Plasmonic photothermal driven MXene-based gas sensor for highly sensitive NO2 detection at room temperature

Abstract

Gas-sensing devices built on two-dimensional layered transition metal carbide/nitride (MXene) have gathered burgeoning interest in the exploration of next-generation artificial olfaction system, yet it still suffers from weak sensitivity and sluggish or incomplete response/recovery characteristics especially when operating at room temperature, which can drastically restrict its large-scale application in the field of Internet of Things. Herein, the sensitization strategy based on the plasmonic photothermal effect is proposed to exploit a light-assisted MXene-based gas sensor for achieving the highly sensitive detection of NO2 at room temperature. In-situ grown Ti3C2Tx/TiO2/Au heterostructures are employed as the sensitive element for the adsorption and reaction with target gas molecules. Most remarkably, under the activation of 530 nm light, the plasmonic photothermal driven Ti3C2Tx/TiO2/Au sensor exhibits prominent response capability for 1 ppm NO2 which is 7.6 and 2.34 folds larger than that of Ti3C2Tx/TiO2 and Ti3C2Tx/TiO2/Au sensor without light illumination, respectively. The as-designed gas sensor also manifests fast response/recovery times (5.4/15.3 s), superior sensitivity, and excellent selectivity. The association of theoretical and experimental investigations confirms that the enhanced gas-sensitive properties are principally ascribed to the elevation of photon utilization induced by the localized surface plasmon resonance (LSPR) effect and the multiplication of the gas-sensitive reaction pathway derived from the localized photothermal effect. These results illustrate that photothermal-activated enhancement can be used as an effective and general strategy to offer a promising perspective for developing high-performance room-temperature-operated gas-sensing devices.