Catalytic reaction between adsorbed oxygen and hydrogen on Rh(111)

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Nucleation, Growth, and Relaxation of Thin Films: Metal(100) Homoepitaxial Systems

We describe work in our laboratory that has shed new light on nucleation, growth, and relaxation processes in thin metal films. The progress comes from the synergistic and synchronous implementation of theory and experiment, which reveals surprising secrets hidden a very simple model system

Work function of a quasicrystal surface: Icosahedral Al–Pd–Mn

The work function of a surface is one of its most basic and influential features. It has long been recognized that work function controls thermionic and field emission. The work function of a solid surface affects charge transfer to or from an adsorbate. It influences the electron tunneling probability between surfaces. It plays a role in quantization of electron states parallel to the surface in metal-supported metallic nanoislands. There is also evidence linking the work function of a metal surface to its friction coefficient

Homogeneous and Heterogeneous Front Nucleation in a Bistable Surface Reaction: The NO + CO Reaction on a Cylindrical Pt Crystal

Under continuous flow conditions the oscillatory NO + CO reaction on Pt(100) exhibits bistability in the temperature range below 440 K. In this range, an inactive stationary branch coexists with a reactive oscillatory branch. The transition from the inactive branch, which is only metastable, to the truly stable active branch proceeds via propagating reaction fronts. The associated nucleation process has been investigated in the 10-6 mbar range using photoemission electron microscopy (PEEM) as a spatially resolving method. A Pt sample of cylindrical shape whose surface comprises the highly active orientational range between (100) and (3 10) was used as a catalyst. Depending on the degree of supersaturation, both heterogeneous and homogeneous nucleation have been found. Homogeneous nucleation manifests itself in the occurrence of a so-called “surface explosion” at Tc = 440 K. Below this temperature, heterogeneous nucleation occurs. Depending on the preparation of the inactive state, we observe two different nucleation scenarios which we can tentatively assign to two different kinds of defects