Hierarchical regrowth of flowerlike nanographene sheets on oxygen-plasma-treated carbon nanowalls

Cauliflorous nanographene sheets were hierarchically regrown on the spearlike structures of carbon nanowalls (CNWs) produced by O-2-plasma etching. The spears on the CNWs acted as a stem for the growth of flowerlike flaky nanographene sheets, where the root of the nanoflower was located at a defect or disordered site. The defects on the graphitic structures were induced by irradiation with oxygen-related radicals and ions in the O-2-based plasmas and acted as sites for the nucleation of flowerlike nanographene. The porous carbon nanostructures regrown after O-2-plasma treatment have a relatively higher surface area and are thus promising materials for electrochemical applications. (C) 2014 The Japan Society of Applied Physics