468347 Mechanistic Insights into Carbon-Oxygen Bond-Breaking on Mo2c Catalysts: Ethanol Dehydration

Thursday, November 17, 2016: 12:30 PM
Franciscan D (Hilton San Francisco Union Square)
Carrie A. Farberow, Connor Nash and Joshua A. Schaidle, National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO

Molybdenum carbide catalysts have been shown to be active catalysts for the deoxgenation of biomass-derived oxygenates, an important reaction for the production of fuels and chemicals via ex situ catalytic fast pyrolysis (CFP).1-3 Under typical ex situ CFP conditions, the Mo2C catalyst is likely highly covered in oxygen, and possesses metallic-like sites, oxygen vacancy sites and acidic sites, which may each play a different role in controlling the observed activity and selectivity of deoxygenation reactions. To elucidate the role of these various sites, we apply first principles electronic structure calculations to investigate the reaction mechanism of ethanol dehydration on Mo2C. Temperature programmed reaction experiments have shown that ethanol dehydration occurs at low temperatures (150 °C) on Mo2C to produce primarily ethylene and water. In this work, we elucidate the reaction pathways and active sites for C-O bond-breaking in ethanol dehydration as well as the relationship between the energetics of the competing pathways, the Mo2C surface termination, and the oxygen coverage under reaction conditions.

1. Schaidle, J. A..; Blackburn, J.; Farberow, C. A.; Nash, C.; Steirer, K. X.; Clark, J.; Robichaud, D. J.; and Ruddy, D. A.; ACS Catal.20166, 1181.

2. Bej, S. K. and Thompson, L. T.; Appl. Catal. A. 2004, 264, 141.

3. Sullivan, M. M.; Chen, J.-C.; Bhan, A. Catal. Sci. Tech. 2016, 6, 602.

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