Surface alloying of Pt monolayer on nanoporous gold for enhanced oxygen reduction
Surface alloying of Pt monolayer on nanoporous gold for enhanced oxygen reduction
复制标题
纳米多孔金上 Pt 单层的表面合金化增强氧还原
DOI：
10.1016/j.electacta.2018.04.067
复制
发表时间：
2018
影响因子：
6.6
通讯作者：
Ding Yi
中科院分区：
文献类型：
--
作者：
Zhao Yang;Zhang Weiqing;Yin Huiming;He Jia;Ding Yi
引入稳定元素如Au已被认为是增加Pt电催化剂对氧还原反应（ORR）的耐久性的有效途径。然而，由于Au核上的Pt层的约3.8%的拉伸应变，与天然Pt相比，该系统中涉及的显著拉伸应变导致其固有ORR活性的不期望的降低。在这项工作中，我们证明，对于核-壳结构的Pt单层纳米多孔金（NPG），电化学电位循环可以诱导PtAu表面合金的形成，这导致其ORR活性的意想不到的改善。理论计算表明，Pt Au表面合金具有更合适的配置，使相对较低的变化的自由能为相应的过电位决定步骤在ORR相对于Pt单层Au。纳米多孔金属基电极由于具有良好的氧化还原性能和铂的高利用率，在绿色能源技术中具有广阔的应用前景。
The introduction of stabilizing elements, such as Au, has been recognized as an effective approach to increasing the durability of Pt electrocatalysts toward oxygen reduction reaction (ORR). However, significant tensile strain involved in this system leads to an undesirable decrease of its intrinsic ORR activity as compared to the native Pt, due to a ∼3.8% tensile strain of Pt layer on Au core. In this work, we demonstrate that for a core-shell structured Pt monolayer on nanoporous gold (NPG), electrochemical potential-cycling can induce PtAu surface alloy formation, which results in unexpected improvement of its ORR activity. Theoretical calculations suggest that PtAu surface alloys possess more suitable configurations that give relatively low changes of free energy for the corresponding overpotential-determining step during ORR relative to Pt monolayer on Au. The improved ORR performance and high utilization of Pt make the nanoporous metal-based electrodes promising for green energy technologies.