Graphene Oxide (go) And Sulfonated Graphene Oxide (sgo) Preparation And Its Modified Electrode Electrochemical Research

Graphene oxide (GO) was synthesized with the Hummers method, and it was integrated with sulfonic acid group to formed sulfonic graphene oxide (SGO). Then myoglobin (Mb), Nafion and GO or SGO were assembled into a glass carbon electrode to produce the Mb-GO-Nafion composite film modified electrode and Mb-SGO-Nafion composite film modified electrode. Fourier transform infrared (FT-IR) spectra, Scanning electron microscopy (SEM) measurements, X-ray photoelectrospectrocopy (XPS), differential scanning calorimetry (DSC) and thermogravimetry (TG) were employed to characterize the GO and SGO produced by our experiment. Ultraviolet-visible Absorption Spectrometry (Uv-vis), cyclic voltammetry (CV), Alternating current impedance (A C impedance), Square-Wave Voltammetry (SWV) and amperometry were taken to characterize the fabrication procedure and properties of these two composite films. Electrocatalytic behavior of the Mb-GO-Nafion films and Mb-SGO-Nafion films toward hydrogen peroxide (H2O2), oxygen (O2) and sodium nitrite (NaN02) was investigated by CV. Some important electrochemical kinetic parameters such as apparent heterogeneous electron-transfer rate constant (ks) and formal potential (E0’) were estimated by the experiment.The experimental result showed that some oxidizing groups including carboxyl group、hydroxy and epoxy group were introduced to the GO by the characterization of the morphology and functional group; and the sulfonic acid groups and oxidizing groups were lead into SGO. The result of Uv-vis indicated that Mb can keep it native structure on the GO-Nafion composite film and SGO-Nafion composite film. The consequence of electrochemical experiments demonstrated that there were quickly and quasi reversible redox process of these two modified electrodes in the electrolyte solution. And in a certain range, an increase of pH in solution led to a negative shift in potential for both reduction and oxidation peaks, which indicated that the transfer of electron was accompanied by the transfer of proton. Electrocatalytic reduction of hydrogen peroxide, oxygen and sodium nitrite showed that these two composite films could display good electrochemical and catalytic activities.