Mxene Ti3C2Tx derived lamellar Ti3C2Tx-TiO2-CuO heterojunction: Significantly improved ammonia sensor performance

Ammonia (NH3), as main industrial gas emissions, are extremely harmful to the human beings. So the detection of NH3 concentrations in special environments at room temperature (25 °C) is essential. Herein, the composite MXene Ti3C2Tx-TiO2-CuO was successfully prepared by one-step in-situ oxidation method using Cu(NO3)2·6H2O as a precursor. The morphology of Ti3C2Tx-TiO2-CuO shows layered accordion-like structure. Ti3C2Tx-TiO2-CuO sensor exhibits improved NH3 gas sensing response of 56.9 toward 100 ppm NH3 at room temperature under ultraviolet (UV) light exposure, which is 89.8 % higher than that of pristine Ti3C2Tx material. The improved gas sensing performance is attributed to the irradiation of UV light, the retention of Ti3C2Tx layered structure and the construction of TiO2-CuO heterojunction. Further, the possible gas sensing mechanism of the material was proposed and discussed.