In Situ Formation Of Graphene Layers On Graphite Plate And Its Application In Electrochemistry

A graphene layers/graphite plate(GL/GP)electrode obtained by exfoliation provides a special surface structure with parallel graphene sheets,low oxidation degree(a C/O ratio of 2.7)and defect density(ID/IG=0.83).Electrochemical analysis shows that the GL/GP electrode improved electron transfer rate,surface polarization,and hydrophilicity.Electrolysis time is a significant factor of the properties of the GL/GP electrode.The GL/GP-60 electrode exhibits the best electrochemical properties.When the GL/GP electrode is used as a substrate for loading Pt nanoparticles to fabricate Pt-GL/GP electrode for hydrogen evolution reaction(HER),the surface density of the Pt loading is lower than commercial Pt/C(wt.20%)by one order of magnitude without compromising its electro-catalytic activity.The high electron transfer rate,surface density of active sites and the surface polarization of GL/GP electrode plays crucial roles to achieve high efficiency.The GL/GP electrode was easily obtained and low-cost,which provides great potential as a catalyst substrate for fabricating various high efficient electro-catalysts.Polyaniline modified graphene layers/graphite plate(GL/GP/PANI)electrodes were prepared by electrochemical polymerization of aniline on graphene layers/graphite electrodes,which were obtained via in-situ formation of graphene layers on graphite plate by electrochemical exfoliation.The surface features of the electrodes were characterized by SEM.The electrochemical performances of the electrodes were measured in 0.5 M H2SO4 electrolyte,including cyclic voltammetry,galvanostatic charge-discharge and electrochemical stability test.The results indicated that the PANI on the GL/GP electrodes had rodlike structure with high specific surface area.At current density of 0.085 mA/cm2,the specific capacitance GL/GP/PANI reached 1042.8 F/g.