Enhanced H2S gas sensing properties of multiple-networked Pd-doped SnO2-core/ZnO-shell nanorod sensors

Pd-doped SnO2-core/ZnO-shell nanorods were synthesized by using a three,step process: thermal evaporation of Sn powders in an oxygen atmosphere, atomic layer deposition of ZnO, and Pd diffusion followed by annealing. The sensitivity of the multiple networked SnO2-core/ZnO-shell nanorod sensor to H2S gas was found to be improved further significantly by Pd doping. The Pd-doped SnO2-core/ZnO-shell nanorod sensor showed sensitivities of 6.4, 15.4, and 36.2% at H2S concentrations of 20, 50, and 100 ppm at room temperature. The sensitivity of the nanorods was improved by more than 10 times at a H2S concentration of 100 ppm. The sensitivity enhancement of the SnO2-core/ZnO-shell nanorods by Pd doping may be attributed to the spillover effect, active reaction site generation, and the enhancement of chemisorption and dissociation of gas. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.