PNNL

Plastics were initially hailed as affordable, lightweight, and durable materials with a variety of uses. These qualities became a double-edged sword; plastics quickly packed landfills and are now a primary environmental concern. To curb plastic waste, the U.S. Department of Energy (DOE) is sponsoring research for the chemical upcycling of these materials.

Upcycling aims beyond recycling of plastic; it attempts to obtain more valuable chemicals than the initial starting materials. Pacific Northwest National Laboratory scientist Oliver Gutiérrez was recently awarded DOE funding for a team project “Towards a Polyolefin-Based Refinery: Understanding and Controlling the Critical Reaction Steps.” Under this project, Gutiérrez and his collaborators from the University of California Santa Barbara, Princeton University, Columbia University, and Pacific Northwest National Laboratory will explore how coupling different reactions together can lower the energy cost of converting plastics into fuels and lubricants.

Plastics contain long chains of carbon atoms bonded together. Breaking the bonds between these carbons at specific locations within the chains to produce desired products requires selective catalysts. Even with a catalyst, however, the energy required to break the stable carbon–carbon bonds in plastics limits their conversion. Conversely, forming new bonds between carbons, or between carbon and hydrogen atoms, releases energy. Gutiérrez and his team will study ways in which breaking bonds in plastics can be coupled with the creation of new bonds at specific places within the chains to yield fuels and value-added chemicals using catalysts. By coupling these reactions, the overall conversion of plastics can be carried out at low temperatures.

The team seeks to understand the fundamental mechanisms that underly each step of these reactions. This information may then be used to improve the reaction conditions and catalysts that drive the reactions.

“This project presents a unique opportunity for me to lead and collaborate with a spectacular team of scientists in a novel area of catalysis,” said Gutiérrez. “We want to discover new ways to use chemistry and catalysis to make an impact on industry and society. The proposed work will point to new research directions in both fundamental and applied levels.”