Preparation Of Nano-fibrous Conductive Polyaniline And Applied Research

A novel method, termed by pulse galvanostatic method(PGM), was proposed to synthesize polyaniline(PANI) films at stainless electrode in 0.5mol/L H2SO4 or Imol/L HNO3 aqueous solution. The synthetic conditions, morphology and electrochemical properties of PANI films prepared by PGM were investigated in detail by different methods, such as, scanning electron microscopy, transmitting electron microscopy, IR spectra and cyclic voltammtry. The results show that the morphology of PANI doped is nano-fiber with about 100nm in diameter and several micrometers in length. The nano-fibular PANI films has more excellent electrochemical properties than that of granular PANI films prepared by galvanostatic method. Additionally, a systematic study of electropolymerization of aniline using PGM was carried out by electrochemical method. In order to obtained the optimal nano-fibular PANI films with excellent electrochemical properties, the synthetic parameters should be controlled at the following conditions: ton/toff, l:l(for H2SO4 solution) and 10:1 (for HNO3); pulse frequency, 10Hz; mean current density of PGM, 1~3mA/cm2; temperature of electrolyte, 20 ; monomer concentration, 0.3mol/L.The applications of PANI nano-fiber in carrier for metal catalyst and in electrode material of supercapacitor were investigated. The electrode of nano-fibualr PANI modified by Pt microparticles with about 30nm diameter exhibits a considerably higher electrocatalytic activity for methanol oxidation than that of the granular polyaniline, prepared by GM, electrode modified by Pt microparticles at the condition of the same Pt loading. The?nano-fibular PANI has a synergism'for methanol oxidation. Meanwhile, The results of the AC impedance show that the nano-fibular PANI electrode modified by Pt microparticles has relatively lower electrochemical impedance on methanol oxidation than that of granular PANI electrode modified by Pt microparticles. Furthermore, the influences of electrodepositing methods of Pt microparticles, such as cyclic voltammetrymethod(CVM) and pulse galvanostatic method(PGM), on electrocatalytic activity of Pt/PANI electrodes were investigated. The composited electrode, which the Pt microparticles was electrodeposited by PGM, indicates higher electrocatalytic activity. Additionally, the supercapacitor using nano-fibular PANI as electrode possesses specific capacitance as high as 608F/g, which is higher than activate carbon and granular PANI. Conducting nano-fibular PANI offers the advantages of lower cost in comparison with noble metal oxidation, such as RuO2, it will have potential application prospects in supercapacitor.Finally, the composite materials of PANI/Ag were prepared by PGM and cyclic voltammtry method(CVM). The PANI/Ag composite film with structure of alternate overlap between PANI and Ag was obtained by CVM. Differently, the PANI/Ag composite nano-material, which nano-particles with 30nm in diameter is dispersed homogeneously on PANI nano-fiber, was prepared by PGM. Furthermore, the most appropriate synthetic conditions for PANI/Ag composite films with excellent electrochemical properties were investigated by cyclic viltammtry.