纳米铂微粒修饰电极上甲醛电催化氧化的电位振荡和电流振荡

Potential and Current Oscillations During Electrocatalytic Oxidation of Formaldehyde at a Pt Nanoparticles Modified Electrode

通过阴极还原-阳极氧化法制备了钛基纳米铂微粒修饰电极,扫描电镜观察发现,分布于钛基体表面的氧化钛膜三维网状孔道中的纳米铂微粒具有高度分散状态.采用多种电化学手段在该电极上不仅观察到甲醛在恒电流条件下产生的电位振荡,而且在循环伏安和恒电位两种条件下均观察到强烈的电流振荡,这进一步证明高度分散的纳米铂微粒使电极的催化活性大大提高,促进了甲醛及其毒化中间产物的电催化氧化过程,从而有利于电极上电化学振荡的产生.研究结果还表明,甲醛底物浓度、硫酸介质浓度、恒电位或恒电流大小等多种因素对振荡强度、范围或类型会产生规律性的影响.

The platinum （Pt） nanoparticles modified titanium electrode was prepared via the method of cathodic reduction followed by anodic oxidation. Scanning electron microscopy（SEM） analysis illustrated that Pt nanoparticles were dispersed highly in the three-dimensional pore network of titanium oxide on the surface of this electrode. Not only potential oscillations under galvanostatic conditions but also current oscillations under both cyclic voltammetric and potentiostatic conditions during the formaldehyde （HCHO） oxidation were observed with several different electrochemical methods. This further revealed that the highly-dispersed Pt nan- oparticles improved greatly the electrocatalytic activities of electrode, then facilitated the oxidation process of HCHO and its intermediate product so that these were favorable to the production of electrochemical oscillations. Also, many factors such as the concentration of HCHO and H2SO4, the applied potential or current were shown to have regular influence on the intensity, region or pattern of oscillations.