SrTiO3/ Ti3C2Tx based Gas Sensor for Room Temperature Detection of NO2

Abstract

NO2 (Nitrogen dioxide) is among the most hazardous gases and common air pollutants as declared by the World Health Organization (WHO) which is produced by combustion processes and exhaust fumes of cars. It can cause diseases such as respiratory irritation, emphysema, and bronchitis even at a low concentration [1]. Therefore, the development of ideal gas sensors with high stability, rapidity, repeatability, and sensitivity is desirable. ABO3 type metal oxide perovskite have garnered attention due to their outstanding features. The n-type semiconductor strontium titanate (STO) exhibits good thermal and chemical stability, high dielectric constant, superconductivity, large absorption coefficient with a band gap of 3.2 eV. These properties bestow SrTiO3 excellent potential in gas sensing application [2]. Ti3C2Tx (Mxene) has emerged as an outstanding support material improving the sensing property. They have a unique laminar structure, high surface area, conductivity, and excellent adsorption capability which helps in the ease of charge transfer during the sensing process. Focusing on these characteristics we have synthesized SrTiO3 based on Ti3C2Tx for the sensing of NO2 gas. The synergistic effect of SrTiO3 and Ti3C2Tx is believed to enhance the NO2 sensing behaviour and show better sensing ability compared to other reported sensing materials. The Mxene-based nanocomposite showed a higher response of 42.4% with response and recovery time of 8s and 23s for 100 ppm NO2 gas with a lower limit of detection. Our synthesized material performed better than the pristine SrTiO3 and MXene (Ti3C2Tx). The synthesized material was confirmed by using sophisticated characterization techniques like Powder X-Ray diffraction (PXRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, UV- Visible Spectroscopy (UV-Vis), Scanning Electron microscopy (SEM), Transmission Electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS).