Particle size distributions in heterogeneous catalysts: What do they tell us about the sintering mechanism?
Particle size distributions in heterogeneous catalysts: What do they tell us about the sintering mechanism?
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DOI：
10.1016/j.cattod.2005.10.013
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发表时间：
2006-01-15
期刊：
影响因子：
5.3
通讯作者：
McCarty, JM
中科院分区：
文献类型：
--
作者：
Datye, AK;Xu, Q;McCarty, JM
在高达900 ℃的温度下处理负载型金属催化剂，烧结时间高达4000 h，并通过透射电子显微镜（TEM）、SEM和扫描透射电子显微镜（STEM）测定粒度分布。烧结条件的选择，使烧结机制的范围从奥斯特瓦尔德熟化颗粒迁移和聚结。以前的理论模型表明，向小颗粒倾斜的尺寸分布可以由奥斯特瓦尔德熟化产生，而具有长尾的尺寸分布朝向大颗粒只能来自颗粒迁移和聚结。我们的一些实验测量是在有利于奥斯特瓦尔德熟化的条件下进行的，而另一些是在有利于颗粒迁移和聚结的条件下进行的。在每种情况下，实验颗粒尺寸分布可以拟合对数正态分布，并且总是向右倾斜，尾部朝向较大的颗粒直径。因此，我们的结论是，没有推断烧结机制可以从粒度分布。(c)2005 Elsevier B.V.保留所有权利。
Supported metal catalysts were treated at temperatures up to 900 degrees C, and sintering times up to 4000 h and the particle size distributions were determined via transmission electron microscopy (TEM), SEM and scanning transmission electron microscope (STEM). Sintering conditions were chosen so that the mechanism of sintering would range from Ostwald ripening to particle migration and coalescence. Previous theoretical models have suggested that a size distribution skewed towards small particles can arise from Ostwald ripening, while a size distribution with a long tail towards large particles can only come from particle migration and coalescence. Some of our experimental measurements were performed under conditions that favor Ostwald ripening, while others were performed under conditions that favor particle migration and coalescence. In every instance, the experimental particle size distributions could be fitted to a log normal distribution, and were always skewed to the right, with a tail towards larger particle diameters. Hence, we conclude that no inference about sintering mechanism can be derived from the particle size distribution. (c) 2005 Elsevier B.V. All rights reserved.