Pd-Based nanoparticles are excellent alternatives to the typically used Pt-based materials that catalyze fuel cell reactions. Specifically, Pd-based intermetallic nanomaterials have shown great promise as electrocatalysts for the oxygen reduction reaction (ORR) in alkaline media; however, their synthesis remains a challenge and shape-controlled nanoparticles are limited. Here, a low-temperature approach to intermetallic Pd3Pb nanocubes is demonstrated and their electrocatalytic properties evaluated for the ORR. The intermetallic Pd3Pb nanocubes outperformed all reference catalysts, with a mass activity of 154 mA mgPd-1 which is a 130% increase in activity compared to the commercial Pd/C reference and a 230% increase compared to Pd nanocubes. Tafel analysis reveals that the Pd3Pb nanocubes are highly selective for the 4-electron reduction pathway, with minimal HO2- formation. Density functional theory (DFT) calculations show that the increased activity for the intermetallic nanocubes compared to Pd is likely due to the weakening of OH* adsorption, decreasing the required overpotential. These results show that intermetallic Pd3Pb nanocubes are highly efficient for the 4-electron pathway of the ORR and could inspire the study of other shape-controlled intermetallics as catalysts for fuel cell applications.

中文翻译：

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金属间化合物Pd3Pb纳米立方体对4-电子氧还原反应路径具有高选择性。

钯基纳米颗粒是催化燃料电池反应的常用铂基材料的极佳替代品。具体地说，钯基金属间化合物纳米材料作为在碱性介质中进行氧还原反应（ORR）的电催化剂具有广阔的前景。然而，它们的合成仍然是一个挑战，并且形状控制的纳米颗粒受到限制。在这里，展示了一种金属间Pd3Pb纳米立方体的低温方法，并评估了其对ORR的电催化性能。金属间化合物Pd3Pb纳米立方体的性能优于所有参比催化剂，其质量活性为154 mA mgPd-1，与商用Pd / C参比相比活性提高了130％，与Pd纳米立方体相比提高了230％。Tafel分析表明，Pd3Pb纳米立方体对4电子还原途径具有高度选择性，生成最少的HO2-。密度泛函理论（DFT）计算表明，与Pd相比，金属间纳米立方体的活性增加可能是由于OH *吸附作用减弱，从而降低了所需的超电势。这些结果表明，金属间化合物Pd3Pb纳米立方体对于ORR的4电子途径非常有效，并且可以激发其他形状受控的金属间化合物作为燃料电池应用催化剂的研究。