Preparation And Electrochemical Properties Of Polyaniline/inorganic Particle Composites

In recent years,Conductive polymers and inorganic materials compound as a new type of composite material with excellent physical and chemical properties,are widely used in many fields.The research of conductive polyaniline/modified inorganic particle composites slowly aroused our interest.People want to get new composite materials prepared by valence bond connection,and the new composite materials were modified on the rotating disc electrode to form a thin film electrode.Composite itself had good electrical conductivity and electrocatalytic activity,which could provide theoretical support fordevelopment of polymeric materials on the hydrometallurgy of zinc anodes.In this thesis,our main aim was to research on the preparation and electrochemical properties of polyaniline/modified inorganic particles composites.The research is focused in three aspects:1.The cerium dioxide?CeO₂?/toluene-2,4-diisocyanate?TDI?bybrid composite was successfully fabricated via the addition reaction between TDI and hydioxyl at CeO₂ surface.The PANI/CeO₂-TDI composites were synthesized by the surface of CeO₂-TDI served as active sites for the graft polymerization of aniline?An?.when that proportion of CeO₂/TDI was 30mL:1.8g,the electrochemical activity and conductive of the composite showed the best.The structure and thermal stability of obtained composites were characterized by Fourier-transform infrared spectra?FTIR?,X-ray diffraction?XRD?and Thermogruimetric analysis?TGA?.The electrochemical performance was studied using PANI/CeO₂-TDI composites modified rotating disc electrode?RDE?in an electrolyte of 65g/L Zn²⁺ and 150g/L H₂SO₄ at 35?.The results showed that the PANI/CeO₂-TDI composites substantially improved electrocatalytic activity regarding with oxygen evolution reaction,the electrode surface current density for PANI/CeO₂-TDI/GC modified electrode is to 2.9*10-4 A cm-2,rised by one order of magnitude compared with the PAN I modified electrode.XRD analyses confirmed TDI had no effect on crystal structure of CeO₂ particles.The thermal stability of PANI/CeO₂-TDI composite was the best comparing to those of pure PANI and PANI/CeO₂.There was a strong interaction between CeO₂-TDI particles and PAN I molecular chains.2.After Cerium dioxide?CeO₂?was modified by 3-Aminopropyltrimethoxysilane?APTMS?,polymerization with aniline?An?would be obtained the structure of polyaniline?PANI?/CeO₂-APTMS composites with the CeO₂ as the carrier and it's surface loaded on polyaniline.when that proportion of CeO₂/APTMS was 6mL:1.8g,the electrochemical activity and conductive of the composite showed the best.The electrochemical properties of PANI/CeO₂-APTMS?PANI-CeO₂ composites without CeO₂ modification in synthesis process and pure PANI were compared by means of FT-IR,XRD,TGA and rotating disk electrochemical testing technique.From the compared results,we could find that PANI/CeO₂-APTMS composite had the best grafting morphology,and the structure of PANI on the surface of CeO₂-APTMS was the same to pure PANI.After APTMS modified,PAN I/CeO₂-APTMS was grafted through the valence bond between CeO₂ and PANI,which showed the best thermal stability as PANI/CeO₂-APTMS had the initial decomposition temperature at about 242? and the lowest decomposition rate in the range of 200?-600?.PANI/CeO₂-APTMS composite modified electrode in the synthetic zinc electrowinning electrolyte 65g/L Zn²⁺,150g/L H₂SO₄,which had excellent peak symmetry and a maximum anodic peak current by means of cyclic voltammetry test,which for oxygen evolution potential value was low compared with three modified electrodes by anodic polarization curves at different speeds,could reflect the good stability and the best oxygen evolution electrocatalytic activity.3.AfterTungsten carbide?WC?was modified by 3-Aminopropyltrimethoxysilane?APTMS?and toluene-2,4-diisocyanate?TDI?,polymerization with aniline?An?would be obtained the structure of polyaniline?PANI?/modified WC composites with the WC as the carrier and it's surface loaded on polyaniline.The structure and thermal stability of obtained composites were characterized by Fourier-transform infrared spectra?FTIR?,X-ray diffraction?XRD?and Thermogrurimetric analysis?TGA?.By the comparing results,it was found that PANI/modified WC composite had the best grafting morphology,and the structure of PANI on the surface of modified WC was the same as pure PANI.After Modifier?APTMS?TDI?modified,PANI/modified WC was grafted through the valence bond between WC and PANI,which showed the best thermal stability as the initial decomposition temperature of PANI/WC-APTMS and PANI/WC-TDI is about 260? and 287?,respectively.PANI/modified WC composite showed better stability and optimum catalytic compared with PANI/modified CeO₂ composites in the synthetic zinc electrowinning electrolyte 65g/L Zn²⁺,150g/L H₂SO₄,indicating that modified CeO₂ is more suitable for carring PANI.