▎ 摘　　要

NOVELTY - Preparation of a graphene-encapsulated metal nanoparticles, involves supplying gas comprising carbon dioxide, methane and water on a metal catalyst and reacting and cooling the resultant product. The mole ratio of methane, carbon dioxide and water is 1:0.20-0.50:0.01-1.45. USE - Preparation of graphene-encapsulated metal nanoparticles used in LED, battery or solar cell and drug delivery material (all claimed). ADVANTAGE - The method provides graphene-encapsulated metal nanoparticles with high efficiency at low reaction temperature. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of hollow graphene nanoparticles, which involves removing the metal nanoparticles from the graphene-encapsulated metal nanoparticles. DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of a supported form of catalyst for graphene growth.