A copper tetramer
catalyst created by researchers at Argonne National Laboratory may help
capture and convert
carbon dioxide in a way that ultimately saves energy. It consists of
small clusters of
four copper atoms each, supported on a thin film of aluminum oxide.
These catalysts work
by binding to carbon dioxide molecules, orienting them in a way that is
ideal for chemical
reactions. The structure of the copper tetramer is such that most of its
binding sites are
open, which means it can attach more strongly to carbon dioxide
and can better
accelerate the conversion. (Image courtesy Larry Curtiss;
(August 8, 2015) Capture and convert—this is the motto of carbon dioxide
reduction, a process that stops the greenhouse gas before it escapes from
chimneys and power plants into the atmosphere and instead turns it into a
useful product.
One possible end product is methanol, a liquid fuel and the
focus of a recent study conducted at the U.S. Department of Energy’s (DOE)
Argonne National Laboratory. The chemical reactions that make methanol from
carbon dioxide rely on a catalyst to speed up the conversion, and Argonne
scientists identified a new material that could fill this role. With its unique
structure, this catalyst can capture and convert carbon dioxide in a way that
ultimately saves energy.
They call it a copper tetramer.
It consists of small clusters of four copper atoms each,
supported on a thin film of aluminum oxide. These catalysts work by binding to
carbon dioxide molecules, orienting them in a way that is ideal for chemical
reactions. The structure of the copper tetramer is such that most of its
binding sites are open, which means it can attach more strongly to carbon
dioxide and can better accelerate the conversion.
The current industrial process to reduce carbon dioxide to
methanol uses a catalyst of copper, zinc oxide and aluminum oxide. A number of
its binding sites are occupied merely in holding the compound together, which
limits how many atoms can catch and hold carbon dioxide.
“With our catalyst, there is no inside,” said Stefan Vajda,
senior chemist at Argonne and the Institute for Molecular Engineering and
co-author on the paper. “All four copper atoms are participating because with
only a few of them in the cluster, they are all exposed and able to bind.”