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Brookhaven-Delaware team designs catalyst for biofuel production

Scientists at the Department of Energy's Brookhaven National Laboratory (BNL) and the University of Delaware have designed a catalyst to improve the conversion of a plant derivative into biofuel.

The catalyst, composed of very low concentrations of platinum (single atoms and clusters smaller than billionths of a meter) on the surface of titanium dioxide, significantly enhances the rate of breaking a particular carbon-oxygen bond for the conversion of a plant derivative (furfuryl alcohol) into a potential biofuel (2-methylfuran). This strategy—described in a paper published on March 23 by Nature Catalysis—could be applied to design stable, active, and selective catalysts based on a wide range of metals supported on metal oxides to produce industrially useful chemicals and fuels from biomass-derived molecules.

“For a molecule to generate a particular product, the reaction has to be directed along a certain pathway because many side reactions are possible that are not selective for the desired product,” explained co-author Anibal Boscoboinik, a staff scientist in BNL's Center for Functional Nanomaterials (CFN) Interface Science and Catalysis Group. “To convert furfuryl alcohol into biofuel, the bond between carbon and oxygen atoms on the side group attached to the ring-shaped part of the molecule must be broken, without producing any reactions in the ring. Typically, the metal catalyst that breaks this bond also activates ring-related reactions. However, the catalyst designed in this study only breaks the side group carbon-oxygen bond.”

Aromatic rings are structures with atoms connected through single or double bonds. In molecules derived from plant waste, aromatic rings often have oxygen-containing side groups. Transforming plant waste derivatives into useful products requires the removal of oxygen from these side groups by breaking specific carbon-oxygen bonds.

Hydrodeoxygenation, a reaction in which hydrogen is used as a reactant to remove oxygen from a molecule, is used to converting biomass into other products. In this study, theoretical calculations and modeling confirmed the scientists' hypothesis that adding noble metals to the surfaces of moderately reducible metal oxides—those that can lose and gain oxygen atoms—would promote hydrodeoxygenation. To test their hypothesis, the team selected platinum as the noble metal and titanium dioxide (titania) as the metal oxide. After synthesizing the platinum-titania catalyst at the University of Delaware, they performed various structural and chemical characterization studies using facilities at Brookhaven and Argonne National Labs.

Back at Delaware, the team performed reactivity studies in which they put the catalyst and furfuryl alcohol in a reactor and detected the products through gas chromatography. In addition to these experiments, they calculated the amount of energy theoretically required for different steps of the reaction and ran computer simulations to determine the preferred reaction pathways. The simulated and experimental findings both indicated that negligible ring-reaction products are generated when a low concentration of platinum is present. As this concentration is increased, the platinum atoms begin to aggregate into larger clusters that incite ring reactions.

This research was supported by the Catalysis Center for Energy Innovation, a DOE Energy Frontier Research Center at the University of Delaware.

Read more: https://www.bnl.gov/newsroom/news.php?a=117096

Read the study here: https://www.nature.com/articles/s41929-020-0445-x

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