Humidity-independent gas sensors in the detection of hydrogen sulfide based on Nd2O3-loaded In2O3 porous nanorods

Water vapor greatly interferes with gas sensing characteristics of metal oxide semiconductors (MOS). Consequently, for the first time, Nd2O3-loaded In2O3 porous nanorods were synthesized which exhibited excellent H2S sensitivity along with prominent humidity-independent characteristics, whereas pristine In2O3 without Nd2O3 showed deteriorated H2S sensing features under increasing ambient humid conditions in a wide operating temperature range. The mechanism of humidity-independent H2S sensing properties was researched via X-ray photoelectrons spectroscopy (XPS), in-situ Fourier Transform infrared spectroscopy (in-situ DRIFTS) and the corresponding gas sensing measurements, which is in close relations with the inhibition of chemisorbed oxygen and scavenging hydroxyl groups on In2O3 surface induced by surficial Nd2O3 component. This strategy poses a cutting-edge comprehending of temperature-dependent humidity-interference on MOS, paves a novel route for fabricating H2S sensors with exceptional sensitivity, selectivity and anti-humidity properties, which will be quite conducive for real-time exhaled breath analyses in disease diagnosis.