Fabrication of durable and sensitive SnO2-Based gas sensor for NO2 detection

Abstract

There is growing interest in monitoring low-concentration gases in fields such as mobility, healthcare and indoor environment control. This highlights the need to develop the gas sensors with ultra high sensitivity for detecting gases and compounds at trace concentrations, with metal oxide nanomaterials being particularly attractive due to their remarkable surface area, good thermal stability and ease of synthesis methods. In this research, tin oxide (SnO₂) was synthesized using a simple hydrothermal approach, with reaction times of 16, 20 and 24 h. Different structural and morphological characteristics of materials were analysed using XRD, UV-Vis, FTIR, SEM, TEM and BET. The FE-SEM results confirmed the formation of uniform spherical SnO₂ particles, with the sample synthesized at a 24-hour reaction time exhibiting the highest surface area of 36.28 m²/g. The gas sensing behaviour for nitrogen dioxide (NO₂) was evaluated using a gas sensor setup and the sample synthesized with a reaction time of 24 h demonstrated the highest response of 54% at 40 ppm, with operating temperature 100 °C, attributed to its remarkable surface activity. This sample also exhibited excellent repeatability and selectivity, indicating its good sensitivity and stability for NO₂ detection. The developed SnO₂ based gas sensors that can play a crucial role in environmental protection by monitoring and controlling air pollution levels, ensuring better air quality.

Graphical Abstract