A series of CeZrOx catalysts was prepared by calcination of hydrothermally obtained metal oxide precipitate at increasing temperatures. The samples were characterized by HRSEM, XRD and Raman spectroscopy, showing a change in morphology and particle size as a function of calcination temperature. Catalytic testing for ethylbenzene dehydrogenation with CO2 showed a decreasing activity per gram with increasing calcination temperature due to the decreasing particle size. However, ethylbenzene dehydrogenation activity per m(2) also steadily decreased. Correlation of the catalytic results with Raman analysis showed that not only the number of oxygen vacancies decreases with increasing particle size due to a lower surface area, but also their specific reactivity decreased because of a change in the particle morphology. (C) 2013 Elsevier B.V. All rights reserved.