Collaborative Research: Engineering Selectivity by Catalyst Architecture Control

Significant progress has been made in recent years in chemically deconstructing biomass to produce smaller molecules that can be used as building blocks for a broad range of chemicals and fuels. Such a strategy is now being investigated for the deconstruction of waste plastic polymers to provide building block molecules either for re-synthesis of plastics or for synthesis of other chemicals.

In both cases, catalysis plays an important role in directing chemical attack towards specific chemical bonds. The project continues catalysis research by the investigators relevant to both biomass and waste plastic deconstruction and re-synthesis toward a range of products. In particular, the investigators will build on their experience in biomass catalysis to explore fundamental aspects of waste plastics processing.

The resulting understanding will provide critical insights toward identification of cost-effective and environmentally benign chemical pathways for processing of waste polymer plastic feedstocks. Beyond the technical aspects, the project will embrace educational and outreach activities at both institutions focused on underrepresented minority students.

Designing catalysts that are selective for the activation of specific chemical bonds in multifunctional organic molecules is a long-standing goal for the sustainable and cost-effective production of chemicals and fuels to meet societal demands with minimal environmental impact. Selective cleavage of carbon-oxygen (C-O) bonds, especially, has become significantly important in recent years due to its relevance in chemical processing of multifunctional organic molecules from biomass and plastic polymers.

Hydrogenolysis is an approach widely implemented for the activation of C-X (X = C, H, O) bonds in organic molecules, as aided by hydrogen. However, most hydrogenolysis catalysts are challenged by the ability to selectively catalyze hydrogen-assisted C-O bond cleavage over other C-X (X = C, H) bonds within multifunctional organic molecules. The central objective of this project is to develop an understanding of how tuning the overall architecture of heterogeneous catalysts can affect the selective cleavage of C-O bonds in multifunctional organic molecules through hydrogenolysis.

The project will combine synthesis, microscopic/spectroscopic characterization, and kinetic studies to gain fundamental understanding of the mechanisms that govern hydrogenolysis of model organic substrate molecules on dual-site catalysts. The research will lead to an understanding of the selective cleavage of C-O bonds over dual-site catalysts, which will be critical in identifying catalytic site and architecture requirements to enhance product selectivity in multifunctional organic molecules.

This understanding will provide critical insights toward identification of cost-effective and environmentally benign chemical pathways for processing both biomass and waste polymer plastic feedstocks. The proposed research will have broader impacts related to the advancement of catalytic science and engineering training/education of underrepresented minorities.

Outreach activities will focus on providing mentorship, active learning, and research opportunities to underrepresented minorities from the University of Puerto Rico – Mayaguez and the University of Michigan to foment pathways and engage students towards pursuing graduate studies in science and engineering. As part of the outreach activities an "Energy, Environment, and Engineering" day camp will be developed to introduce middle- and high-school students, from the west coast area of Puerto Rico and the Metro area of Detroit, to the importance of catalysis in minimizing carbon emissions and promoting circularity in the manufacture of fuels and chemicals.

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.