A first-of-its-kind catalyst mimics natural processes to break down
plastics

Date:
October 19, 2020
Source:
DOE/Ames Laboratory
Summary:
A team of scientists has developed a first-of-its-kind catalyst
that is able to process polyolefin plastics, types of polymers
widely used in things like plastic grocery bags, milk jugs,
shampoo bottles, toys, and food containers.



FULL STORY ========================================================================== While plastics recycling is not new science, current processes don't
make it economically worthwhile -- waste plastics get "down-cycled" into
lower grade, less useful material. It's a challenge that continues to
be an obstacle in tackling a growing global pollution crisis in single
use plastics.


==========================================================================
A multi-institutional team of scientists led by the U.S. Department of
Energy's Ames Laboratory has developed a first-of-its-kind catalyst
that is able to process polyolefin plastics such as polyethylene and polypropylene, types of polymers widely used in things like plastic
grocery bags, milk jugs, shampoo bottles, toys, and food containers. The process results in uniform, high- quality components that can be used to produce fuels, solvents, and lubricating oils, products that have high
value and could potentially turn these and other used plastics into an
untapped resource.

"We've made a big step forward with this work," said Aaron Sadow,
a scientist at Ames Laboratory and the Director of the Institute for Cooperative Upcycling of Plastics (iCOUP). "We hypothesized that we could borrow from nature, and mimic the processes by which enzymes precisely
break apart macromolecules like proteins and cellulose. We succeeded
in doing that, and we're excited to pursue optimizing and developing
this process further." The unique process relies on nanoparticle
technology. Ames Lab scientist Wenyu Huang designed a mesoporous silica nanoparticle consisting of a core of platinum with catalytic active
sites, surrounded by long silica pores, or channels, through which the
long polymer chains thread through to the catalyst.

With this design, the catalyst is able to hold on to and cleave the
longer polymer chains into consistent, uniform shorter pieces that have
the most potential to be upcycled into new, more useful end products.

"This type of controlled catalysis process has never before been designed
based on inorganic materials," Huang, who specializes in the design of structurally well-defined nano-catalysts. "We were able to show that
the catalytic process is capable of performing multiple identical deconstruction steps on the same molecule before releasing it."
Ames Laboratory's solid state NMR expert Fred Perras' measurements
allowed the team to scrutinize the catalyst's activity at the atomic
scale, and confirmed that the long polymer chains moved readily through
the catalyst pores in the manner resembling the enzymatic processes that
the scientists were aiming to emulate.

This research will be expanded and continued under direction of the
Institute for Cooperative Upcycling of Plastics (iCOUP), led by Ames Laboratory. iCOUP is an Energy Frontier Research Center consisting of scientists from Ames Laboratory, Argonne National Laboratory, UC Santa
Barbara, University of South Carolina, Cornell University, Northwestern University, and the University of Illinois Urbana-Champaign.


========================================================================== Story Source: Materials provided by DOE/Ames_Laboratory. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Akalanka Tennakoon, Xun Wu, Alexander L. Paterson, Smita Patnaik,
Yuchen
Pei, Anne M. LaPointe, Salai C. Ammal, Ryan A. Hackler, Andreas
Heyden, Igor I. Slowing, Geoffrey W. Coates, Massimiliano
Delferro, Baron Peters, Wenyu Huang, Aaron D. Sadow, Fre'de'ric
A. Perras. Catalytic upcycling of high-density polyethylene
via a processive mechanism. Nature Catalysis, 2020; DOI:
10.1038/s41929-020-00519-4 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201019125505.htm

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