Lecture

Mass Transport in Butler-Volmer Equation

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In course

ChE-407: Electrochemical engineering

This course builds upon the underlying theory in thermodynamics, reaction kinetics, and transport and applies these methods to electrosynthesis, fuel cell, and battery applications. Special focus is placed on addressing current challenges in state-of-the-a ...

Description

This lecture delves into the impact of mass transport on the Butler-Volmer Equation, focusing on the 'leveling' effect at extreme potentials. It explores the simplifications for small n using Taylor series and their application to the equation. The lecture also covers the implications of large n, highlighting the behavior of the equation under different conditions. The total overpotential and its components are thoroughly analyzed, shedding light on the interpretation of various regimes and their effects on current and potential. The Tafel analysis, electrochemical reaction coordinate diagrams, and the determination of standard rate constants are also discussed.

Instructors (2)

Nikolaos Vlachopoulos

Ardemis Anoush Boghossian

Official source

Ontological neighbourhood

Chemistry

Physical chemistry: Electrochemistry

Related concepts (32)

Tafel equation

The Tafel equation is an equation in electrochemical kinetics relating the rate of an electrochemical reaction to the overpotential. The Tafel equation was first deduced experimentally and was later shown to have a theoretical justification. The equation is named after Swiss chemist Julius Tafel." It describes how the electrical current through an electrode depends on the voltage difference between the electrode and the bulk electrolyte for a simple, unimolecular redox reaction ".

Electrochemical kinetics

Electrochemical kinetics is the field of electrochemistry that studies the rate of electrochemical processes. This includes the study of how process conditions, such as concentration and electric potential, influence the rate of oxidation and reduction (redox) reactions that occur at the surface of an electrode, as well as an investigation into electrochemical reaction mechanisms.

Voltammetry

Voltammetry is a category of electroanalytical methods used in analytical chemistry and various industrial processes. In voltammetry, information about an analyte is obtained by measuring the current as the potential is varied. The analytical data for a voltammetric experiment comes in the form of a voltammogram which plots the current produced by the analyte versus the potential of the working electrode. Voltammetry is the study of current as a function of applied potential.

Electrochemistry

Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential difference, as a measurable and quantitative phenomenon, and identifiable chemical change, with the potential difference as an outcome of a particular chemical change, or vice versa. These reactions involve electrons moving via an electronically-conducting phase (typically an external electrical circuit, but not necessarily, as in electroless plating) between electrodes separated by an ionically conducting and electronically insulating electrolyte (or ionic species in a solution).

Overpotential

In electrochemistry, overpotential is the potential difference (voltage) between a half-reaction's thermodynamically-determined reduction potential and the potential at which the redox event is experimentally observed. The term is directly related to a cell's voltage efficiency. In an electrolytic cell the existence of overpotential implies that the cell requires more energy than thermodynamically expected to drive a reaction. In a galvanic cell the existence of overpotential means less energy is recovered than thermodynamics predicts.

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