Ultrahigh-response hydrogen sensor based on PdO/NiO co-doped In₂O₃ nanotubes

Hydrogen can be regarded as an ideal type of secondary energy considering its potential for achieving renewable and sustainable development due to water being its sole combustion product and its possible production by solar energy-based water electrolysis. Monitoring the presence and concentration of hydrogen during production, transportation, and application requires a hydrogen gas sensor with high response, high selectivity, and fast response and recovery times. In an attempt to meet these requirements, NiO and PdO are used in the co-doping of In₂O₃ nanotubes by subsequent electrospinning and impregnation under UV irradiation. The fabricated hydrogen gas sensor demonstrates an ultrahigh response of 487.52, a fast response time of 1 s and high selectivity at an operating temperature of 160 °C, which characteristics are superior to reported monometal-doped hydrogen sensors. The remarkable gas sensing performance could be attributed to the synergistic effect of the resistance modulation, the chemical sensitization of PdO, and the catalytic effect of NiO. This study demonstrates that co-doping of PdO and NiO on In₂O₃ nanotubes is an effective way to improve hydrogen sensing characteristics more effectively than doping with PdO or NiO alone, and provides a potential application for the fast and accurate detection of hydrogen.