In Situ Observations of the Atomistic Mechanisms of Ni Catalyzed Low Temperature Graphene Growth

• DOI: 10.1021/nn402927q
• Publication Date: 2013-08-08T04:38:45Z
• Authors: Laerte L. Patera; Cristina Africh; Robert S. Weatherup; Raoul Blume; Sunil Bhardwaj; Carla Castellarin...; Axel Knop-Gericke; Robert Schloegl; Giovanni Comelli; Stephan Hofmann; Cinzia Cepek
• Keywords: Carbon fibers

The key atomistic mechanisms of graphene formation on Ni for technologically relevant hydrocarbon exposures below 600 °C are directly revealed via complementary in situ scanning tunneling microscopy and X-ray photoelectron spectroscopy. For clean Ni(111) 500 °C, two different surface carbide (Ni2C) conversion dominant which both yield epitaxial graphene, whereas above predominantly grows replacement leading to embedded and/or rotated domains. Upon cooling, additional carbon structures form exclusively underneath growth mechanism also critically depends the near-surface concentration hence is intimately linked full history catalyst all possible sources contamination. detailed XPS fingerprinting these processes allows a direct link high pressure measurements wide range conditions, including polycrystalline catalysts recipes commonly used industrial reactors nanotube CVD. This enables an unambiguous consistent interpretation prior literature assessment how quality/structure as-grown nanostructures relates modes.