(479b) Controlling Selectivity in Reactions of Complex Oxygenates over Metal Catalysts

Complex reactants such as biomass-derived oxygenates often have multiple reactive functional groups. A consequence of this multi-functionality is that these reactants can potentially adsorb in many configurations on catalyst surfaces. We have found that selectivity to desired reaction products is often closely related to the favorability of a particular configuration of the adsorbed reactant. To engineer more selective catalysts, it is therefore desirable to be able to predict how adsorbate geometry is influenced by catalyst structure and composition. This presentation will focus on our efforts to understand how adsorbate structure is controlled by catalyst properties, and to manipulate those properties to control surface-adsorbate interactions and thus improve catalyst performance. Not surprisingly, key parameters in catalyst design include surface composition and catalyst nanostructure. However, in some cases (such as the hydrodeoxygenation of biomass pyrolysis compounds) these properties influence adsorbate configurations—and thus product selectivities—in surprising ways. Moreover, controlling the near-surface environment through coadsorption of organic species is seen to exert a powerful influence over reactant adsorption and product selectivity. Methods for engineering the near-surface environment through incorporation of organic ligands or inorganic films for chemoselective hydrogenation reactions will be discussed.