Low temperature operated highly sensitive, selective and stable NO2 gas sensors using N-doped SnO2-rGO nanohybrids

In this study, we report synthesis of SnO2-rGO and N-doped SnO2-rGO nanohybrids by facile hydrothermal method. The XRD analysis of the synthesized nanohybrids revealed a tetragonal rutile structure of SnO2 lattice. Further structural, chemical, morphological and optical properties of SnO2-rGO and SnO2-NrGO nanohybrids were investigated by Raman, X-Ray Photoelectron spectroscopy, Transmission Electron Microscopy, UV-Vis spectroscopy and Photoluminescence spectroscopy. Furthermore, the gas sensing properties of the synthesized nanohybrids were studied in detail. It was observed that SR2 and SRN2 nanohybrids exhibited superior NO2 sensing response (55.2 and 84.5% respectively) at low operating temperature (120 degrees C) and low gas concentration (0.5 ppm). Moreover, SR2 and SRN2 also exhibited excellent selectively towards NO2 along with remarkable stability upto 90% over 30 days. This improved performance can be attributed to the synergetic effect of small particle size, high defect concentration and high surface area due to incorporation of SnO2 along with N doping in rGO. Therefore, SR2 and SRN2 can be utilized as effective NO2 gas sensors.

Automated summary

In this study, SnO2-rGO and N-doped SnO2-rGO nanohybrids were synthesized by a facile hydrothermal method. The synthesized nanohybrids exhibited a tetragonal rutile structure of SnO2 lattice. Various characterization techniques were used to investigate the structural, chemical, morphological and optical properties of the nanohybrids. The gas sensing properties of the nanohybrids were also studied in detail, showing excellent NO2 sensing response at low temperature and low gas concentration, as well as remarkable stability. The superior performance can be attributed to the synergetic effect of small particle size, high defect concentration and high surface area.