▎ 摘　　要

NOVELTY - Carboxyl functionalized graphene material is prepared by mixing concentrated sulfuric acid and phosphoric acid, adding potassium permanganate and graphite to the mixed acid, and reducing with 30% hydrogen peroxide solution to obtain graphite oxide powder; reacting graphite oxide powder with sodium carbonate and sodium borohydride to obtain graphene; and ultrasonically dispersing graphene in sodium dodecyl benzene sulfonate solution, adding mixed solution of p-aminobenzoic acid, sodium hydroxide and sodium nitrite, and stirring to react to obtain carboxyl functionalized graphene. USE - Method for preparing carboxyl functionalized graphene material (claimed). ADVANTAGE - The method has simple operation and low cost, and can prepare carboxyl functionalized graphene under mild reaction conditions. The prepared carboxyl functionalized graphene can be easily dispersed and is provided with multi-atom layer carrier structure. DETAILED DESCRIPTION - Preparation of carboxyl functionalized graphene material comprises: (A) mixing 95-98% concentrated sulfuric acid and 85% phosphoric acid at volume ratio of 9:1-10:1 to obtain 100 mL mixed acid, adding 3-5 g potassium permanganate and 1-2 g graphite to the mixed acid, stirring to react for 10-30 hours in water bath at 35-55 degrees C, and naturally cooling to room temperature; (B) diluting reaction product with 500-1000 ml deionized water, reducing with 300-400 ml of 30% hydrogen peroxide solution, collecting reduced product, washing with deionized water or ethyl alcohol, and vacuum drying at room temperature to obtain graphite oxide powder; (C) adding 200-400 mg graphite oxide powder to 300-400 ml deionized water, ultrasonically dispersing for 5-10 hours, adding 3-5 mass% sodium carbonate (Na2CO3) solution to the dispersion liquid, regulating pH value to 9-10, and stirring in water bath at 70-90 degrees C for 5-10 hours; (D) adding the dispersion liquid with 80-100 ml of 3-5 mass% sodium borohydride solution, then adding 3-5 mass% Na2CO3 and regulating pH value to 9-10, stirring in water bath at 60-80 degrees C for 3-5 hours, washing using deionized water to neutral, and vacuum drying at room temperature to obtain graphene; (E) mixing 1-1.2 mmol p-aminobenzoic acid, 1-1.2 mmol sodium hydroxide, 1-1.2 mmol sodium nitrite and 10 ml deionized water, adding 2-2.5 ml of 36-38 mass% concentrated hydrochloric acid, and stirring for 30 minutes to 1 hour at 0-4 degrees C under ice water bath condition to obtain mixed solution; and (F) ultrasonically dispersing 100-200 mg graphene in 200-300 ml of 1-1.5 mass% sodium dodecyl benzene sulfonate solution for 5-10 hours, then adding the mixed solution to the graphene dispersion liquid, stirring at 0-4 degrees C in ice water bath condition for 5-10 hours, then naturally raising temperature to room temperature, stirring for 3-5 hours, washing product with deionized water or organic solvent, and vacuum drying at room temperature to obtain carboxyl functionalized graphene powder.