Gold-vanadia catalysts supported on ceria-alumina for complete benzene oxidation

Gold-vanadia catalysts supported on ceria:alumina with different ratios (1: 1 and 1:4) for complete benzene oxidation (CBO) were studied and compared with the same type of catalysts on pure ceria. These were characterized by means of X-ray, TPR, Raman and ESR spectroscopy. It was established that the catalysts based on ceria:alumina (1:1) exhibited higher activity than that on ceria-alumina (1:4). A correlation between the reducibility of vanadia surface layers in the presence of gold and CBO activity was found. The observed by Raman spectra increased FWHM values of the dominated ceria line in the presence of alumina could be related to the oxygen vacancies formation. The highest stability and activity was exhibited by the gold-vanadia catalyst on ceria-alumina (1:1) and the lowest vanadia loading. Alumina in the mixed support prevents the gold and ceria agglomeration at the extreme operation conditions during the test of stability. (C) 2004 Elsevier B.V. All rights reserved.