Study And Application Of A Novel Platinum Nanoparticles-attached Glassy Carbon Electrode

A novel glassy carbon electrode surface modified with platinum nanoparticles was fabricated by a one-step in situ chemical reduction growth method. Electrochemical experiments and surface analyses such as scanning electron microscopy (SEM) and X-ray energy-dispersive spectra (EDS) were employed to characterize the modified electrode. The electrochemical behavior of L-cysteine (L-Cys), hydrogen peroxide (H₂O₂), methanol and ethylene glycol (EG) on the modified electrode was studied. By electrochemical impedance measurements, hemoglobin (Hb) immobilized on the platinum nanoparticles modified glassy carbon surface was characterized using [Fe(CN)₆]^3-/[Fe(CN)₆]^4- redox probe. Furthermore, the electrocatalytic activity of the Hb film to H₂O₂ was investigated.Platinum nanoparticles were successfully attached onto glass carbon electrode by the one-step in situ chemical reduction growth method. The surface analysis indicated that many spherical metallic platinum nanoparticles were presented on GC surface. The diameter of these spherical nanoparticles was in the range of 40²00nm. The surface coverage of platinum nanoparticles on GC surface was 1.28×10^-7mol·cm^-2. The electrochemical behavior of L-cysteine on the modified electrode surface was studied. Compared with the Pt bulk electrode, the electrocatalytic oxidation potential of L-cysteine on modified electrode shifts negatively by 0.3V, and the oxidation peak current of L-cysteine on modified electrode increased by 12 times. The modified electrode also showed a much better electrochemical response to hydrogen peroxide than bulk Pt electrode. The results indicated that the linear relationship existed between the peak currents and the concentrations of L-cysteine or hydrogen peroxide. The H₂O₂ concentration of the disinfection solution was tested by the modified electrode with a relative error of 0.2%.In addition, the efficient electrocatalytic activity of the modified electrode towards the oxidation of methanol and ethylene glycol at bulk platinum was observed. Compared with the bulk Pt electrode, the modified electrode significantly improved the electrocatalytic activity toward the oxidation of methanol and ethylene glycol.The hemoglobin (Hb) was successfully immobilized on the platinum nanoparticles modified glassy carbon surface. The Hb immobilization was characterized by EIS techniques. The results indicated that the immobilized Hb film blocked the reaction of [Fe (CN)₆]^4-/^3- while showed electrocatalytic activity to H₂O₂.