Electrochemical reduction of nitrate on graphene modified copper electrodes in alkaline media

The electrochemical reduction of nitrate on a new graphene modified Cu electrode prepared by chemical vapor deposition (CVD) has been studied in strongly alkaline solution by using cyclic voltammetry and controlled potential techniques. Electrocatalytic performance measurements of this composite electrode toward reduction of nitrate showed an increase of 3.5-folds in reduction peak densities compared to the bare copper electrode. Detection limits of 10 x 10(-6) and 8.0 x 10(-4) M were obtained for graphene modified Cu electrode and bare Cu electrodes by amperometric measurements respectively. The amperometric response of the modified electrode increased with the increase of nitrate concentration with a linear range of 9.0 x 10(-6)-9.4 x 10(-4) M and a detection limit of 10.0 mu M (signal-to-noise ratio of 3). Our results indicated that the modification of copper electrode with graphene adlayer exhibits a fast response (below ca. 5 s), a high sensitivity of 173.7 mu A mM(-1) cm(-2) and a remarkable increase of the electrocatalytic activity of Cu electrode for the nitrate reduction. (C) 2013 Elsevier B.V. All rights reserved.