Graphene Coatings: Probing the Limits of the One Atom Thick Protection Layer
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- 作者：Louis Nilsson ; Mie Andersen ; Richard Balog ; Erik L忙gsgaard ; Philip Hofmann ; Flemming Besenbacher ; Bj酶rk Hammer ; Ivan Stensgaard ; Liv Hornek忙r
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：November 27, 2012
- 年：2012
- 卷：6
- 期：11
- 页码：10258-10266
- 全文大小：722K
- 年卷期：v.6,no.11(November 27, 2012)
- ISSN：1936-086X
文摘
The limitations of graphene as an effective corrosion-inhibiting coating on metal surfaces, here exemplified by the hex-reconstructed Pt(100) surface, are probed by scanning tunneling microscopy measurements and density functional theory calculations. While exposure of small molecules directly onto the Pt(100) surface will lift the reconstruction, a single graphene layer is observed to act as an effective coating, protecting the reactive surface from O2 exposure and thus preserving the reconstruction underneath the graphene layer in O2 pressures as high as 10鈥? mbar. A similar protective effect against CO is observed at CO pressures below 10鈥? mbar. However, at higher pressures CO is observed to intercalate under the graphene coating layer, thus lifting the reconstruction. The limitations of the coating effect are further tested by exposure to hot atomic hydrogen. While the coating can withstand these extreme conditions for a limited amount of time, after substantial exposure, the Pt(100) reconstruction is lifted. Annealing experiments and density functional theory calculations demonstrate that the basal plane of the graphene stays intact and point to a graphene-mediated mechanism for the H-induced lifting of the reconstruction.