par Bilinska, Sylwia;Lambeets, Sten 
;Visart de Bocarmé, Thierry ;Bryl, Robert ;Markowski, Leszek
Référence International Workshop on Surface Physics (7: 2015-06-22: Trzebnica, Poland)
Publication Non publié, 2015-06-22
;Visart de Bocarmé, Thierry ;Bryl, Robert ;Markowski, LeszekRéférence International Workshop on Surface Physics (7: 2015-06-22: Trzebnica, Poland)
Publication Non publié, 2015-06-22
Poster de conférence
| Résumé : | The studies of thermal faceting of crystals of platinum group metals induced by oxygen adsorption were triggered among others by their rich catalytic properties and widespread in numerous catalytic applications. In this context Field Ion Microscopy (FIM) is a great experimental tool for studying the crystal morphology. The specimen – a metal tip of radius of curvature around 15-25 nm - can be regarded as a good model of a particle of a real catalyst, by its size and its shape. Faceting experiments carried out on curved surfaces can show morphological and structural changes of many different planes simultaneously, giving an insight into the evolution of shape of the microcrystals of the catalyst.In this contribution the influence of oxygen adsorption on the shape of the Pt nanosized crystal will be presented. The clean Pt tip annealed at around 700 K exposed only low index {001} and {111} planes. For low oxygen exposures the crystal shape did not change considerably. When the crystal was exposed to more than 100 L at around 300 K the development of {113}, {111}, {100} planes was observed after annealing of the tip at 700 K. The planes of such reconstructed crystal were separated by relatively broad zones of corrugated, rounded 'edges', what is in contrast to sharp interplanar edges observed during faceting of Pd [1] and Ir [2] crystals adsorbed with low amounts of oxygen. |
