Synthesis of small-sized intermetallic PtCo fuel cell catalysts by promoting inner surface utilization of carbon supports

Carbon-supported PtCo intermetallic nanoparticles are competitive low-platinum cathodic oxygen reduction reaction (ORR) catalysts for proton exchange membrane fuel cells (PEMFCs), but their synthesis needs high-temperature annealing that causes the catalyst to severely sinter. Here, we contrastively investigate the wet-impregnation and oleylamine-mediated colloid methods for the syntheses of PtCo intermetallic catalysts on various high-surface-area carbon supports with different porous structures. We identify that the efficient utilization of the internal surface area of porous carbon supports is crucial for the synthesis of small-sized PtCo intermetallic catalysts, which is highly dependent on the metal deposition method as well as the pore structure of the carbon supports. Accordingly, small-sized PtCo intermetallic catalysts with enhanced ORR activity and promoted PEMFC performance were prepared by the wet-impregnation method on mesoporous carbon supports.