Engineers have developed a way to reduce the consumption of platinum in chemical reactions, the approach, devised by researchers from the University of New Mexico and Washington State University (WSU), involves trapping platinum atoms to improve the efficiency and stability of the reactions.An illustration of platinum oxides moving to the cerium oxide trap. Image credit: Cortland Johnson/PNNL.

Platinum is used as a catalyst to facilitate chemical reactions for many commonly used products and processes, such as converting poisonous carbon monoxide to less harmful carbon dioxide in catalytic converters. But because of its expense and scarcity, industries are continually looking to use less of it and to develop catalysts that more efficiently use individual platinum atoms in their reactions.

At high temperatures, the atoms become mobile and fly together into clumps, which reduces the catalyst’s efficiency and negatively impacts its performance. This is the primary reason why catalytic converters must be tested regularly to ensure they don’t become less effective over time.

With this in mind, the researchers developed a method to capture the platinum atoms that keep the reactions stable and let them continue their catalyzing activity. The team employed a commonly used and inexpensive manufacturing material, known as cerium oxide, to create a tiny trap, shaping it into nanometer-sized rods and polyhedrons to capture the platinum atoms. With their large surface areas and sufficiently high number of defects, the cerium oxide nano-shapes are able to capture the platinum atoms on their surfaces and keep them from clumping together, so that the platinum can continue to do its work.

Adding the cerium oxide to the catalyst is a simple process, too, with no exotic precursors needed.

“The atom-trapping technique should be broadly applicable for preparing single-atom catalysts,” notes Abhaya Datye, professor of chemical and biological engineering at the University of New Mexico. “It is remarkable that simply combining the ceria with a platinum catalyst was sufficient to allow trapping of the atoms and retaining the performance of the catalyst."