Concept and Role of Electrochemical Engineering

Abstract

An electrode process is a heterogeneous catalytic reaction accompanied by charge transfer at the electrode surface in contact with the electrolyte. The amount of mass transfer is exactly proportional to the amount of electricity passing through the electrode—electrolyte interface and is governed by the Faraday law. Hence, the current density on the working electrode is the same as the reaction rate. There is a potential difference at the electrode—electrolyte interface, called the electrode potential, which is related to the free energy change for the electrode process under discussion. The electrode potential may deviate from its equilibrium state, called the equilibrium or reversible potential, when the charge transfer reaction takes place. Consequently, analysis of the electrode process of interest can be made from the viewpoints of both thermodynamics and chemical kinetics by using the experimental relationship between the electrode potential (the driving force for the reaction) and the current density (the reaction rate). Advancement of electronic instrumentation has promoted scientific research in these fields.