▎ 摘　　要

NOVELTY - Preparation of composite catalyst includes oxidizing commercial graphite to obtain graphite oxide, dispersing in distilled water, sonicating, centrifuging, removing supernatant to obtain graphene oxide (GO) dispersion precipitate, and drying; polishing glass carbon electrode with polishing powder, washing with distilled water and with ethanol, drying, dropping GO dispersion, and oven-drying to obtain graphene-modified glassy carbon electrode (GO/GC); and soaking in phosphate buffer solution, and subjecting to reduction reaction using platinum wire and saturated calomel electrode. USE - Method for preparation of composite catalyst (claimed). ADVANTAGE - The method decreases aluminum nitride initial oxidation potential in the surface of graphene compared to bare glassy carbon electrode surface, improves product electrochemical activity, stability and physical and electrochemical properties, and has improved electrochemical activity and polymerization efficiency. DETAILED DESCRIPTION - Preparation of composite catalyst comprises: (A) oxidizing commercial graphite to obtain graphite oxide, dispersing in distilled water, sonicating for 2 hours to obtain dark brown solution, centrifuging at speed of 4000 revolutions/minute for 15 minutes, removing supernatant to obtain 0.5 mg/mL graphene oxide (GO) dispersion precipitate, and drying; (B) polishing glass carbon electrode with polishing powder, washing with distilled water and with ethanol, drying, dropping GO dispersion, and oven-drying to 60 degrees C to obtain a graphene-modified glassy carbon electrode (GO/GC); and (C) soaking in phosphate buffer solution, and subjecting to reduction reaction using platinum wire as electrode and saturated calomel electrode as reference electrode at constant potential of - 1 V for 10 minutes. The GE/GC is used as working electrode.