The Study On The Catalysis Of Polyporphyrin Modified Electrode For Oxygen Reduction Reaction

With deteriorating energy reliability, the mission for mankind to seek for a new energy source with high efficiency and clean is imminent. Being a green energy source,the fuel cell has been receiving widespread attention. Thanks to the efforts of many scholars, its development advanced by leaps and bounds.Platium being the best catalyst for oxygen reduction reaction(ORR), has several unfavorable factor: expensive, limited reserve, susceptible to carbon monoxide(CO) poison [CO in gas fuel or as a by-product during methanol anodic electro-oxidation]. These has limited platinum’s electrocatalyst applications.Thus, finding high efficiency and cost-effect catalyst becomes a hot research topic. Metalloporphyrin processes relatively high conjugated structure and chemical stability, processes good oxygen reduction electrocatalytic activity. Being one of the most promising catalyst for air electrode, it promotes disintegration of H2O2,increasing the working voltage and discharging capacity. Porphyrins catalytic process is two electron process, recent studies have shown that metal porphyrins can catalytic reduction of oxygen in four electron reaction process.The first, In this work the metal porphyrin complexes were prepared and characterized, electropolymerization for preparing p Co TPP modified gold electrode and its catalytic properties in acidic medium were studied. Four phenyl porphyrin(TPP) was prepared by Alder method and ultraviolet visible(UV-Vis) spectra of the two substances were characterized. Electrochemical behavior of was measured by cyclic voltammetry.The results show that the synthetic material is target product. The second part mainly studied the method of electro polymerization to prepare p Co TPP modified gold electrode. The Co TPP polymerization film was obtained by cyclic voltammetric electrochemical polymerization method. Then, we explored the effect of polymerization potential, polymerization coils and material of electrode to electrochemical polymerization. the morphology of polymer film was observed by electron microscopy(SEM), a two-dimensional sheet structure material apeared on the surface of the electrode what is the p Co TPP. The UV-Vis spectra also confirmed that the formation of the polymer film on electrode surface was p Co TPP. Compared monomer Co TPP with p Co TPP, the Soret band of p Co TPP was red-shifted and its absorption peak was wider than monomer Co TPP. The last part reserched the catalytic properties and the electrochemical behavior of p Co TPP in acidic medium. The relationship of differentscanning speeds with the oxygen reduction peak current showed that catalytic process of oxygen reduction was affected by the molecular oxygen diffusion; p Co TPP modified gold electrode cycled 100 laps in oxygen saturated 0.5 mol/L H2SO4 solution, the result indicated the reduction peak current and the peak potential are basically without difference between the first coil with the 100 th coil. The result show that this modified electrode have good stability; the p H value and oxygen reduction potential showed a good linear relationship, result showed that the number of electron and protons are equal during the oxygen reduction reaction. p Co TPP modified gold electrode has catalytic properties for oxygen In the alkaline.