Fabrication of Delaminated 2D Metal Carbide MXenes (Nb2CTx) by CTAB‐based NO2 Gas Sensor with Enhanced Stability

Sensitivity is the prime factor in solid‐state gas sensors in terms of explicit noting of the change in signal. For achieving this, two vital prerequisites to be satisfied simultaneously: (i) electrical noise should be null and (ii) significant signal which is not met by the existing sensing materials. This study demonstrates that 2D metal carbide MXenes (Nb2CTx) have strong metal conductivity for noise reduction and abundant functional groups for detecting the signal toward higher sensitivity. This work shows successful exfoliation of Nb2CTx in the presence of cationic surfactants like cetyltrimethylammonium bromide (CTAB), which is significantly stable. The confirmation about the successful stabilization of Nb2CTx in DI water is obtained from material characterization and gas sensing observations. The experiments show that the dynamic sensing response of the Nb2CTx‐CTAB sensor increases by ≈3 times for NO2 gas detection. The sensitivity of the Nb2CTx and Nb2CTx‐CTAB found 0.543 and 1.686 ppm–1, respectively, toward NO2 gas. Over time (up to 30 d), CTAB functionalized Nb2CTx MXene noticed trace‐level detection capability with better environmental stability than pristine MXene. Herein, the obtained results show the gas sensing characteristics of Nb2CTx‐CTAB and witness a selective and ultra‐sensitive response toward NO2 gas detection. A method and material to control the oxidation of Nb2CTx MXene and its application in NO2 gas sensing at room temperature are described. The obtained results confirm that the fabricated sensor shows high stability (more than 30 d) and can select even minute gas at ppb level that can be helpful in detecting the NO2 gas in industries.