UNS: Mechanistic Studies of Hydrodeoxygenation of Lignin-Derived Aromatic Oxygenates over Bimetallic Catalysts

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

1508048 Vohs, John M. Bio-refining of lignin-based biomass results in production of oxygenated aromatic compounds that must be further processed by hydrodeoxygenation (HDO) to produce higher-value aromatic compounds. The study will involve molecular-level investigation of the adsorption and reaction of several oxygenated aromatics on bimetallic catalysts ranging from single crystals to supported catalysts. The resulting insight will aid the discovery and development of catalysts that convert oxygenated aromatic compounds to useful fuels and chemicals. The work will also train students at both the undergraduate and graduate levels in skills relevant to the realization of a sustainable energy and environmental future. Bimetallic catalysts composed of a group-10 metal (Ni, Pd, Pt) and a second more oxyphilic metal, such as Fe or Zn, will be chosen based on previous demonstration of HDO activity in aldehyde and aldose HDO. Specifically, the proposal will investigate how changes in the metal d-band resulting from the addition of a second more oxyphilic metal (e.g., Fe or Zn) influence the interaction of aromatic rings with the catalyst surface and the role this plays in decreasing overall activity for undesirable ring hydrogenation. The study will also examine the role of the oxyphilic metal in providing specific binding sites for the oxygen atoms in the aromatic oxygenates and the role of these sites in facilitating C-O bond cleavage in HC=O, C-OH, and C-O-C groups. In addition to the single crystal studies, high-surface-area supported bimetallic catalysts will be prepared and subjected to spectroscopic characterization of adsorbed species, and evaluated in a gas-phase flow-reactor to obtain reaction kinetics and selectivity to desired products. The proposal clearly addresses a critical step (HDO) in the overall biomass refining scheme. As such, it will provide fundamental insight that will aid the development of biomass refining schemes and thereby move lignocellulosic biomass conversion closer to an economically realizable process, with attendant benefits for renewable energy and chemicals. The project will also train both graduate and undergraduate students in the fields of energy conversion, heterogeneous catalysis, and reaction engineering - skills highly sought by the U.S. petrochemical industry.