In situ observations of the structural dynamics of platinum–cobalt–hydroxide nanocatalysts under CO oxidation
In situ observations of the structural dynamics of platinum–cobalt–hydroxide nanocatalysts under CO oxidation
复制标题
CO氧化下铂钴氢氧化物纳米催化剂结构动力学的原位观察
DOI：
10.1039/c9nr10950a
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发表时间：
2020
期刊：
影响因子：
6.7
通讯作者：
Zhihu Sun
中科院分区：
文献类型：
--
作者：
Li Huang;Xueyang Song;Yue Lin;Chengyong Liu;Wenxue He;Siyu Wang;Zhixin Long;Zhihu Sun
金属催化剂的结构、组成和化学状态易于响应于反应条件而动态变化。在这项工作中，结合原位X射线吸收精细结构光谱和漫反射红外傅里叶变换光谱已被用来监测的温度依赖性的结构动力学在Pt-Co（OH）2纳米催化剂在CO氧化过程中。与供电子Co合金化可提高金属Pt对CO低温氧化的催化活性。在高温氧化气氛下，O2驱动Pt-Co合金偏析成氧化钴和铂金属，合金化程度从300 K时的约30%急剧下降到473 K时的0。高温还原可恢复Pt-Co合金的形成，且合金化程度相同。所观察到的结构动力学可以很好地与催化剂的动力学行为。这项工作强调了跟踪工作催化剂的动态结构变化的重要性，以正确理解其催化行为。
The structures, compositions and chemical states of metal catalysts are prone to dynamic changes in response to reaction conditions. In this work, a combination of in situ X-ray absorption fine structure spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy has been used to monitor the temperature-dependent structural dynamics in bimetallic Pt–Co(OH)2 nanocatalysts during CO oxidation. Alloying with electron-donating Co promotes the catalytic activity of metallic Pt for CO oxidation at low temperature. At elevated temperatures under an oxidation atmosphere, O2 drives the segregation of the Pt–Co alloy into cobalt oxide and platinum metal, with the extent of alloying sharply decreasing from ∼30% at 300 K to 0 at 473 K. Reduction at high temperature could recover the formation of the Pt–Co alloy with the same alloying extent. The observed structural dynamics could be well correlated with the kinetic behavior of the catalysts. This work highlights the importance of tracking the dynamic structural changes of working catalysts for a correct understanding of their catalytic behavior.