Gas phase metal cluster model systems for heterogeneous catalysis

Lang, Sandra M.; Bernhardt, Thorsten M.

doi:10.1039/c2cp40660h

Cited by 353 publications

(301 citation statements)

References 146 publications

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“…3234 As shown in Figure 7, gold clusters composed of only 3 to 5 atoms can efficiently catalyze the addition of water to alkynes at a very low concentration, giving reaction turnover numbers of 10 7 . Another advantage is that catalytic gold clusters can be readily formed in a reactant solution in the absence of stabilizing ligands.…”

Section: Gold Clusters Stabilized or Supported By Organic Compounds Imentioning

confidence: 99%

Size- and Structure-specificity in Catalysis by Gold Clusters

2014

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Although gold in bulk is poorly active as a catalyst, it exhibits surprisingly high catalytic activity when deposited as nanoparticles (NPs) on base metal oxides. The catalytic performance of supported gold NPs can be created by choosing the kind of support materials, by controlling the size of gold, and by building up strong contact of gold with the supports. Since perimeter interfaces around gold NPs act, in principle, as the active sites for oxidation and hydrogenation, gold should be smaller than 10 nm in diameter. A new area of research is clusters, which are smaller than 2 nm in diameter and less than 200 atoms. Gold clusters possess electronic structures different from those of bulk gold and at the same time provide increased fractions of edges and corners which are highly unsaturatedly coordinated sites. Accordingly, gold clusters will be blessed by unique catalytic performance, and many examples have recently been emerging. This article summarizes such examples in terms of "size-and structure-specificity," covering gas-phase free clusters, polymer-or organic-ligand-stabilized clusters in liquid phase, and clusters supported on base metal oxides, carbon materials, and organic polymers for gas-phase and liquid-phase reactions.

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Section: Gold Clusters Stabilized or Supported By Organic Compounds Imentioning

confidence: 99%

Size- and Structure-specificity in Catalysis by Gold Clusters

2014

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“…[1][2][3][4][5]). The important rationale behind these studies is that gas-phase transition metal clusters have served model systems for catalysis [6]. By contrast, hydrogen activation by main group metal clusters has been investigated on a smaller scale.…”

Section: Introductionmentioning

confidence: 99%

Dissociation of multiple hydrogen molecules on the three-dimensional aluminium cluster: theoretical study

Moc

2013

Theor Chem Acc

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Compared to hydrogen activation on bare transition metal clusters, such reactions involving main group metal clusters have been less studied. Here, dissociative addition of multiple H 2 to the group 13 metal cluster Al 6 is investigated theoretically to examine the viability of generating Al 6 H 8 , the novel alane proposed experimentally by Li et al. Coupled-cluster CCSD(T) calculations with the aug-cc-pVTZ basis set are employed to determine the energetics of these additions, and density functional calculations are used to extensively probe the relevant potential energy surfaces. We find the sequential hydrogenations of Al 6 via Al 6 H 2k-2 ? H 2 ? Al 6 H 2k (k = 1-4) exothermic, where the Al 6 H 2k cluster global minima structures exhibit the same 'H-bridging motif' with two hydrogens sitting on the neighbouring threefold-bridged sites. Of various H 2 dissociation modes probed including octahedral-and trigonal prism-like clusters, we find those involving dissociation transition states with the octahedrallike Al 6 cores as kinetically most favoured. A correlation is identified between the H 2 dissociation barriers and highest occupied molecular orbital-lowest unoccupied molecular orbital gaps of the Al 6 H 2k-2 clusters versus k. For k = 1, the H 2 dissociation is predicted to have no enthalpy barrier at the CCSD(T)/aug-cc-pVTZ level, and a good agreement is found between the coupled cluster and G4-calculated energetics. For k = 2, 3 and 4, the lowest enthalpic hydrogen dissociation barriers are determined to be 12, 14 and 20 kcal/mol, respectively, as measured relative to the Al 6 H 2k-2 cluster global minimum isomer plus H 2 reactants. According to our calculations, the entropy contribution (-TS) to the free energy dissociation barrier is 8 kcal/mol per H 2 .

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“…Noble metal nanoclusters are nowadays widely recognized as promising building blocks for novel electro-optical devices [1][2][3][4][5][6][7][8][9]. Their unique optical, chemical and electronic properties find applications in nanoscience and nanotechnology, providing nonlinear optical sources [5,10,11], biosensors [12][13][14][15], energy transport systems [16][17][18] , solar cell elements [19,20], etc.…”

Section: Introductionmentioning

confidence: 99%