十六烷基吡啶在玻碳电极表面上的吸附过程

STUDY ON THE ADSORPTION OF CETYL PYRIDINIUM BROMIDE ON GC ELECTRODE SURFACE

本文用交流阻抗法在长光程薄层光谱电解池中研究了溴化十六烷基吡啶(CPyBr)在玻碳电极上的吸附过程。在复数平面图的高频区获得了与电解池结构电容有关的半圆,低频区获得了与CPyBr吸附有关的阻抗及Warburg阻抗,建立了CPyBr的单分子层吸附模型及电极过程的交流阻抗等效电路。理论预测与实验数据吻合较好。

The adsorption process of cetyl pyridinium bromide (CPyBr) on glassy carbon (GC)electrode surface in a long optical path length thin-layer cell(LOPLTC) has been investigatedby an AC impedance measurement. In the high freqency region of the AC impedance complex diagram, the capacity obtai-ned from a large semicircle with rotation was 4 times larger than that theoretically calcu-lated from a parallel plate condenser. In the low frequency region the impedance diagrams were related to the adsorption ofCPyBr and the Warburg′s impedance. A charge transfer model between the layer of CPyBradsorbed on GC electrode surface and the bulk soluticn has been suggested. A low value ofdiffusion coefficient and large fluid dynamics radius of CPyBr (r=352A) were calculatedfrom Warburg′s impedance. An equivalent circuit for the impedance in the whole frequencytested has been Euggested.