Structure sensitivity of catalytic reactions

Somorjai, Gábor A.; Carrazza, J.

doi:10.1021/i100021a009

Cited by 176 publications

(99 citation statements)

References 26 publications

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“…Pt/SiO 2 , having an open porous structure, showed markedly higher activity than these samples. A previous study using Pt/SiO 2 as a model catalyst showed a monotonic increase of TOR with decreasing Pt cluster size in a range of 1. sites play an important role in the C-C bond breakage 23,24 . Because the Pt cluster sizes in the Pt-encapsulated catalysts and Pt/SiO 2 are comparable (B1.0 nm), as determined from the EXAFS analysis (Supplementary Table 1), all the catalysts are expected to show similar hydrogenolysis activity if the reaction occurs on the Pt cluster surface.…”

Section: Resultsmentioning

confidence: 99%

“…However, it should be emphasized again that the catalytic turnover rates in this work were calculated based on the total number of Pt rather than that of Pt accessible by H 2 or CO. For the minor external Pt species to cover the entire catalytic activities observed in the hydro-/ dehydrogenation reactions, their specific activity should be orders of magnitude higher than ordinary Pt species. Considering that the specific activities of Pt in hydro-/dehydrogenation have been reported to be relatively insensitive to Pt cluster size and shapes 24 , the assumption of the existence of 'super-active' Pt is unreasonable. Furthermore, the distinct chemoselectivity (suppressed hydrogenolysis) and the remarkable dependence of catalytic activity on the hydroxyl concentration of support surface cannot be explained by the conventional reaction mechanism on metal surface.…”

Section: Discussionmentioning

confidence: 99%

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Maximizing the catalytic function of hydrogen spillover in platinum-encapsulated aluminosilicates with controlled nanostructures

et al. 2014

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Hydrogen spillover has been studied for several decades, but its nature, catalytic functions and even its existence remain topics of vigorous debate. This is a consequence of the lack of model catalysts that can provide direct evidences of the existence of hydrogen spillover and simplify the catalytic interpretation. Here we use platinum encapsulated in a dense aluminosilicate matrix with controlled diffusional properties and surface hydroxyl concentrations to elucidate the catalytic functions of hydrogen spillover. The catalytic investigation and theoretical modelling show that surface hydroxyls, presumably Brønsted acids, are crucial for utilizing the catalytic functions of hydrogen spillover on the aluminosilicate surface. The catalysts with optimized nanostructure show remarkable activities in hydro-/dehydrogenation, but virtually no activity for hydrogenolysis. This distinct chemoselectivity may be beneficial in industrially important hydroconversions such as propane dehydrogenation to propylene because the undesired hydrogenolysis pathway producing light hydrocarbons of low value (methane and ethane) is greatly suppressed.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Maximizing the catalytic function of hydrogen spillover in platinum-encapsulated aluminosilicates with controlled nanostructures

et al. 2014

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“…During the past decades, metal single-crystal surfaces have been widely adopted by surface scientists as model catalysts to systematically study the effect of surface structure on catalysis reactions, such as ammonia synthesis, isomerization of light alkanes, hydrogenolysis of alkanes and so on. [17][18][19] In order to gain a clear picture on the surface structure effect, such studies were typically performed in ultrahigh vacuum (UHV), leading to the pressure and material gaps between many model catalysis studies and real catalysis.…”

Section: Introductionmentioning

confidence: 99%

Small Adsorbate‐Assisted Shape Control of Pd and Pt Nanocrystals

et al. 2012

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The shape control of noble metal nanocrystals is crucial to their optical properties and catalysis applications. In this Progress Report, the recent progress of shape-controlled synthesis of Pd and Pt nanostructures assisted by small adsorbates is summarized. The use of small strong adsorbates (e.g., I(-) , CO, amines) makes it possible to fabricate Pd and Pt nanostructures with not only well-defined surface structure but also morphologies that have not been achieved by other synthetic strategies. The roles of small adsorbates in shape control of Pd and Pt nanocrystals are discussed in the Report. Also presented in the Report are unique optical and catalytic properties of several Pd and Pt nanostructures (e.g., ultrathin Pd nanosheets, concave Pt octapod, concave Pd tetrahedra), as well as their bioapplications, to demonstrate the power of using small strong adsorbates in the shape control of Pt and Pd nanostructures.

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“…Still, catalytic reactions often occur preferably on surface steps and edges. 12 In this study, we use phenol as an oxygen-containing model component for biomass-based liquids. We will discuss the behavior of phenol on Pt(111), Rh(111) and stepped Pt and Rh surfaces based on periodic DFT calculations.…”

Section: Introductionmentioning

confidence: 99%