Preparation method of circular graphene

A preparation method of circular graphene comprises the following steps: (1) cleaning the surface of a metal copper sheet, putting the cleaned metal copper sheet into a tube furnace, heating to make the temperature rise to 900-1040 DEG C under normal pressure conditions and in an inert gas atmosphere, then introducing hydrogen gas, and calcining for 10-25 min in inert gas and hydrogen gas atmospheres; (2) maintaining the calcination temperature and the gas atmospheres in the step (1), introducing a carbon source gas to the tube furnace, making the volume ratio of the carbon source gas to hydrogen gas be 2:5-2:3, growing graphene on the metal copper sheet, and growing for 30 s-10 min; and (3) closing the carbon source gas and the hydrogen gas, fast moving the tube furnace, making a quartz tube area placed with the metal copper sheet exposed at room temperature, and fast cooling to room temperature in the inert gas atmosphere. The preparation method has simple preparation technology and can be used for large-sc