New research from the University of Arkansas has revealed that platinum nanoparticles automatically limit their own size and organize into specific patterns when they’re bonded to freestanding graphene.
When exhibiting these behaviors, the platinum nanoparticles retain the ability to function effectively as a catalyst for chemical reactions — a finding that the researchers think may lead to lowered production costs for platinum-catalyzed fuel cells.
“Because platinum is a rare metal, a lot of the expense that goes into manufacturing hybrid vehicles is coming from the platinum needed to catalyze fuel cells,” explained Paul Thibado, a professor of physics at the University of Arkansas.
“Platinum, when placed on solid surfaces, diffuses to form random particles that grow uncontrollably, and that limits their reactivity,” he continued. “On the other hand, freestanding graphene has a very flexible surface, and we found that, due to local strain effects, there is an 80% reduction in the amount of platinum needed to maintain effective catalysis.”
Something else that the new research shows is that “a functionally superior, single-crystal platinum nanoparticle emerges from its application to graphene.”
“What we found was pretty exciting,” Thibado explained. “It’s really quite special.”
The University of Arkansas, Fayetteville provides more:
The recent study, consisted of high-resolution transmission electron microscopy combined with scanning tunneling microscopy and state-of-the-art computational molecular dynamics. That is a combination rarely seen in physics.
Scanning tunneling microscopy, which produces images of individual atoms on a surface, was used to view the behavior of the platinum nanoparticles on the graphene. Researchers in Missouri used transmission electron microscopy, a technique in which a beam of electrons is transmitted through an ultra-thin material, to confirm the crystalline properties.
The merger of both experimental techniques with theoretical modeling yielded an unexpected result for the researchers: the bonding of the graphene to the platinum nanoparticles was unusual.
“Because it is so strong and flexible, graphene typically wraps itself around the material that it is bonding with,” Thibado stated. “In this case, the bonding with the platinum was completely different, more like a pyramid.”
The new findings were detailed in a paper published in the journal ACS Nano.
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