Enhanced hydrogen sensing based on MXene surface-loaded ZnO nanospheres

Hydrogen energy, as an efficient and clean energy carrier, shows great potential in fuel cells and energy storage systems. However, the flammable and explosive nature of hydrogen poses a serious challenge to its safe use, and the development of highly sensitive and fast-response hydrogen sensors is crucial. In this work, a novel ZnO/MXene based gas sensor was developed for applied in hydrogen detection by using electrostatic self-assembly technology. The effect of the MXene ratio on enhancing the hydrogen-sensing properties of ZnO and the heterostructure synergistic sensing mechanism of the ZnO/MXene composite were elucidated. Results showed that the composite material exhibits optimal performance when the mass ratio of ZnO to MXene is 10:1. The ZnO/MXene composites exhibited a sensitivity of 702 at 100 ppm hydrogen, representing a 26 % improvement over pure ZnO, and achieved notable response at an ultralow concentration of 50 ppb (247). Meanwhile, the response/recovery times of composites were shortened to 5.4 s and 120.6 s, with a 74 % improvement in response time compared with pure ZnO. In gas selectivity tests, composites indicate pronounced affinity for hydrogen. Furthermore, in the detection of mixed gases created by simulated lithium battery thermal runaway, performing an average response time reduced by 71.2 % compared to pure ZnO, an average recovery time reduced by 12.6 %, and an average response value enhanced by 41.8 %, which demonstrated the potential of ZnO/MXene sensors in identifying risks within Li-ion battery systems. This work will provide a theoretical basis for the design and application of high-performance hydrogen sensors.