Surface redox catalysis and reduction kinetics of oxygen on copper–nickel alloys

SILVIA CERE; MARCELA VAZQUEZ; SUSANA R.DE SANCHEZ; DAVID J. SCHIFFRIN

JOURNAL OF ELECTROANALYTICAL CHEMISTRY

ELSEVIER

Año: 2001 vol. 505 p. 118 - 124

0022-0728

The reduction of oxygen on single phase Cu90Ni10 and Cu70Ni30 alloys in contact with 0.1 M borax at pH 9.2 has beeninvestigated. The rate constant measured is independent of alloy composition for steady-state measurements. When the currentsare measured in sweep experiments the current densities are larger for the alloy richer in nickel, indicating slow surface equilibriumprocesses. The value of n is 3.5
0.2 for pre-reduced electrodes in a wide potential range, from −1.5 to −0.8 V versus theHg
Hg2SO4
K2SO4 (sat) electrode. The proposed reduction mechanism involves a bifurcation between a direct and a sequentialmechanism involving O2 chemisorbed on Cu(0). © 2001 Elsevier Science B.V. All rights reserved.