Facile Design of Ti₃C₂T_X (MXene) Modified Spherical SrTiO₃ Structure toward Highly Sensitive Room Temperature Detection of NO₂

Two-dimensional nanomaterials have garnered recent interest among scientists in gas sensing applications. MXene (Ti 3 C 2 T x ) [MX] is one of the top priorities among researchers owing to its numerous advantages like abundant surface-active sites, large surface area, and high conductivity. Designing a room temperature gas sensor has become indispensable in the era of environmental and industrial monitoring. Heterojunction creation helps in the band alignment by transfer of charge at the junction, which further helps in better sensor performance and enhanced response. In this work, a SrTiO 3 (STO) perovskite-MX-based nanocomposite has been developed by using the simple electrostatic self-assembly technique combining the spherically shaped STO on the 2D layered MX sheet. The fabricated nanocomposite exhibits good selectivity, high sensitivity, and long-term stability toward NO 2 gas detection at 27 °C. The response recorded for the STO-MX composite was 38.79% toward 50 ppm of NO 2 gas, which was triple the response of MX and five times higher than the pristine STO sensor with an exceptional response and recovery time of 8 and 12s. Also, the study demonstrates an outstanding linearity with a 9-fold increase from 1 to 30 ppm with good reproducibility. The LOD (limit of detection) achieved for the material was lower, that is, 300 ppb. This work unveils the utility of the perovskite based MXene sensor as an efficient strategy in room temperature detection of the toxic NO 2 gas.