Tomography and High-Resolution Electron Microscopy Study of Surfaces and Porosity in a Plate-like 纬-Al2O3

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• 作者：Libor Kovarik ; Arda Genc ; Chongmin Wang ; Annie Qiu ; Charles H. F. Peden ; J谩nos Szanyi ; Ja Hun Kwak
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：January 10, 2013
• 年：2013
• 卷：117
• 期：1
• 页码：179-186
• 全文大小：508K
• 年卷期：v.117,no.1(January 10, 2013)
• ISSN：1932-7455

文摘

Morphological and surface characteristics of 纬-Al₂O₃ are topics of high relevance in the field of catalysis. Using tomography and high-resolution transmission electron microscopy (TEM) imaging, we have studied the surface characteristics of a model 纬-Al₂O₃ synthesized in the shape of platelets and macroscopically defined by (110)_Al2O3 and (111)_Al2O3 surface facets. We show that the dominant (110)_Al2O3 surface of the synthesized 纬-Al₂O₃ is not atomically flat but undergoes a significant reconstruction, forming nanoscale (111)_Al2O3 facets. In addition to high-resolution imaging, tomographic analysis was carried out, enabling an examination of the pores/voids, which were found to be mostly enclosed within the bulk and inaccessible to gases or solvents carrying precursors for metal particles. Tomographic analysis shows that the surfaces of the pores are defined exclusively by (100)_Al2O3 and (111)_Al2O3 facets. The importance of these findings is discussed in the context of relative surface energies of low index surfaces and ethanol desorption characteristics.