▎ 摘　　要

Multilayered graphene (MLG) Is an interesting material for electrochemical sensing and biosensing because of its very large 2D electrical conductivity and large surface area. We propose a less toxic, reproducible, and easy method for producing functionalized multilayer graphene from multiwalled carbon nanotubes (MWCNTs) in mass scale using only concentrated H2SO4/HNO3. Electron microscopy results show the MLG formation, whereas FTIR and XPS data suggest its carboxylic and hydroxyl-functionalized nature. We utilize this functionalized MLG for the fabrication of a novel amperometric urea biosensor. This biosensor shows linearity of 10-100 mg dL(-1), sensitivity of 5.43 mu A mg(-1) dL cm(-2), lower detection limit of 3.9 mg dL(-1), and response time of 10 s. Our results suggest that MLG Is a promising material for electrochemical biosensing applications.