The catalytic activity of supported platinum:

Poulain, E.; Bertin, V.; Castillo, S.; Cruz, A.

doi:10.1016/s1381-1169(96)00176-8

Cited by 23 publications

(20 citation statements)

References 17 publications

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“…Whereas, the ground state Pt ( 3 D:5d 9 6s 1 ) does not present H 2 capture. So a Pt atom in its ground state does not chemisorb H 2 , as was experimentally found by Gazellot et al 39 We also carried out theoretical studies over the Pt 2 -H 2 interaction; 31 it was found that the Pt 2 cluster with H 2 reaction in parallel approach lead to spontaneous H 2 capture through avoided crossings of potential energy curves.…”

Section: Introductionmentioning

confidence: 58%

“…The RECP parameters for platinum and the basis, as well as the hydrogen atom basis set have been successfully used before. 27,[31][32][33] The Pt 4 geometry considered corresponds to the Pt 4 (111) cluster of a catalyst particle. The Pt-Pt nearest neighbor distance used is 2.75 Å.…”

Section: Computational Detailsmentioning

confidence: 99%

“…26 The electronic structure of small monometallic clusters a͒ and their activity with H 2 have been studied in many theoretical works. [27][28][29][30][31][32][33][34][35][36][37][38] Theoretical studies of small metal clusters and their interaction with atoms, radicals, and small molecules allow detailed and tractable research during the elementary processes of chemisorption reactions of isolated gas phase molecules (H 2 ,CO,NO x ) on metal surface particles. The studies, in these small clusters, are especially attractive since, systematic growth in the atom number allow one to monitoring their changes in structure, dynamics, and electronic properties involved with the size.…”

Section: Introductionmentioning

confidence: 99%

“…For this interaction we use the same successful methodology of previous studies about reactions of small metal systems with the hydrogen molecule. 27,[31][32][33] Here, for the properties determination of a complex systems, we take advantage of the few models we can solve with accuracy, although they could represent only a simplified schemes of a real one, but they will show the general features of the complex system. In this way, we can be sure that we found properties inherent to the model and that they do not come from a possible faulty approximation.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical study of the H2 reaction with a Pt4 (111) cluster

Cruz¹,

Bertin²,

Poulain³

et al. 2004

The Journal of Chemical Physics

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The C(s) symmetry reaction of the H(2) molecule on a Pt(4) (111) clusters, has been studied using ab initio multiconfiguration self-consistent field plus extensive multireference configuration interaction variational and perturbative calculations. The H(2) interaction by the vertex and by the base of a tetrahedral Pt(4) cluster were studied in ground and excited triplet and singlet states (closed and open shells), where the reaction curves are obtained through many avoided crossings. The Pt(4) cluster captures and activates the hydrogen molecule; it shows a similar behavior compared with other Pt(n) (n=1,2,3) systems. The Pt(4) cluster in their lowest five open and closed shell electronic states: (3)B(2), (1)B(2), (1)A(1) (3)A(1), (1)A(1), respectively, may capture and dissociate the H(2) molecule without activation barriers for the hydrogen molecule vertex approach. For the threefolded site reaction, i.e., by the base, the situation is different, the hydrogen adsorption presents some barriers. The potential energy minima occur outside and inside the cluster, with strong activation of the H-H bond. In all cases studied, the Pt(4) cluster does not absorb the hydrogen molecule.

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Section: Introductionmentioning

confidence: 58%

Section: Computational Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Theoretical study of the H2 reaction with a Pt4 (111) cluster

Cruz¹,

Bertin²,

Poulain³

et al. 2004

The Journal of Chemical Physics

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“…As shown in the literature, 13,14 molecularly chemisorbed hydrogen is very unlikely. When a hydrogen molecule chemisorbs on a Pt surface, the antibonding σ* orbital of H 2 is completely filled by electrons from platinum.…”

Section: Introductionmentioning

confidence: 78%

The Nature of the Pt−H Bonding for Strongly and Weakly Bonded Hydrogen on Platinum. A XAFS Spectroscopy Study of the Pt−H Antibonding Shaperesonance and Pt−H EXAFS

2001

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A long-standing problem in the research of H 2 chemisorption on supported Pt catalysts is the unclarity about the difference in nature of the Pt-H bonding for weakly and strongly bonded hydrogen. On the basis of Pt-Pt EXAFS and a newly developed XANES analysis of the Pt L 2 and L 3 edges, it will be shown that both types of hydrogen are truly chemisorbed species. The EXAFS analysis shows a similar contraction of the Pt-Pt bond irrespective of the removal of weakly or strongly bound hydrogen, indicating a similar nature for both interactions. Moreover, the analysis of the L 2 and L 3 X-ray absorption edges shows unambiguously the presence of a Pt-H antibonding state for both the weakly and strongly bonded hydrogen. This is a clear indication for chemisorption of hydrogen for both types of hydrogen. The Pt-H EXAFS shows a smaller Pt-H bond length in the case of strongly adsorbed, which is in correlation with the expected strength of the Pt-H bond.

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Theoretical characterization of H2 adsorption on AuPt clusters

Cruz¹,

Poulain²,

Angel³

et al. 1998

Int. J. Quant. Chem.

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Linear and triangular AuPt cluster reactions with H are studied n 2 Ž . theoretically, using ab initio multiconfiguration self-consistent field MC-SCF Ž . calculations, followed by extensive multireference configuration interaction MR-CI variational and perturbative. Both the linear dimer and the triangular trimers capture the hydrogen molecule by the Pt cluster side and by the Au cluster side. Gold has an electronic effect on the Pt activity, more important than a geometrical one, poisoning the Pt activity to dissociate H and lowering the adsorption heats. This effect is stronger in 2 the AuPt dimer, where the H capture occurs only at the molecular level, without 2 showing hydrogen bond dissociation. The trimers look more active, relaxing the H-H bond until breakage. No activation barriers are observed in all the cases considered. The hydrogen molecule is not able to cross the clusters due to the large barriers present.

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The catalytic activity of supported platinum:

Cited by 23 publications

References 17 publications

Theoretical study of the H2 reaction with a Pt4 (111) cluster

Theoretical study of the H2 reaction with a Pt4 (111) cluster

The Nature of the Pt−H Bonding for Strongly and Weakly Bonded Hydrogen on Platinum. A XAFS Spectroscopy Study of the Pt−H Antibonding Shaperesonance and Pt−H EXAFS

Theoretical characterization of H2 adsorption on AuPt clusters

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