Innovative Measurement Techniques in Surface Science

Freund, Hans‐Joachim; Nilius, Niklas; Risse, Thomas; Schauermann, Swetlana; Schmidt, Thomas

doi:10.1002/cphc.201000812

Cited by 28 publications

(24 citation statements)

References 65 publications

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“…In order to identify the active part of the material we need to be able to study a very small amount of starting material and of products at the surface of the complex material, and we need to be simultaneously able to differentiate the surface of the material from its bulk. This requires the development of specific, surface sensitive techniques and, in order to isolate the action of the various material components, a systematic variation in the complexity of the studied material [7]. This variation has to proceed from the most simple to the more complex, and not vice versa.…”

Section: Introductionmentioning

confidence: 99%

Models in Catalysis

2014

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The paper discusses the hierarchy of model studies with increasing complexity towards an understanding of industrial catalysts under reaction conditions. We use three case studies to document the progress in systems complexity as well as the development of instruments that allow us to approach the study of acting catalysts: magnesium oxide clusters in the gas phase, gold nanoparticles on metal oxide surfaces, and palladium nanoparticles compared to crystal surfaces. While the examples are from the field of heterogeneous catalysis, we discuss the relation to homogeneous and enzymatic catalysis.

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Section: Introductionmentioning

confidence: 99%

Models in Catalysis

2014

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“…A rapidly increasing number of surface science studies [3][4][5][6][7] reflects the actuality of this research, that has been initiated and influenced for years by the groups of Somorjai et al 8 , Hayek et al 9 , Goodman et al 10 and Ertl et al 11 . The second step is the systematic testing of the different model catalysts at higher pressures, i.e.…”

Section: Introductionmentioning

confidence: 99%

Combined UHV/high-pressure catalysis setup for depth-resolved near-surface spectroscopic characterization and catalytic testing of model catalysts

Mayr

Rameshan

Klötzer

et al. 2014

Review of Scientific Instruments

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An ultra-high vacuum (UHV) setup for "real" and "inverse" model catalyst preparation, depth-resolved near-surface spectroscopic characterization and quantification of catalytic activity and selectivity under technologically relevant conditions is described. Due to the allquartz reactor attached directly to the UHV-chamber, transfer of the catalyst for in-situ testing without intermediate contact to the ambient is possible. The design of the UHV-compatible re-circulating batch reactor setup allows the study of reaction kinetics under close to technically relevant catalytic conditions up to 1273 K without contact to metallic surfaces except those of the catalyst itself. With the attached differentially pumped exchangeable evaporators and the quartz-microbalance thickness monitoring equipment, a reproducible, versatile and standardised sample preparation is possible. For three-dimensional near-surface sample characterization, the system is equipped with a hemispherical analyser for X-ray photoelectron spectroscopy (XPS), electron-beam or X-ray-excited Auger-electron spectroscopy (AES) and low-energy ion scattering (LEIS) measurements. Due the dedicated geometry of the X-ray gun (54.7°, "magic angle") and the rotatable sample holder, depth analysis by angle-resolved XPS measurements can be performed. Thus, by the combination of characterisation methods with different information depth, a detailed three-dimensional picture of the electronic and geometric structure of the model catalyst can be obtained.To demonstrate the capability of the described system, comparative results for depth-resolved sample characterization and catalytic testing in methanol steam reforming (MSR) on PdGa and PdZn near-surface intermetallic phases (NSIP) are shown.3

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“…in the 1990s and further developed by Campbell et al . The results from this method have been reviewed previously . The major advantage of using SCAC is the ability to directly measure the interaction strength of gaseous molecules with the surface of interest.…”

Section: Introductionmentioning

confidence: 99%

“…These restrictions can be completely overcome by using a direct calorimetric measurement. To date, SCAC has been successfully applied to study the energetics of adsorbate–surface interactions for different molecular adsorbates on metal single crystals as well as on metal nanoparticles supported on thin model oxide layers . In the latter case, direct calorimetric measurement of adsorption and reaction energies by SCAC was combined with the tools for in situ preparation of model catalysts consisting of metal nanoparticles supported on thin well‐defined oxide films .…”

Section: Introductionmentioning

confidence: 99%

Single‐Crystal Adsorption Calorimetry on Well‐Defined Surfaces: From Single Crystals to Supported Nanoparticles

Schauermann

Silbaugh

Campbell

2014

The Chemical Record

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Single-crystal adsorption calorimetry (SCAC) measures the energetics of gas-surface interactions in a direct way and can be applied to a broad range of well-defined model surfaces. In this Personal Account we review some of the recent advances in understanding the interaction of gaseous molecules with single-crystal surfaces and well-defined supported metallic nanoparticles by this powerful technique. SCAC was applied on single-crystal surfaces to determine formation enthalpies of adsorbed molecular fragments typically formed during heterogeneously catalyzed reactions involving hydrocarbons. On supported metal nanoparticles, the binding energies of gaseous species were determined by SCAC as a function of the particle size. The reported data provide valuable information for ongoing research in many fields of heterogeneous catalysis and materials science. In addition, direct calorimetric measurements serve as benchmarks for the improvement of computational approaches to understanding surface chemistry.

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Innovative Measurement Techniques in Surface Science

Cited by 28 publications

References 65 publications

Models in Catalysis

Models in Catalysis

Combined UHV/high-pressure catalysis setup for depth-resolved near-surface spectroscopic characterization and catalytic testing of model catalysts

Single‐Crystal Adsorption Calorimetry on Well‐Defined Surfaces: From Single Crystals to Supported Nanoparticles

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