A facile one-step electrochemical fabrication of reduced graphene oxide-mutilwall carbon nanotubes-phospotungstic acid composite for dopamine sensing

A novel one-step electrochemical method is developed to fabricate the composite of reduced graphene oxide-mutilwall carbon nanotubes-phospotungstic acid (RGO-MWNTs-PTA) on electrodes and used for the detection of dopamine (DA) in the presence of high concentrations of ascorbic acid (AA). Comparing with RGO, PTA, RGO-PTA, RGO-MWNTs, MWNTs-PTA modified electrodes, the RGO-MWNTs-PTA modified electrode is more sensitive and selective to DA due to a synergistic effect. The synergistic effect results from: (i) the enlarged area of electrodes due to the intercalation of mutilwall carbon nanotubes between the stacked reduced graphene oxide with associated large electrochemical active sites and 3D nano-structured RGO-MWNTs covered by numerous PTA particles; (ii) the improved conductivity through the formation of a 3D network aided by mutilwall carbon nanotubes; (iii) the accelerated electron transfer rates which is due to aromatic pi-pi stacking and electrostatic attraction between positively-charged DA and negatively-charged RGO-MWNTs-PTA-modified electrode. The sensing performance of RGO-MWNTs-PTA-modified electrode is investigated by differential pulse voltammetry (DPV), revealing a linear range of 0.5-20 mu M with a detection limit of 1.14 mu M (3 sigma method). (C) 2013 Elsevier B.V. All rights reserved.