Fe2O3/ Co3O4 composite nanoparticle ethanol sensor

摘要

In this study Fe2O3/Co3O4 nanocomposites were synthesized by using a simplehydrothermal route. The X-ray diffraction analysis results showed thatsynthesized powders were pure, and nanocrystalline in nature. Moreover,Scanning electron microscopy revealed that Fe2O3 nanoparticles had sphericalshapes while Co3O4 particles had a rod-like morphology. Ethanol sensingproperties of Fe2O3/Co3O4 nanocomposites were examined and compared with thoseof pristine Fe2O3 nanoparticles. It was shown that the gas sensing propertiesof Fe2O3/Co3O4 nanocomposites were superior to those of pristine Fe2O3nanoparticles and for all concentrations of ethanol, the response of thenanocomposite sensor was higher than the pristine Fe2O3 nanoparticle sensor. Indetail, the response of Fe2O3/Co3O4 nanocomposite sensor to 200 ppm of ethanolat 300{\deg}C was about 3 times higher than pristine one. Also in general, theresponse and recovery times of Fe2O3/Co3O4 nanocomposite sensor were shorterthan those of the pristine one. The improved sensing characteristics of theFe2O3/Co3O4 sensor were attributed to a combination of several effects: theformation of a potential barrier at the Fe2O3-Co3O4 interface, the enhancedmodulation of the conduction channel width accompanying the adsorption anddesorption of ethanol gas, the catalytic activity of Co3O4 for the oxidation ofethanol, the stronger oxygen adsorption of p-type Co3O4, and the formation ofpreferential adsorption sites.