Composition-Controlled PtCo Alloy Nanocubes with Tuned Electrocatalytic Activity for Oxygen Reduction
Composition-Controlled PtCo Alloy Nanocubes with Tuned Electrocatalytic Activity for Oxygen Reduction
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DOI：
10.1021/am301824w
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发表时间：
2012-11-01
影响因子：
9.5
通讯作者：
Park, Joon T.
中科院分区：
文献类型：
--
作者：
Choi, Sang-Il;Lee, Su-Un;Park, Joon T.
通过控制Pt合金纳米催化剂的形貌和组成来改变其电子结构和晶格收缩是提高其电催化氧还原反应（ORR）活性的关键问题。在本工作中，我们合成了PtCo合金纳米立方体与控制的组成（PtxCo NC，x = 2，3，5，7，和9）通过调节表面活性剂的比例和钴前体的量，以阐明纳米催化剂的组成对其ORR活性的影响。PtxCo纳米粒子在电化学处理后具有Pt皮结构。电催化实验表明，ORR活性和Co组成之间有很强的相关性。在各种PtxCo NC中，Pt 3Co NC表现出最佳的ORR性能。通过密度泛函理论计算，发现Pt 3Co纳米碳表面氧结合能（E-OB）与ORR活性之间存在典型的火山型关系，表明Pt 3Co纳米碳具有最佳的E-OB，从而获得最大的ORR活性. X射线光电子能谱（XPS）和X射线衍射（XRD）测试表明，PtxCo纳米碳的电子结构和晶格收缩可以通过控制纳米碳的组成来调节，这与E-OB的变化趋势高度相关。
Modification of the electronic structure and lattice contraction of Pt alloy nanocatalysts through control over their morphology and composition has been a crucial issue for improving their electrocatalytic oxygen reduction reaction (ORR) activity. In the present work, we synthesized PtCo alloy nanocubes with controlled compositions (PtxCo NCs, x = 2, 3, 5, 7, and 9) by regulating the ratio of surfactants and the amount of Co precursor to elucidate the effect of the composition of nanocatalysts on their ORR activity. PtxCo NCs had a Pt-skin structure after electrochemical treatment. The electrocatalysis experiments revealed a strong correlation between ORR activity and Co composition. Pt3Co NCs exhibited the best ORR performance among the various PtxCo NCs. From density functional theory calculations, a typical volcano-type relationship was established between ORR activity and oxygen binding energy (E-OB) on NC surfaces, which showed that Pt3Co NCs had the optimal E-OB to achieve the maximum ORR activity. X-ray photoelectron spectroscopy and X-ray diffraction measurements demonstrated that the electronic structure and lattice contraction of the PtxCo NCs could be tuned by controlling the composition of NCs, which are highly correlated with the trends of E-OB change.