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, Nd 2 O 3 -loaded In 2 O 3 porous nanorods were synthesized which exhibited excellent H 2 S sensitivity along with prominent humidity-independent characteristics, whereas pristine In 2 O 3 without Nd 2 O 3 showed deteriorated H 2 S sensing features under increasing ambient humid conditions in a wide operating temperature range. The mechanism of humidity-independent H 2 S 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 In 2 O 3 surface induced by surficial Nd 2 O 3 component. This strategy poses a cutting-edge comprehending of temperature-dependent humidity-interference on MOS, paves a novel route for fabricating H 2 S sensors with exceptional sensitivity, selectivity and anti-humidity properties, which will be quite conducive for real-time exhaled breath analyses in disease diagnosis.