par McEwen, Jean-Sabin ;Pineda, M;Garcia Cantu Ros, Anselmo ;Gaspard, Nicolas ;Barroo, Cédric ;Visart de Bocarmé, Thierry ;Kruse, Norbert
Référence International Conference on Statistical Physics of the International Union for Pure and Applied Physics (IUPAP) (24: 2010-07-19->23: Cairns, Australie)
Publication Non publié, 2010-07-19
Communication à un colloque
Résumé : We demonstrate that field ion microscopy (FIM) experiments along with corresponding DFT calculations strongly indicate that a positive electric field promotes the oxidation of a rhodium field emitter tip. We also show that the nonequilibrium oscillatory nanopatterns, as observed when H2 and O2 are exposed on a rhodium field emitter tip, find their origin in the anisotropic catalytic properties of the nanofacets that are simultaneously exposed at the tip’s surface. The basis of such conclusions is a kinetic model for hydrogen, oxygen and subsurface oxygen, which takes into account the anisotropy of the surface by expanding the kinetic constants into kubic harmonics suitable for the underlying fcc crystal.In the case of platinum field emitter tips, the dependence of the decomposition barrier of NO, (NO)2 and NO2 on the underlying facet orientation is examined with DFT and compared to experimental results. In particular, the adsorption behavior of NO2 on Pt{012} in the presence and in the absence of an electric field is undertaken so as to better understand the regular oscillations that are observed when H2 and NO2 are exposed to platinum.