▎ 摘　　要

NOVELTY - A carbon fiber comprises a coaxial stacking morphology of truncated conical tubular graphene layers. Each layer includes a hexagonal carbon layer (10) and has a large ring end at one end and a small ring end at the other end in an axial direction. At least part of edges of the hexagonal carbon layers is exposed at the large ring ends. A catalytic metal is supported on the exposed edges. USE - The carbon fiber is for supporting catalytic metal (claimed). The catalytic metal is for a fuel cell. ADVANTAGE - The exposed edges of the hexagonal carbon layers have an extremely high activity. The carbon fiber is capable of increasing a catalytic effect due to the reduced size of the support and the capability of supporting a large number of catalytic metal particles. DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of an enlarged transmission electron micrograph of a carbon fiber having a herring-bone structure manufactured by a vapor growth process. Hexagonal carbon layer (10)