Pd and Pd-Co Oxygen Reduction Nanocatalysts in Acidic Media

• Published in: International journal of electrochemical science 2012-08, Vol.7 (8), p.7140-7151
• Main Authors: Martínez, Adarely Velasco, Rodríguez, Miguel Torres, Arzaluz, Mirella Gutiérrez, del Ángel Vicente, Paz, Feria, Omar Solorza
• Format: Article
• Language: English
• Subjects: electrocatalysts; nanoparticles; oxygen reduction reaction (ORR); Pd-Co
• ISSN: 1452-3981; 1452-3981
• DOI: 10.1016/S1452-3981(23)15774-9

Palladium (Pd) and palladium-cobalt (Pd-Co) nanocatalysts were successfully synthesized by the chemical reduction method and characterized for the molecular oxygen reduction reaction (ORR) in acid medium. Both Pd and Pd-Co nanoparticles were prepared by the chemical reduction of palladium (II) chloride, PdCl2, and cobalt (II) chloride, CoCl2, as precursors and polyvinylpyrrolidine (PVP) as a protecting agent. The synthesized Pd/C and Pd-Co/C materials were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Results conducted to the formation of bimetallic nanoparticles with an average size of 5 to 12 nm and a good dispersion of Pd-Co on carbon, as well as the formation of some nano-sized clusters particles. The crystallographic planes identified as (111) and a (200) corresponds to the formation of face-centered cubic (FCC) Pd with nanocrystalline structure. The nanocatalyst were supported on Vulcan® carbon XC-72 by the impregnation method and their electrochemical activity for the ORR was evaluated by cyclic voltammetry and rotating disk electrode techniques. The obtained results demonstrated that the Pd-based catalysts promoted the activity toward the ORR through a multi-electron charge transfer mechanism for the oxygen reduction to water formation.