In2O3 Doped ZnO Nanosheets for Ultra-Trace Detection of NO2

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ABSTRACT

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 300^ΟC. The response of In₂O₃@ZnO nanosheets was seen to be significantly higher (R_g/R_a = 41.9) than pure ZnO (R_g/R_a = 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 NO_2.  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.

Significance of the study:

This study highlights the development of In₂O3-doped ZnO nanosheets as highly sensitive and selective gas sensors for detecting ultra-trace levels of NO₂. The findings demonstrate a significant advancement in environmental monitoring technologies, emphasizing the importance of accurate and reliable gas detection for ecosystem health.

Summary of the study:

In₂O₃-doped ZnO nanosheets were synthesized using the hydrothermal method and characterized by XRD, UV-DRS, and microscopy techniques. The gas sensor, optimized to operate at 300°C, exhibited a significantly higher response to NO₂ (Rg/Ra = 41.9) compared to pure ZnO (Rg/Ra = 14.04) at 100 ppm NO₂. The sensor demonstrated excellent sensitivity, selectivity, stability, and repeatability with a rapid response time of 32 seconds and effective detection of varying NO₂ concentrations. The study underscores the potential of In₂O₃-doped ZnO nanosheets for advanced environmental monitoring applications.