Construction and enhanced gas sensing performances of CuO-modified α-Fe2O3 hybrid hollow spheres

The well-defined three-dimensional (3D) CuO-modified alpha-Fe2O3 hybrid hollow sphere (HS) nanostructures, with thin shell of about 10 nm, were one-pot constructed by the facile carbon sphere template method and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. Using several volatile organic compounds (VOCs) including methanol, ethanol and acetone as probe gases, gas sensing performance of the sensor based the prepared CuO-modified alpha-Fe2O3 hybrid HSs was systematically investigated. The results showed that the CuO-modified alpha-Fe2O3 HS sensor had a remarkably enhanced response to VOCs compared with the single alpha-Fe2O3 HS sensor. The enhanced sensor properties could be attributed to the unique hollow structure with porous shell and the synergic electronic interaction between p-type CuO and n-type alpha-Fe2O3. The 3D hybrid HS sensor exhibited not only high response to ppm level VOCs, but also short response and recovery times within 10 s, demonstrating its potential application as gas sensor. (c) 2012 Elsevier B.V. All rights reserved.