(79a) Development of Metal Carbide, Nitride, and Phosphide Catalysts for Bio-Oil Deoxygenation: Acetic Acid Hydrogenation

The design and development of effective and efficient catalysts for biomass conversion processes is a daunting task; yet it is one that must be successful in order to achieve wide-spread commercialization of cellulosic biofuel production processes. Of particular interest is the development of catalysts for the upgrading of pyrolysis bio-oil to produce diesel and jet fuel. This upgrading step is particularly challenging due to the complex nature of the bio-oil (i.e., high oxygen content, chemical instability, and complex mixture containing acids, aldehydes, esters, alcohols, ethers, ketones, phenolics, sugars, and furans) and the multiple reaction steps (i.e., hydrogenation, deoxygenation, and C-C coupling) that must occur in order to produce fungible liquid fuels. Our approach for developing multi-functional catalysts for the upgrading of pyrolysis bio-oil combines advanced synthesis techniques with parallel computational and experimental efforts.

The focus of this talk will be on the combination of catalytic testing and density functional theory calculations to guide the development of future catalysts. The performance of a series of bulk and supported metal carbide, nitride, and phosphide catalysts for vapor-phase acetic acid hydrogenation has been evaluated using a temperature-programmed reaction system. Two supported noble metal catalysts (Ru and Pt) were also tested and were used as a comparison. Notably, a bulk Mo₂C catalyst was found to favor oxygen removal via H₂O production while a Pt/C catalyst favored decarbonylation. The relative activities and dominant reaction pathways for these catalysts will be presented and will be discussed in terms of their structure-function relationships.