TY - JOUR
T1 - Graphene as an anti-corrosion coating layer
AU - Kyhl, Line
AU - Nielsen, Sune Fuglsang
AU - Čabo, Antonija Grubišić
AU - Cassidy, Andrew
AU - Miwa, Jill A.
AU - Hornekær, Liv
PY - 2015
Y1 - 2015
N2 - Graphene, a single layer of carbon atoms arranged in an aromatic hexagonal lattice, has recently drawn attention as a potential coating material due to its impermeability, thermodynamic stability, transparency and flexibility. Here, the effectiveness of a model system, a graphene covered Pt(100) surface, for studying the anti-corrosion properties of graphene, has been evaluated. Chemical vapour deposition techniques were used to cover the single crystal surface with a complete layer of high-quality graphene and the surface was characterised after exposure to corrosive environments with scanning tunnelling microscopy (STM) and Raman spectroscopy. Graphene covered Pt samples were exposed to: (i) ambient atmosphere for 6 months at room temperature and 60°C for 75 min, (ii) Milli-Q water for 14 hours at room temperature and 60°C for 75 min, and (iii) saltwater (0.513 M NaCl) for 75 min at room temperature and 60°C. STM provides atomic resolution images, which show that the graphene layer and the underlying surface reconstruction on the Pt(100) surface remain intact over the majority of the surface under all conditions, except exposure to saltwater when the sample is kept at 60°C. Raman spectroscopy shows a broadening of all graphene related peaks due to hybridisation between the surface Pt d-orbitals and the graphene π-bands. This hybridisation also survives exposure to all environments except saltwater on the hot surface, with the latter leading to peaks more representative of a quasi free-standing graphene layer. A mechanism explaining the corrosive effect of hot saltwater is suggested. Based on these experiments, graphene is proposed to offer protection against corrosion in all tested environments, except saltwater on a hot surface, and Raman spectroscopy is proposed as a useful method for indirectly assessing the chemical state of the Pt surface.
AB - Graphene, a single layer of carbon atoms arranged in an aromatic hexagonal lattice, has recently drawn attention as a potential coating material due to its impermeability, thermodynamic stability, transparency and flexibility. Here, the effectiveness of a model system, a graphene covered Pt(100) surface, for studying the anti-corrosion properties of graphene, has been evaluated. Chemical vapour deposition techniques were used to cover the single crystal surface with a complete layer of high-quality graphene and the surface was characterised after exposure to corrosive environments with scanning tunnelling microscopy (STM) and Raman spectroscopy. Graphene covered Pt samples were exposed to: (i) ambient atmosphere for 6 months at room temperature and 60°C for 75 min, (ii) Milli-Q water for 14 hours at room temperature and 60°C for 75 min, and (iii) saltwater (0.513 M NaCl) for 75 min at room temperature and 60°C. STM provides atomic resolution images, which show that the graphene layer and the underlying surface reconstruction on the Pt(100) surface remain intact over the majority of the surface under all conditions, except exposure to saltwater when the sample is kept at 60°C. Raman spectroscopy shows a broadening of all graphene related peaks due to hybridisation between the surface Pt d-orbitals and the graphene π-bands. This hybridisation also survives exposure to all environments except saltwater on the hot surface, with the latter leading to peaks more representative of a quasi free-standing graphene layer. A mechanism explaining the corrosive effect of hot saltwater is suggested. Based on these experiments, graphene is proposed to offer protection against corrosion in all tested environments, except saltwater on a hot surface, and Raman spectroscopy is proposed as a useful method for indirectly assessing the chemical state of the Pt surface.
UR - http://www.scopus.com/inward/record.url?scp=84937458375&partnerID=8YFLogxK
U2 - 10.1039/c4fd00259h
DO - 10.1039/c4fd00259h
M3 - Article
AN - SCOPUS:84937458375
SN - 1359-6640
VL - 180
SP - 495
EP - 509
JO - Faraday Discussions
JF - Faraday Discussions
ER -