In₂O₃ Doped ZnO Nanosheets for Ultra-Trace Detection of NO₂

Development of facile sensors for the detection of toxic gases from the environment describes a sustainable approach for monitoring the health of ecosystem. In the current study, In2O3 doped ZnO based gas sensor was designed to detect the trace quantities of NO2 gas in the environment. The synthesis of In2O3@ZnO nanosheets were performed by hydrothermal method. The growth of nanostructure was examined by physical and optical characterizations like X-ray diffraction and Ultra-violet diffuse reflectance spectroscopy. Microscopic studies were performed to investigate the morphological and surface structure of the nanosheets. The gas sensing experiments were carried at different temperature to examine the optimum temperature of working and it was observed the sensor worked best at 300ΟC. The response of In2O3@ZnO nanosheets was seen to be significantly higher (Rg/Ra = 41.9) than pure ZnO (Rg/Ra = 14.04) at 100 ppm concentration of NO2 gas. The higher response of In2O3@ZnO indicates that In2O3 NPs have significantly improved the potentiality of detection and response to detect NO2. On changing concentration of NO2 gas, the sensor showed increased response with increase in the concentration of NO2 gas. Moreover, the sensor showed excellent selectivity, long term stability and good repeatability with lower detection limit.