Trends in the Catalytic CO Oxidation Activity of Nanoparticles

Falsig, Hanne; Hvolbæk, Britt; Kristensen, Iben S.; Jiang, Tao; Bligaard, Thomas; Christensen, Claus H.; Nørskov, Jens K.

doi:10.1002/anie.200801479

Cited by 413 publications

(465 citation statements)

References 36 publications

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“…It has been found that undercoordinated Au atoms have increased chemical activity. 58,59 Of course, turnover for particular reactions will also depend on lateral interactions between adsorbates and thiolate species. In the case of very strong repulsive interactions, thiolate adsorption on Au might even result in decrease of Au reactivity.…”

Section: Thiolate-covered Gold Nanoparticlesmentioning

confidence: 99%

Thiolate adsorption on Au(${\bm {hkl}}$hkl) and equilibrium shape of large thiolate-covered gold nanoparticles

Barmparis

Honkala²,

Remediakis³

2013

The Journal of Chemical Physics

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The adsorption of thiolates on Au surfaces employing density-functional-theory calculations has been studied. The dissociative chemisorption of dimethyl disulfide (CH3S−SCH3) on 14 different Au(hkl) is used as a model system. We discuss trends on adsorption energies, bond lengths, and bond angles as the surface structure changes, considering every possible Au(hkl) with h, k, l ⩽ 3 plus the kinked Au(421). Methanethiolate (CH3S-) prefers adsorption on bridge sites on all surfaces considered; hollow and on top sites are highly unfavourable. The interface tensions for Au(hkl)-thiolate interfaces is determined at low coverage. Using the interface tensions in a Wulff construction method, we construct atomistic models for the equilibrium shape of large thiolate-covered gold nanoparticles. Gold atoms in a nanoparticle change their equilibrium positions upon adsorption of thiolates towards shapes of higher sphericity and higher concentration of step-edge atoms.

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Section: Thiolate-covered Gold Nanoparticlesmentioning

confidence: 99%

Thiolate adsorption on Au(${\bm {hkl}}$hkl) and equilibrium shape of large thiolate-covered gold nanoparticles

Barmparis

Honkala²,

Remediakis³

2013

The Journal of Chemical Physics

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“…5 Their enhanced catalytic properties for CO oxidation are often attributed, much like in nanoparticle catalysts, to the presence of undercoordinated Au atoms. [6][7][8] Among other factors that have been recently discussed in terms of their potential influence on the catalytic activity of NPG are: surface to volume ratio, mechanical strain, as well as the role of residual Ag. 5 Among these factors, the strain effect on reactivity in nanoscale metal catalysts is a topic of intense experimental and theoretical research.…”

Section: Introductionmentioning

confidence: 99%

Thermal properties of nanoporous gold

et al. 2012

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We measured the thermal expansion coefficient and Debye temperature of nanoporous gold (NPG) using Extended X-ray Absorption Fine Structure technique. Reduction of the nearest neighbor distances in NPG by ca. 0.01 Å compared to the bulk gold was attributed to the surface tension caused, in turn, by the finite size effect of the NPG ligaments. We also obtained that the Debye temperature in NPG is 5% lower than in bulk gold. We interpreted these observations in the framework of a bimodal distribution of surface and bulk bonds with different values of Debye temperature. The surface bonds with low Debye temperature extend within ca. 4 layers of Au atoms located on the pore surface, in a good agreement with prior resistivity measurements and theoretical predictions. 63.22.Dc, 61.05.cj, 65.40.De, PACS number(s):

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“…Hence, it becomes easy to establish trends for reactions allowing a first screening for new catalytic materials by means of few simple descriptors. 6,20,21,22,23 …”

mentioning

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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Trends in the Catalytic CO Oxidation Activity of Nanoparticles

Cited by 413 publications

References 36 publications

Thiolate adsorption on Au(${\bm {hkl}}$hkl) and equilibrium shape of large thiolate-covered gold nanoparticles

Thiolate adsorption on Au(${\bm {hkl}}$hkl) and equilibrium shape of large thiolate-covered gold nanoparticles

Thermal properties of nanoporous gold

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

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