▎ 摘　　要

NOVELTY - Preparation of graphene oxide quantum dot (8) involves using a carbon-based three-dimensional block material comprising a graphene lamellar structure as an anode (1), an inert electrode as a cathode (2), and a positive electrode and a negative electrode of a direct-current (DC) power supply (3), immersing the inert electrode in an electrolyte solution (5), contacting end surface (6) of the bulk material with the surface of the electrolyte solution, cutting and dissociating graphene sheet layers at the end face, and dispersing the obtained product in the electrolyte solution. USE - Preparation of graphene oxide quantum dot used for producing composite nanomaterial (all claimed). DETAILED DESCRIPTION - Preparation of graphene oxide quantum dot involves using a carbon-based three-dimensional block material comprising a graphene lamellar structure as an anode, an inert electrode as a cathode, and a positive electrode and a negative electrode of a direct-current (DC) power supply, immersing the inert electrode in an electrolyte solution, bringing an end face of the carbon-based three-dimensional block material into parallel contact with the liquid surface (7) of the electrolyte solution, supplying the power, intermittently or continuously contacting end surface of the three-dimensional bulk material with the surface of the electrolyte solution, discontinuously or continuously cutting and dissociating graphene sheet layers at the end face by electrochemical oxidation to obtain graphene oxide quantum dot, and dispersing the obtained product in the electrolyte solution to obtain an oxidized graphene quantum dot solution. INDEPENDENT CLAIMS are included for the following: (1) production of composite nanomaterial (14) comprising the graphene oxide quantum dot and a graphene and/or a graphene-like structure (9), which involves adding a powder comprising graphene and/or a graphene-like lamellar structure into a solution of the graphene oxide quantum dot, uniformly mixing under the additive mechanical (11) action of high shearing force, separating graphene oxide quantum dots adsorbed on the graphite and/or the graphite-like layered structure in the solution, performing a cyclic process of stripping, re-adsorption and restripping of graphene oxide quantum dots adsorbed (12) on the graphene and/or the graphene-like lamellar structure in the solution to obtain the composite nanomaterial composed of the quasi-zero-dimensional and/or quasi-two-dimensional graphene and/or graphene-like structure and the graphene oxide quantum dot; and (2) composite nanomaterial, which comprises the quasi-zero-dimensional and/or quasi-two-dimensional graphene and/or graphene-like structure and the graphene oxide quantum dot. The composite nanomaterials have thickness of 0.7-10 nm and two-dimensional sheet size diameter of 1 nm to 10 mu m. The mass ratio of the graphene oxide quantum dot to quasi-zero dimensional and/or quasi-two dimensional graphene and/or graphene-like structure is 0.0001-1:1. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view explaining preparation of composite nanomaterial comprising the oxidized graphene quantum dot. Anode (1) Cathode (2)