A room-temperature NO2 sensor based on Ti3C2TX MXene modified with sphere-like CuO

In this paper, the Ti 3 C 2 T x /CuO nanocomposites were successfully prepared by an environment-friendly and simple hydrothermal method . The synthetics are evaluated using a series of characterization techniques, such as XRD , SEM, TEM , XPS , FTIR, UV–vis, and BET techniques. The results show that Ti 3 C 2 T x /CuO nanocomposites are mesoporous and have a higher specific surface area than Ti 3 C 2 T x , confirming the presence of more gas adsorption/diffusion regions. Furthermore, the Ti 3 C 2 T x with the introduction of CuO has rich oxygen vacancies and adsorbed oxygen. In particular, the response of Ti 3 C 2 T x /CuO sensor (56.99%) is 5 times higher than that of Ti 3 C 2 T x (11.17%) sensor to 50 ppm NO 2 at room temperature (RT). Especially, the Ti 3 C 2 T x /CuO sensor exhibits ultra-fast response/recovery time (16.6/31.3 s to 20 ppm NO 2 ), great reversibility , outstanding selectivity to NO 2 , and desirable long-term stability (over 40 days). The enhanced gas sensing performance may be attributed to the formation of hybrid heterojunctions between CuO and Ti 3 C 2 T x that provide carrier migration channels to hasten the redox reaction . At the same time, Ti 3 C 2 T x /CuO possesses more oxygen vacancies and adsorbed oxygen than Ti 3 C 2 T x , which will reduce the required energy for gas adsorption to further enhance the gas sensing performance. Hopefully, the above improved gas sensing performance indicators modified with CuO are expected to become the advantage of constructing Ti 3 C 2 T x -based sensor, which will be put into commercial NO 2 detection in the future.