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Professor Flytzani-Stephanopoulos' research in Science shows benefits of single atoms acting as catalysts in hydrogen-related reactions

2012

A team of researchers at Tufts University's School of Arts and Sciences and School of Engineering have discovered that individual atoms can catalyze industrially important chemical reactions such as the hydrogenation of acetylene, offering potentially significant economic and environmental benefits. The research appears in the March 9 issue of Science.


Individual atoms of palladium, represented
by the yellow peaks, in the surface of copper
help break hydrogen molecules into two atoms,
facilitating important chemical reactions.
Image: Courtesy of Sykes Lab

Hydrogenation - the addition of hydrogen atoms to an organic compound - is critical to the food, petrochemical and pharmaceutical industries. Hydrogenation requires the presence of a catalyst, usually a metal or an alloy of both precious and common metals, that allows the hydrogen atoms to bind with other molecules. It is difficult to produce alloys that are selective hydrogenation catalysts, able to attach the hydrogen atoms to specific sites of another molecule.

Tufts chemists and chemical engineers reported that when single atoms of palladium, an expensive precious metal, were added to copper, which is much cheaper and readily available, the resulting "single atom alloy" became active and selective for hydrogenation reactions.

This is the first published research to directly relate the arrangement of individual atoms in a metal alloy to their ability to catalyze hydrogenation reactions, according to E. Charles H. Sykes, associate professor of chemistry at Tufts and senior author on the paper. Sykes focuses much of his research on single molecule chemistry.

"With the rising cost of precious metals and the increasing scarcity of these metals, learning more about these reactions is encouraging in the search for sustainable global solutions," said Flytzani-Stephanopoulos. "We are looking at how these single-atom alloy catalysts could eventually be used as low-cost alternatives in hydrogenation and dehydrogenation processes for the production of 'green' agricultural chemicals, foods and pharmaceuticals," said Flytzani-Stephanopoulos.