Vanadia supported on ceria: Characterization and activity in liquid-phase oxidation of ethylbenzene

Vanadia/ceria catalysts (2-10 wt% Of V2O5) were prepared by wet impregnation of ammonium metavanadate in oxalic acid solution. Structural characterization was done with energy dispersive X-ray analysis (EDX), powder X-ray diffraction (XRD), BET surface area measurements, FT-IR spectroscopy and nuclear magnetic spectral analysis (V-51 MASNMR). XRD and V-51 MASNMR results show highly dispersed vanadia species at lower loadings and the formation of CeVO4 phase at higher V2O5 loading. The catalytic activity of catalysts was conducted in liquid phase oxidation ofethylbenzene with H2O2, as oxidant. The oxidation activity is increased with loading up to 8 Wt% V2O5 and then decreased with further increase in V2O5 content to 10 wt%. Differeint vanadia species evidenced by various techniques were found to be selective towards ethylbenzene oxidation. The CeVO4 formation associated with increased concentration of vanadia on ceria results the production of acetophenone along with 2-hydroxyacetophenone. (c) 2006 Elsevier B.V. All rights reserved.