Electrochemical synthesis of nanostructured copper-curcumin complex and its electrocatalytic application towards reduction of 4-nitrophenol

Nanostructured Cu(II)-curcumin complex was prepared by an electrochemical route on a glassy carbon electrode (GCE) using CuCl(2 center dot)2H(2)O and curcumin as precursors. The as-prepared complex was systematically characterized by various techniques. The scanning electron microscopy (SEM) images revealed that polycurcumin was formed in a rod-like structure while Cu-curcumin complex was made up of spherical nanoclusters with an average size 80 nm. UV-vis spectrophotometry and cyclic voltammetry data confirmed the formation of Cu-curcumin (1:1) complex. Electrochemical impedance spectroscopy (EIS) data suggest that the charge transfer is very facile at the Cu-curcumin/GCE. The electrocatalytic reduction of 4-nitrophenol on Cu-curcumin/GCE was evaluated with respect to that of polycurcumin/GCE and Cu/GCE by cyclic voltammetry. The catalytic peak current at the Cu-curcumin/GCE was 2.8 times higher and the overpotential was reduced by 310 mV compared to bare GCE. A differential pulse voltammetry (DPV) sensor was developed with a limit of detection of 68.2 nM and a current sensitivity of 1.57 mu A mu M-1 cm(-2). The fabricated sensor showed good selectivity to 4-nitrophenol in the presence of some likely interferents. The sensor showed great promise for sensitive and quantitative detection of 4-nitrophenol in real sample analysis. (C) 2017 Elsevier B.V. All rights reserved.