Real-time observation of structural transformation of siver nanoparticles during carbon gasification
Résumé
Gasification of carbon can be achieved, in the presence of metal catalysts supported on solid carbon materials, at high temperature in oxidative environments. Indeed, oxygen adsorbs and dissociates on the metal surface then interacts with the carbon at the interface with the metal leading to the formation of carbon dioxide; concurrently carbon is consumed and the metallic nanoparticle maintains the interface with the carbon and thus advances, forming in this way a trench on the surface of the carbon. On structured materials such as graphite or graphene these trenches tend to be rather 2D [1,2] at the surface of the material (hereafter named “pacman effect”). In this work we have studied the gasification of a non-structured material (amorphous carbon) by silver-based nanoparticles (NPs) in presence of oxygen and at variable temperatures. We were particularly interested on the dynamic structural evolution of the silver NPs observed in real-time within an environmental TEM and at atomic resolution as permitted by the imaging Cs-corrector.
