Functionalized Graphene Nanoballs | Chemical & Engineering News
Volume 90 Issue 33 | p. 33 | Concentrates
Issue Date: August 13, 2012

Functionalized Graphene Nanoballs

Simple method crumples graphene flakes and coats them with metal or metal oxide nanocrystals
Department: Science & Technology
News Channels: Nano SCENE, Materials SCENE
Keywords: graphene, crumpled graphene, graphene oxide, nanoparticles
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Crumpled graphene sheets decorated with nanocrystals of Mn3O4 (left) and platinum (right) form spontaneously in a one-step procedure.
Credit: ACS Nano
Micrograph images of stable crumpled graphene sheets decorated with Mn3O4 (left) and Pt (right) nanocrystals
 
Crumpled graphene sheets decorated with nanocrystals of Mn3O4 (left) and platinum (right) form spontaneously in a one-step procedure.
Credit: ACS Nano

A one-pot procedure converts solutions of graphene oxide and precursor ions to crumpled sheets of graphene decorated with nanocrystals, according to a study led by researchers at the University of Wisconsin, Milwaukee (ACS Nano, DOI: 10.1021/nn302818j). The method builds on work reported recently by other scientists that shows graphene sheets can be crumpled into nanosized balls that resist uncrumpling, aggregating, and stacking. The wadded-up form of carbon is endowed with high surface area, making it attractive for energy storage and other applications. But access to those applications typically requires additional chemical processing steps. UW Milwaukee’s Shun Mao and Junhong Chen and coworkers created a general method for making graphene nanoballs and functionalizing them with metals or metal oxides in a single step. The team reports that flowing aerosols of graphene oxide suspensions containing nanoparticle precursors through a furnace causes the aerosol droplets to rapidly evaporate. That process crumples and partially reduces the carbon flakes and triggers spontaneous growth of nanocrystals on the inner and outer surfaces of the balls. The researchers made supercapacitors and lithium-ion batteries from nanoballs coated with Mn3O4 and SnO2, respectively, and report that the devices outperform versions made from flat graphene sheets.

 
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