Shin Young-Eun, Sa Young Jin, Park Seungyoung, Lee Jiwon, Shin Kyung-Hee, Joo Sang Hoon, Ko Hyunhyub
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.
Nanoscale. 2014 Aug 21;6(16):9734-41. doi: 10.1039/c4nr01988a. Epub 2014 Jul 7.
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).
多孔石墨烯纳米结构在催化和能量存储应用中备受关注。然而，制备具有可控形态、孔隙率和表面积的三维（3D）大孔石墨烯纳米结构仍然面临重大挑战。在此，我们介绍一种冰模板自组装方法，用于将二维石墨烯纳米片整合到分级多孔石墨烯纳米卷网络中，其中在冰模板自组装过程中，通过改变pH条件可以轻松控制多孔结构的形态。我们表明，还原氧化石墨烯（rGO）溶液的冷冻铸造在pH值低于8时会形成3D多孔石墨烯微泡沫，在pH值为10时会形成分级多孔石墨烯纳米卷网络。此外，我们证明石墨烯纳米卷网络对氧还原反应（ORR）显示出有前景的电催化活性。
