Copper substrate as a catalyst for the oxidation of chemical vapor deposition-grown graphene

• A copper-supported graphene can be oxidized in Ar (O2<3 ppm, 600 °C, 2 h).
• O2 intercalates between graphene and copper upon exposure to air.
• The copper foil should not be considered as an inert substrate.

We report the catalytic effect of copper substrate on graphene–oxygen reaction at high temperature. Previous studies showed that graphene grown on copper are mostly defect-free with strong oxidation resistance. We found that a freshly prepared copper-supported graphene sample can be completely oxidized in trace amount of oxygen (<3 ppm) at 600 °C within 2 h. Both X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) suggest that upon ambient air exposure, oxygen molecules diffuse into the space between graphene and copper, resulting in the formation of copper oxide which acts as catalytic sites for the graphene-oxygen reaction. This result has important implications for the characterization, processing, and storage of copper-supported graphene samples.

The copper substrate enhances the thermel oxidation of single-layer graphene.Figure optionsDownload as PowerPoint slide