Ethylene glycol interaction on alkaline earth oxides: A periodic DFT study

被引：16

作者：

Calatayud, Monica ^{[1
,2
]}

机构：

[1] Univ Paris 06, UPMC, UMR 7616, Chim Theor Lab, F-75005 Paris, France

[2] CNRS, UMR 7616, Chim Theor Lab, F-75005 Paris, France

来源：

CATALYSIS TODAY | 2010年 / 152卷 / 1-4期

关键词：

Diol; Alcohol; Basic catalyst; INITIO MOLECULAR-DYNAMICS; AUGMENTED-WAVE METHOD; METAL-OXIDES; MGO; ADSORPTION; BASICITY; SURFACES; CAO; CATALYSTS; WATER;

D O I：

10.1016/j.cattod.2009.08.011

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

The present paper describes the interaction of ethylene glycol CH(2)OH-CH(2)OH with alkaline earth oxide basic catalysts MO (M = Mg, Ca, Sr, Ba) from periodic DFT calculations. The geometry of adsorption depends on the nature of the metallic site: on MgO the alcohol groups bind to the metal sites on quasi-top positions, while on CaO, Sr and BaO the molecule is located on bridging positions. The adsorption is exothermic and the strength correlates with the basicity of the alkaline earth oxide, the more basic the substrate, the more exothermic the adsorption energy: MgO < CaO < SrO < BaO. The glycol molecule deprotonates to form surface alkoxy groups bound to the metal sites. The extent of such deprotonation is also correlated to the basicity of MO:Mg (completely protonated) < CaO (partially protonated) < SrO (completely deprotonated) = BaO (completely deprotonated). Defects, modeled for a stepped CaO slab, are found to enhance the strength of the interaction and the deprotonation extent, inducing a different adsorption mode. The step is found to be more reactive than the most basic BaO regular surface, in agreement with experimental observations on glycerol. The implications of these aspects in chemical reactivity are discussed. (C) 2009 Elsevier B.V. All rights reserved.

引用

页码：88 / 92

页数：5

共 22 条

[1] A spectroscopy and catalysis study of the nature of active sites of MgO catalysts: Thermodynamic Bronsted basicity versus reactivity of basic sites [J].

Bailly, ML ;

Chizallet, C ;

Costentin, G ;

Krafft, JM ;

Lauron-Pernot, H ;

Che, M .

JOURNAL OF CATALYSIS, 2005, 235 (02) :413-422

[2] PROJECTOR AUGMENTED-WAVE METHOD [J].

BLOCHL, PE .

PHYSICAL REVIEW B, 1994, 50 (24) :17953-17979

[3] Electron-count control on adsorption upon reducible and irreducible clean metal-oxide surfaces [J].

Calatayud, M ;

Markovits, A ;

Minot, C .

CATALYSIS TODAY, 2004, 89 (03) :269-278

[4] Adsorption on perfect and reduced surfaces of metal oxides [J].

Calatayud, M ;

Markovits, A ;

Menetrey, M ;

Mguig, B ;

Minot, C .

CATALYSIS TODAY, 2003, 85 (2-4) :125-143

[5] Theoretical Study on the Role of Surface Basicity and Lewis Acidity on the Etherification of Glycerol over Alkaline Earth Metal Oxides [J].

Calatayud, Monica ;

Ruppert, Agnieszka M. ;

Weckhuysen, Bert M. .

CHEMISTRY-A EUROPEAN JOURNAL, 2009, 15 (41) :10864-10870

[6] Dynamic ion pairs in the adsorption of isolated water molecules on alkaline-earth oxide (001) surfaces [J].

Carrasco, Javier ;

Illas, Francesc ;

Lopez, Nuria .

PHYSICAL REVIEW LETTERS, 2008, 100 (01)

[7]

Chizallet C, 2006, J PHYS CHEM B, V110, P15878, DOI [10.1021/jp060840l, 10.1021/jp0608401]

[8] Optimization of alkaline earth metal oxide and hydroxide catalysts for base-catalyzed reactions [J].

Corma, A ;

Iborra, S .

ADVANCES IN CATALYSIS, VOL 49, 2006, 49 :239-302

[9] Water on extended and point defects at MgO surfaces [J].

Costa, D. ;

Chizallet, C. ;

Ealet, B. ;

Goniakowski, J. ;

Finocchi, F. .

JOURNAL OF CHEMICAL PHYSICS, 2006, 125 (05)

[10] A density functional study of water and methanol chemisorption on MgO(110) [J].

Gay, ID ;

Harrison, NM .

SURFACE SCIENCE, 2005, 591 (1-3) :13-22

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