Role of Steps in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">N</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Activation on Ru(0001)

Dahl, Søren; Logadóttir, Áshildur; Egeberg, Rasmus; Larsen, Jørgen Hannover; Chorkendorff, Ib; Törnqvist, E.; Nørskov, Jens K.

doi:10.1103/physrevlett.83.1814

Cited by 751 publications

(556 citation statements)

References 22 publications

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“…19 Recently, the same sites (B 5 ) were shown to have analogous properties in Ru nanoparticles, 10 and the concentration of these sites has been correlated with particle size.…”

Section: Introductionmentioning

confidence: 99%

Exploring the phase space of time of flight mass selected Pt_xY nanoparticles

Masini

Hernández-Fernández

Deiana³

et al. 2014

Phys. Chem. Chem. Phys.

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Mass-selected nanoparticles can be conveniently produced using magnetron sputtering and aggregation techniques. However, numerous pitfalls can compromise the quality of the samples, e.g. double or triple mass production, dendritic structure formation or unpredicted particle composition. We stress the importance of transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS) for verifying the morphology, size distribution and chemical composition of the nanoparticles. Furthermore, we correlate the morphology and the composition of the Pt x Y nanoparticles with their catalytic properties for the oxygen reduction reaction. Finally, we propose a completely general diagnostic method, which allows us to minimize the occurrence of undesired masses.

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“…19 Recently, the same sites (B 5 ) were shown to have analogous properties in Ru nanoparticles, 10 and the concentration of these sites has been correlated with particle size.…”

Section: Introductionmentioning

confidence: 99%

Exploring the phase space of time of flight mass selected Pt_xY nanoparticles

Masini

Hernández-Fernández

Deiana³

et al. 2014

Phys. Chem. Chem. Phys.

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“…Model surfaces of the face-centered cubic crystal (fcc{211}) were used to represent the step sites, which was found to be the important active site for a number of catalytic reactions. 15,16,17,18 A (1×2) cell with 10 atomic layers in the (211) direction corresponding to 3 layers in the closepacked (111) direction was used to model the adsorbate-metal structures. The atoms in the bottom 7 layers of the slab were fixed to their bulk positions, while the atoms in the top 3 layers were allowed to relaxation during the calculations.…”

Section: Abstract Density Functional Theory -Stepped Surfaces -Couplimentioning

confidence: 99%

Universal Brønsted-Evans-Polanyi Relations for C–C, C–O, C–N, N–O, N–N, and O–O Dissociation Reactions

Temel²,

et al. 2010

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It is shown that for all the essential bond forming and bond breaking reactions on metal surfaces, the reactivity of the metal surface correlates linearly with the reaction energy in a single universal relation. Such correlations provide an easy way of establishing trends in reactivity among the different transition metals. Keywords Density Functional Theory -Stepped surfaces -Coupling reactions -Bond breaking reactions -BEP relations -Scaling relationsTo bridge the gap between macroscopic properties of a catalyst, such as turn-over rates and selectivity and the microscopic properties obtained from electronic structure methods based on density functional theory (DFT), an in depth understanding of the underlying thermodynamics and kinetics of the corresponding metal surfaces is needed. Today, DFT has reached a level of sophistication where it can be used to describe complete catalytic reactions and hence provide an insight that pinpoints to the origin of the catalytic activity and selectivity. 1,2,3,4,5,6 However, extensive DFT calculations that eventually lead to this understanding are still computationally demanding. A simplification that connects the reactivity and selectivity of a catalytic surface to one or few descriptors is therefore extremely useful. Such a simplification, e.g. the Brønsted-Evans-Polanyi (BEP) relations, is able to show that the transition state energy of a reaction is linearly depending on the reaction energy. 7,8,9,10,11,12 * Corresponding author SLAC-PUB-14285 2 Herein, we investigate the transition state energies of a large number of essential bond breaking and forming reactions that play a key role in the catalytic transformation of a large fraction of base chemicals. The transition state energies investigated include C-C, C-O, C-N, N-O, N-N, and O-O coupling and have been calculated on different stepped surfaces of transition metals such as Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au. For a dissociation reaction (AB → A+B), the transition state energy (E ts ) is calculated by Equation (1), in which E ts/slab , E slab and E gas are the total energies of the slab with transition states, the clean slab, and the gas phase molecules relevant for the reactions, respectively. The dissociative adsorption energy (E diss ) is calculated by Equation (2), in which E A/slab and E B/slab are the total energies of the slab with adsorbates A and B, respectively.(1)All calculations were performed using the DACAPO plane-wave pseudo potential DFT code. 13 Ionic cores were described by ultrasoft pseudopotentials 14, and the Kohn-Sham one-electron valence states were expanded in a basis of plane wave functions with a cutoff energy up to 340 eV. For most adsorption systems, the surface Brillouin zone was sampled using a Monkhorst-Pack grid of size 4×4×1, while 2×3×1 was used for O 2 , and 8×6×1 was used for N 2 and NO as a test of the parameters. The self-consistent electron density was determined by iterative diagonalization of the Kohn-Sham Hamiltonian. A Fermi distribution for the population of...

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“…The data will be part of a larger database of surface reaction data that are being developed under the Quantum Materials Informatics Project, see ref. [17][18][19][20][21][22] where the details of the calculations can be found. The important point here is that they have all been calculated with the same code (DACAPO), the same exchange-correlation energy functional (GGA-RPBE), [23] and similar calculational parameters.…”

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confidence: 99%

CatApp: A Web Application for Surface Chemistry and Heterogeneous Catalysis

et al. 2011

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We introduce a web application (CatApp) for looking up calculated reaction and activation energies for elementary coupling reactions occurring on metal surfaces. It provides access to reaction and activation energies for all reactions involving C-C, C-H, C-O, O-O, O-H, N-N, C-N, O-N, N-H splittingSolid catalysts form the backbone of the chemical industry and the hydrocarbon-based energy sector. Most catalysts and processes today are highly optimized, but there is still considerable room for improvements in reactivity and selectivity that would lower energy consumption and waste production. In addition there are tremendous challenges to catalysis science and engineering in developing a sustainable energy solutions. The ability to store solar energy as a fuel calls for new catalysts and so does the development of a sustainable chemical industry based on biomass and other non-fossil building blocks.The development of new catalysts could be accelerated significantly if we had access to systematic data for activation energies of elementary surface reactions. Once the key parameters determining the activity or selectivity of a certain process has been established though experiments or calculations, such a database would enable searches for new catalyst leads. Ideally, data would come from detailed, systematic experiments, but it is in general not possible to find such data. Electronic structure calculations provide a powerful alternative. The accuracy is not such that detailed predictions of absolute rates of elementary reaction steps can be made, but for classes of interesting catalysts (transition metals) it is possible to create systematic data with sufficient accuracy to predict trends in reactivity. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] In the present paper, we introduce such a set of calculated reaction energies and activation energies for a large number of elementary surface reactions on a series of metal single crystal surfaces including surfaces with defects such as steps. We will also introduce a simple web application (CatApp) that can be downloaded to access these data.

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Role of Steps inN2Activation on Ru(0001)

Cited by 751 publications

References 22 publications

Exploring the phase space of time of flight mass selected Pt_xY nanoparticles

Exploring the phase space of time of flight mass selected Pt_xY nanoparticles

Universal Brønsted-Evans-Polanyi Relations for C–C, C–O, C–N, N–O, N–N, and O–O Dissociation Reactions

CatApp: A Web Application for Surface Chemistry and Heterogeneous Catalysis

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Role of Steps inN2Activation on Ru(0001)

Cited by 751 publications

References 22 publications

Exploring the phase space of time of flight mass selected PtxY nanoparticles

Exploring the phase space of time of flight mass selected PtxY nanoparticles

Universal Brønsted-Evans-Polanyi Relations for C–C, C–O, C–N, N–O, N–N, and O–O Dissociation Reactions

CatApp: A Web Application for Surface Chemistry and Heterogeneous Catalysis

Contact Info

Product

Resources

About

Exploring the phase space of time of flight mass selected Pt_xY nanoparticles

Exploring the phase space of time of flight mass selected Pt_xY nanoparticles