Electrocatalytic oxidation of nitrites on glassy carbon electrode modified with cobalt (ii) tetra-carboxy phthalocyanine/ nitrogen doped graphene oxide nanosheets composite.

Abstract

This research is based on the modification of a glassy carbon electrode with cobalt (II) tetra carboxy phthalocyanine and nitrogen doped graphene oxide nanosheets composite (CoTCPc/N GONS) was used for the electrocatalytic oxidation of nitrites. The synthesised cobalt (II) tetra carboxy phthalocyanine (CoTCPc) and nitrogen doped graphene oxide nanosheets (N-GONS) were characterized by FTIR spectroscopy, UV-Vis spectroscopy, electrochemical impedance and cyclic voltammetry. The electrode surface area for CoTCPc/N-GONS-GCE was 0.174 cm2, which was at least twice that of a BGCE indicating that the modified electrode provided larger surface area for electro catalysis. The modified electrode had a surface coverage of 1.22. The CoTCPc/N-GONS-GCE had kapp and RCT values of 3.64 and 145.47 Ω respectively. The electrochemical detection of the nitrite with CoTCPc/N-GONS GCE was successful producing high peak currents compared to other electrodes. The electrocatalytic oxidation of nitrite was determined to be a 1st order reaction and with a Tafel slope of 270 mV/decade. Limit of detection (LOD) was M and Limit of quantification (LOQ) was M. The electrode showed good reproducibility with lower oxidation potential at 0.86 V and high sensitivity towards nitrite.