A New Type of Strong Metal-Support Interaction Caused by Antimony Species

• 作者: A. Benhmid B. Lücke K. Edbey K. El Ttaib V. N. Kalevaru
• 来源期刊: 金属学报(美国)
• 学科: 化学
• 关键词: BET-SA and Pore Size Distribution TEM SMSI Effect Metal Oxide Supports TPR CO-Chemisorption SbOx Species
• 年，卷（期）: 2020,（2）
• 页码范围: 17-33
• 页数: 17页
• 分类号: O64

摘要

Interactions between metals and supports are of fundamental interest in heterogeneous catalysis, Noble metal particles supported on transition metal oxides (TMO) may undergo a so-called strong metal-support interaction via encapsulation. This perspective addresses catalytic properties of the metal catalysts in the SMSI state which can be explained on the basis of complementary studies. The electronic geometric and bifunctional effects originating from strong metal-support interactions (SMSI) that are responsible for the catalyst’s activity, selectivity, and stability are key factors that determine performance. A series of Pd-Sb supported on different metal oxide (<em>i.e.</em> SiO₂, <em>γ</em>-Al₂O₃, TiO₂, and ZrO₂) were prepared by the impregnation method. The catalysts were characterized by N₂ adsorption (BET-SA and pore size distribution), TEM (transmission electron microscope), TPR (temperature-programmed reduction), CO-chemisorption, the structural characterization of Pd (dispersity, surface area), interaction between Pd and Sb₂O₃ and also the influence of the nature of the support were investigated. SiO₂ supported Pd catalyst exhibited the highest surface area (192.6 m²/g) and pore volume (0.542 cm³/g) compared to the other supported oxides catalysts. The electron micrographs of these catalysts showed a narrow size particle distribution of Pd, but with varying sizes which in the range from 1 to 10 nm, depending on the type of support used. The results show almost completely suppressed of CO chemisorption when the catalysts were subjected to high temperature reduction (HTR), this suppression was overcome by oxidation of a reduced Pd/MeOx catalysts followed by re-reduction in hydrogen at 453 K low temperature reduction (LTR), almost completely restored the normal chemisorptive properties of the catalysts, this suppression was attributed by SbOx species by a typical SMSI effect as known f