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

Due to their large surface-to-volume ratio and low electronic noise, two-dimensional transition metal carbides (Ti3C2Tx MXene) and their derived transition metal oxides have demonstrated significant potential for use in high-precision gas sensing. However, the construction of high-sensitivity Ti3C2Tx 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 Ti3C2Tx MXene–derived transition metal oxide (TiO2) nanosheets for high-sensitivity NH3 detection. AgNPs can not only serve as spacers to effectively prevent the restacking of MXene-derived TiO2 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@TiO2 nanocomposite–based sensors revealed an extraordinary response value of 71.8 to 50 ppm NH3 at RT with a detection limit as low as 5 ppm. In addition, the Ag@TiO2 NH3 sensor also exhibits excellent selectivity and outstanding repeatability. This strategy provides an avenue for the development of MXene derivatives for advanced gas sensors.