Voltammetric Studies of the Mechanism of the Oxygen Reduction in Alkaline Media at the Spinels Co3O4 and NiCo2O4. Issue 10 (3rd August 2016)

• Record Type: Journal Article
• Authors: Sönmez, Turgut; Thompson, Stephen J.; Price, Stephen W. T.; Pletcher, Derek; Russell, Andrea E.
• Is Part Of: Journal of the Electrochemical Society. Volume 163:Issue 10(2016)
• Page Start: H884
• Page End: H890
• Publication Date: 2016-08-03
• Subjects: Alkaline Electrolyte -- Oxygen Reduction -- RDE -- RRDE -- Spinel; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0111610jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : The mechanism of O2 reduction at the spinels, Co3 O4 and NiCo2 O4, in KOH electrolyte is probed using voltammetry at rotating disc and rotating ring-disc electrodes by examination of the rotation rate dependent limiting currents. The analysis shows that the products and mechanisms at the two spinels are quite different. At the cobalt spinel, a substantial amount of the 2e − reduction product, H2 O2, is formed while at NiCo2 O4 the 4e − reduction strongly predominates. In terms of both the overpotential for reduction and its limiting current density, the mixed spinel is a substantially better electrocatalyst. It is proposed that the differences arise from an enhanced rate of O-O bond cleavage early in the reduction process at NiCo2 O4 .