In electrochemistry, the auxiliary electrode, often also called the counter electrode, is an electrode used in a three-electrode electrochemical cell for voltammetric analysis or other reactions in which an electric current is expected to flow. The auxiliary electrode is distinct from the reference electrode, which establishes the electrical potential against which other potentials may be measured, and the working electrode, at which the cell reaction takes place. In a two-electrode system, either a known current or potential is applied between the working and auxiliary electrodes and the other variable may be measured. The auxiliary electrode functions as a cathode whenever the working electrode is operating as an anode and vice versa. The auxiliary electrode often has a surface area much larger than that of the working electrode to ensure that the half-reaction occurring at the auxiliary electrode can occur fast enough so as not to limit the process at the working electrode. When a three-electrode cell is used to perform electroanalytical chemistry, the auxiliary electrode, along with the working electrode, provides a circuit over which current is either applied or measured. Here, the potential of the auxiliary electrode is usually not measured and is adjusted so as to balance the reaction occurring at the working electrode. This configuration allows the potential of the working electrode to be measured against a known reference electrode without compromising the stability of that reference electrode by passing current over it. The auxiliary electrode may be isolated from the working electrode using a glass frit. Such isolation prevents any byproducts generated at the auxiliary electrode from contaminating the main test solution: for example, if a reduction is being performed at the working electrode in aqueous solution, oxygen may be evolved from the auxiliary electrode. Such isolation is crucial during the bulk electrolysis of a species which exhibits reversible redox behavior.

About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Related courses (31)
EE-519: Bioelectronics and biomedical microelectronics
The course covers the fundaments of bioelectronics and integrated microelectronics for biomedical and implantable systems. Issues and trade-offs at the circuit and systems levels of invasive microelec
NX-421: Neural signals and signal processing
Understanding, processing, and analysis of signals and images obtained from the central and peripheral nervous system
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 p
Show more
Related lectures (70)
Osmotic Pressure: Electrochemical Potential
Explores osmotic pressure and electrochemical potential, highlighting their calculation and significance in electrolyte behavior.
Quantum and Nanocomputing
Explores the fabrication and behavior of quantum and nanocomputing devices, focusing on molecular conduction and device characteristics.
Quantum Computing: Molecular Transistors and Logic Gates
Delves into molecular transistors, logic gates, and their design using molecular technology.
Show more
Related publications (303)

Membrane electrode assembly simulation of anion exchange membrane water electrolysis

Jan Van Herle, Suhas Nuggehalli Sampathkumar, Khaled Lawand, Zoé Mury

Anion exchange membrane water electrolysis (AEMWE) offers a green hydrogen production method that eliminates the need for platinum group metals (PGM) as electrocatalysts. This study employs a COMSOL (R) 6.0 model to simulate a 1x1 cm(2) Ni fibre - Raney (R ...
Amsterdam2024

Electrochemical sensors modified with iron oxide nanoparticles/ nanocomposites for voltammetric detection of Pb (II) in water: A review

Sandro Carrara

Permissible limits of Pb 2+ in drinking water are being reduced from 10 mu gL -1 to 5 mu gL -1 , which calls for rapid, and highly reliable detection techniques. Electrochemical sensors have garnered attention in detection of heavy metal ions in environmen ...
Cell Press2024

Carbon based printed electrodes for DEAs: study of pad, inkjet, and stencil printing

Yves Perriard, Yoan René Cyrille Civet, Thomas Guillaume Martinez, Stefania Maria Aliki Konstantinidi, Armando Matthieu Walter, Simon Holzer

Dielectric elastomer actuators (DEAs) have raised interest due to their remarkable capabilities in various applications, such as soft robotics, haptic feedback systems, and biomedical devices. To harness the full potential of DEAs, the choice of the electr ...
Society of Photo-Optical Instrumentation Engineers (SPIE)2024
Show more
Related concepts (6)
Working electrode
In electrochemistry, the working electrode is the electrode in an electrochemical system on which the reaction of interest is occurring. The working electrode is often used in conjunction with an auxiliary electrode, and a reference electrode in a three-electrode system. Depending on whether the reaction on the electrode is a reduction or an oxidation, the working electrode is called cathodic or anodic, respectively.
Liquid metal electrode
A liquid metal electrode is an electrode that uses a liquid metal, such as mercury, Galinstan, and NaK. They can be used in electrocapillarity, voltammetry, and impedance measurements. The dropping mercury electrode (DME) is a working electrode made of mercury and used in polarography. Experiments run with mercury electrodes are referred to as forms of polarography even if the experiments are identical or very similar to a corresponding voltammetry experiment which uses solid working electrodes.
Reference electrode
A reference electrode is an electrode that has a stable and well-known electrode potential. The overall chemical reaction taking place in a cell is made up of two independent half-reactions, which describe chemical changes at the two electrodes. To focus on the reaction at the working electrode, the reference electrode is standardized with constant (buffered or saturated) concentrations of each participant of the redox reaction. There are many ways reference electrodes are used.
Show more