Novel Waste-Derived Catalysts for Biomass Hydrogenation
Objective: This project will upgrade agricultural waste to novel catalysts that incorporate a single metal adatom (Mad) into a graphene (G) matrix via a patented reactive mechanochemical (RMC) process. Formation of the novel Mad/G structure will be confirmed via spectroscopy, advanced electron microscopy, and X-ray photoelectron spectroscopy. The catalyst will be characterized using temperature programmed desorption (TPD), catalyst dispersion measurements, and evaluated for catalytic properties using probe hydrogenation reactions.
Relation to PSIEE Strategic Priorities: The novel catalytic properties of Mad/G will lead to improved life cycle carbon and hydrogen efficiency of biomass pyrolysis. Low temperature hydrogenation reactions promote the migration of organic molecules from the aqueous to the organic phase and convert highly reactive components (acids, aldehydes, ketones) to less reactive hydrocarbons or alcohols, thereby mitigating the role the thermal instability of pyrolysis oils. Many aqueous-phase hydrogenation catalysts rely on metal nanoparticles supported on activated carbons, a close analog to the waste-derived catalysts to be developed in the proposed work.
Intellectual Merit: A covalently bound single Mad covalently bound to G will be resistant to sintering, make more efficient use of metals, and alter the electronic and magnetic properties of G to enhance catalytic performance. Even low-cost metals such as Fe and Ni may have superior catalytic performance when atomically dispersed in G. In a related field, increasing experimental evidence supports that highly active catalytic sites consist of single cationic Mad rather than Mnp. We hypothesize that compression of irregular polyaromatics (from carbon wastes) in the presence of metals will lead to the formation of Mad/G, as the network will inevitably be carbon deficient, and highly reactive to capture metals within the high energy “shock impact” RMC environment. Formation of Mad/G may account for previously observed unusual hydrogenation properties for RMC materials.