Correlation of the Topology of the Electron Density of Pyrite-Type Transition Metal Sulfides with Their Catalytic Activity in Hydrodesulfurization

Aray, Yosslen; Rodríguez, Jesús; Vega, David; Rodríguez-Arias, Eloy Nouel

doi:10.1002/1521-3773(20001103)39:21<3810::aid-anie3810>3.0.co;2-n

Cited by 36 publications

(33 citation statements)

References 22 publications

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“…It is suggested the nature of these sites is intimately related to the metal-sulfur bond strength [16][17][18][19]. Basic studies support the idea that differences between catalytic activity is related to variations in the concentration of CUS (the Lewis acid sites), which in turn depend on the metal-sulfur bond strength [20][21][22][23][24][25][26][27][28][29][30][31]. Nickel (and cobalt)-promoted molybdenum sulfide catalysts have for many years been regarded as being among the most important catalysts used in refineries.…”

Section: An Application To Nanocatalyts -Exploring the Structure Of Tsupporting

confidence: 87%

“…Along the MoaS bond paths, both atoms have curved faces corresponding to MoaS bonds -concave in the basin of the molybdenum and convex in that of the sulfur. This result agrees with a transfer of electronic density from the Mo atom to the sulfur atom [1,31]. These basins display the full local point-group symmetry at the nuclear sites and fill the space without overlapping each other.…”

Section: Catalyst Modelsmentioning

confidence: 99%

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Atoms in Molecules Theory for Exploring the Nature of the Active Sites on Surfaces

Aray¹,

Rodríguez²,

Vega³

2007

The Quantum Theory of Atoms in Molecules

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The atoms in molecules theory provides a rigorous definition of chemical bonds for all types of molecules and solids [1][2][3][4][5][6][7][8][9][10] and has proven useful in analysis of the physical properties of insulators, pure metals, and alloys [4][5][6][7][8]. In particular, it has been observed that the strength of the bonding between a given pair of atoms in a molecule correlates with the values of the electron density at the bond critical point, r b [1]. A simple relationship between the binding energy and r b in periodic solids has also been reported [4,6,8]. The AIM theory also leads to unique partition of three-dimensional space into a collection of chemically identifiable regions called atomic basins (the atoms in a molecule or in a crystal). These are the most transferable pieces one can define in exhaustive partitioning of the real space [1]. In this chapter we describe the implementation of an algorithm that uses the r(r) topological information to determine the main elements of the AIM theory for periodic systems, and discuss an application to nanocatalysis. Implementing the Determination of the Topological Properties of r(r) from a Three-dimensional GridThe CPs are usually calculated using the Newton-Raphson (NR) technique [11]. The NR algorithm starts from a truncated Taylor expansion at a point r ¼ r 0 þ h, about r 0 of a multidimensional scalar function ð'rðrÞÞ:where H is the Hessian (the Jacobian of 'rðrÞÞ at point r 0 . The best step, h, to move from the initial r 0 to the CP is h ¼ ÀH À1 'rðr 0 Þ. This correction is then used to obtain a vector r new ¼ r old þ th (t is a small value) and the process is iter- 231The Quantum Theory of Atoms in Molecules. Edited

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Section: An Application To Nanocatalyts -Exploring the Structure Of Tsupporting

confidence: 87%

Section: Catalyst Modelsmentioning

confidence: 99%

Atoms in Molecules Theory for Exploring the Nature of the Active Sites on Surfaces

Aray¹,

Rodríguez²,

Vega³

2007

The Quantum Theory of Atoms in Molecules

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“…17,33,35,[37][38][39]66 Recently, the nature of the MoS 2 18 and NiMoS 67 catalyst edges using QTAIM was studied. Interestingly, it was found that potential active sites on the catalyst surface can be localized by direct visualization of the outermost surface atoms basin.…”

Section: Introductionmentioning

confidence: 99%

First Principles Study of Low Miller Index RuS₂Surfaces in Hydrotreating Conditions

et al. 2009

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Density functional theory (DFT) calculations combined with surface thermodynamic arguments and the Gibbs-Curie-Wulff equilibrium morphology formalism have been employed to explore the effect of the reaction conditions, temperature (T), and gas-phase partial pressures (p H 2 and p H 2 S ) on the stability of low Miller index ruthenium sulfide (RuS 2 ) surfaces. The calculated thermodynamic surface stabilities and the resulting equilibrium morphology models suggest that unsupported RuS 2 nanoparticles in HDS conditions are like to a polyhedron with six, eight, and twelve (100), (111), and (102) faces, respectively. The area of these faces covers about 40%, 37%, and 23% of the total particle, respectively. The atomic basins of the outermost individual atoms of the exposed surfaces were determined using the quantum theory of atoms in molecules methodology. Direct visualization of these basins has shown that a hole just at the middle of the outermost sulfur basins provides access to uncovered metal sites. Analysis of the electrostatic potential mapped onto a selected electron density isocontour (0.001 au) on the exposed surface reveals a very high potential reactivity of these holes toward electrodonating reagents. Consequently, the high attraction between these uncovered sites and S atoms coming from reagent polluting molecules makes these kinds of particles quite active for HDS catalysis.

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“…A clever connection of DFT calculations with industrial reactor design and catalyst selection for ammonia synthesis has been performed by Nørskov and coworkers [46]. Aray et al [47], using electron density topology of pyrite-type transition metal sulfides, explained the experimentally observed reactivity volcano curves. An improvement of the description of Pd(1 1 1) adhesion to ␣-Al 2 O 3 (0 0 0 1) has been carried out by Mattsson and Jennison [48] that computed accurate surface energies and showed the importance of electron self-energy in metal/metal-oxide adhesion.…”

Section: Ab Initio Methods In Catalysismentioning

confidence: 99%

Application of computational methods to catalytic systems

Ruette

Sanchéz²,

Sierraalta

et al. 2005

Journal of Molecular Catalysis A: Chemical

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Correlation of the Topology of the Electron Density of Pyrite-Type Transition Metal Sulfides with Their Catalytic Activity in Hydrodesulfurization

Cited by 36 publications

References 22 publications

Atoms in Molecules Theory for Exploring the Nature of the Active Sites on Surfaces

Atoms in Molecules Theory for Exploring the Nature of the Active Sites on Surfaces

First Principles Study of Low Miller Index RuS₂Surfaces in Hydrotreating Conditions

Application of computational methods to catalytic systems

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Correlation of the Topology of the Electron Density of Pyrite-Type Transition Metal Sulfides with Their Catalytic Activity in Hydrodesulfurization

Cited by 36 publications

References 22 publications

Atoms in Molecules Theory for Exploring the Nature of the Active Sites on Surfaces

Atoms in Molecules Theory for Exploring the Nature of the Active Sites on Surfaces

First Principles Study of Low Miller Index RuS2Surfaces in Hydrotreating Conditions

Application of computational methods to catalytic systems

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Product

Resources

About

First Principles Study of Low Miller Index RuS₂Surfaces in Hydrotreating Conditions