Synthesis of OMC supported Pt catalysts and the effect of the metal loading technique on their PEM fuel cell performances.

Ordered mesoporous carbon (OMC) supported Pt catalysts were prepared by different loading techniques, in order to be used in the catalysis of oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells. OMC was synthesized by an organic-inorganic self assembly route using Pluronic F127 as surface directing agent, resorcinol-formaldehyde as carbon source and tetraethyl ortosilicate (TEOS) as silica source. Pt loading was achieved by three different approaches; one pot in situ synthesis, wet impregnation and surface-modified wet impregnation. Nitrogen adsorption studies showed slight reductions in surface areas, which can be attributed to partial losses of micropore volumes. The XRD and TEM analysis revealed a better metal distribution and smaller particle size in the surface-modified sample with a mean Pt particle size of 3.83 nm. The modified sample also gave the most promising performance among the catalysts with a maximum power density of 73 mW cm−2, which was very close to the commercial Pt/C catalyst. [ABSTRACT FROM AUTHOR]