Water-assisted highly enhanced crystallographic etching of graphene by iron catalysts*
Xue Lei-Jianga), Yu Fangb), Zhou Hai-Qingb)†, Sun Lian-Fengb)‡
       
Turning of channels along the symmetry lines with angles of 120° or 60° in graphite at 900 °C for 30 min by iron etching without (a) and with water addition (b). A typical AFM image (c) and height profiles (d) showing the etched nanotrenches on graphite without water addition. It is worth noting that almost no iron nanoparticles can be detected if some water vapor is introduced during the etching processs, for which the underlying mechanism is still not clear.