CAREER: Advancing Mechanistic Understanding of Catalytic Plastic Waste Upcycling via Ab Initio Enhanced Sampling

About This Grant

Plastic waste poses a pressing environmental challenge, with over 90% ending up in landfills or incinerated, resulting in severe ecological damage. Traditional recycling often leads to "down-cycling," where plastics are converted into lower-quality materials with limited use. One promising recycling approach is hydrogenolysis, which transforms plastic waste into valuable materials and chemicals by breaking down plastics like polyethylene into smaller, higher-value chemicals using metal catalysts and hydrogen gas. Unlike conventional chemical recycling methods, hydrogenolysis operates under milder conditions without the need for harmful solvents, making it a more sustainable solution. However, there are challenges in adopting this technology for widespread use owing to low efficiency, undesirable byproducts, and difficulties in scaling the process for industry. This CAREER award aims to overcome these obstacles using advanced computational tools based on quantum mechanics, machine learning, and statistical thermodynamics. The goal is to uncover the molecular mechanisms of hydrogenolysis for the world's most common plastic polyethylene, and develop new predictive models for optimizing its efficiency and selectivity. This research promotes global environmental preservation and circular economies by designing sustainable chemical processes to reduce plastic waste. The proposed work also integrates research with educational and outreach activities to enhance computational literacy among students. This CAREER award focuses on uncovering the molecular mechanisms underlying the chemical upcycling of polyethylene, the world's most common plastic. As the amount of plastic in our environment steadily increases, there is an urgent need for efficient recycling methods. Chemical recycling based on hydrogenolysis offers a promising approach to managing plastic waste by deconstructing long-chain polymers with metal catalysts and hydrogen gas to create smaller hydrocarbon products, some of which are high-value chemical commodities. Despite progress in converting polyethylene into liquid fuels, challenges remain in controlling the reaction specificity and efficiency of waste-to-liquid fuel conversion, due to the limited understanding of the mechanisms responsible for this conversion. A comprehensive understanding of these complex systems has remained elusive because of the difficulties associated with ab initio methods in producing free energy landscapes relevant to operando conditions. The integrated education and outreach program seeks to enhance computational literacy among students,from K-12 to college. Proposed activities include developing computational materials science laboratory courses for chemistry, physics, and engineering undergraduate and graduate students, as well as creating open-source online tools based on the simulation code and data generated from this research. Additionally, workshops and curricula on materials sustainability and computational research will be designed for students in collaboration with a local nonprofit specializing in cognitive-behavioral training. This CAREER award advances the fundamental understanding of the sustainable chemical process of plastic waste deconstruction. This project is jointly funded by the Process Systems, Reaction Engineering and Molecular Thermodynamics (PRM) program in the ENG/CBET division, and the Chemical Theory, Model and Computational Methods program (CTMC) in the MPS/CHE division. 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.