Binary Pt-Me/C nanocatalysts: Structure and catalytic properties toward the oxygen reduction reaction

Pt/C, Pt 3 Ni/C, and Pt 2 Co/C nanocatalysts for oxygen electrochemical reduction reaction (ORR) were prepared using the borohydride wet synthesis method. The composition and structure of the catalysts were studied using the XRD method and X-ray fluorescence analysis (XRF) methods. It was found that the catalysts are nanostructured metallocomposites. The average diameter of platinum or alloy nanoparticles was 2.5–3.2 nm. The specific metal surface area determined using the carbon monoxide oxidative desorption (CO stripping) method increases in the series of Pt/C < Pt 3 Ni/C < Pt 2 Co/C from 30 to 38 m 2 /g of Pt. The rotating disk electrode (RDE) method was used to investigate the ORR kinetics on the studied electrodes. The limiting kinetic current, overall process rate constant, and reaction order were determined. The character of the obtained dependences allows us to conclude that the process rate of the electrodes with the studied catalytic systems is limited both by diffusion and by kinetic components. The binary catalysts are characterized by the same process mechanism with a slow stage of the first electron transfer as in the case of a pure platinum electrode. Herewith, the specific activity of nanostructured catalysts increases in the series Pt/C < Pt 3 Ni/C < Pt 2 Co/C.