INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
artículos
Título:
Oxygen reduction on cu-zn alloys
Autor/es:
R. PROCACCINI,; S. CERÉ; M. VÁZQUEZ
Revista:
JOURNAL OF APPLIED ELECTROCHEMISTRY
Editorial:
Springer
Referencias:
Año: 2008 p. 1 - 8
ISSN:
0021-891X
Resumen:
The reduction of oxygen on brass type Cu77Zn21Al2
in contact with 0.1 mol L-1 borax at pH 9.2 with
and without chlorides was investigated and compared with
the results on spectroscopic Cu. The surface film was
characterized in situ by means of reflectance spectroscopy
and by electrochemical impedance in the potential range
negative to the open circuit potential. The main parameters
associated to the kinetics of the oxygen reduction reaction
were analyzed with a rotating disc electrode. The results
show that within the potentials studied, a porous film was
formed on brass while no significant spectral features were
observed, except at -1.2 V where zinc oxo-hydroxides
grow in chloride-free solutions and dissolve when chlorides
are present in the system. The number of electrons
exchanged for brass was close to 4 in both solutions,
showing that oxygen is predominantly reduced to hydroxyl
ions, with a reaction order equal to one. The residual
presence of oxides on the surface results in Koutecky
Levich plots with slopes dependent on the applied potential
and interfere with the calculation of the Tafel slope.-1 borax at pH 9.2 with
and without chlorides was investigated and compared with
the results on spectroscopic Cu. The surface film was
characterized in situ by means of reflectance spectroscopy
and by electrochemical impedance in the potential range
negative to the open circuit potential. The main parameters
associated to the kinetics of the oxygen reduction reaction
were analyzed with a rotating disc electrode. The results
show that within the potentials studied, a porous film was
formed on brass while no significant spectral features were
observed, except at -1.2 V where zinc oxo-hydroxides
grow in chloride-free solutions and dissolve when chlorides
are present in the system. The number of electrons
exchanged for brass was close to 4 in both solutions,
showing that oxygen is predominantly reduced to hydroxyl
ions, with a reaction order equal to one. The residual
presence of oxides on the surface results in Koutecky
Levich plots with slopes dependent on the applied potential
and interfere with the calculation of the Tafel slope.-1.2 V where zinc oxo-hydroxides
grow in chloride-free solutions and dissolve when chlorides
are present in the system. The number of electrons
exchanged for brass was close to 4 in both solutions,
showing that oxygen is predominantly reduced to hydroxyl
ions, with a reaction order equal to one. The residual
presence of oxides on the surface results in Koutecky
Levich plots with slopes dependent on the applied potential
and interfere with the calculation of the Tafel slope.