Adsorption of Methanol on the MgO(100) Surface:  An Infrared Study at Room Temperature

Rudberg, Jennifer; Foster, Michelle

doi:10.1021/jp0468713

Cited by 21 publications

(25 citation statements)

References 41 publications

(78 reference statements)

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“…The total surface oxygen content of NanoMgO remained largely unaffected by dosing even for water exposure up to 1x10 6 L ( temperature. [59][60][61][62][63][64][65][66][67][68] In contrast, the surface oxygen concentration of NanoMgO-700 increased monotonically with water exposure, equating to a 2 % rise following 1x10 6 L. This corroborates the hypothesis that NanoMgO-700 is the more reactive surface reflecting its higher proportion of (111) facets and low coordination defects. [27,28] Further evidence for changes in surface oxygen species upon H2O adsorption was apparent from the corresponding high resolution O 1s spectra.…”

Section: Auger Parameter () = Ke (Auger E -From Photoelectron) + Be supporting

confidence: 74%

“…For this uncalcined parent material, it is possible that residual methoxide groups from the methoxide precursor used in its synthesis, coupled with the intrinsically weaker surface basicity of the (100) facets which predominate over these smaller oxide nanocrystals, hinder methanol adsorption and/or dissociation, the latter in accordance with previous studies over single crystal MgO(100) wherein vapour pressures >5 Torr were required to drive molecular adsorption. [67] As seen for water, methanol…”

Section: Scheme 3: Dissociation Of H2o Over Mg 2+ -O 2-dimersmentioning

confidence: 91%

“…Indeed, any observed adsorption over this facet appears due to the presence of low-coordinate defects on the oxide surface, as evidenced by studies in which defects are deliberately introduced through ion bombardment. [60,67] Efforts to study adsorption over the less stable/more electron-rich (111) surface [60,62,66,68,70] have proven problematic due to surface reconstruction resulting in a highly facetted termination. [71,72] In spite of this difficulty, adsorption studies over the highly stepped (111) surface which contains a high proportion of corner sites, [72] have provided a useful contrast to the comparatively atomically smooth (100) terraces.…”

Section: Methodsmentioning

confidence: 99%

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The surface chemistry of nanocrystalline MgO catalysts for FAME production: An in situ XPS study of H2O, CH3OH and CH3OAc adsorption

et al. 2016

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An in situ XPS study of water, methanol and methyl acetate adsorption over as-synthesised and calcined MgO nanocatalysts is reported with a view to gaining insight into the surface adsorption of key components relevant to fatty acid methyl esters (biodiesel) production during the transesterification of triglycerides with methanol. High temperature calcined NanoMgO-700 adsorbed all three species more readily than the parent material due to the higher density of electron-rich (111) and (110) facets exposed over the larger crystallites. Water and methanol chemisorb over the NanoMgO-700 through the conversion of surface O 2-sites to OH -and coincident creation of Mg-OH or Mg-OCH3 moieties respectively. A model is proposed in which the dissociative chemisorption of methanol occurs preferentially over defect and edge sites of NanoMgO-700, with higher methanol coverages resulting in physisorption over weakly basic (100) facets. Methyl acetate undergoes more complex surface chemistry over NanoMgO-700, with C-H dissociation and ester cleavage forming surface hydroxyl and acetate species even at extremely low coverages, indicative of preferential adsorption at defects.Comparison of C 1s spectra with spent catalysts from tributyrin transesterification suggest that ester hydrolysis plays a key factor in the deactivation of MgO catalysts for biodiesel production.

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Section: Auger Parameter () = Ke (Auger E -From Photoelectron) + Be supporting

confidence: 74%

Section: Scheme 3: Dissociation Of H2o Over Mg 2+ -O 2-dimersmentioning

confidence: 91%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The surface chemistry of nanocrystalline MgO catalysts for FAME production: An in situ XPS study of H2O, CH3OH and CH3OAc adsorption

et al. 2016

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“…This result has been seen in previously published work. 38,45 However, since ATR-FTIR only probes surfaces, we could only perform a direct comparison between the ionic liquid surface before and after exposure to the gas. For the case of methanol, the spectra show formation of a new spectral feature at 3250 cm À1 .…”

Section: Methodsmentioning

confidence: 99%

Computational and experimental study of the interactions between ionic liquids and volatile organic compounds

Gao

Andino

Álvarez-Idaboy

2010

Phys. Chem. Chem. Phys.

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Computational chemistry calculations were performed to investigate the interactions of ionic liquids with different classes of volatile organic compounds (VOCs), including alcohols, aldehydes, ketones, alkanes, alkenes, alkynes and aromatic compounds. At least one VOC was studied to represent each class. Initially, 1-butyl-3-methylimindazolium chloride (abbreviated as C(4)mimCl) was used as the test ionic liquid compound. Calculated interaction lengths between atoms in the ionic liquid and the VOC tested as well as thermodynamic data suggest that C(4)mimCl preferentially interacts with alcohols as compared to other classes of volatile organic compounds. The interactions of methanol with different kinds of ionic liquids, specifically 1-butyl-3-methylimidazolium bromine (C(4)mimBr) and 1-butyl-3-methylimidazolium tetrafluoroborate (C(4)mimBF(4)) were also studied. In comparing C(4)mimCl, C(4)mimBr, and C(4)mimBF(4), the computational results suggest that C(4)mimCl is more likely to interact with methanol. Laboratory experiments were performed to provide further evidence for the interaction between C(4)mimCl and different classes of VOCs. Fourier transform infrared spectroscopy was used to probe the ionic liquid surface before and after exposure to the VOCs that were tested. New spectral features were detected after exposure of C(4)mimCl to various alcohols. The new features are characteristic of the alcohols tested. No new IR features were detected after exposure of the C(4)mimCl to the aldehyde, ketone, alkane, alkene, alkyne or aromatic compounds studied. In addition, after exposing the C(4)mimCl to a multi-component mixture of various classes of compounds (including an alcohol), the only new peaks that were detected were characteristic of the alcohol that was tested. These experimental results demonstrated that C(4)mimCl is selective to alcohols, even in complex mixtures. The findings in this work provide information for future gas-phase alcohol sensor design.

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“…Metal oxides are commonly used as catalyzers or catalytic supports because of their chemical properties. Such is the case with the magnesium oxide MgO, used in the decomposition of methanol 1, 2, formic acid 3, or ethanol 4, among other reactions. MgO is a solid that crystallizes in rock salt structure.…”

Section: Introductionmentioning

confidence: 99%

Ab initio density functional study of MgO (001) surface with topological defects

Licona

Rivas-Silva

2005

Int J of Quantum Chemistry

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Magnesium oxide (MgO) is a useful material because of its catalyticalproperties. Moreover, surface defects have been found to play a crucial role in determining the activity and selectivity of catalytic surfaces. We present the results of a theoretical investigation of the electronic structure of the MgO (001) surface with three different topological defects. Our calculations are based on density functional theory (DFT) and the pseudopotential method. Slab geometry and periodic boundary conditions have been included with occupied orbitals expanded in plane waves. We compare the obtained results of the (001) MgO clean surface with those containing topological defects. The density of states DOS is analyzed in each case, as well as the chemical nature of the atoms belonging to the defects.

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Adsorption of Methanol on the MgO(100) Surface: An Infrared Study at Room Temperature

Cited by 21 publications

References 41 publications

The surface chemistry of nanocrystalline MgO catalysts for FAME production: An in situ XPS study of H2O, CH3OH and CH3OAc adsorption

The surface chemistry of nanocrystalline MgO catalysts for FAME production: An in situ XPS study of H2O, CH3OH and CH3OAc adsorption

Computational and experimental study of the interactions between ionic liquids and volatile organic compounds

Ab initio density functional study of MgO (001) surface with topological defects

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