Metal cations doped vanadium oxide nanotubes: Synthesis, electronic structure, and gas sensing properties

Abstract The potential sensor materials of scroll-like dodecylamine-templated vanadium oxide VO x nanotubes doped with Co 2+ or Fe 3+ have been prepared using a sol-gel technique followed by the hydrothermal treatment. The resultant samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning and transmission electron microscopies, thermal and elemental analysis. The gas sensing properties of the metal cations doped VO x nanotubes have been tested in the wide range of working temperatures and targets’ concentrations towards ammonia, ethanol, methanol, toluene and acetone. The highest sensor activity was revealed for ethanol. Stability and electronic properties of pristine and metal doped VO x layers as well as their ad-complexes with O 2 as intermediates during the working process of a sensor were studied by DFT calculations. The study suggests two different mechanisms of cations' action on sensing properties of a VO x compound. In absence of steric obstacles, Co 2+ doing is predicted to be the most efficient dopants for beneficial activation of VO x sensing properties.