LAUSR

Rh-doped coral-like SnO2 were prepared by hydrothermal treatment followed by heat treatment at 500 °C. The obtained Rh-doped SnO2 samples were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope and nitrogen adsorption–desorption. Super sensitive H2 sensors were achieved based on the Rh-doped coral-like SnO2. The effects of Rh doping on H2 sensing property were investigated. The response of the sensor based on 0.5 mol% Rh-doped coral-like SnO2 was 312–100 ppm H2 at 260 °C, which is 26 times higher than that of pure coral-like SnO2, and higher than the other reported gas sensors based on semiconductor. The response time (6 s) and the recovery time (9 s) of the sensor were short, comparing to other semiconductor gas sensors. The Rh-doped coral-like SnO2 showed negligible cross-response to benzene, toluene, xylene, acetone, trimethylamine, methane and methanol. The high sensitivity and selectivity detection of the sensor to H2 were attributed to the electronic interactions between Rh2O3 and SnO2 and high catalytic activity of Rh for H2 oxidation. The super hydrogen sensing performances of the Rh-doped SnO2 sensor indicated that Rh-doped coral-like SnO2 could be a promising candidate for good hydrogen sensors.