XPS characterisation of iron-modified vanadyl phosphate catalysts

Iron-modified vanadyl phosphate is an interesting material with potential a pplications in catalysis due to the oxidising and dehydrogenating proper-ti es of the trivalent metal. Alumina-supported samples have been characterise d by X-ray photoelectron spectroscopy (XPS) and compared with respect to th e temperature of calcination and their catalytic behaviour in the oxidative dehydrogenation of ethane, XPS has been used to analyse the surface chemic al composition of the samples and the modifications induced by different te mperatures of calcination and catalysis. The oxidation state, amount, distr ibution and evolution of vanadium species have been investigated both after calcination at T = 450 and 550 degreesC and after catalytic tests at T = 4 50, 550 and 650 degreesC. Quantitative XPS analysis has been used to determ ine the surface concentration of different vanadium species. (C) 2001 Elsev ier Science B.V All rights reserved.