Examination and prevention of ring collection failure during gas-evolving reactions on a rotating ring-disk electrode

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2019-10, Vol.850, p.113363, Article 113363
• Main Authors: Vos, J.G., Koper, M.T.M.
• Format: Article
• Language: English
• Subjects: Bubbles; Chemical evolution; Chlorine; Chlorine evolution; Collection; Collection efficiency; Current density; Electrodes; Gas bubbles; Gas evolution; Gas formation; Hydrogen evolution; Oxygen; Oxygen evolution; Reliability aspects; Rotating disks; Rotating ring-disk electrode; Rotation
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2019.113363

Use of a rotating ring-disk electrode during gas-evolving reactions has been shown liable to errors under higher current densities, since product collection on the ring is vulnerable to the formation of gas bubbles at the disk-ring interspace. In this study, we explored methods of reducing such bubble-related errors and improving the reliability of the collection factor under high-intensity gas evolution. We attempted the mounting of a thin wire close to the surface, to dislodge bubbles that formed specifically on the interface between the disk and the disk-ring spacer. This approach was tested for the detection of chlorine during parallel chlorine and oxygen evolution, and resulted in a notable alteration of the collection efficiency; its value became lower than theoretical expectations and also quite stable, even under higher current densities. We also coated the RRDE tip in a hydrophilic polymer, to reduce the tendency of bubble formation; this was tested for the collection of hydrogen and oxygen gas, and led to a mild increase in overall performance. The coating allowed for approximately 50% higher hydrogen evolution current density without ring failure, and for oxygen collection led to an overall improvement in behaviour.