Carbon-supported Pt catalysts were prepared using NaBH
4 as a reducing agent in either ethylene glycol or water for use as a cathode catalyst in PEMFCs (polymer electrolyte membrane
fuel cells). Aqueous NaBH
4 solution was used to reduce Pt precursor and to produce the Pt-W catalyst, while Pt-E and Pt-E-base catalysts were synthesized
using NaBH
4 in ethylene glycol for the reduction of Pt. Compared to Pt-W catalyst, Pt-E and Pt-E-base catalysts have higher Pt dispersion
and larger EAS (electrochemically active surface area) due to the stabilizing effect of ethylene glycolic NaBH
4 solution on Pt particles. In addition, increasing pH of the preparation solution improved the Pt dispersion (Pt-E-base).
In unit cell tests the performance of Pt catalysts decreased in the following order: Pt-E-base > Pt-E > Pt-commercial > Pt-W.
Higher metal dispersion and larger EAS are believed to be responsible for the superior performance of Pt-E catalysts, particularly
Pt-E-base, compared to other catalysts.
Keywords Supported Pt catalyst - pH - Dispersion - Ethylene glycol - PEMFC