Cyclic Voltammetry Part 2: Surface Adsorption, Electric Double Layer, and Diffusion Layer†

Abstract

This paper “Part 2: Surface Adsorption, Electric Double Layer, and Diffusion Layer” is the applicational part and is a continuation of “Part 1: Fundamentals” (https://doi.org/10.5796/electrochemistry.22-66082). This part explains the principles of cyclic voltammetry on adsorption, electric double layer, and diffusion layer with microelectrodes. Moreover, recent trends, such as polymer electrolyte fuel cells (PEFCs), electric double layer capacitors (EDLCs), and sensors, are highlighted. The relationship between the electrochemical surface area (ECSA) and electric quantity estimated on the basis of cyclic voltammograms is explained in the chapter on adsorption, where the adsorption of hydrogen and carbon monoxide on Pt is discussed. The following chapter introduces the pseudo-capacitance of activated carbon, which exhibits characteristic capacitor-like behavior, with Faradaic current flow on the surface. Finally, an explanation concerning the effect of diffusion-limiting currents on two types of microelectrodes and a practical case of enzyme sensing using a microelectrode is included.