title: An ice-templated, pH-tunable self-assembly route to hierarchically porous graphene nanoscroll networks.
abstract: Porous graphene nanostructures are of great interest for applications in catalysis and energy storage. However, the fabrication of three-dimensional (3D) macroporous graphene nanostructures with controlled morphology, porosity and surface area still presents significant challenges. Here we introduce an ice-templated self-assembly approach for the integration of two-dimensional graphene nanosheets into hierarchically porous graphene nanoscroll networks, where the morphology of porous structures can be easily controlled by varying the pH conditions during the ice-templated self-assembly process. We show that freeze-casting of reduced graphene oxide (rGO) solution results in the formation of 3D porous graphene microfoam below pH 8 and hierarchically porous graphene nanoscroll networks at pH 10. In addition, we demonstrate that graphene nanoscroll networks show promising electrocatalytic activity for the oxygen reduction reaction (ORR).
authors.affiliation: School of Energy and Chemical Engineering, KIER-UNIST Advanced Center for Energy, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, 689-798, Republic of Korea. shjoo@unist.ac.kr hyunhko@unist.ac.kr.
authors.forename: Young-Eun
authors.initials: YE
authors.lastname: Shin
authors.forename: Young Jin
authors.initials: YJ
authors.lastname: Sa
authors.forename: Seungyoung
authors.initials: S
authors.lastname: Park
authors.forename: Jiwon
authors.initials: J
authors.lastname: Lee
authors.forename: Kyung-Hee
authors.initials: KH
authors.lastname: Shin
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Joo
authors.forename: Hyunhyub
authors.initials: H
authors.lastname: Ko