Dealloyed Pt-based core-shell catalysts

Dealloyed Pt-Based Core-Shell Catalysts for Oxygen Reduction... 

Figure 3.3.14 displays the results of voltammetric ORR activity measurements of a dealloyed Pt-Cu and a dealloyed Pt-Ni core-shell catalyst under fuel cell relevant conditions. The typical sigmoidal current density electrode potential (i-E) shape (compare to Figure 3.3.10B) of the Pt-based catalyst is clearly evident. The large... 

We have reviewed the family of dealloyed Pt-based nanoparticle electrocatalysts for the electroreduction of oxygen at PEMFC cathodes, which were synthesized by selective dissolution of less-noble atoms from Pt alloy nanoparticle precursors. The dealloyed PtCua catalyst showed a promising improvement factor of 4-6 times on the Pt-mass ORR activity compared to a state-of-the-art Pt catalyst. The highly active dealloyed Pt catalysts can be implemented inside a realistic MEA of PEMFCs, where an in situ voltammetric dealloying procedure was used to constructed catalytically active nanoparticles. The core-shell structural character of the dealloyed nanoparticles was cmifirmed by advanced STEM and elemental line profile analysis. The lattice-contracted transition-metal-rich core resulted in a compressive lattice strain in the Pt-rich shell, which, in turn, favorably modified the chemisorption energies and resulted in improved ORR kinetics. 

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