Surface relaxation, platinum crystals

Surface Relaxation of Platinum Single Crystals Induced... 

The adsorption of anions on metal electrodes has been studied in electrochemistry since the midfifties by many authors. The two main problems with these studies were the cleanliness of the electrolyte and the crystal orientation and topology of the noble-metal surfaces. At the beginning of the twenty-first century, the incorporation of in situ surface sensitive techniques became a reality among the electrochemists. The case of the specific adsorbable anions deserves special attention because their interaction with the surface can induce surface relaxation of the metal. One of the most interesting and important interfaces is the (bi)sulfate/platinum system. 

A variety of model catalysts have been employed we start with the simplest. Single-crystal surfaces of noble metals (platinum, rhodium, palladium, etc.) or oxides are structurally the best defined and the most homogeneous substrates, and the structural definition is beneficial both to experimentalists and theorists. Low-energy electron diffraction (LEED) facilitated the discovery of the relaxation and reconstruction of clean surfaces and the formation of ordered overlayers of adsorbed molecules (3,28-32). The combined application of LEED, Auger electron spectroscopy (AES), temperature-programmed desorption (TPD), field emission microscopy (FEM), X-ray and UV-photoelectron spectroscopy (XPS, UPS), IR reflection... 

Gold, platinum and iridium (100) crystal faces all show reconstruction [1]. Figure 10 shows the stucture of the reconstructed silicon (100) crystal face. In this surface, the silicon atoms form a dimer-like surface structure and there is a relaxation or contraction at... 

There are two major findings of modern surface science that were uncovered during studies of clean, solid surfaces. These are reconstruction, as was demonstrated for the platinum and silicon crystal surfaces, and there is also relaxation. During relaxation the atoms are contracted in their interlayer distance near the surface region with respect to the interlayer distance in the bulk. However, the atomic locations in... 

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