Oxygen reduction in alkaline solution at glassy carbon surfaces and the role of adsorbed intermediates

Journal article

Oxygen reduction at glassy carbon (GC) exhibits distinctively different voltammetric behavior at high (> 10) and low (< 10) pH. The peak potential is found to be around − 0.4 V at pH 13, compared to − 0.6 V at pH 7.4 as measured against a saturated calomel reference electrode. Using experimental voltammetry and numerical simulation, the difference in peak potential is interpreted in terms of a difference in reaction mechanism. At low pH, O2 reduction is evidenced to proceed via a solution phase pathway initially resulting in the reduction of oxygen to superoxide. Conversely, at higher pH, a different mechanism is favored involving the formation of a surface bound superoxide species. The switch between the two mechanisms is related to the protonation of the surface bound intermediate under less basic conditions.

Authors: Zhang, H; Lin, C; Sepunaru, L; Batchelor-McAuley, C; Compton, R

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Journal of Electroanalytical Chemistry
• Volume: 799
• Pages: 53-60
• Publication date: 2017-05-22
• Acceptance date: 2017-05-21
• DOI: 10.1016/j.jelechem.2017.05.037
• EISSN: 1873-2569
• ISSN: 1572-6657
• Keywords: oxygen reduction; electrochemistry; electron transfer kinetics; carbon surfaces; adsorbed intermediates