XPS characterisation of iron-modified vanadyl phosphate catalysts Original Research Article

Iron-modified vanadyl phosphate is an interesting material with potential applications in catalysis due to the oxidising and dehydrogenating properties of the trivalent metal. Alumina-supported samples have been characterised by X-ray photoelectron spectroscopy (XPS) and compared with respect to the temperature of calcination and their catalytic behaviour in the oxidative dehydrogenation of ethane. XPS has been used to analyse the surface chemical composition of the samples and the modifications induced by different temperatures of calcination and catalysis. The oxidation state, amount, distribution and evolution of vanadium species have been investigated both after calcination at T=450 and 550°C and after catalytic tests at T=450, 550 and 650°C. Quantitative XPS analysis has been used to determine the surface concentration of different vanadium species.