▎ 摘　　要

We present the first report concerning the one-step synthesis of Ni/graphene nanocomposites via a substrate-free, atmospheric-pressure chemical vapor deposition process. The as-grown thin graphene sheets are produced in large scale with the thickness of similar to 2 nm, and they are decorated with numerous Ni/graphene core-shell nanoparticles. The nucleation and growth mechanism of the composite has been proposed based on careful transmission electron microscopy analysis. Ni3C domains within Ni nanoparticles have been observed, indicating a transformation between nickel and nickel carbide during graphene growth owing to the diffuse and precipitation of carbon atoms. Moreover, such Ni/graphene nanocomposites exhibit excellent microwave absorption and electrochemical ethanol sensing properties. This study opens up a new synthesis route for graphene-based materials. (C) 2012 Elsevier B.V. All rights reserved.