Fabricaiton of MXene-TiO2-ZnO ternary composites for low temperature and low concentration H2 gas detection by one-step preparation

Hydrogen becomes an important clean energy origin, which will explode in open fire at a certain concentration. This leads to great property and personal safety hazards in the process of hydrogen storage, transportation and leakage. Low temperature and low concentration hydrogen detection is very necessary. In this paper, MXene-TiO 2 -ZnO ternary composites were successfully prepared by one-step in-situ oxidation method using MXene and Zn(NO 3 ) 2 ·6H 2 O as precursors for 1h. The microstructure of the samples was characterized by XPS, TEM, SEM and Raman, and their gas sensing properties were tested. The results show that the Ti 3 C 2 T x -TiO 2 -ZnO structure exhibits a layered accordion-like morphology. Under room temperature (RT 25 °C) and UV light irradiation, the response value of MTZ-1 sample to 1000 ppm hydrogen reaches 73.39 %, which is 96.8 % higher than that of pure Ti 3 C 2 T X . At the optimum operating temperature (100 °C), the response value of MTZ-1 to 1000 ppm hydrogen reached 96.77 %, the detection limit was as low as 1 ppm, and the response value was 1.7 %. The results show that the formation of TiO 2 -ZnO heterojunction, the retention of Ti 3 C 2 T x layered structure and UV irradiation are the main reasons to improve the gas sensing performance (GSP). In this paper, the formation of TiO 2 -ZnO heterojunction, the retention of MXene layered structure and the synergistic enhancement of gas sensitivity by UV excitation were revealed by systematic characterization and mechanism analysis. This research provides a new idea for the development of low energy consumption and high sensitivity room temperature hydrogen sensor, which has important practical application value.