Ultrasensitive detection of trimethylamine using Rh-doped SnO2 hollow spheres prepared by ultrasonic spray pyrolysis

Abstract

An ultrasensitive trimethylamine (TMA) sensor was achieved using Rh-doped SnO2 hollow spheres prepared by ultrasonic spray pyrolysis followed by heat treatment at 500 degrees C, and the effects of Rh doping on TMA sensing characteristics were investigated. The response (resistance ratio) of the Rh-doped SnO2 hollow spheres to 5 ppm TMA at 400 degrees C was 1177.5, which is 33 times higher than that of pure SnO2 hollow spheres. The detection limit of the sensor was as low as 5 ppb. In addition, the Rh-doped SnO2 hollow spheres showed negligible cross-responses to HCHO, benzene, toluene, p-xylene, NH3, CO, H-2, and NO2, and a decreased cross-response to C2H5OH, whereas pure SnO2 hollow spheres did not show selective detection of a specific gas. The ultrahigh sensitivity and selective detection to TMA were attributed to the electronic interactions between Rh and SnO2 and the high catalytic activity of Rh to TMA. (C) 2014 Elsevier B.V. All rights reserved.