Pt-Au-Co Alloy Electrocatalysts Demonstrating Enhanced Activity and Durability toward the Oxygen Reduction Reaction
Pt-Au-Co Alloy Electrocatalysts Demonstrating Enhanced Activity and Durability toward the Oxygen Reduction Reaction
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DOI：
10.1021/cs501710b
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发表时间：
2015-03-01
期刊：
影响因子：
12.9
通讯作者：
Mitlin, David
中科院分区：
文献类型：
--
作者：
Tan, XueHai;Prabhudev, Sagar;Mitlin, David
在这里，我们研究了氧还原反应的电催化活性和腐蚀稳定性的几个三元Pt-Au-Co和Pt-Ir-Co合金，与Pt-Au-Co以前从未研究过的ORR。添加Au微调晶格参数和表面电子结构，以实现在Pt-25原子% Co（现有技术的二元基线）中无法实现的活性和循环稳定性。Pt-2.5 atom % Au-25 atom % Co合金在0.95 V时的比活度为1.41 mA cm-2，比同成分合成的Pt-Co合金和纯Pt合金分别高16%和404%。这种增强是有前途的，在一系列以前公布的铂骨架和铂皮肤合金相比，事实上是最佳的报道的一个criminon型系统。随着Au或Ir取代水平的增加，催化剂显示出显著改善的腐蚀稳定性，在0.6-1.0 V的100，000次电位循环后，所有三元合金的比活性上级Pt-Co的比活性。例如，循环后的Pt-10原子% Au-25原子% Co显示出0.63 mA cm（-2）的比活性，比Pt-Co高140%，比Pt高439%。HRTEM和XPS表明，Au合金化促进形成原子级薄的Pt-Au-富表面层，这赋予动力学稳定对溶解的较低的贵溶质组分。
Here we investigate the oxygen reduction reaction electrocatalytic activity and the corrosion stability of several ternary Pt-Au-Co and Pt-Ir-Co alloys, with Pt-Au-Co having never been previously studied for ORR. The addition of Au fine tunes the lattice parameter and the surface electronic structure to enable activity and cycling stability that is unachievable in Pt-25 atom % Co (state-of-the-art binary baseline). The ternary alloys exhibit a volcano-type dependence of catalytic efficacy on the content of Au or Ir. Pt-2.5 atom % Au-25 atom % Co alloy shows a specific activity of 1.41 mA cm-2 at 0.95 V, which is 16% and 404% higher than those of identically synthesized Pt-Co and pure Pt, respectively. This enhancement is promising in comparison to a range of previously published Pt skeleton and Pt skin alloys and is in fact the most optimum reported for a skeleton-type system. The catalysts exhibit dramatically improved corrosion stability with increasing levels of Au or Ir substitution, with the specific activity of all the ternary alloys being superior to that of Pt-Co after 100,000 potential cycles of 0.6-1.0 V. For instance, postcycled Pt-10 atom % Au-25 atom % Co shows a specific activity of 0.63 mA cm(-2), which is 140% higher than that of Pt-Co and 439% higher than that of Pt. HRTEM and XPS shows that Au alloying promotes the formation of an atomically thin Pt-Au-rich surface layer, which imparts kinetic stabilization against the dissolution of the less noble solute component.