Model studies on heterogeneous catalysts at the atomic scale: From supported metal particles to two-dimensional zeolites

Freund, Hans‐Joachim; Heyde, Markus; Nilius, Niklas; Schauermann, Swetlana; Shaikhutdinov, Shamil K.; Sterrer, Martin

doi:10.1016/j.jcat.2013.06.007

Cited by 27 publications

(41 citation statements)

References 106 publications

(171 reference statements)

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“…Adsorption on defect-free oxides is generally weak given the high degree of bond saturation at their surface and the large gap, in particular, that governs their electronic structure [14,15,24,26,31,38,44,45,[52][53][54]58]. Metal atoms deposited onto pristine oxides have essentially two means to interact with the surface [58].…”

Section: Introductionmentioning

confidence: 99%

Oxygen activation on oxide surfaces: A perspective at the atomic level

Freund

2014

Catalysis Today

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a b s t r a c tThin oxide films have been used as model supports to unravel the influence of the oxide-metal and oxide-gas interface. We discuss the influence of defects in the oxide lattice and the oxide surface on properties of adsorbed species, in particular the formation of oxide particles from a deposited transition metal onto ceria and of adsorbed oxygen from the gas phase. Here we correlate the structure of the particles, as revealed by a combination of STM and spectroscopic as well as theoretical calculations, with their reactive properties. The nature of the involved defects is characterized by adsorption of Au as a way to correlate the influence of various defects of different structure on the Au charge state. In a second case study, we demonstrate the influence of dopants within the supporting oxide on the adsorption of oxygen on a defect free surface. This is shown to be potentially relevant for the activation of methane in oxidative methane coupling reactions, as recently demonstrated.

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Section: Introductionmentioning

confidence: 99%

Oxygen activation on oxide surfaces: A perspective at the atomic level

Freund

2014

Catalysis Today

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“…There are a number of reviews available on * ) freund@fhi-berlin.mpg.de various aspects of those thin-film-based model systems [2][3][4][5]. The main advantage of using this approach is the fact that we may use the toolbox of surface science to study those systems at the atomic level, employing scanning tunneling microscopy and variants, as well as spectroscopic techniques based on charged information carriers because those systems do not show charging.…”

Section: Introductionmentioning

confidence: 99%

Model Studies on Heterogeneous Catalysts at the Atomic Scale

2014

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Thin single crystalline oxide films comprise perfect supports to grow nanoparticles of metals and other catalytically relevant materials. The model systems thus created can be thoroughly investigated with respect to structure and/or chemical activity applying both, the techniques of surface science under ultrahigh vacuum conditions as well as the traditional techniques applied in catalysis to study chemical kinetics under ambient conditions. We discuss here in particular the oxidation of methanol to formaldehyde on ceria supported vanadia nanoclusters as well as the effect of transition-metal dopants in single crystalline oxides, such as CaO, on the activation of molecular oxygen

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“…[1][2][3][4] In a simplified picture, substitution of a small number of intrinsic ions with aliovalent dopants changes the internal charge balance of the material. [1][2][3][4] In a simplified picture, substitution of a small number of intrinsic ions with aliovalent dopants changes the internal charge balance of the material.…”

Section: Introductionmentioning

confidence: 99%

Surface defects and their impact on the electronic structure of Mo-doped CaO films: an STM and DFT study

Cui

Shao

Prada

et al. 2014

Phys. Chem. Chem. Phys.

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The functionality of doped oxides sensitively depends on the spatial distribution of the impurity ions and their interplay with compensating defects in the lattice. In our combined scanning tunneling microscopy (STM) and density functional theory (DFT) study, we analyze defects occurring in Mo-doped CaO(001) films at the atomic scale. By means of topographic imaging, we identify common point and line defect in the doped oxide, in particular Mo donors and compensating Ca vacancies. The influence of charged defects on the oxide electronic structure is analyzed by STM conductance spectroscopy. The experimentally observed defect features are connected to typical point defects in the CaO lattice by means of DFT calculations. Apart from the identification of individual defects, our study reveals a pronounced inhomogeneity of the oxide electronic structure, reflecting the uneven spatial distribution of dopants in the lattice. Our results provide the basis for a better understanding of adsorption and reaction patterns on doped oxides, as widely used in heterogeneous catalysis.

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Model studies on heterogeneous catalysts at the atomic scale: From supported metal particles to two-dimensional zeolites

Cited by 27 publications

References 106 publications

Oxygen activation on oxide surfaces: A perspective at the atomic level

Oxygen activation on oxide surfaces: A perspective at the atomic level

Model Studies on Heterogeneous Catalysts at the Atomic Scale

Surface defects and their impact on the electronic structure of Mo-doped CaO films: an STM and DFT study

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