Fe-catalyzed thermal conversion of sodium lignosulfonate to graphene

► The study first time shows that graphene nanosheets can be prepared from sodium lignosulfonates.► Lignin, from pulping and bio-ethanol processes, can be a carbon source for nanomaterials.► Lignin with a sp2 structure makes its conversion to graphene easier than wood carbohydrates.► Graphene synthesized from lignin exists in overlapped graphene form with turbostratic structure.