Peeling off the graphene sheets layer-by-layer

http://www.sciencemag.org/content/331/6021/1168.abstract

Once again, the James Tour's group.
They just put zinc metal onto the graphene sheets and dissolve the metal with HCl....
The metal and the topmost graphene sheet is removed without affecting the underlying sheets.
What a strange thing it is!
The the bonding between metal and graphene is unlikely stronger than the carbon-carbon network!
Well, they have given an resonable explanation for that. They attributed the ease of removal to the defect formed during sputtering process, so that the damaged region of graphene can be easily removed during metal dissolving process.
In addition, they pointed out the dissolving process that accompanied with hydrogen formation is also play a role in removing process.
They also dissolved gold and copper with KI/I2 and HCl/CuCl2, respectively, which no hydrogen is formed during these two reactions. As a result, no carbon layer was removed by these two method....

That's a really interesting work!