▎ 摘　　要

NOVELTY - The preparation of large-diameter graphene oxide nanosheet involves (a) preparing a graphite electrode by cutting high-purity graphite paper into strips as an anode, (b) taking platinum wire and concentrated sulfuric acid, performing an electrochemical reaction by applying direct current voltage between anode and cathode, taking out graphite paper, and draining concentrated sulfuric acid to obtain expanded composite graphite paper, (c) taking expanded composite graphite paper and dilute sulfuric acid, and applying direct current voltage between anode and cathode until the anode-expanded composite graphite paper is completely peeled off, (d) vacuum filtering the solution, ultrasonically dispersing and washing with ultrapure water, repeating several times until the pH of solution is neutral to obtain aqueous graphene oxide dispersion, and (e) recovering the concentrated sulfuric acid and the diluted sulfuric acid used in the electrochemical reaction, treating and recycling. USE - Preparation method of large-diameter graphene oxide nanosheet. ADVANTAGE - The method enables preparation of large-diameter graphene oxide nanosheet with high product transformation ratio, by simple, economical, environmentally-friendly and industrial process. DETAILED DESCRIPTION - The preparation method of large-diameter graphene oxide nanosheet involves (a) preparing a graphite electrode by cutting high-purity graphite paper into strips as an anode, (b) using a platinum wire as a cathode, using 98 wt.% concentrated sulfuric acid as an electrolyte, performing an electrochemical reaction for 20 minutes by applying direct current voltage of 1.6 V between anode and cathode, taking out graphite paper, and draining concentrated sulfuric acid to obtain expanded composite graphite paper, (c) using the expanded composite graphite paper as an anode, taking 50 wt.% dilute sulfuric acid as an electrolyte, and applying direct current voltage of 5 V between anode and cathode until the anode-expanded composite graphite paper is completely peeled off, (d) vacuum filtering the solution, ultrasonically dispersing and washing with ultrapure water, repeating the same several times until the pH of the solution is neutral to obtain aqueous graphene oxide dispersion, and (e) recovering the concentrated sulfuric acid and the diluted sulfuric acid used in the electrochemical reaction, treating and recycling.