Water-induced Formation of Cobalt Oxides Over Supported Cobalt/Ceria-Zirconia Catalysts under Ethanol-Steam Conditions

Journal Article · Wed Jul 28 04:00:00 EDT 2010 · Journal of Catalysis, 273(2):229-235

DOI:https://doi.org/10.1016/j.jcat.2010.05.016· OSTI ID:988634

Lin, Sean S.-Y.; Kim, Do Heui; Engelhard, Mark H; Ha, Su Y

The formation of water-induced cobalt oxides by re-oxidizing the metallic cobalt in the pre-reduced 10% Co/CeO2-ZrO2 catalyst was verified by in-situ TPR and in-situ XPS studies under various ethanol-steam conditions. The formation and transformation of water-induced cobalt oxide species were affected by the pre-reduction conditions used for the catalysts and the feed stream composition used in the reaction. This result suggests that the surface composition of the cobalt species in 10% Co-CZ catalyst, initially governed by the catalyst pre-treatment, was changed toward an equilibrium state that governed by the feed stream composition as the reaction proceeds. In addition, the reducibility of the ceria sites may play a significant role in the redox process involved both cobalt and ceria sites under ethanol-steam environment. Finally, the effect of the water-induced cobalt oxides on the catalytic performance, in particular for the carbon-carbon bond cleavage of ethanol, is negligible. However, these water-induced oxides may show importance for the subsequent reaction steps that determine the product selectivity during ethanol steam reforming, as their coexistence with the metallic cobalt species was revealed by the in-situ study under ethanol-steam conditions.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 988634
• Report Number(s): PNNL-SA-69727; 30484; 24826; KP1704020
• Journal Information: Journal of Catalysis, 273(2):229-235, Journal Name: Journal of Catalysis, 273(2):229-235 Journal Issue: 2 Vol. 273; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CATALYSTS
CATALYTIC EFFECTS
CERIUM OXIDES
COBALT
COBALT OXIDES
ETHANOL
Environmental Molecular Sciences Laboratory
HYDROLYSIS
REDOX PROCESS
STEAM
SYNTHESIS
ZIRCONIUM OXIDES