Redox Behavior of (CuO)_0.15(CeO₂)_0.85 Mixed Oxide Catalyst Prepared by Sol-Gel Peroxide Method

Albin Pintar, Jurka Batista, and Stanko Hočevar*
Laboratory for Catalysis and Chemical Reaction Engineering, National Institute of Chemistry,
Hajdrihova 19, P.O. Box 660, SI-1001 Ljubljana, Slovenia

Abstract
Temperature-programmed reduction (TPR), oxidation (TPO) and desorption (TPD) studies were performed on (CuO)_0.15(CeO₂)_0.85 copper-ceria mixed oxide sample prepared by sol-gel peroxide route. The obtained results reveal that despite initial drop in specific surface area after consecutive redox cycles the hydrogen consumption remains constant. This is because CuO is highly dispersed over the surface of CeO₂ nano-crystallites and remains highly dispersed even after the agglomeration of CeO₂ nano-crystallites in more dense secondary structure. The dispersed CuO is reduced to Cu⁰ during the TPR, forming agglomerated metal particles on the surface of partially reduced CeO₂. After subsequent TPO step all the Cu⁰ is oxidized back into CuO and re-dispersed over the CeO₂ crystallites.

Key words: catalyst, (CuO)_0.15(CeO₂)_0.85, redox properties, TPR, TPO, TPD