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We report a simple route based upon seed‐mediated growth to the synthesis of Pd@AuxPd1−x (0.8≤x≤1) core–shell nanocubes. Benefiting from the well‐defined {100} facets and an optimal Au/Pd ratio for the surface, the nanocubes bearing a shell made of Au0.95Pd0.05 work as an efficient electrocatalyst toward H2O2 production, with high selectivity of 93–100 % in the low‐overpotential region of 0.4–0.7 V. When the Au0.95Pd0.05 alloy is confined to a shell of only three atomic layers in thickness, the electrocatalyst is able to maintain its surface structure and elemental composition, endowing continuous and stable production of H2O2 during oxygen reduction at a high rate of 1.62 mol g(Pd+Au)−1 h−1. This work demonstrates a versatile route to the rational development of active and durable electrocatalysts based upon alloy nanocrystals. [ABSTRACT FROM AUTHOR]

We report a facile synthesis of Ag@Pd core−shell icosahedral nanocrystals for the development of cost‐effective electrocatalysts toward formic acid oxidation. With 12.4 nm Ag icosahedra serving as seeds, Pd shells of controlled thicknesses in the range of 3.6–5.8 atomic layers are grown by adjusting the experimental parameters. When examined as catalysts toward formic acid oxidation, all the Ag@Pd nanocrystals exhibit enhanced mass activities relative to a commercial Pd/C catalyst, with the Ag@Pd4.2L nanocrystals showing enhanced mass activity that is almost twice that of a commercial Pd/C. The chronoamperometry measurements indicate that all the Ag@Pd/C catalysts are more robust than the Pd/C, with the catalyst based on Ag@Pd4.2L nanocrystals showing a mass activity greater than that of the pristine Pd/C after holding in a mixture of HCOOH and HClO4 at 0.75 V for 1,000 s. We believe that the strategy demonstrated here can also be extended to the development of other types of advanced electrocatalysts. [ABSTRACT FROM AUTHOR]

We report a new catalytic system by partially covering the uniform Pt nanocrystals on a carbon support with an ultrathin film derived from polyacrylonitrile (PAN). The use of Pt nanocrystals uniform in both size and shape effectively suppresses Ostwald repining, while partially covering them with a PAN‐derived film prevents migration, aggregation, and detachment from the support. In addition, the pyridinic N atoms on the edges of the thermally‐treated PAN film can also weaken the O=O bond, accelerating the reduction of oxygen. Upon optimization, the new catalyst exhibits a mass activity of 0.51 mA ⋅ μg−1Pt toward oxygen reduction, substantially enhanced relative to the same catalyst without PAN (0.22 mA ⋅ μg−1Pt) and a commercial Pt/C (0.41 mA ⋅ μg−1Pt). The mass activity is essentially retained after 10,000 cycles of accelerated durability test between 0.6 V and 1.1 V in oxygen‐saturated HClO4. Even after aging in H3PO4 at 220 °C for one week, the electrochemical surface area of the catalyst is still maintained. This catalytic system holds great promise for use in various types of fuel cells with a long lifetime. [ABSTRACT FROM AUTHOR]

The development of dual catalysts with high efficiency toward oxygen reduction and evolution reactions (ORR and OER) in acidic media is a significant challenge. Here an active and durable dual catalyst based upon cubic Pt39Ir10Pd11 nanocages with an average edge length of 12.3 nm, porous walls as thin as 1.0 nm, and well‐defined {100} facets is reported. The trimetallic nanocages perform better than all the reported dual catalysts in acidic media, with a low ORR‐OER overpotential gap of only 704 mV at a Pt‐Ir‐Pd loading of 16.8 µgPt+Ir+Pd cm−2geo. For ORR at 0.9 V, when benchmarked against the commercial Pt/C and Pt‐Pd nanocages, the trimetallic nanocages exhibit an enhanced mass activity of 0.52 A mg−1Pt+Ir+Pd (about four and two times as high as those of the Pt/C and Pt‐Pd nanocages) and much improved durability. For OER, the trimetallic nanocages show a remarkable mass activity of 0.20 A mg−1Pt+Ir at 1.53 V, which is 16.7 and 4.3 fold relative to those of the Pt/C and Pt‐Pd nanocages, respectively. These improvements can be ascribed to the highly open structure of the nanocages, and the possible electronic coupling between Ir and Pt atoms in the lattice. [ABSTRACT FROM AUTHOR]