▎ 摘　　要

NOVELTY - Preparing graphene involves mixing graphite flake, concentrated nitric acid and hydrogen peroxide in mass ratio of 1:(4-7):(2-5) and stirring for 2-6 hours. The mixture is filtered and washed with distilled or deionized water until the filtrate conductivity is 14-18.25 megaohm centimeter. The mixture is dried to constant weight. The pretreated graphite flake raw material is prepared by Hummers method and dried to constant weight in vacuum oven at 60-80 degrees C. The obtained graphite oxide powder is weighed and then dispersed in sodium hydroxide solution of pH 10. USE - Method for preparing graphene (claimed). ADVANTAGE - The method enables to prepare graphene in eco-friendly and cost-effective manner that consumes less energy. DETAILED DESCRIPTION - Preparing graphene involves mixing graphite flake, concentrated nitric acid and hydrogen peroxide in mass ratio of 1:(4-7):(2-5) and stirring for 2-6 hours. The mixture is filtered and washed with distilled or deionized water until the filtrate conductivity is 14-18.25 megaohm centimeter. The mixture is dried to constant weight. The pretreated graphite flake raw material is prepared by Hummers method and dried to constant weight in vacuum oven at 60-80 degrees C. The obtained graphite oxide powder is weighed and then dispersed in sodium hydroxide solution of pH 10. The dispersion solution is allowed to stand and the lower layer solution having impurities and precipitates is discarded to obtain graphite oxide. The upper solution is centrifuged and then stripped to remove non-precipitated graphite oxide and impurities to obtain graphene oxide solution. The graphene oxide is added to hydrazine hydrate and the mixture is washed. The solid is dried in vacuum oven to constant weight to obtain graphene product.