  Graphene oxide (GO) is one of the important functional materials. Large-scale
synthesis of it is very challenging. Following a simple cost-effective route,
large-scale GO was produced by mechanical (ball) milling, in air, of carbon
nanoparticles (CNPs) present in carbon soot in the present study. The thickness
of the GO layer was seen to decrease with an increase in milling time. Ball
milling provided the required energy to acquire the in-plane graphitic order in
the CNPs reducing the disorders in it. As the surface area of the layered
structure became more and more with the increase in milling time, more and more
oxygen of air got attached to the carbon in graphene leading to the formation
of GO. An increase in the time of the ball mill up to 5 hours leads to a
significant increase in the content of GO. Thus ball milling can be useful to
produce large-scale two-dimensional GO for a short time.
