Dealloying of Cobalt from CuCo Nanoparticles under Syngas Exposure
Dealloying of Cobalt from CuCo Nanoparticles under Syngas Exposure
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DOI：
10.1021/jp4000297
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发表时间：
2013-03-28
影响因子：
3.7
通讯作者：
Salmeron, Miguel
中科院分区：
文献类型：
--
作者：
Carenco, Sophie;Tuxen, Anders;Salmeron, Miguel
研究发现，在清洁预处理和常压下暴露于合成气（CO + H-2）时，核壳型CuCo纳米颗粒的结构和组成发生了变化。原位x射线吸收和光电子能谱显示了颗粒的氧化状态以及合成气下吸附物的存在。用透射电镜对反应后的形状、元素组成和结构进行了非原位分析。经纯O-2氧化和纯H-2还原预处理后，原核壳结构转变为空心CuCo合金。暴露于合成气30分钟后，相当一部分（5%）的颗粒在钴中被强烈耗尽，形成富铜纳米颗粒。这个分数随着合成气暴露时间的延长而增加，这种现象在纯CO或纯H-2下不会发生。该研究表明，Co和Cu各自都可以在CuCo催化剂下促进合成气的转化。
The structure and composition of core-shell CuCo nanoparticles were found to change as a result of cleaning pretreatments and when exposed to syngas (CO + H-2) at atmospheric pressure. In situ X-ray absorption and photoelectron spectroscopies revealed the oxidation state of the particles as well as the presence of adsorbates under syngas. Transmission electron microscopy was used for ex situ analysis of the shape, elemental composition, and structure after reaction. The original core-shell structure was found to change to a hollow CuCo alloy after pretreatment by oxidation in pure O-2 and reduction in pure H-2. After 30 min of exposure to syngas, a significant fraction (5%) of the particles was strongly depleted in cobalt giving copper-rich nanoparticles. This fraction increased with duration of syngas exposure, a phenomenon that did not occur under pure CO or pure H-2. This study suggests that Co and Cu can each individually contribute to syngas conversion with CuCo catalysts.