Step interactions on Pt(111) vicinal surfaces determined by grazing incidence X-ray diffraction: Influence of the step orientation

Abstract

We have studied the step-step interactions on the Pt(997) vicinal surface. Grazing incidence X-ray diffraction (GIXD) allowed us to measure the elastic atomic relaxations near the surface due to the steps. By means of the model of buried elastic dipoles, within the framework of anisotropic linear elasticity (ALE) calculations, the surface stress of Pt (111), and the elastic interaction between steps are deduced. The values so-obtained are compared to the values previously measured on the Pt(779) surface with the same technique. The comparison shows the strong influence of step geometry on step interactions.

Size-Dependent and Step-Modulated Supramolecular Electrochemical Properties of Catechol-Derived Adlayers at Pt(hkl) Surfaces

“…This trend is reinforced by the reversal of the Smoluchowski effect 54 arising from dipole−dipole interactions between steps at high surface step-densities, expected to be largest at Pt(100) steps due to their relative dipole spatial orientation as portrayed in Figures 1d and 2d. 55 Finally, at the turning point of the vicinal series, that is, Pt(311), the highest (100) step density is reached and the 2D phase transition vanishes as expected from Figure 3 for a system that does not reach the critical dimensionality or as expected, from the Peierls theorem, for a 1D system. 41…”

“…In this limit, terrace-to-terrace aggregation effects dominate energy minimization, favoring the incorporation of molecules near the step to the growing surface aggregate, leading to interterrace band formation and to the “unexpected” decreases in fwhm due to the re-establishment of the freely propagating 2D PT predominant at extended well-ordered Pt(111) domains. This trend is reinforced by the reversal of the Smoluchowski effect arising from dipole–dipole interactions between steps at high surface step-densities, expected to be largest at Pt(100) steps due to their relative dipole spatial orientation as portrayed in Figures d and d . Finally, at the turning point of the vicinal series, that is, Pt(311), the highest (100) step density is reached and the 2D phase transition vanishes as expected from Figure for a system that does not reach the critical dimensionality or as expected, from the Peierls theorem, for a 1D system …”

Electronic and structural study of Pt-modified Au vicinal surfaces: a model system for Pt–Au catalysts

“…4 shows two topographic profiles traced in the direction parallel to the step edge for Pt/Au(887) with y Pt = 0.29 and 0.59. Considering the theoretical value of 2.26 Å for a monoatomic height of a Pt island, 41 we determine that there is a monolayer to bilayer transition in the growth mode of Pt nanoislands on the fcc sites of Au(887) as coverage increases. Also, the FFT of STM image shown in Fig.…”

Diatomic Steps in Pt(997) Surfaces Are Better Catalysts than Monatomic Steps for the CO Oxidation Reaction near Atmospheric Pressure

“…These differences might be related to the different interaction energies between steps on both surfaces. Previous work − showed that, within an elastic deformation framework, the repulsive energy between (111) steps is significantly higher (a factor of 3.5) than that for (100) steps, which might explain the step doubling for the (997) surface in contrast to the faceting observed for Pt(977). Step fluctuations leading to faceting are easier on Pt(977) due to the lower energetic cost of terrace width fluctuations.…”