Synthesis and Characterization of Iron- and Vanadium-Doped Titania Aerogel Nanopowders

Abstract

Nanopowders of anatase Fe x V 0.05 Ti 0.95Àx O y (x 5 0, 0.02) solid solutions have been synthesized by a sol-gel process with ensuing supercritical drying. Changes in the surface state and crystal structure about the iron doping were characterized by X-ray photoelectron spectroscopy (XPS), electron spin resonance, and X-ray diffraction. XPS revealed an electronic interaction between Fe and V atoms in the ternary compound and the formation of Fe and V redox pairs on the surface. The oxide aerogels were evaluated as catalyst for methanol oxidation. Formaldehyde was favorably produced over the V-doped titania, and the Fe addition enhanced the rate of carbon oxides formation. Results demonstrate that the reducible Fe-O-V bond acts as active sites and influences product distribution. The competitive reactivity between Fe and V sites is responsible for the transformation of surface nature from redox to basic characters. The ceramic nanostructures are promising materials for use in many processes involving electron transfer.