Morphology effect of Ru/CeO2 catalysts for the catalytic combustion of chlorobenzene

The present work elucidated the morphology and crystal-plane effects of nanoscale ceria on the activity of Ru/CeO2 catalysts toward catalytic combustion of chlorobenzene taken as a model of chlorinated aromatic hydrocarbons (CAHs). CeO2 nanorods (CeO2-r), nanocubes (CeO2-c) and nano-octahedra (CeO2-o) (enclosed by {110} and {100}, {100} and {111}, respectively) as supports, were prepared by wet impregnation. The status and structure of Ru species is quite dependent on the enclosed various facets. Ru/CeO2-r possesses much more Ru4+, oxygen vacancies and Ru-O-Ce bonds than Ru/CeO2-c and Ru/CeO2-o, indicating that there is a stronger interaction between Ru and CeO2-r. The surface oxygen mobility and reducibility follow the order of Ru/CeO2-r > Ru/CeO2-c > Ru/CeO2-o. The activity test of chlorobenzene oxidation shows that Ru/CeO2-r is more active than that of Ru/CeO2-c and Ru/CeO2-o, with T-10% and T-90% of 160 and 280 degrees C, respectively, which can be related to a larger number of Ru-O-Ce bonds, higher content of Ru4+ and surface oxygen mobility and reducibility. These results confirm that the activity of Ru/CeO2 catalysts for CB oxidation is greatly affected by CeO2 shape/crystal plane. (C) 2014 Published by Elsevier B.V.