Design of Hierarchically Porous Carbons with Interlinked Hydrophilic and Hydrophobic Surface and Their Capacitive Behavior

In this contribution, we report a general surface engineering strategy to transform nonpolar nanocarbons (e.g., carbon nanotube and graphene) into amphiphilic nanocarbons with unique ultrahydrophilic@ultrahydrophobic surface configuration and hierarchical structure by grafting a thin layer of metal–organic frameworks followed by pyrolysis and leaching. The outer ultrahydrophilic carbon layer features rich surface heterogeneity (B-/N-doping both up to ca. 10 at. %) and high density of microporosity, while the inner nonpolar CNT or graphene provides a high electronic conductivity. The unique bipolar surface and high heterogeneity as well as highly accessible hierarchical structures render this family of nanocarbons capable of a high surface efficiency under both aqueous and organic conditions, as it is reflected in the behavior of the electrodes for supercapacitors by comparing a wide range of highly porous nonpolar carbons. The bipolar hierarchical carbons’ efficiency in terms of areal capacitance and ener...