Simulation shows a 10-atom platinum nanocatalyst cluster supported on a magnesia surface. The “bulge” caused by the 10th atom gives the cluster improved catalytic properties.
Combining experimental investigations and theoretical simulations, researchers have explained why platinum nanoclusters within a specific size range facilitate the hydrogenation reaction used to produce the chemical ethane from ethylene. The research offers new insights into the role of cluster shapes in catalyzing reactions at the nanoscale and could help materials scientists optimize nanocatalysts for a broad class of other reactions.
At the macroscale, the conversion of ethylene has long been considered among the reactions insensitive to the structure of the catalyst used. By examining reactions catalyzed by platinum clusters containing between 9 and 15 atoms, however, researchers in Germany and the United States found that, at the nanoscale, this belief no longer holds true. The shape of nanoscale clusters, they found, can dramatically affect reaction efficiency.
While the study investigated only platinum nanoclusters and the ethylene reaction, the fundamental principles could apply to other catalysts and reactions, demonstrating how materials at small sizes can provide different properties than the same material in bulk. Supported by the Air Force Office of Scientific Research and the Department of Energy, the research was reported in the journal Nature Communications.
“The knowledge gained from our re-examination of the validity of a fundamental concept in catalysis, and the emergent paradigm shift that we uncovered concerning structure sensitivity of reactions catalyzed by nanosize catalysts, may open new vistas for the design and control of catalytic activity in the nanoscale,” said Uzi Landman, a Regents Professor and F.E. Callaway Chair in the Georgia Tech School of Physics. — John Toon