▎ 摘　　要

NOVELTY - A multi-boundary graphene foam with controllable porosity and aperture comprises graphene sheets grown vertically on the deposition substrate in the multi-boundary graphene foam. The graphene sheets have multi-boundary structure and form a bridge connecting adjacent hollow graphene spheres. The mass ratio of silica nanosphere powder and urea powder in the mixed powder is controlled, and the porosity and pore size of the multi-boundary graphene foam is controlled. The particle size of silica nanospheres, diameter of hollow graphene spheres in multi-boundary graphene foams, temperature and time during chemical vapor deposition are controlled to control the size and thickness of the graphene sheets in the graphene foam. USE - Multi-boundary graphene foam with controllable porosity and aperture used in conductive material, heat conducting composite material, electromagnetic shielding and wave absorbing material applications. ADVANTAGE - The multi-boundary graphene foam has low density, high porosity, and controllable porosity and pore size. The method is environmentally-friendly. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of multi-boundary graphene foam with controllable porosity and aperture, which involves (s1) dry-pressing the mixed powder of silicon dioxide nanosphere powder and urea powder in the mass ratio of 1:0.2-1:4, (s2) depositing vertically grown multi-boundary graphene on the surface of silicon dioxide nanosphere using chemical vapor deposition process to obtain porous silicon dioxide wafers with vertically structured multi-boundary graphene, and (s3) placing porous silicon dioxide wafers with vertically structured multi-boundary graphene in the mixed solution of hydrofluoric acid and absolute ethyl alcohol to remove silicon dioxide.