Strongly veined carbon nanoleaves as a highly efficient metal-free electrocatalyst

Effective integration of one-dimensional carbon nanofibers (CNF) and two-dimensional carbon sheets into three-dimensional (3D) conductive frameworks is essential for their practical applications as electrode materials. Herein, a novel "vein-leaf"-type 3D complex of carbon nanofibers with nitrogen-doped graphene (NG) was prepared through a simple thermal condensation of urea and bacterial cellulose. During the formation of the 3D complex CNF@NG, the graphene species was tethered to CNF via carbon-carbon bonds. Such an interconnected 3D network facilitates both the electron transfer and mass diffusion for electrochemical reactions.