Leveraging Epitaxial Growth to Deconvolute Particle Size and Density Effects in Thermal Catalysis

About This Grant

Management of waste plastics and other polymeric materials has become a critical environmental issue in recent years. Effective mitigation has generated research and development efforts to “up-cycle” waste plastic to more valuable chemicals or embrace “circular” plastics process technology. When combined with more efficient manufacturing processes, the re-use of plastics, in any form, stands to contribute significantly to net-zero carbon emissions. To those goals, the project investigates a novel catalyst design to break down polyolefin-based plastics (e.g., polyethylene or polypropylene) into smaller molecules that can be used as building blocks for either the remanufacture of polymeric materials or production of commodity chemicals. The novel catalyst design improves overall manufacturing efficiency by lowering energy requirements and directing the chemistry towards desired products. Beyond the technical aspects, the project includes educational and outreach initiatives promoting STEM opportunities for K-12 students, and training opportunities for both undergraduate and PhD students. The project investigates an aspect of supported heterogeneous supported metal catalyst design that is typically not considered or controlled, i.e., the relationship between particle size and particle density. Specifically, this will be accomplished by varying the particle size and site density of rutile-RuO2 supported on rutile-SnxTi1-xO2 where x ranges from 0 to 1 and to study the effects of these parameters on polyolefin hydrogenolysis. The project leverages the lead investigator’s skills in catalysis with polymer characterization and synthesis capabilities at the University of Akron, thus enabling new methods to analyze polymer upcycling kinetics on well-controlled polymer samples. The RuO2 particle size will be controlled by varying the calcination temperature and/or the misfit strain during epitaxial growth of RuO2 on the rutile-oxide support. Site density will be controlled by the metal precursor loading. Polyolefins (POs) are ideal substrates, and PO hydrogenolysis is a well-chosen probe reaction for elucidating the kinetics as related to the effects of particle size vs density, given the large substrate size and potential for oligomers to bridge multiple particles. The study thus carries practical implications for polymer upcycling, benefitting from new “drop-in” catalyst technology potentially applicable to a broad range of catalytic processes. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.