The application of ultramicroelectrode in homogeneous catalytic reaction—V. Electrochemical behaviour of macro-micro-macro triple and micro-micro twin electrodes and the quasi-first-order homogeneous catalytic reaction (EC′) at generation/collection electrode

Abstract

A new type of macro-micro-macro triple electrode has been fabricated, the steady-state currents of solution redox species have been observed at an ultramicroband electrode by linear potential scan voltammetry, and generation/collection experiments have also been performed at macro-micro-macro triple and micro-micro twin electrodes. The electrochemical behaviour of a single reversible couple with a homogeneous catalytic reaction has been studied at each of the above two kinds of electrodes. We firstly obtained the kinetic equation based on a decrease of the collection current to determine the kinetic constant of the quasi-first-order homogeneous catalytic reaction, as (1 − i cc/ i c) i G  nF AD 1 2 0 C 0[(1 + m) kC z ] 1 2 and we gave the experimental method to determine the kinetic constant. This method can be used with versatility to study homogeneous chemical reactions over a wide range of kinetic constants, which overcomes the disadvantage that an ultramicroelectrode is only suitable for fast catalytic reactions. Two systems, K 4Fe(CN) 6-ascorbic acid and benzoquinone ( Q) − O 2 were chosen to check the equation and to determine their kinetic constants.