Ostwald ripening in a Pt/SiO2 model catalyst studied by in situ TEM
Ostwald ripening in a Pt/SiO2 model catalyst studied by in situ TEM
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DOI：
10.1016/j.jcat.2011.04.011
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发表时间：
2011-07
影响因子：
7.3
通讯作者：
S. Simonsen;I. Chorkendorff;S. Dahl;M. Skoglundh;J. Sehested;S. Helveg
中科院分区：
文献类型：
--
作者：
S. Simonsen;I. Chorkendorff;S. Dahl;M. Skoglundh;J. Sehested;S. Helveg
通过原位透射电子显微镜 (TEM) 研究了分散在平面 SiO2 载体上的 Pt 纳米粒子的烧结。 Pt 纳米颗粒暴露于 650 °C 10 mbar 合成空气中时获得的一系列延时 TEM 图像表明，烧结是由奥斯特瓦尔德熟化机制控制的。原位 TEM 图像还提供有关 Pt 粒径分布的时间演化以及单个纳米颗粒的生长或衰变的信息。观察到的 Pt 纳米颗粒变化与平均场动力学模型对成熟的预测相吻合，但单个纳米颗粒的时间演化存在偏差。通过动力学模型可以更好地描述单个纳米颗粒的成熟，该模型包括原子交换过程中相邻纳米颗粒之间的局部相关性。
Sintering of Pt nanoparticles dispersed on a planar SiO2support was studied byin situtransmission electron microscopy (TEM). A time-lapsed TEM image series of the Pt nanoparticles, acquired during the exposure to 10 mbar synthetic air at 650 °C, reveal that the sintering was governed by the Ostwald ripening mechanism. Thein situTEM images also provide information about the temporal evolution of the Pt particle size distribution and of the growth or decay of the individual nanoparticles. The observed Pt nanoparticle changes compare well with predictions made by mean-field kinetic models for ripening, but deviations are revealed for the time-evolution for the individual nanoparticles. A better description of the individual nanoparticle ripening is obtained by kinetic models that include local correlations between neighboring nanoparticles in the atom-exchange process.