Inelastic neutron scattering investigation on the site occupation of atomic hydrogen on platinum particles of different size

Albers, Peter; Lopez, Marco; Sextl, Gerhard; Jeske, Gerald; Parker, Stewart F.

doi:10.1016/j.jcat.2003.12.018

Cited by 24 publications

(10 citation statements)

References 34 publications

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“…According to the literature, 54,56,57,68,69 all these bands are due to Pt−H vibrations of n-fold coordinated (bridged, hollow, and 4-fold coordinated) Pt−H species. Bands in similar positions were previously reported for platinum hydrides on Pt singlecrystals, 69 on 40 wt % Pt/C catalysts, 54,56,57 and very recently by some of the authors on a very low loaded, industrially relevant, 5 wt % Pt/C catalyst having a particle size comparable with our Pt/Al 2 O 3 . 58 The exact assignment of these bands is challenging and would require an accurate modeling of the Pt nanoparticles in the presence of hydrogen, which will be the subject of a successive report.…”

Section: Resultsmentioning

confidence: 99%

“…Hydrogen has the largest incoherent cross section among all the elements and also the largest amplitude of motion because of its lightweight . The use of INS in this field has been limited so far, − due to the difficulty in having access to the neutron sources, the time required for collecting high-quality data (especially in comparison with X-ray based techniques that in the last decades have seen the rapid development of ultrafast methods), and the large amount of sample necessary for the measurements. Only in recent years the neutron instruments have progressed enough, in terms of neutron flux on the sample and efficiency in the neutron detection, to allow an easier investigation of samples of interest in catalysis …”

Section: Introductionmentioning

confidence: 99%

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Dynamics of Reactive Species and Reactant-Induced Reconstruction of Pt Clusters in Pt/Al₂O₃Catalysts

et al. 2019

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We report a complete experimental characterization of the surface Pthydride species on an industrial 5 wt % Pt/Al 2 O 3 catalyst (average particle size of 1.4 ± 0.4 nm) under different hydrogenation/dehydrogenation conditions. By combining inelastic neutron scattering, FT-IR spectroscopy, and synchronous DRIFT/XAS/MS, we identified n-fold coordinated Pt-hydrides and four different types of linear Pthydrides characterized by different adsorption strength, whose relative proportion depends on the experimental conditions. In particular, we observed that the n-fold coordinated hydrides convert into linear ones upon decreasing hydrogen coverage, and vice versa, and we traced this phenomenon to a morphological and electronic reconstruction of the Pt nanoparticles. Although only a fraction of the surface Pthydrides are directly involved in the hydrogenation of toluene, all the others play an indirect but fundamental role, maintaining the Pt nanoparticles electronically and morphologically stable during the reaction and hence avoiding the occurrence of deactivation processes. Our results, which are in good agreement with the theoretical predictions reported in the literature, offer a comprehensive picture of the dynamics of Pt nanoparticles in hydrogenation conditions. This always involves a change in the relative proportion of the Pt-hydride species, and only in some cases an electronic and morphological reconstruction of the Pt particles.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dynamics of Reactive Species and Reactant-Induced Reconstruction of Pt Clusters in Pt/Al₂O₃Catalysts

et al. 2019

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“…The same group further studied platinum and platinum/ ruthenium particles supported on carbon black throughn eutron spectroscopy. [25] They found that, as the particle size increased,t he vibrational mode of atomic hydrogen at C 3v sites narrowed and the maximum shiftedt ol ower energies. The hydrogen atom occupied more (111)s ites of Pt particles, and the contribution from C 4v sites decreased.V ibrationalm odes for PtÀOH, Pt/RuÀOH, and water were also discriminated.I na study published two years later (2006), by some of the same authors, [26] on-top adsorption of hydrogen was observed on platinum nanoparticles supported on high-surface-area carbon black.…”

Section: Hydrogen Adsorption and Spillovermentioning

confidence: 99%

“…[6] Hydrogen spillover on carbon-supported Pt (Pt/C),R u( Ru/C), and PtRu (PtRu/C) has been detected by means of INS and reportedi nv ariousp ublications. [22,23,25,[38][39][40] In the work of Mitchell et al on aR u/C catalyst, they reported that at 23 KH 2 adsorbed as as trongly adsorbed monolayer anda saweakly adsorbed second layer. [22] Starting at 80 K, H 2 dissociates and H atoms spillover to the support.S pillover is concluded due to the failure to observe significant INS intensity from the RuÀH speciesa taratio of H/Ru of three.…”

Section: Hydrogen Adsorption and Spillovermentioning

confidence: 99%

Neutron Scattering Investigations of Hydride Species in Heterogeneous Catalysis

et al. 2018

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In heterogeneous catalysis, hydrides on the surface or in the bulk play a critical role as either active components or reaction intermediates in many hydrogen‐involving reactions, but characterization of the nature and structure of these hydride species remains challenging. Neutron scattering, which is extremely sensitive to light elements, such as hydrogen, has shown great potential in meeting this challenge. In this Minireview, recent advances in neutron studies of hydride species, mainly over the two most typical classes of catalysts—metals and oxides—are surveyed. Findings on catalysts outside these categories are raised if they are considered to be relevant for contextualization in the present Minireview. The adsorption, dissociation, spillover, and reactivity of hydrogen, especially hydride species over supported metal and oxide catalysts, have been successfully investigated, mostly by means of neutron vibrational spectroscopy. Insights from these neutron studies, which are otherwise not possible with other techniques, shed light on the interaction mechanism of hydrogen with solid surfaces and reaction mechanisms in which hydrogen is involved. Future research challenges on neutron scattering studies of hydrides, as well as catalysis in general, are also highlighted, and more operando‐type neutron studies need be conducted to advance the field.

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“…PEMFC use Pt/C catalysts for both the hydrogen (cathode) and oxygen (anode) splitting reactions. The adsorbed states of hydrogen on platinum have been studies by INS for decades (e.g., [89][90][91][92][93][94]). The spectra show a remarkable degree of commonality, implying that similar species are present, irrespective of whether the platinum is supported or not.…”

Section: Fuel Cellsmentioning

confidence: 99%

Net Zero and Catalysis: How Neutrons Can Help

Parker

Lennon

2021

Physchem

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Net Zero has the aim of achieving equality between the amount of greenhouse gas emissions produced and the amount removed from the atmosphere. There is widespread acceptance that for Net Zero to be achievable, chemistry, and hence catalysis, must play a major role. Most current studies of catalysts and catalysis employ a combination of physical methods, imaging techniques and spectroscopy to provide insight into the catalyst structure and function. One of the methods used is neutron scattering and this is the focus of this Perspective. Here, we show how neutron methods are being used to study reactions and processes that are directly relevant to achieving Net Zero, such as methane reforming, Fischer–Tropsch synthesis, ammonia and methanol production and utilization, bio-mass upgrading, fuel cells and CO2 capture and exploitation. We conclude by describing some other areas that offer opportunities.

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Inelastic neutron scattering investigation on the site occupation of atomic hydrogen on platinum particles of different size

Cited by 24 publications

References 34 publications

Dynamics of Reactive Species and Reactant-Induced Reconstruction of Pt Clusters in Pt/Al₂O₃Catalysts

Dynamics of Reactive Species and Reactant-Induced Reconstruction of Pt Clusters in Pt/Al₂O₃Catalysts

Neutron Scattering Investigations of Hydride Species in Heterogeneous Catalysis

Net Zero and Catalysis: How Neutrons Can Help

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Inelastic neutron scattering investigation on the site occupation of atomic hydrogen on platinum particles of different size

Cited by 24 publications

References 34 publications

Dynamics of Reactive Species and Reactant-Induced Reconstruction of Pt Clusters in Pt/Al2O3Catalysts

Dynamics of Reactive Species and Reactant-Induced Reconstruction of Pt Clusters in Pt/Al2O3Catalysts

Neutron Scattering Investigations of Hydride Species in Heterogeneous Catalysis

Net Zero and Catalysis: How Neutrons Can Help

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Product

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Dynamics of Reactive Species and Reactant-Induced Reconstruction of Pt Clusters in Pt/Al₂O₃Catalysts

Dynamics of Reactive Species and Reactant-Induced Reconstruction of Pt Clusters in Pt/Al₂O₃Catalysts