화학공학소재연구정보센터
Applied Surface Science, Vol.274, 64-70, 2013
Influence of growth ambient on the surface and structural properties of vanadium oxide nanorods
The influence of growth ambient on the surface and structural properties of vanadium oxide nanorods have been studied by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy (RS). The vanadium oxide nanorods, which were synthesized through an ambient controlled vapor transport process, exhibit different surface electronic properties depending upon the growth ambient. The Raman data indicates that the as-grown samples are orthorhombic V2O5 phase with a small variation of stoichiometry. Under highly oxidative conditions, nearly stoichiometry sample can be grown. If the samples were grown under less oxidizing conditions, an increase of structural disorder was observed. The observed V 2p core level spectra of both samples showed a single peak with chemical shifts corresponding to the V5+ and V4+. XPS results suggested that the highly oxidized vanadium ions (V5+) are gradually reduced to lower oxidation state (V4+) with the decreases of ambient oxygen levels during growth. The results clearly show that surface non-stoichiometry may be correlated with structural disorder of V2O5 nanorods. The growth ambient and post-annealing may influence the vanadium oxidation state and subsequent surface reactivity significantly. (C) 2013 Elsevier B.V. All rights reserved.