Through my graduate research project, I seek to gain a molecular level understanding of the reactions of polyols with coadsorbed oxygen on the Pd(111) catalytic surface. Polyols are molecules with multiple hydroxyl groups (sometimes called “alcohol sugars”), and are common biomass derivatives in biorefining processes. Using advanced surface science (spectroscopic) and computational techniques, a detailed mechanistic understanding of these reactions may be used to design catalysts for the selective oxidation of polyols. For example, the selective oxidation of the polyol glycerol’s secondary, interior hydroxyl group to a ketone group produces dihydroxyacetone, a chemical worth $20 per gallon. Glycerol is a polyol of interest because it is an abundant byproduct in the production of biodiesel. There are several valued chemicals resulting from the oxidation of glycerol (depending on oxidation of the primary or secondary alcohol) e.g. glyceraldehyde, glyceric acid, glycolic acid and hydroxypyruvic acid.
Currently, the system of interest being studied is 1,2-propanediol (PDO) reacting with coadsorbed oxygen on a Pd(111) single crystal surface. PDO is chosen as a probe molecule for its similarity to the more complex glycerol, where PDO has both a primary and secondary alcohol to study.
Overall, the project is aimed at understanding mechanisms relevant to the production of valued chemicals from the oxidation of biomass-derived carbohydrates. The fundamental work of surface science studies may be applied to rationally design a catalytic surface. The next step is to evaluate the designed technical catalytic surface in a flow reactor. Another part of this project will involve studying these polyol reactions with coadsorbed oxygen over supported metal catalysts under steady state conditions, providing insight into the preparation of industrially-relevant catalysts and tying in the current fundamental studies.