Shape-dependency activity of nanostructured CeO2 in the total oxidation of polycyclic aromatic hydrocarbons

A morphological phase diagram is determined to relate the effect of base concentration and temperature during the hydrothermal synthesis with the final ceria nanostructured morphology. Representative samples of nanoparticles, nanorods and nanocubes have been characterized by XRD, N2 adsorption, TEM, XPS and Raman and catalytically tested for the total oxidation of naphthalene as a model polycyclic aromatic hydrocarbon. Ceria nanoparticles present the highest surface area and smallest crystalline size, leading to the most active of these structures. However if the catalytic activity is normalized by unit of surface area, the observed reactivity trend (nanorods<nanocubes<nanoparticles) is directly related to the concentration of surface oxygen vacancies as a result of the exposure of the (110) and (100) preferential planes.