Comparative Study of Pt and PtCo Nanoparticle Catalysts on a Nitrogen-Doped Carbon Support in the Oxygen Reduction Reaction

Nitrogen-doped carbon materials are promising supports for synthesis of electrocatalysts used in low-temperature fuel cells. Pt/C and PtCo/C catalysts with different platinum weight fractions on a nitrogen-doped Ketjenblack EC-300J support have been obtained by the liquid-phase synthesis. The transmission electron microscopy study of the catalyst microstructure has shown that both materials exhibit a narrow size distribution of metallic nanoparticles and a low degree of their agglomeration. Study of the electrochemical behavior of the catalysts on a rotating disk electrode has shown that both materials significantly outperform their commercial counterparts in both the electrochemically active surface area and activity in the oxygen reduction reaction. It has been found that the maximum efficiency of a membrane-electrode assembly with the use of the obtained catalysts on the cathode is achieved at an ionomer/carbon weight ratio of 0.9. The peak powers of the membrane-electrode assemblies achieved using this ratio have been 652 and 666 mW/cm2 for mono- and bimetallic catalysts, respectively. The use of the obtained PtCo/C catalyst on the cathode of the membrane-electrode assembly allowed for an increase in its productivity by 8% as compared with its commercial counterpart.