Surfactant Assisted Catalyst Layer Deposition for PEM Fuel Cells

Abstract

The potentiostatic electrodeposition of platinum onto gold coated Si wafers and a gold rotating disk electrode (RDE) was carried out with non-ionic surfactants that functioned as templating agents to obtain mesoporous deposits with size features in the nanometer range. The particle size and morphology were studied by surface analysis (SEM and AFM). The electrochemically active surface area of Pt electrodeposited onto the RDE by using a mixture of Brij 56 and n-heptane was increased by a factor of ~2 compared to Pt deposited without structure directing additives. Corresponding oxygen reduction tests at 2500 rpm revealed an improvement of about 14 % (from 5.9 to 7.2 x 10-4 A cm-2) for the cathodic current density at 0.9 V vs. RHE while the mass transfer limited current density was increased by ~25 % from 4.4 to 5.5 x 10-3 A cm-2.