Growth of carbon nanotubes on graphene by chemical vapor deposition

Graphite oxide powder impregnated with an Ni(NO₃)₂ solution was freeze-dried, thermally-reduced at 300℃ and then chemical-vapor deposition at 1000℃ was used to grow carbon nanotubes(CNTs) on graphene using methane as the carbon source.The morphology and electrical conductivities of the graphite oxide, reduced graphene and CNT-graphene hybrids were characterized.Results indicate that the density of CNTs on the graphene and the electrical conductivity of the hybrids increase with increasing Ni(NO₃)₂ concentration in the solution.Isolated graphene lamellae were connected by CNTs, giving rise to a 3D conducting network that provided conducting channels for electron transport.