Gold Nanoparticles Decorated Multilayer MXene: Towards Highly Selective and Sensitive Gas Sensor at Room Temperature

The catalytic properties of noble metal nanoparticles can enhance the adsorption capacity of sensors for target gases when compounded with MXene. In this study, a nanocomposite of gold nanoparticles (Au NPs) and MXene was prepared using a simple self-reduction process, and its microstructure, electrochemical valence states, specific surface area, and other properties were characterized. Gas sensitivity tests conducted on the Au@MXene-20 sensor revealed excellent selectivity for NH3 at room temperature. The response value to 100 ppm NH3 at room temperature was 15.1%, approximately three times that of pure MXene, with response and recovery times of 118 s and 219 s, respectively. Moreover, the composite sensor exhibited a low detection limit, demonstrating a response of 3.496% to 5 ppm NH3 at room temperature. Additionally, the Au@MXene-20 sensor possessed good repeatability, long-term stability, and moisture resistance. Therefore, the Au@MXene-20 sensor studied and prepared in this paper has been proven to be well-suited for NH3 detection in harsh environments.