Will Medlin, University of Colorado
December 10, 2013
11:00 AM - 12:00 PM
Understanding and Controlling Selectivity in Heterogeneous Catalysis of Biomass Derivatives
Abstract:
Performing specific transformations of reactants with multiple functional groups is a challenging objective, since each functional group can potentially adsorb and react on a catalytic surface. Addressing this problem is particularly important for the conversion of biomass to chemicals and fuels, because carbohydrates and their downstream intermediates contain multiple reactive functional groups. For example, furfural and hydroxymethyl furfural, which can be produced in high volumes from dehydration of sugars, contain one or more oxygenate (alcohol or aldehyde) functions together with a furan ring. Alcohols, aldehydes, and furan in isolation are all reactive on Pt-group metal surfaces, and the individual reaction pathways of each group are observable when these functions are located on the same molecule. Furthermore, as will be demonstrated in this presentation, the multiple functions on furfuryl oxygenates have synergistic effects on reactivity, opening up additional reaction pathways not available to reactants containing only a single functional group. Thus, controlling selectivity through heterogeneous catalyst design is highly complex.Our group has conducted surface-level investigations of a number of reactions important for the conversion of biomass to fuels and chemicals. This presentation will focus on how these studies can be used to understand key aspects of reaction mechanisms on surfaces, and furthermore how this understanding can lead to design of catalysts with improved performance. Several examples will be presented. In the selective conversion of furfurals to fuel-grade products, we have found that selectivity can be drastically improved by preparing catalysts that control crowding of reactants on the surface. For the selective oxidation of biomass-derived polyols to key renewable chemicals, local surface composition can be controlled to influence reactant binding in a way that improves desired product yields. Finally, reforming of biomass-derived “tars” can be improved by using atomic layer deposition to make catalysts with precise control over both surface structure and composition. A general approach for approaching catalyst design in reactions of complex oxygenated chemicals will also be discussed.
Date posted
Jun 17, 2019
Date updated
Jun 17, 2019