Sintering of Pd Catalyst Particles on SiO2-TiO2 Carrier Particles of Different Mixing Ratios
Sintering of Pd Catalyst Particles on SiO2-TiO2 Carrier Particles of Different Mixing Ratios
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DOI：
10.1021/jp100763q
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发表时间：
2010-04
影响因子：
3.7
通讯作者：
A. Binder;M. Seipenbusch;G. Kasper
中科院分区：
文献类型：
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作者：
A. Binder;M. Seipenbusch;G. Kasper
在气相中，在几秒的时间尺度上，测量在二氧化硅、二氧化钛及其混合物上的几乎单分散的Pd模型催化剂颗粒的初始烧结速率作为温度的函数。支持粒子和活性相的合成气溶胶为基础的技术，允许高度的实验控制。有人发现，Pd颗粒烧结更慢的二氧化硅比二氧化钛。这归因于SiO2的较高表面粗糙度。向二氧化硅或二氧化钛中添加少量的第二氧化物相增加了表面粗糙度，因此也增加了Pd的热稳定性。这种效果对于二氧化钛来说更为明显。大量的第二氧化物相并没有进一步增强稳定性，因为发生相分离，并且在载体中形成具有相似表面形态的核-壳结构。
Initial sintering rates of nearly monodisperse Pd model catalyst particles on silica, titania, and mixtures thereof were measured as a function of temperature on the time scale of a few seconds in the gas phase. Support particles and active phase were synthesized by aerosol based techniques permitting a high degree of experimental control. It was found that Pd particles sintered more slowly on silica than on titania. This is attributed to the higher surface roughness of the SiO2. Adding a small amount of the second oxide phase to either silica or titania increased the surface roughness and thus also the thermal stability of the Pd. This effect was more pronounced for titania. High amounts of the second oxide phase did not further enhance the stability, because phase separation occurred and core−shell structures with similar surface morphologies were formed in the carriers.