The metal wire counter (auxiliary) electrode is provided in the electrochemical cell as a current sink to shunt excess current away from the reference electrode. The counter electrode is generally chosen to be inert under reaction conditions, typically platinum, rhodium, palladium, or gold wire. It well fits aqueous (FKM O-Ring) and organic solvent (FFKM O-Ring) electrolyte requirements.

In this electrode concept, the plug is made of PTFE. This electrode is used wherever PEEK 35HX15 0.6/235 mm electrode fails, i.e. when using electrolytes containing:

• Aqua regia - HNO3 + HCl
• Benzenesulfonic acid - aqueous C6H5SO3H
• Bromine (liquid) - pure Br2
• Carbolic Acid (Phenol) - C6H5OH
• Carbon Disulfide - CS2
• Chlorine (aqueous and anhydrous liquid) - Cl2
• Chlorosulfonic acid - pure ClSO3H
• Chromic Acid - aqueous H2CrO4 >50%
• Ethylene bromide (anhydrous) - pure CH2CHBr
• Fuming sulphuric acid (Oleum) - pure H2SO
• Hydrobromic acid - aqueous HBr
• Hydrofluoric acid - concentrated aqueous HF
• Nitric acid - aqueous HNO3 >50%
• Sulphuric acid - concentrated (96%) H2SO4
• Sulphurous acid - aqueous H2SO3

The PTFE plug is also alkali-resistant, so it can be used instead of PEEK in experiments including high pH hot electrolytes. A full description of the difference between PEEK and PTFE cells can be found in our blog post.

Application note This electrode is typically used with low volume (1-2 mL) electrochemical cells (e.g. spectro-electrochemical cells, or photo-electrochemical flow cells), where space limitations do not allow using PTFE 50HX15 0.6/250 mm model. The metal wire electrode is immersed in the ion-conducting solution as a counter electrode. An electric current is passed between the working electrode and the counter electrode for a certain amount of time. After the process, the electrode should be washed several times with isopropanol or ethanol and dried under the nitrogen flow. Store the metal wire electrode in the glass vial sealed with O-rings (all included in the package).

Product includes 1x metal wire electrode with PEEK plug and selected electrical connector 1x O-Ring 1x glass vial