Synthesis of iron-doped vanadium-tin oxide nanocrystallites for CO gas sensing

Iron-doped vanadium-tin oxide nanoparticles have been synthesized by a hydrolysis and co-precipitation method from iron(II) acetate, vanadium(III) acetylacetonate and tin tetrachloride. The mixed oxide was characterized as a tetragonal cassiterite structure by X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS) revealed an electronic interaction between tin, vanadium and iron atoms in the oxide structure. Addition of iron species into the vanadium-tin oxide led to a decrease in the crystallite size and changes in the oxidation states of vanadium and iron cations in the surface region. Based on sensitivity measurements in a semiconductor CO gas sensor, the iron doping resulted in a shift of the maximum sensitivity toward the lower temperature side. A correlation between the surface state and sensor performance is proposed. (C) 2009 Elsevier B.V. All rights reserved.