| AVS 61st International Symposium & Exhibition | |
| Atom Probe Tomography Focus Topic | Thursday Sessions |
| Session AP+AS+EN+NS+SS-ThA |
| Session: | APT and FIM Analysis of Catalysts and Nanomaterials |
| Presenter: | Cédric Barroo, Université Libre de Bruxelles, Belgium |
| Authors: | C. Barroo, Université Libre de Bruxelles, Belgium Y. De Decker, Université Libre de Bruxelles, Belgium N. Kruse, Université Libre de Bruxelles, Belgium T. Visart de Bocarmé, Université Libre de Bruxelles, Belgium |
| Correspondent: | Click to Email |
Thecatalytic hydrogenation of NO2 over platinum field emitter tips has been investigated by means of field emission techniques. Field emission microscopy (FEM), as well as field ion microscopy (FIM), has been proved to be an efficient method to study the dynamics of catalytic reactions occurring at the surface of a nanosized metal tip, which represents a good model of a single catalytic nanoparticle. These studies are performed during the ongoing reaction which is imaged in real time and space. Nanoscale resolution allows for a local indication of the instantaneous surface composition.
The presence of adsorbates modifies the value of the local work function. These variations are expressed by modulations of the brightness of field emission patterns. A qualitative investigation of the local surface composition is then possible as function of time.
The microscope is run as an open nanoreactor, ensuring that the system is kept far from thermodynamic equilibrium. Under these conditions, chemical reactions can induce time and space symmetry breaking of the composition of a system, for which periodic oscillations and target patterns are well-known examples.
Self-sustained periodic oscillations have been reported for the NO2 reduction. By increasing the time resolution of the system, it is now possible to study the emergence of these oscillations and to observe the propagation of chemical waves at the nanoscale, on a single facet of a nanocrystal. The velocity of wave propagation is estimated to be in the μm/s range, which is in accordance with previous studies of catalytic reaction at the mesoscale.