Highly Stable Pt/Ordered Graphitic Mesoporous Carbon Electrocatalysts for Oxygen Reduction

Abstract

In this manuscript, we have synthesized a stable fuel cell catalyst composed of presynthesized Pt nanocrystals (<4 nm) on graphitic mesoporous carbon. The catalyst shows negligible loss in mass activity and active surface area after an accelerated durability test (1000 cycles, 0.5-1.2 V), whereas the commercial Pt on amorphous carbon loses similar to 70% in activity and area. Strong Pt graphite interactions, resulting from metal/support orbital overlap (pi-backbonding) coupled with partial charge transfer, as shown by XPS, and a low coverage of weakly bound ligands on the Pt surface facilitated high dispersion and loadings up to 20 wt %. The high oxidation resistance of the graphitized carbon, along with the strong Pt-C interactions, helped to maintain electrical contact between the metal and carbon while mitigating Pt dissolution, ripening, and coalescence. The ability to disperse well-defined metal nanoparticles onto graphitic mesoporous carbon offers the potential for creating highly stable and active catalysts.