Investigation of oxygen reduction in alkaline media on electrocatalysts prepared by the mechanical alloying of Pt, Co, and Ni

• Published in: Journal of applied electrochemistry 2015-10, Vol.45 (10), p.1101-1112
• Main Authors: García-Contreras, M. A., Fernández-Valverde, S. M., Basurto-Sánchez, R.
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Electrochemistry; Fuel cells; Industrial Chemistry/Chemical Engineering; Physical Chemistry; Research Article
• ISSN: 0021-891X; 1572-8838
• DOI: 10.1007/s10800-015-0870-8

Pt, PtCo, and PtNi electrocatalysts were prepared by mechanical alloying, and their activity for oxygen reduction reaction in 0.5 M KOH was investigated using cyclic voltammetry (CV) and rotating ring-disk electrode techniques. Electrocatalysts were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Physical characterization showed that all electrocatalysts are alloys in the form of agglomerated particles that consist of nanocrystals. To perform an electrocatalytic evaluation, polarization curves, Koutecky–Levich and Tafel plots were obtained to calculate the kinetic parameters. Additionally, the molar fraction of the generated HO 2 − and the number of transferred electrons were determined. PtCo alloy showed a better performance for oxygen reduction reaction with a higher exchange current density, a lower overpotential, as well as higher specific and mass activities due to a synergistic effect between Pt and Co atoms as a result of the alloying process.