Thermo-chemical metastability of multilayer epitaxial graphene oxide: Experiments and density functional theory calculations

2012 ◽  
Vol 1451 ◽  
pp. 39-44
Author(s):  
Si Zhou ◽  
S. Kim ◽  
Y. Hu ◽  
C. Berger ◽  
W. de Heer ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Graphene Oxide ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Epitaxial Graphene ◽  
Great Promise ◽  
Hydroxyl Groups ◽  
Minimal Amount ◽  
Multilayer Graphene ◽  
Functional Theory

ABSTRACTGraphene oxide holds great promise for future applications in nano-technology. The chemistry of this material is not well understood. This understanding is crucial to enable future applications of graphene oxide. In this study, experiments and density functional theory calculations are combined to elucidate the chemical properties of multilayer graphene oxide obtained by oxidizing epitaxial graphene grown on silicon carbide via the Hummers method. This study shows that at room temperature as prepared graphene oxide films exhibit a uniform and homogeneous structure, include a minimal amount of edges and holes, and have an oxidation ratio of about 0.44. The comparison with density-functional calculations shows that graphene oxide includes a minimal amount of intercalated water molecules and well-defined fractions of epoxide and hydroxyl groups.

Ammonia Dissociation on Graphene Oxide: An Ab Initio Density Functional Theory Calculation

2015 ◽  
Vol 229 (7-8) ◽  
Author(s):  
Liangliang Huang ◽  
Keith E. Gubbins
Keyword(s):  
Density Functional Theory ◽  
Graphene Oxide ◽  
Ab Initio ◽  
Functional Groups ◽  
Density Functional ◽  
Density Functional Theory Calculation ◽  
Exothermic Reaction ◽  
Density Functional Theory Method ◽  
Hydroxyl Groups ◽  
Functional Theory

AbstractInteractions of ammonia and water with the oxygen-containing functional groups of graphite oxide have been studied by ab initio density functional theory method. The results show that ammonia can dissociate on the carboxyl, epoxy and hydroxyl groups. The dissociation on the epoxy group is an exothermic reaction with a small activation energy barrier. Water is found to form a hydrogen bond with the carboxyl, epoxy and hydroxyl groups, and thus will block ammonia from interacting with those functional groups. The results in this work provide a fundamental understand of previous experiments about ammonia adsorption on graphene oxide materials.

scholarly journals Catalytic water dissociation by greigite Fe 3 S 4 surfaces: density functional theory study

2016 ◽  
Vol 472 (2188) ◽  
pp. 20160080 ◽  
Author(s):  
A. Roldan ◽  
N. H. de Leeuw
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Iron Sulfide ◽  
Density Functional Theory Calculations ◽  
Sulfide Mineral ◽  
Water Dissociation ◽  
Molecular Adsorption ◽  
Hydroxyl Groups ◽  
Functional Theory ◽  
Production Of Hydrogen

The iron sulfide mineral greigite, Fe 3 S 4 , has shown promising capability as a hydrogenating catalyst, in particular in the reduction of carbon dioxide to produce small organic molecules under mild conditions. We employed density functional theory calculations to investigate the {001},{011} and {111} surfaces of this iron thiospinel material, as well as the production of hydrogen ad-atoms from the dissociation of water molecules on the surfaces. We systematically analysed the adsorption geometries and the electronic structure of both bare and hydroxylated surfaces. The sulfide surfaces presented a higher flexibility than the isomorphic oxide magnetite, Fe 3 O 4 , allowing perpendicular movement of the cations above or below the top atomic sulfur layer. We considered both molecular and dissociative water adsorption processes, and have shown that molecular adsorption is the predominant state on these surfaces from both a thermodynamic and kinetic point of view. We considered a second molecule of water which stabilizes the system mainly by H-bonds, although the dissociation process remains thermodynamically unfavourable. We noted, however, synergistic adsorption effects on the Fe 3 S 4 {001} owing to the presence of hydroxyl groups. We concluded that, in contrast to Fe 3 O 4 , molecular adsorption of water is clearly preferred on greigite surfaces.

scholarly journals Structure Characterization of [N-Phenylamino(2-boronphenyl)-R-methyl]phosphonic Acid by Vibrational Spectroscopy and Density Functional Theory Calculations

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Natalia Piergies ◽  
Edyta Proniewicz
Keyword(s):  
Density Functional Theory ◽  
Fourier Transform ◽  
Phosphonic Acid ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Density Functional Theory Calculations ◽  
Structure Characterization ◽  
Hydroxyl Groups ◽  
Functional Theory ◽  
Ft Ir

We present the first Fourier-transform infrared absorption (FT-IR) and Fourier-transform Raman (FT-Raman) analysis of vibrational structure of [N-phenylamino(2-boronphenyl)-R-methyl]phosphonic acid ([PhN-(2-PhB(OH)2)-R-Me]PO3H2). Assignments of experimental wavenumbers are based on performed theoretical calculations using density functional theory (DFT). Theoretical calculations show that the most stable structure of the investigated molecule is dimer incis-transconformation created by a pair of intermolecular hydrogen bonds between the boron hydroxyl groups of two monomers.

scholarly journals Doping of epitaxial graphene by direct incorporation of nickel adatoms

Nanoscale ◽  
2019 ◽  
Vol 11 (21) ◽  
pp. 10358-10364 ◽  
Author(s):  
Virginia Carnevali ◽  
Laerte L. Patera ◽  
Gianluca Prandini ◽  
Matteo Jugovac ◽  
Silvio Modesti ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Scanning Tunneling Microscopy ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Epitaxial Graphene ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Functional Theory ◽  
Direct Incorporation

Ni adatoms incorporated in epitaxial graphene during growth on Ni(111) are identified by scanning tunneling microscopy and density functional theory calculations.

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