Development of a rapid NO2 gas sensor based on SnO2 nanoparticles synthesized with glycine

Abstract

Amino acids, as naturally occurring small molecules, have shown potential as materials for gas sensor-assisted synthesis. In this study, we present a novel method based on amino acid templates for the assisted synthesis of small-sized SnO2 nanoparticles at a low temperature of 140℃. Specifically, the Gly/SnO2-2 sample, synthesized with 20 % wt glycine incorporation, exhibited a sensitivity of 22.74 towards a low concentration (3 ppm) of NO2 under UV irradiation at 365 nm, with a rapid response/recovery time of 12/11 s. Remarkably, even under UV-free room-temperature conditions, the sensor continued to respond to NO2. Crystal structure analysis of the material was conducted through scanning electron microscopy (SEM) and transmission electron microscopy (TEM), revealing excellent crystallinity with a particle size of approximately 10 nm. Additionally, BET characterization indicated a well-defined spatial structure with a specific surface area of 58.17 m2/g. Experimental data further demonstrated that the Gly/SnO2-2 displayed good selectivity, reproducibility, and stability. These findings underscore the potential of amino acid templating in advancing gas sensing technologies, offering avenues for the development of highly efficient sensing materials.