Fast economical synthesis of Fe-doped ZnO hierarchical nanostructures and their high gas-sensing performance

The Fe-doped ZnO with excellent porous features was successfully fabricated via a fast economical solution combustion synthesis. The morphology and the porous nature were characterized by SEM, TEM and BET-N₂ adsorption-desorption analysis. The results of XRD Rietveld refinements and Raman spectra demonstrate that the dopant was successfully incorporated into the nanostructure ZnO lattice. The gas-sensing tests show that the sensors based on Zn_0.97Fe_0.03O have high sensitivity, quick response, excellent selectivity and long-time stability for detecting ethanol vapor. AC impedance spectroscopy and DC electrical conductivity measurements were used to investigate the gas-sensing mechanism, and the results demonstrate that the O^- (300-400 °C) on the surface is the most reactive species with ethanol gas.