High-Performance Hydrogen Sensor Fabricated by Layer-by-Layer Self-Assembly for Real-Time Monitoring of Hydrogen Production by Water Electrolysis.

In this study, ZnO/Co3O4 composite thin-film room-temperature hydrogen (H2) sensors were prepared via the hydrothermal method and self-assembly techniques. The test results show that the composite sensor with a layer assembly ratio of 1:1 has good sensing performance for H2. The ZnO/Co3O4 composite sensor can detect a wide range of H2 concentrations from 100 to 50,000 ppm, and the response toward 300 ppm H2 is more than six-times that of a single nanomaterial. In addition, it has a faster response recovery speed, better repeatability, selectivity and long-term stability. The improvement in composite sensor performance results from the synergistic effect between ZnO and Co3O4 materials and the formation of heterostructures. The prepared ZnO/Co3O4 composite thin-film sensor was successfully applied to detect the H2 production concentration and behavior of an electrolytic cell for hydrogen production by water electrolysis.