Fabrication And Properties Of Polypyrrole/metal-calixarene Cluster Composites

Metal-calixarene clusters are a class of nanoscale 0-dimensional metal-organic complexes with highly ordered structure,large specific surface area,high porosity,capable of rationnal synthesis and functionalization.Compared with other metal-organic complexes,the multifunctional 0-dimensional structures make them widely used in adsorption/separation,catalysis and magnetism.However,the none conductive nature prevented them for further applications in the electrochemical fields.As a typical conductive polymer material,polypyrrole has been widely used as conductive carrier and attracted growing attention due to its simple synthesis method and good stability.In this thesis,metal-calixarene cluster wereutilized with polypyrrole to synthesize composite materials by chemical oxidation polymerization.The composite materials were characterized by transmission electron microscopy,FT-IR spectroscopy,thermogravimetric analysis and X-ray photoelectron spectroscopy,and they were used as electrodes to investigate the electrochemical properties for oxygen evolution reaction.The main works of the thesis are as follows:1.Nanospheres Co₃₂ clusters were synthesized,and polypyrrole/Co₃₂cluster composites with different mass fractions were prepared by chemical oxidative polymerization in water/ethanol reaction system.The working electrodes loading withthe Co₃₂ clusters,pure polypyrrole as well as bare carbon paper electrode,were also prepared and investigated for comparison.The oxygen evolution reaction was carried out in the three-electrode system.The electrochemical properties of the composites with different mass fractionsof Co₃₂ cluster and polypyrrole were explored.It was found that the composies have smaller resistance and larger electrocatalytic activity surface area,which were 38.14?and 57.86 m F·cm^-2,respectively.The dispersion of Co₃₂ cluster and the polymerization degree of polypyrrole were improved by adjusting the volume of ethanol in the reaction solvent.The results show that the increase of ethanol content further improves the conductivity of the composite,and the charge transfer resistance decreases from 72.73?of the Co₃₂ cluster to 5.582?,and the oxygen evolution catalytic performance of the normalized composite is significantly better than that of the Co₃₂ cluster.2.Polypyrrole/Co₂₄ cluster composites with different mass ratios were prepared by chemical oxidation polymerization.The composites of polypyrrole and circular metal cluster Co₂₄ were tested for oxygen evolution reaction.The comparing electrodes with Co₂₄ cluster,polypyrrole and bare electrodes were also fabricated for electrochemical tests.The ratio of ethanol in reaction solvents were adjusted inorder to invetigate the influence of solvent on polymerization reaction and product.The electrochemical tests showed that the introduction of polypyrrole improved the electrochemical performance of the Co₂₄ cluster,and the volume of ethanol used had a significant impact on the electrochemical performance of the composites,with the increase of ethanol content,the maximum double layer capacitance of the composite increased to 19.66 m F·cm^-2,and the charge transfer resistance decreased to 4.368?.The oxygen evolution catalytic performance of the normalized composite was greatly improved compared with that of the Co₂4 cluster compound.