Effect of Particle Size of Platinum and Platinum-Cobalt Catalysts on Stability Against Load Cycling

Abstract

To investigate the effect of load cycling, platinum (Pt) and platinum-cobalt (PtCo) fuel cell catalysts with different particle sizes were prepared and evaluated for their durability against load cycling. The particle size of the Pt and PtCo catalysts was controlled by changing the catalyst loading and by applying heat treatment. Pt catalysts with particle sizes of 2–3 nm and 4–5 nm and PtCo catalysts with sizes of 3–4 nm, 4–5 nm and 7–8 nm were obtained. A potential sweep from 0.65 V to 1.05 V was applied to the cathode of membrane electrode assemblies (MEAs) prepared with these catalysts,and the degradation of their mass activity and cell voltage were evaluated. As a result of this investigation, it was found that Pt catalysts with particle sizes of 4–5 nm and PtCo catalysts of particle sizes 7–8 nm showed better stability against potential sweep, with the Pt catalysts of sizes 4–5 nm showing the best stability of all the catalysts tested.

Key findings

• ▸Pt catalysts with particle sizes of 2-3 nm showed lower stability against potential sweep.
• ▸PtCo catalysts with particle sizes of 3-4 nm showed moderate stability against potential sweep.
• ▸Pt catalysts with particle sizes of 4-5 nm showed the best stability of all the catalysts tested.

Keywords

Identifiers

DOI

10.1595/147106710x523698

Journal

Platinum Metals Review

Year

2010