Highly selective NO2 gas sensing with SnO2-Ti3C2Tx nanocomposites synthesized via the microwave process

Abstract

MXene materials are becoming increasingly prevalent in gas sensing as a result of their metallic conductivity and surface functional groups. In this study, we prepared SnO2-(0.5, 1, 2, and 5 wt%) Ti3C2Tx MXene nanocomposites for NO2 gas sensing. The sensor with 2 wt% Ti3C2Tx showed improved gas responses and was subsequently irradiated by microwaves (MWs) for 1, 3, 5, and 8 min. The gas sensing studies demonstrated that the MW-irradiated SnO2-(2 wt%) Ti3C2Tx nanocomposite exhibited a response of 24.8–10 ppm NO2 at 150 °C, which is superior to those of pristine Ti3C2Tx, pristine SnO2, and un-irradiated SnO2-(2 wt%) Ti3C2Tx nanocomposite gas sensors. In addition, the optimized gas sensor exhibited high stability and excellent NO2 selectivity. The sensing mechanism can be described by the synergetic effects of SnO2 and Ti3C2Tx as much as the presence of functional groups on Ti3C2Tx.