The chemistry of reaction-diffusion fronts investigated by microscopic LEED I–V fingerprinting

Schmid, Andreas K.; Świȩch, W.; Rastomjee, C.S.; Rausenberger, B.; Engel, W.; Zeitler, E.; Bradshaw, Alexander M.

doi:10.1016/0039-6028(95)00128-x

Cited by 25 publications

(17 citation statements)

References 17 publications

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“…This problem can be overcome by measuring the I͑V͒ characteristics in real space with sufficient resolution to isolate individual nanoscale domains; a concept realized in IV low-energy electron microscopy ͑IV-LEEM͒. 4 Spectroscopic stacks of images of a surface are acquired from the ͑00͒ diffraction beam as a function of electron energy, V, so that the local image intensity, I͑x , y ; V͒, represents the specular low-energy electron reflectivity of nanoscale surface areas. From a time-lapse sequence of such stacks time-dependent I͑V͒ spectra can be obtained at every image pixel.…”

Section: Introductionmentioning

confidence: 99%

Structural imaging of surface oxidation and oxidation catalysis on Ru(0001)

2008

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Using simultaneous imaging and structural fingerprinting under reaction conditions, we probe the initial oxidation pathway and CO oxidation catalysis on Ru͑0001͒. Oxidation beyond an initial ͑1 ϫ 1͒-O adlayer phase produces a heterogeneous surface, comprising a disordered trilayerlike surface oxide and an ordered RuO 2 ͑110͒ thin-film oxide, which form independently and exhibit similar stability. The surface oxide and RuO 2 phases both show high intrinsic catalytic activity. The oxygen adlayer is inactive in isolation but becomes active due to cooperative effects in close proximity to the surface oxide.

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Section: Introductionmentioning

confidence: 99%

Structural imaging of surface oxidation and oxidation catalysis on Ru(0001)

2008

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“…This so-called I(V )-LEEM technique facilitates the measurement of the individual I(V ) dependence of nanosized surface phases and has already been applied to processes in epitaxial growth, 26 surface chemical reactions, 27 and oxidation catalysis.…”

Section: 20mentioning

confidence: 99%

Self-limited oxide formation in Ni(111) oxidation

et al. 2011

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The oxidation of the Ni(111) surface is studied experimentally with low energy electron microscopy and theoretically by calculating the electron reflectivity for realistic models of the NiO/Ni(111) surface with an ab initio scattering theory. Oxygen exposure at 300 K under ultrahigh-vacuum conditions leads to the formation of a continuous NiO(111)-like film consisting of nanosized domains. At 750 K, we observe the formation of a nano-heterogeneous film composed primarily of NiO (111) surface oxide nuclei, which exhibit virtually the same energy-dependent reflectivity as in the case of 300 K and which are separated by oxygen-free Ni(111) terraces. The scattering theory explains the observed normal incidence reflectivity R(E) of both the clean and the oxidized Ni(111) surface. At low energies R(E) of the oxidized surface is determined by a forbidden gap in the k = 0 projected energy spectrum of the bulk NiO crystal. However, for both low and high temperature oxidation a rapid decrease of the reflectivity in approaching zero kinetic energy is experimentally observed. This feature is shown to characterize the thickness of the oxide layer, suggesting an average oxide thickness of two NiO layers.

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“…It has long been recognized that not only adlayers containing rather heavy (high‐ Z ) elements, as discussed in the previous section, considerably modify the electron reflectivity, but also light (low‐ Z ) elements all the way down to hydrogen 13, 111, 112, providing evidence for the usefulness of LEEM and VLEED for studying gas adsorption and chemical reactions. The sensitivity of $ I(V)$ curves to adsorbate‐induced surface reconstructions has convincingly been demonstrated by Schmid and coworkers 110, who compiled an $ I(V)$ catalog for selectively prepared surface phases as shown in Fig. 5.…”

Section: Case Studiesmentioning

confidence: 52%

Section: Case Studiesmentioning

confidence: 99%