The Preparation Of Graphene Modified Glassy Carbon Electrode And Electric Catalytic Application

Since2004, graphene, as a kind of new carbon material, was found by the Geim, aresearch team of the Manchester university in UK, has got more and more attention of people,and became one of electroanalysis chemistry research hot spots quickly. Because of graphenehas a larger surface area and the superior properties, such as electrical conduction ability,make it has been utilized effectively in the electrochemical detection and electrochemicalsensor. Based on the advantages above, this paper studies the preparation of graphenemodified electrodes and the application in the determination of chemical.1. The preparation of graphene modified glassy carbon electrode based on theelectrochemical reductionIn this experiment, the method of intercalation and oxidation was used to obtain graphiteoxide from the natural flake graphite, the graphene oxide was obtained after centrifugal anddrying. The method of ultrasonic was adopt to get graphene oxide dispersion and get agraphene modified electrode after the electrode was reduction online by electrochemicalmethod. In this method, the graphene oxide has good hydrophilicity, it can be stable on theelectrode surface; The graphene can be obtained from the graphene oxide by the method ofelectrochemical reduction directly, the conditions are easy to control and the method are easyto operate. In the K3Fe（CN）6solution, the electrochemical characterization of the electrodewas discuss. We found that, compared with the bare electrode, the reversibility of electrodewas greatly improved after modification, the oxidation-reduction reactions are more likely tohappen, the modified electrode is better in electrochemical performance.2. Electrochemical behavior and determination of diethylstilbestrol at graphenemodified glassy carbon electrodeThe electrode was reduction online by electrochemical method and the electrochemicalbehavior of diethylstilbestrol was studied at the graphene modified glassy carbon electrode.Experimental results show that the graphene modified glassy carbon electrode has goodelectrical catalysis to the oxidation of diethylstilbestrol in the pH=6.0,0.2mol/L NaH₂PO₄-H₃PO₄buffer solution. Compared with bare glassy carbon electrode, the oxidation potential ofdiethylstilbestrol shift to the negative at graphene modified glassy carbon electrodes, andappear more apparent reduction peaks. It improves the sensitivity and selectivity for thedetermination of diethylstilbestrol significantly. The determination linear range ofdiethylstilbestrol is5.0×10^-8mol/L⁵.0×10^-6mol/L, detection limit is2.8×10-9mol/L （3times the noise） by using the modified electrode. It also got satisfactory result in the determinationof the actual drug.3. Simultaneous determination of catechol （CC） and hydroquinone （HQ） at the graphenemodified glassy carbon electrodeThis paper studied the simultaneous determination and electrical catalysis of catecholand hydroquinone at the graphene modified glassy carbon electrode. In the pH=7.0,0.1mol/L NaH₂PO₄-H₃PO₄buffer solution, using cyclic voltammetry, It can be true thatdetermine the catechol and hydroquinone respectively or simultaneously by using graphenemodified glassy carbon electrode. Using differential pulse method to determine catechol andhydroquinone, the linear range of CC was8.0×10^-6mol/L¹.2×10^-4mol/L and the linearrange of HQ was3.0×10^-6mol/L¹.0×10^-4mol/L, and detection limit were1.2×10^-6mol/Land3.7×10^-7mol/L （3times the noise）.