The present invention relates to a method of producing carbon nanomaterials using tyres, characterized by the steps of: thermal decomposition of the tyre to produce coal; grinding the coal to obtain particulates; mixing the particulates with transition metal-based catalyst; and heating the particulates to produce carbon nanomaterials; wherein said carbon nanomaterials comprises graphene, carbon nanostructures including nano-dendrites, nano-hexacones, nanospheres, nano-donuts, nanoparticles and nanorods, or combination thereof.