A study on novel combined processes for preparation of high performance Pt–Co/C electrocatalyst for oxygen reduction in PEM fuel cell

The preparation of a Pt–Co/C electrocatalyst for the oxygen reduction reaction in PEM fuel cells was achieved via a novel combined process of impregnation and seeding. The effect of seeding and non-seeding approaches on the morphologies and activities of the electrocatalyst was explored. The results indicated that the seeding or non-seeding approaches provided the similar results of Pt structure and phase composition in the Pt–Co/C electrocatalyst. However, the seeding approach provided a more uniform dispersion and smaller particle size of electrocatalyst compared with that of the non-seeding approach. Also, higher values of kinetic parameters including i₀, E₀, i_0.9V and E_10mA/cm2 were obtained in case of seeding electrocatalyst. Finally, the rotating disk electrode experimental results showed that the mechanism of oxygen reduction involved the four-electron pathway.     

Preparation of a high performance Pt–Co/C electrocatalyst for oxygen reduction in PEM fuel cell via a combined process of impregnation and seeding

The preparation of a Pt–Co/C electrocatalyst for the oxygen reduction reaction in PEM fuel cells was achieved via a combined process of impregnation and seeding. The effects of initial pH of the precursor solution and Pt loading were all found to have a significant effect on both the electrocatalyst morphology and the cell performance when tested in a single PEM fuel cell. The optimum condition found for preparing the Pt–Co/C electrocatalyst was from an initial precursor solution pH of 2 at the metal loading of 23.6–30.3% (w/w). The Pt–Co/C electrocatalysts, formed under these optimal conditions, tested in a single PEM fuel cell with the carbon sub-layer, gave a cell performance of 772 mA/cm² or 460 mW/cm² at 0.6 V in a H₂/O₂ system. An electron pathway of oxygen reduction on the prepared Pt–Co/C electrocatalyst was also determined using a rotating disk electrode.