Ceramic foams directly-coated with fame-made V2O5/TiO2 for synthesis of phthalic anhydride

Flame-made airborne V2O5/TiO2 nanoparticles were deposited directly onto mullite foam supports to create ready-to-use catalysts for the o-xylene conversion to phthalic anhydride. These particles containing 10% (w/w) V2O5 were created by combustion of liquid precursor sprays and characterized by transmission electron microscopy, nitrogen adsorption, X-ray diffraction (XRD), temperature-programmed reduction (TPR), and Raman spectroscopy. The specific surface area, anatase content, and dominantly monomeric vanadia species on titania were thermally stable up to 450 degrees C. Catalyst structure was controlled in situ during deposition by the particle-laden gas flow rate through the foam, resulting in homogeneous to patchy V2O5/TiO2 coatings. The catalytic activity and selectivity were affected by both coating texture and particle morphology. These flame-coated foams showed superior catalytic activity and selectivity at high conversions than classic, wet-made V2O5/TiO2 catalysts. (c) 2006 Elsevier Inc. All rights reserved.