MXene-derived TiO2 nanosheets decorated with Ag nanoparticles for highly sensitive detection of ammonia at room temperature

Abstract

• A novel AgNPS-anchored Ti 3 C 2 T x MXene–derived TiO 2 nanocomposite is fabricated for high-precision gas sensors. • The Ag@TiO 2 gas sensor exhibited a response value of 71.8 to 50 ppm NH 3 at room temperature with a detection limit of 5 ppm. • Enhanced NH 3 sensing response mechanism of the Ag@TiO 2 nanocomposite is discussed. Due to their large surface-to-volume ratio and low electronic noise, two-dimensional transition metal carbides (Ti 3 C 2 T x MXene) and their derived transition metal oxides have demonstrated significant potential for use in high-precision gas sensing. However, the construction of high-sensitivity Ti 3 C 2 T x MXene–based gas sensors operated at room temperature (RT) is still a major challenge. Herein, we demonstrate a sensitive nanocomposite prepared by uniformly anchoring silver nanoparticles (AgNPs) on Ti 3 C 2 T x MXene–derived transition metal oxide (TiO 2 ) nanosheets for high-sensitivity NH 3 detection. AgNPs can not only serve as spacers to effectively prevent the restacking of MXene-derived TiO 2 nanosheets and ensure an effective transmission highway for target gas molecules, but also enhance the sensitivity of the sensor through chemical and electronic sensitization. By integrating the unique merits of the individual components and the synergistic effects of the composites, the optimized Ag@TiO 2 nanocomposite–based sensors revealed an extraordinary response value of 71.8 to 50 ppm NH 3 at RT with a detection limit as low as 5 ppm. In addition, the Ag@TiO 2 NH 3 sensor also exhibits excellent selectivity and outstanding repeatability. This strategy provides an avenue for the development of MXene derivatives for advanced gas sensors.