Preparation And Eletrochemical Properties Of Core-shell Structure Polypyrrole Composite And Hydrogels

Conductive polymers have attracted attention due to their low cost and excellent charge storage performance.Among them,polypyrrole?PPy?has drawn wide attention due to its excellent charge storage performance and its environmentally friendly properties,and has broad and good application prospects.This paper aims to prepare polypyrrole complexes and then study on their electrochemical properties.These include improving conductivity and developing low-cost,high-performance oxygen reduction catalysts to promote the development of clean electrochemical energy.On the one hand,the fabrication of graphitized diamond covered with polypyrrole?D@G@PPy?core-shell nanocomposites has been achieved by using a superficial electrochemical polymerization and self-assembly strategy.The conductivity of the core-shell nanocomposites was influenced by polymerization time,current as well as the concentration of ions.The obtained excellent conductivity appeared with the current of 0.6mA and the duration time of 1 h.In addition,the corresponding enhanced electrochemical performance of polypyrrole grown on graphitized diamond substrate is demonstrated compared with pristine polypyrrole.The morphologies of the obtained composites were illuminated through scanning electron microscopy?SEM?and the conductivity wasdemonstrated by electrochemical impedance spectroscopy?EIS?.The characteristic peaks of polypyrrole and qualitative analysis of surface elements have been investigated by Raman spectra and X-ray photoelectron spectroscopy?XPS?.The present research could demonstrate a new aspiration for the design and preparation of novel polypyrrole core-shell composites materials.On the other hand,two kinds of supramolecular doped one-dimensional nanostructured conductive polymer hydrogels,PPy/CuPcTs and PPy/NiPcTs,were successfully synthesized by one-step method.The morphology of the metal phthalocyanine was successfully doped into the polypyrrole chain.After soaking,it was successfully doped into Co²⁺to form PPy/CuPcTs,PPy/CuPcTs/Co,PPy/NiPcTs,and PPy/NiPcTs/Co four kind of supramolecular hydrogels.After pyrolysis at 800 ^oC,a double-doped porous trifunctional M-N-C catalyst,PPy/CuPcTs,PPy/CuPcTs/Co,PPy/NiPcTs and PPy/NiPcTs/Co catalyst were formed.The catalytic performance of the four catalysts was demonstrated by electrochemical characterization.Through the calculation of the K-L equation,we can know that the three catalysts PPy/CuPcTs,PPy/CuPcTs/Co and PPy/NiPcTs/Co can achieve complete reduction of O₂ through the4-electron pathway.The PPy/NiPcTs catalyst is converted into water by a two-electron route.By comparing the PPy/NiPcTs catalyst with the PPy/NiPcTs/Co catalyst,we can draw a conclution that the addition of Co²⁺is beneficial to enhance the catalytic activity of the oxygen reduction catalyst.In addition,the catalysts were proved to have good stability by the chronopotentiometry.We expect this approach to facilitate the development of low-cost,high-efficiency fuel cell catalysts that facilitate the practical application of fuel cells.