电解质溶液对聚吡咯电聚合中过氧化行为的影响

分别以硫酸/水和高氯酸锂/乙腈为电解质溶液, 采用循环伏安法在铂基底电极上电聚合制备了聚吡咯, 研究了电解质溶液对聚吡咯电聚合过程中过氧化行为的影响. 与硫酸/水溶液相比, 在高氯酸锂/乙腈溶液中电聚合制备的聚吡咯发生过氧化的峰电位正移了0.42 V. 采用原位傅里叶变换红外(in situ FTIR)光谱技术检测, 结果表明, 电聚合制备的聚吡咯在2种电解质溶液中均发生了过氧化反应, 其β-C经氧化生成C—OH或CO. 在硫酸/水溶液中, 部分聚吡咯发生电氧化降解生成CO2, 致使其共轭结构被破坏, 电导率迅速下降. 而在高氯酸锂/乙腈溶液中, 在更高的电位范围内, 聚吡咯并没有氧化降解成CO2.

Effects of Electrolyte Solutions on Overoxidation of Polypyrrole During Its Electrochemical Polymerization

Polypyrrole(PPy) was prepared by cyclic voltammetry on a platinum electrode in H2SO4/H2O and LiClO4/CH3CN solutions,respectively.The effects of electrolyte solutions on overoxidation of polypyrrole during its electrochemical polymerization were studied by in situ spectroelectrochemical measurements.Compared with the solution of H2SO4/H2O,the overoxidative peak potential of polypyrrole in LiClO4/CH3CN was positively shifted by 0.42 V.The results show that the β-C of the pentacycle is oxidized to oxygen-containing groups such as C—OH and C-O during the overoxidation of polypyrrole at high potentials.Polypyrrole partially degraded with the formation of CO2 in H2SO4/H2O solutions,which resulted in loss of conductivity,and did not obviously degrade during overoxidation in the solution LiClO4/CH3CN at the higher potentials.