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.