Pt-Cu合金纳米枝晶的合成及其氧还原催化性能

纳米材料的结构和化学成分对其催化性能的显著影响已经得到验证. 因此，本文通过一种简易的蚀刻方法，合成出具有均匀合金结构且尺寸和形貌均一的Pt-Cu纳米枝晶（NDs）作为高效氧还原（ORR）催化剂. 其树枝状形貌的形成得益于由Br^-/O₂氧化蚀刻剂引起的蚀刻效应. 通过改变Pt/Cu前驱体的比例可以容易地调节Pt-Cu NDs的Pt/Cu原子比，而不会使其树枝状形貌发生改变. 活性最高的碳载Pt₁Cu₁ NDs（Pt₁Cu₁ NDs/C）的面积比活性为1.17 mA·cm^-2@0.9V（vs. RHE），约为商业Pt/C的5.32倍. 此外，Pt₁Cu₁ NDs/C还具有卓越的电化学耐久性，即使在经过加速衰减实验的12000个电势循环后仍保持其优异的ORR催化活性. Pt₁Cu₁ NDs/C优异的ORR催化活性和电化学耐久性得益于由其合金结构和枝晶形貌产生的电子效应和结构效应.

Facile Synthesis of Pt-Cu Alloy Nanodendrites as High-Performance Electrocatalysts for Oxygen Reduction Reaction

Structures and compositions have significant effects on the catalytic properties of nanomaterials. Herein, a facile etching-based method was employed to synthesize Pt-Cu nanodendrites (NDs) with uniform and homogeneous alloy structures for enhancing oxygen reduction reaction (ORR). The formation of dendritic morphology was ascribed to the etching effect caused by the oxidative etchants of the Br^-/O₂ pair. The atomic ratio of Pt/Cu in Pt-Cu NDs could be easily tuned by altering the ratio of the Pt/Cu precursors, without deteriorating the dendritic morphology. The most active carbon-supported Pt₁Cu₁ NDs (Pt₁Cu₁ NDs/C) exhibited the area-specific activity of 1.17 mA·cm^-2@0.9 V (vs. RHE), which is ~5.32 times relative to that of commercial Pt/C. Moreover, Pt₁Cu₁ NDs/C also possessed a remarkable electrochemical durability, preserving its superior ORR catalytic activity even after 12000 potential cycles during the accelerated degradation test. Such excellent catalytic activity and electrochemical durability of Pt₁Cu₁ NDs/C toward ORR were resulted from the combined electronic and structural effects, which are imparted by the Pt-Cu alloy structure and the dendritic morphology.