Pt, PtNi and PtCoNi film electrocatalysts prepared by chemical vapor deposition for the oxygen reduction reaction in 0.5 M KOH

Pt, PtNi and PtCoNi films were deposited by metal-organic chemical vapor deposition (MOCVD) upon glassy carbon rods. Physical characterization was performed by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. It was found that films consisted of crystalline and nanometric particles with more than one phase as a result of the interactions among reactants, intermediate and product species during the chemical vapor deposition process. The electrochemical set-up to test the films for the oxygen reduction reaction was a three-electrode cell where the reference electrode was Hg/HgO/0.5 M KOH, the working electrodes were the films upon glassy carbon rods. The films were tested in 0.5 M KOH electrolyte; polarization curves were obtained by using the rotating disk electrode technique to evaluate the electrocatalytic activity of the prepared films. The kinetic parameters of Pt, PtNi and PtCoNi electrocatalysts were calculated. PtCoNi showed the best performance for the oxygen reduction reaction due to a synergetic effect of alloying Pt with transition metals.