A synergistic approach to enhance sensitivity and selectivity of room temperature operable ammonia gas sensor with humidity assistance using RGO/WO3 nanocomposite

Abstract In this study, the fabrication of an ultrahigh selective NH 3 gas sensor based on RGO/WO 3 nanocomposite has been proposed. The hydrothermal method was employed to synthesize the RGO/WO 3 nanocomposite. The formation of RGO/WO 3 nanocomposite and the elemental composition, structure and morphology of the as-synthesized materials were confirmed through an array of analytical techniques, including XRD, Raman, FT-IR, XPS and TEM. For gas sensing applications, pure RGO and RGO/WO 3 have effectively spin-coated onto the interdigitated electrodes (IDE’s) based on fluorine doped tin oxide (FTO) respectively, and their sensitivity towards NH 3 was tested. Gas sensing characteristics of prepared materials were analyzed at room temperature (25 °C) under different relative humidity (RH) levels. The developed RGO/WO 3 sensor was subjected to different NH 3 concentrations, demonstrating a high sensing response of 89% towards 500 ppm NH 3 under 11%–97%–11% RH conditions. Notably, the sensor exhibited rapid response and recovery times with an average response time of 92 s and recovery time of 26 s when exposed to 500 ppm NH 3 under the specified RH conditions. To gauge the material selectivity, the prepared nanocomposite was exposed to a range of volatile organic compounds and the results showcased the sensor’s remarkable selectivity and sensitivity specifically toward NH 3 vapor. This superior performance can be attributed to the abundant active sites and the excellent electron transport properties inherent to the RGO component. Importantly, the RGO/WO 3 sensor displayed high reproducibility and consistent responses, with minimal degradation (1.98% degradation) over 30 d at 11%–97%–11% RH. Furthermore, we examined the sensor’s response with varying levels of relative humidity to assess its potential for real-world applications. The sensor exhibited extremely low power consumption, outperforming a commercially available metal oxide sensor while operating at ambient temperature. The robust performance of RGO/WO 3 coupled with low power requirements and ambient temperature operation, positions it as a promising candidate for next-generation gas sensing technologies.