Preparation and super hydrogen gas sensing properties of Rh-doped coral-like SnO_2

摘要

Rh-doped coral-like SnO_2 were prepared by hydrothermal treatment followed by heat treatment at 500 ℃. The obtained Rh-doped SnO_2 samples were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope and nitrogen adsorption-desorption. Super sensitive H_2 sensors were achieved based on the Rh-doped coral-like SnO_2. The effects of Rh doping on H_2 sensing property were investigated. The response of the sensor based on 0.5 mol% Rh-doped coral-like SnO_2 was 312-100 ppm H_2 at 260℃, which is 26 times higher than that of pure coral-like SnO_2, 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 SnO_2 showed negligible cross-response to benzene, toluene, xylene, acetone, tri-methylamine, methane and methanol. The high sensitivity and selectivity detection of the sensor to H_2 were attributed to the electronic interactions between Rh_2O_3 and SnO_2 and high catalytic activity of Rh for H_2 oxidation. The super hydrogen sensing performances of the Rh-doped SnO_2 sensor indicated that Rh-doped coral-like SnO_2 could be a promising candidate for good hydrogen sensors.