功能化聚(2,5-二甲氧基苯胺)膜的电化学和电催化性质研究

聚(2，5-二甲氧基苯胺)含有对称的环取代基，其电化学活性可与PAni相比拟．该聚合物具有三种氧化态，即完全还原态(L)、半氧化态(E)和完全氧化态(P)，在伏安曲线上分别于0．19和0．51V处出现L／E和E／P转变峰．掺杂态聚合物和本征态聚合物的氧化还原分别经历L=EH=P和LH=EH=P路径，其中E／P转变峰电位随pH升高而发生负移．铂化的聚合物电极对异丙醇的氧化具有明显的催化作用，且随着扫描时间延长，氧化电流逐渐提高；聚合物与铂微粒相互作用，改变铂微粒的几何结构和电子性质，使催化体系具有良好的催化活性和抗中毒能力．在pH=4．7的缓冲溶液中，该修饰电极对异丙醇氧化仍具有催化活性．聚合物在空气中存放太久(3年)会发生降解，从而影响其电化学性质．

Studies on Electrochemical and Electrocatalytic Properties of Functional Poly-2,5-dimethoxyaniline Membrane

Electrochemical activity of poly-2,5-dimethoxyaniline(PDMAn) is similar to parent polyaniline because of two symmetric substituted groups. Three oxidation states of PDMAn can transform reversibly, known as the completely reduced leucoemeraldine(L), intermediate emeraldine(E) and the fully oxidized pernigraniline(P). In voltammograms, the L/E, E/P transformation peaks are located at 0.19 and 0.51 V, respectively. Doping polymer and intrinsic polymer follow the redox transformation as L{EHP} and LHEHP separately. And E/P transformation peak shifts to lower potential by increasing pH value. In de-aerated solution the platinized polymer has an evidently catalytic activity on isopropanol oxidation. Furthermore the oxidative current enhances with increasing potential cycling numbers, whereas it decreases for platinized Pt electrode. The Pt particles not only highly disperse in PDMAn membrane, but also interact with PDMAn, resulting in changing their geometric structure and the electron properties of that metal. It is illustrated that as a catalytic system with a high catalytic and anti-poisoning activity, platinized PDMAn membrane electrode will also catalyze isopropanol oxidation in pH=4.7 buffer solution. It is pointed that PDMAn will degrade after preservation in air for three years.