Beyond γ-Al2O3 crystallite surfaces: The hidden features of edges revealed by solid-state 1H NMR and DFT calculations

被引：47

作者：

Batista, Ana T. F. ^{[1
]}

Wisser, Dorothea ^{[1
,2
,3
]}

Pigeon, Thomas ^{[1
]}

Gajan, David ^{[2
]}

Diehl, Fabrice ^{[1
]}

Rivallan, Mickael ^{[1
]}

Catita, Leonor ^{[1
]}

Gay, Anne-Sophie ^{[1
]}

Lesage, Anne ^{[2
]}

Chizallet, Celine ^{[1
]}

Raybaud, Pascal ^{[1
]}

机构：

[1] IFP Energies Nouvelles, F-69360 Solaize, France

[2] Univ Lyon, UCB Lyon 1, CNRS, ENS Lyon,Ctr RMN Tres Hauts Champs, F-69100 Villeurbanne, France

[3] Friedrich Alexander Univ Erlangen Nurnberg, Erlangen Catalysis Resource Ctr, D-91058 Erlangen, Germany

来源：

JOURNAL OF CATALYSIS | 2019年 / 378卷

关键词：

Alumina; Density functional theory; Edge; Hydroxyls; NMR spectroscopy; GAMMA-ALUMINA; CATALYTIC ALUMINAS; NMR-SPECTROSCOPY; HYDROXYL-GROUPS; PLATINUM; SITES; TRANSITION; DEPTH;

D O I：

10.1016/j.jcat.2019.08.009

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Elucidating the nature of high surface area gamma alumina sites is of great interest for numerous catalytic applications. In this work, the structural and spectroscopic features of edge sites are unravelled thanks to density functional theory (DFT) calculations combined with high field H-1 MAS NMR of two high surface area alumina samples exhibiting distinct morphologies. DFT chemical shift calculations were carried out for relevant surface models with different hydration degrees. However, the best assignment is achieved by considering the first DFT model representing the hydroxylated edges located at the intersection of (1 1 0) and (1 0 0) alumina facets. The sharp H-1 NMR peak at 0 ppm corresponds to mu(1)-OH groups which are located on this edge and are free from hydrogen bonding. Moreover, we show that these edge sites are the most reactive with respect to chlorine exchange. (C) 2019 Elsevier Inc. All rights reserved.

引用

页码：140 / 143

页数：4