The search for high-performance non-platinum (Pt) electrocatalysts is the most challenging issue for fuel cell technology. Creating bimetallic non-Pt nanocrystals (NCs) with core/shell structures or alloy features has widely been explored as the most effective way for enhancing their electrochemical properties but still suffered from undesirable performance due to the limited interactions between the different components. By addressing the above issue, we report on a new class of active and stable bimetallic non-Pt electrocatalysts with palladium (Pd) icosahedra as the core and nickel (Ni) decorating the surface toward cathodic oxygen reduction reaction (ORR) under alkaline conditions. The optimized Pd₆Ni icosahedra with unique interaction between an icosahedral Pd core and surface Ni yield the highest ORR activity with a mass activity of 0.22 A mg_Pd^-1, which is better than those of the conventional Pd₆Ni icosahedra with alloy surfaces or Pd-rich surfaces, and even two times higher than that of the commercial Pt/C (0.11 A mg_Pt^-1), representing one of the best non-Pt electrocatalysts. Simulations reveal that the Pd icosahedra decorated with Ni atoms emerged in the subsurface can weaken the interaction between the adsorbed oxygen and Pd (111) facet and enhance the ORR activities due to an obvious shift of d-band center. More significantly, under electrochemical accelerated durability test, the Pd₆Ni icosahedra can endure at least 10,000 cycles with negligible activity decay and structural change. The present work demonstrates an important advance in surface tuning of bimetallic NCs as high-performance non-Pt catalysts for catalysis, energy conversion, and beyond.

中文翻译：

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表面调制的钯镍二十碳六烯酸酯，是高性能的非铂氧还原电催化剂。

寻求高性能的非铂（Pt）电催化剂是燃料电池技术面临的最具挑战性的问题。广泛探索创建具有核/壳结构或合金特征的双金属非Pt纳米晶体（NCs），是增强其电化学性能的最有效方法，但由于不同组分之间的相互作用有限，仍然表现出不良的性能。通过解决上述问题，我们报告了一种新型的活性和稳定的双金属非Pt电催化剂，其以钯（Pd）二十面体为芯，镍（Ni）修饰了碱性条件下的表面，以实现阴极氧还原反应（ORR）。优化的Pd ₆二十面体Pd核与表面Ni之间具有独特相互作用的Ni二十面体Ni具有最高的ORR活性，其质量活度为0.22 A mg _Pd ^-1，优于具有合金表面或富Pd面的常规Pd ₆ Ni二十面体。 ，甚至比市售Pt / C（0.11 A mg _Pt ^-1）高出两倍，代表了最好的非Pt电催化剂之一。模拟结果表明，表面下出现有Ni原子修饰的Pd二十面体会削弱吸附的氧与Pd（111）晶面之间的相互作用，并由于d波段中心的明显移动而增强ORR活性。更重要的是，在电化学加速耐久性测试中，Pd ₆Ni icosahedra可以承受至少10,000个循环，而活性衰减和结构变化可忽略不计。本工作证明了双金属NC的表面调节方面的重要进展，作为用于催化，能量转化及其他方面的高性能非Pt催化剂。