Catalytic Nanopatterning of Few-Layer Graphene

5 years ago

Catalytic Nanopatterning of Few-Layer Graphene

Ovidiu Ersen, Cuong Pham-Huu, Walid Baaziz, Simona Moldovan, Charles Hirlimann, Sylvie Bégin-Colin, Georgian Melinte

The catalytic nanopatterning of few-layer graphene (FLG) sheets using metallic nanoparticles as catalytic “nanogouges” is a promising method for fabricating graphene nanoribbons. However, in the absence of in situ observations of the active nanoparticles during the catalytic process, a unified model of the channeling mechanism is unavailable. On the basis of a real-time TEM investigation of iron nanoparticle patterning of FLG, this study addresses key aspects of the channeling mechanism. As the catalytic reactions take place at temperatures at which the active nanoparticles present a melted superficial layer, the adhesion forces at the nanoparticle/FLG interface were found to have a crucial role in defining their faceting geometry. Mono- and multifaceted frontal geometries are induced by the interaction with the vertical FLG edges, and only such faceting arrangements can support a controlled anisotropic channeling. When the channeling direction is changed, nanoparticles go through a process of surface rearrangement that aims at rebuilding a faceting geometry in equilibrium with the FLG edge. The melted superficial layer appears as the main nanoparticle region that supports the dissolution of FLG edges, and a concentration gradient is moving the dissolved carbon atoms from the interface regions toward the rear side of the nanoparticles.

Publisher URL: http://dx.doi.org/10.1021/acscatal.7b01777

DOI: 10.1021/acscatal.7b01777