▎ 摘　　要

NOVELTY - Synthesizing (M1) carbon-based materials, comprises providing precursors, forming carbon-encapsulated metal structures from the precursors, and forming nano-shell structure-based graphene materials from the carbon-encapsulated metal structures. USE - The method is useful for synthesizing carbon-based materials. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) synthesizing (M2) carbon-based materials, comprising (a) preparing precursors from biomass and catalyst, (b) forming carbon-encapsulated metal structures from the precursors, where the step of forming of the carbon-encapsulated metal structures includes thermally treating the precursors, and (c) forming nano-shell structure-based graphene materials from the carbon-encapsulated metal structures, where the step of forming of the nano-shell structure based graphene materials includes opening the carbon-encapsulated metal structures to form shell-like structures, then welding and reconstructing the shell-like structures to form the nano-shell structure-based graphene materials; (2) synthesizing (M3) carbon-based materials, comprising preparing precursors from kraft lignin and transition metal catalyst, pretreating the precursors, and the steps (b)-(c) as above per se; and (3) synthesizing (M4) carbon-encapsulated metal structures, comprising preparing precursors from a biomass and a catalyst, optionally pretreating the precursors, and thermally treating the precursors to form carbon-encapsulated metal structures.