H2S gas sensing properties of Fe2O3 nanoparticle-decorated NiO nanoplate sensors

Fe2O3 nanoparticles and Fe2O3 nanoparticle-decorated NiO nanoplates were synthesized via a facile solvothermal route using FeCl3, nickel acetate, and NaOH as starting materials. The structure and morphology of the synthesized nanoparticles were examined using X-ray diffraction and scanning electron microscopy, respectively. The gas sensing properties of the Fe2O3 nanoparticles and Fe2O3 nanoparticle-decorated NiO nanoplate sensors toward H2S gas were examined at different concentrations of H2S (5-200 ppm) gas at various temperatures (200-350 degrees C). The Fe2O3 nanoparticle-decorated NiO nanoplate sensor exhibited a stronger response to H2S than the Fe2O3 nanoparticle sensor. The response of the Fe2O3 nanoparticle-decorated NiO nanoplate sensor was 26.55 for 200 ppm H2S at 300 degrees C, whereas the maximum response of the Fe2O3 nanoparticle sensor was 7.46 under the same condition. The Fe2O3 nanoparticle-decorated NiO nanoplate sensor also exhibited shorter response and recovery times than those of the Fe2O3 nanoparticle sensor. The improved sensing performance of the Fe2O3 nanoparticle-decorated NiO nanoplate sensor was attributed to the enhanced modulation of the conduction channel width and potential barrier height at the NiO-Fe2O3 interface, catalytic activity of NiO in the oxidation of H2S, larger surface-to-volume ratio of the decorated sensor, and stronger adsorption of oxygen molecules by p-type NiO. (C) 2016 Elsevier B.V. All rights reserved.