Abstract

Hydrogen (H2) is considered one of the promising energy sources to replace fossil fuels so efficient H2 sensing technology is a necessary condition to ensure the safety of people's livelihood and economic development. In this paper, ZnO obtained by calcination of precursor ZIF-8 has a regular dodecahedral structure. The product of In2O3 obtained with the participation of the surfactant PEO-PPO-PEO has two different crystal forms, namely cubic phase c-In2O3 and hexagonal h-In2O3. Crystal form c-In2O3 is 7.07 wt% of the mass of h-In2O3. When ZnO is 5 wt% of In2O3, the H2 sensor based on the ZnO (5 %)-Inc/Inh composite material has the best response performance and the operating temperature is 450 °C. The sensor's response time for detecting 5000 ppm H2 is less than 1 s, and the recovery time is 6 s with a response intensity of 79.91. The limit of detection (LOD) is 53 ppb, which is much lower than the explosive concentration (4–75 V/V%). Density functional theory (DFT) is utilized for investigating the performance advantages of Inc/Inh composites over pure c-In2O3 and h-In2O3 and further elaborating the mechanism of ZnO improving the gas-sensing performance of ZnO (5 %)-Inc/Inh. The sensor based on ZnO (5 %)-Inc/Inh composite may guide the research of high-performance H2 sensors. The H2 adsorption mechanism of the sensor was analyzed based on the oxygen adsorption mechanism.