Electrocatalysis Of High Surface Area Activated Carbon Modified Electrode

Four kinds of high surface area activated carbon(HSAAC) were prepared from petroleum coke by KOH activation in this article. Modified glassy carbon electrodes with high surface area activated carbon(HSAAC/GCE)were prepared by dropping HSAAC on the substrate of glassy carbon electrode.Electrocatalysis of HSAAC/GCE to the electrochemical reaction of p-dihydroxybenzene was investigated by use of cyclic voltammetry and electrochemical impedance spectroscopy. The results show that the electrode process is controlled by diffusion. The HSAAC/GCE presents the high electrocatalytic activity to the redox reaction of p-dihydroxybenzene. Compared to the naked glass carbon electrode, the currents of the anodic and cathodic peak for HSAAC/GCE increased by 17.9 and 29.8 times, respectively, when the HSAAC/GCE was used. In the 0.1 mol/L HCl solution, the anodic peak current increases linearly with the concentration of p-dihydroxybenzene in the range of 0.01-7 mmol/L, and the linear equation can be expressed by Ipa(mA)=9E-06+5E-05×C(mmol/L) (R2=0.9967).p-dihydroxybenzene, o-dihydroxybenzene and m-dihydroxybenzene are three isomers of dihydroxybenzene. HSAAC/GCE showed electrocatalytic responses towards o-dihydroxybenzene and m-dihydroxybenzene as well as that toward p-dihydroxybenzene.In addition, the difference between the anodic potentiala on the cyclic voltammograms of p-dihydroxybenzene and o-dihydroxybenzene could be as wide as 0.100V on the HSAAC/GCE. Thus, the HSAAC/GCE can be applied to simultaneous determination of p-dihydroxybenzene,o-dihydroxybenzene and m-dihydroxybenzene. Moreover, the HSAAC/GCE could be readily prepared and is stable in the properties.In this work, four kinds of HSAAC were used to adsorb p-dihydroxybenzene, o-dihydroxybenzene and m-dihydroxybenzene. The results showed that the adsorption isotherms for the adsorption of p-dihydroxybenzene, o-dihydroxybenzene and m-dihydroxybenzene on the HSACCs were well described by Langmuir equation. A higher adsorption capacity of HSACCs lead to a stronger electrocatalysis of HSACC/GCE to the redox reaction of dihydroxybenzene.