异丙醇在Pt微盘电极上的电化学氧化

Abstract

采用微电极伏安技术，研究异丙醇在PT微盘电极（rd＝10μM）上氧化的稳态和暂态的电化学行为，得出一系列重要的动力学参数：异丙醇氧化反应的反应电子数n为1.95，扩散系数d为3.22x10-5CM2/S，传递系数β值为0.12，电极体系的交换电流密度J0为3.0x10-4A/CM2，标准速度常数kS为1.60x10-4CM/S。由计算结果我们可以推测，异丙醇在PT微盘电极上酸性水溶液体系中的氧化过程由稳态传质扩散及电化学极化联合控制，其中，异丙醇分子到电极表面的扩散吸附为快速步骤，吸附的异丙醇分子在电极表面脱氢为慢步骤；异丙醇在PT微盘电极上的电化学氧化为异丙醇脱氢生成丙酮的2电子转移反应，并由此推测其可能的反应途径。

The stable and transient electrochemical behavior of isopropanol oxidation on Pt microdisc electrode(rd=10μm) were investigated by voltammetric microelectrode technique.A series of an important dynamic parameters were obtained:n=1.95,D=3.22×10-5cm2/s,β=0.12,J0=3.0×10-4A/cm2,Ks=1.60×10-4cm/s(n——number of electrons involved in oxidation process;D——diffusion coefficient;β——transfer coefficient;J0——exchange current density;Ks——standard rate constant).From the results,it can be considered that the processes of isopropanol oxidation on Pt microdisc electrode in the acidic aqueous solution were simultaneously controlled by steady state mass transfer diffusion and electrochemical polarization.In the case of the processes of isopropanol diffuses and absorbs to the surface of electrode are fast step,and the processes of the absorbed isopropanol dehydrogenate on the surface of the electrode are slow step.The results show that the main oxidation reaction is a two electrons transfer reaction of isopropanol hydrogenation to acetone.The probable electrochemical oxidation mechanism were proposed.