title: Large-scale production of edge-selectively functionalized graphene nanoplatelets via ball milling and their use as metal-free electrocatalysts for oxygen reduction reaction.
abstract: Edge-selectively functionalized graphene nanoplatelets (EFGnPs) with different functional groups were efficiently prepared simply by dry ball milling graphite in the presence of hydrogen, carbon dioxide, sulfur trioxide, or carbon dioxide/sulfur trioxide mixture. Upon exposure to air moisture, the resultant hydrogen- (HGnP), carboxylic acid- (CGnP), sulfonic acid- (SGnP), and carboxylic acid/sulfonic acid- (CSGnP) functionalized GnPs readily dispersed into various polar solvents, including neutral water. The resultant EFGnPs were then used as electrocatalysts for oxygen reduction reaction (ORR) in an alkaline electrolyte. It was found that the edge polar nature of the newly prepared EFGnPs without heteroatom doping into their basal plane played an important role in regulating the ORR efficiency with the electrocatalytic activity in the order of SGnP > CSGnP > CGnP > HGnP > pristine graphite. More importantly, the sulfur-containing SGnP and CSGnP were found to have a superior ORR performance to commercially available platinum-based electrocatalyst.
authors.affiliation: Ulsan National Institute of Science and Technology (UNIST), Interdisciplinary School of Green Energy/Low-Dimensional Carbon Materials Center, 100 Banyeon, Ulsan 689-897, South Korea.
authors.forename: In-Yup
authors.initials: IY
authors.lastname: Jeon
authors.forename: Hyun-Jung
authors.initials: HJ
authors.lastname: Choi
authors.forename: Sun-Min
authors.initials: SM
authors.lastname: Jung
authors.forename: Jeong-Min
authors.initials: JM
authors.lastname: Seo
authors.forename: Min-Jung
authors.initials: MJ
authors.lastname: Kim
authors.forename: Liming
authors.initials: L
authors.lastname: Dai
authors.forename: Jong-Beom
authors.initials: JB
authors.lastname: Baek