Nature of the vanadia-ceria interface in V5+/CeO2 catalysts and its relevance for the solid-state reaction toward CeVO4 and catalytic properties

A combination of in situ Raman, XANES, and EPR spectroscopies is used to study the nature of the interaction between V and Ce in the ceria-supported vanadia catalysts. Vanadium oxide species disperse on ceria up to 9 V atoms/nm(2) of support. Surface V5+ species closely interacts with ceria support promoting a reduction of surface Ce4+ to Ce3+. Upon heating or during reaction surface vanadia reacts with ceria support forming a CeVO4 phase. The active site appears to be V5+-O-Ce3+ for both systems. The redox cycle for oxidative dehydrogenation appears to be associated with Ce, rather than with V sites. (C) 2004 Elsevier lnc. All rights reserved.