MXene-based highly sensitive and selective NH3 sensor

Abstract With increasing industrialization in the modern era, the detection of hazardous gases like NH 3 became a global issue due to its detrimental effect on mankind. MXene has emerged as an outstanding gas sensing candidate among two-dimensional materials due to its favorable characteristics like an abundance of interaction sites, metallic conductivity, tunable surface properties, band gap, and excellent mechanical strength. In the present work, a highly sensitive and selective NH 3 gas sensor has been fabricated using MXene-based nanostructures. The morphological and structural characterizations of nanostructures have been performed using X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. The successful etching of Al reveals the formation of MXene having exfoliated multilayered morphology with an average interlayer spacing of ~53 nm. The response kinetics of the sensor has been investigated by estimating their response and selectivity toward different oxidizing and reducing gases. The sensor exhibits high response transient curves toward 5–100 ppm of NH 3 at room temperature (30 °C) with fast response and recovery time. Density functional theory has been used to elucidate the interaction mechanism between NH 3 molecules and MXene surface.