Both synthesis method and heteroatom doping could tailor graphene properties and promise its practical application. Here, a facile electrolytic route was developed to prepare amino-functionalized graphene, which could be directly used to build chemical sensor electrode. In this method, graphene oxide (GO) was electrolyzed in ethylenediamine aqueous solution to induce ammonization and electrochemical reduction successively. The unique chemical structure of ammoniated reduced GO (AErGO) strongly increased the chelation between electrode surface and Pb2+, and provided plenty active sites for electrochemical redox. Therefore, AErGO exhibits good electrical conductivity and high electrocatalytic activities, which ensures high selectivity, low detection limit (0.0924 mu g L-1 at S/N = 3) and ultra wide linear range (0.5-350 mu g L-1) during the Pb2+ detection. This simple and effective route can also be extended in the preparation of S-doping or S, N-dual doping graphene materials with potential applications in chemical sensor, electrochemical catalysis, and energy conversion or storage. (C) 2016 Elsevier Ltd. All rights reserved.