Rational design of heterosynergistic active moieties can significantly improve the intrinsic activity and mechanistic understanding for electrolytic hydrogen evolution reaction (HER), especially crucial to precious platinum group catalysts. Here, we report an alloying Pt with Co atoms to achieve atomic-scale catalytic synergy via spontaneous electronic alteration, resulting in an excellent PtCo nanoalloy catalyst for hydrogen evolution reaction (HER) suitable in both acid and base media. The resultant porous carbon-supported PtCo nanoalloy catalyst enables superior HER performance with high Pt-mass activity, surpassing commercial Pt/C and most state-of-the-art catalysts reported. Combined experimental and theoretical studies reveal that the charge redistribution on adjacent Pt and Co atom sites in alloys optimizes their d-band center positions and creates dual-atomic synergistic active units for intermediate H* and OH* transfers, responsible for highly intrinsic HER activity, especially with water-dissociation activation in basic condition. This work not only develops a low Pt-content HER catalyst but also provides deep insights into synergy modulation for rational design of advanced catalysts.

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The hidden order of atomic packing in amorphous structures and how this may provide the origin of plastic events have long been a goal in the understanding of plastic deformation in metallic glasses. To pursue this issue, we employ here molecular dynamic simulations to create three-dimensional models for a few metallic glasses where, based on the geometrical frustration of the coordination polyhedra, we classify the atoms in the amorphous structure into six distinct species, where “gradient atomic packing structure” exists. The local structure in the amorphous state can display a gradual transition from loose stacking to dense stacking of atoms, followed by a gradient evolution of atomic performance. As such, the amorphous alloy specifically comprises three discernible regions: solid-like, transition, and liquid-like regions, each one possessing different types of atoms. We also demonstrate that the liquid-like atoms correlate most strongly with fertile sites for shear transformation, the transition atoms take second place, whereas the solid-like atoms contribute the least because of their lowest correlation level with the liquid-like atoms. Unlike the “geometrically unfavored motifs” model which fails to consider the role of medium-range order, our model gives a definite structure for the so-called “soft spots”, that is, a combination of liquid-like atoms and their neighbors, in favor of quantifying and comparing their number between different metallic glasses, which can provide a rational explanation for the unique mechanical behavior of metallic glasses.

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