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The commercialization of proton exchange membrane fuel cells (PEMFCs) relies on highly active and stable electrocatalysts for oxygen reduction reaction (ORR) in acid media. The most successful catalysts for this reaction are nanostructured Pt‐alloy with a Pt‐skin. The synthesis of ultrasmall and ordered L10‐PtCo nanoparticle ORR catalysts further doped with a few percent of metals (W, Ga, Zn) is reported. Compared to commercial Pt/C catalyst, the L10‐W‐PtCo/C catalyst shows significant improvement in both initial activity and high‐temperature stability. The L10‐W‐PtCo/C catalyst achieves high activity and stability in the PEMFC after 50 000 voltage cycles at 80 °C, which is superior to the DOE 2020 targets. EXAFS analysis and density functional theory calculations reveal that W doping not only stabilizes the ordered intermetallic structure, but also tunes the Pt‐Pt distances in such a way to optimize the binding energy between Pt and O intermediates on the surface. [ABSTRACT FROM AUTHOR]

The development of superior non-platinum electrocatalysts for enhancing the electrocatalytic activity and stability for the oxygen-reduction reaction (ORR) and liquid fuel oxidation reaction is very important for the commercialization of fuel cells, but still a great challenge. Herein, we demonstrate a new colloidal chemistry technique for making structurally ordered PdCu-based nanoparticles (NPs) with composition control from PdCu to PdCuNi and PtCuCo. Under the dual tuning on the composition and intermetallic phase, the ordered PdCuCo NPs exhibit better activity and much enhanced stability for ORR and ethanol-oxidation reaction (EOR) than those of disordered PdCuM NPs, the commercial Pt/C and Pd/C catalysts. The density functional theory (DFT) calculations reveal that the improved ORR activity on the PdCuM NPs stems from the catalytically active hollow sites arising from the ligand effect and the compressive strain on the Pd surface owing to the smaller atomic size of Cu, Co, and Ni. [ABSTRACT FROM AUTHOR]