▎ 摘　　要

NOVELTY - Iron-based substrate derived from discarded carbon-fixed iron sheets in factories, is claimed. The thickness of the discarded carbon-fixing iron sheet is less than 0.3 mm, the surface roughness is ≯ 1000 nm, and the carbon content is 0.8-1.2 wt.%. USE - The iron-based substrate is useful for producing graphene, which is useful in the field of new material, preferably for preparing large area, high quality single crystal or graphene film. ADVANTAGE - The iron-based substrate: utilizes the waste pure iron sheet which is low in price, easy to obtain, low in hardness and easy to carry out polishing treatment, and has high carbon dissolving ability; utilizes the carbon element contained in the substrate, which is gradually segregated in the CVD preparation process, so as to serve as the role of carbon source, thus avoiding the addition of external gas carbon source; provides few layers graphene with less defects and wrinkles, good mechanical and electric performance, can be completely transferred to the target substrate under the condition without polymer auxiliary, avoids the introduction and complex cleaning process of the polymer impurity, and realizes the utilization of the waste material and low temperature preparation of high quality, graphene connected with the development concept of green chemistry; and provides graphene with high crystallization degree, defect and wrinkle amount. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for the method for producing graphene by using the iron-based substrate.