▎ 摘　　要

In this work, nickel-graphene and nickel-graphene oxide composite electrodes were employed as anodes in the electrocatalytic oxidation of urea in an alkaline solution. These composite electrodes have a higher surface area than the unmodified nickel electrode. As the current density increases during the composite formation process, the roughness of the surface and the adhesion of the coating to the substrate increase. The obtained composites have a higher activity than the nickel electrode in both alkaline solution and alkaline solution supplemented with urea. Furthermore, the nickel-graphene composite electrodes are characterized by a higher electroactivity than nickel-graphene oxide electrodes in the urea oxidation process. (C) 2019 Elsevier Ltd. All rights reserved.