Calcination effects on CeZrOx geometry and styrene production from ethylbenzene

• Calcination at different temperatures converts CeZrOx cubes into spheres.
• Raman revealed decreasing number of oxygen vacancies with increasing temperature.
• The samples were active for ethylbenzene dehydrogenation in the presence of CO2.
• Activity per gram and per m2 decreased with higher calcination temperature.
• Specific reactivity of defect sites is determined by particle size and shape.

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 m2 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.

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