The high loading of precious metal Pt is one of the major obstacles which hinder the Proton exchange membrane fuel cells (PEMFCs)' commercialization. Core-shell or core-shell-like nanostructures with Pt shell supported on another cheaper metal (cheaper metal alloy) as a core element have shown higher utilization of noble metal Pt as well as higher specific activity. A chemical dealloying process (acid wash) to synthesize core-shell structure catalysts was used in the cathode of PEMFCs. Systematical studies of the effects of experiment parameters, including varieties and concentrations of acid, temperature, and the dealloying time, on the structures of final catalysts have been performed. HNO3 was proved to be more effective than H2SO4 in moving Cu out of the alloy surface. Moderate temperature and relatively short dealloying time were recommendable to avoid the aggregation of nanoparticles. Cyclic voltammetry (CV) and oxygen reduction reaction (ORR) polarization curves confirmed that the synthesized Cu@Pt/C catalysts had larger ECAs and higher specific activities than pure Pt/C. Moreover, this facile method could be used to produce large-scale core-shell structure catalysts. 

Synthesis of platinum-based core-shell structure catalysts by chemical dealloying process

247th National Meeting (2014)

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