Surface decoration of multi-walled carbon nanotubes modified carbon paste electrode with CuO nanoparticles for electrocatalytic oxidation of nitrite

Abstract

In this paper, CuO nanoparticles were electrodeposited onto the film of multiwalled carbon nanotubes (MWCNTs) modified carbon paste electrode (MWCPE), which fabricated a sensitive nano-copper oxide coated multi-walled carbon nanotubes modified carbon paste electrode (CuO_nano/MWCPE) to detect nitrite. Scanning electron microscope (SEM) image indicated that copper oxide nanoparticles desposited on MWCPE were homogeneous. The CuO_nano/MWCPE was used to detect nitrite by square wave voltammetry (SWV) and cyclic voltammetry (CV) techniques. The sensor exhibited outstanding performance for the electrocatalysis of nitrite. Electrocatalytic oxidation of nitrite at the surface of CuO_nano/MWCPE has been remarkably improved compared to the unmodified CPE and the MWCPE. Under optimum conditions the oxidation current was linear with the concentration of nitrite ion in the range of 5 μM – 1000 μM. The detection limit was evaluated to be 1.25 μM (S/N = 3). The sensor was successfully used to determine nitrite in water samples with excellent recoveries.