Electrochemical behaviour of mechanically alloyed copper-nickel and copper-cobalt alloys : J.L.Estrada et al. (National Polytechnic Inst., Mexico.)

Abstract

A novel nonenzymatic glucose sensor was developed by electrodepositing dendritic copper-cobalt nanostructures (Cu-Co NSs) on glassy carbon electrode (GCE) which was modified by reduced grapheme oxide-chitosan (RGO-CHIT) nanocomposites. The electrochemical behaviors and electrocatalytic performances of the sensor towards oxidation of glucose were evaluated by cyclic voltammograms, chronoamperometry and amperometric method. Compared to sensors based on monometal Cu or Co NSs, the sensor based on bimetal Cu-Co NSs exhibits good electrocatalytic activity towards oxidation of glucose. The effects of electrodeposition time and the ratio of Cu2+ and Co2+ in an electrodeposition solution on the electrocatalytic performance of the Cu-Co NSs sensor were explored in detail. The best catalytic activity towards oxidation of glucose can be achieved under an optimized condition: electrodepositing time of 2600 s and the Cu2+/Co2+ molar ratio of 2:1. The catalytic current density is linear to the glucose concentration in the range of 0.015–6.95 mM (r = 0.9947) with a sensitivity of 1921 μA cm−2 mM−1, and a detection limit of 10 μM. The good catalytic activity, high sensitivity and good stability indicate that the newly developed sensor based on the dendritic Cu-Co NSs/RGO-CHIT/GCE is a promising sensor for application in real samples.