

GO was used as a substrate to controllable synthesize rGO-SnO2 nanocomposites for preparing high-performance NO2 gas sensors. However, no product was obtained in the absence of GO substrates in a strongly alkaline environment at pH of 13.12. GO makes up for the shortcomings of alkali resistance of ordinary substrates. The flower-like hierarchical rGO-SnO2 nanocomposites were self-assembled from French fries-like SnO2 nanorods and rGO nanosheets. And each flower was composed of several French fries-like SnO2 nanorods with a length of about 800 nm and a square-shaped side length of approximately 80 nm. These SnO2 nanorods exposed profusely {200} crystal faces with high surface energy. The rGO-SnO2 nanocomposites based sensor showed a high response of 1809–1 ppm NO2 with fast response/recovery times of 251 s/14 s at 125 °C as well as good selectivity, high reproducibility, and long-term stability. The fast recovery speed of the sensor is due to the stable heating-assisted recovery method. The use of alkali-resistant GO as a substrate for nanoscale SnO2 growth effectively solves the problem of preparing SnO2 in a strongly alkaline liquid phase environment, which also contributes to the application of GO. This work provides a basis for developing high-performance NO2 gas sensors.