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 .
Source: Clean Technica
Posted by: James Hamilton.
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