Electrooxidation of sulfide by cobalt pentacyanonitrosylferrate film on glassy carbon electrode by cyclic voltammetry

摘要

A glassy carbon (GC) electrode was modified with cobalt pentacyanonitrosylferrate (CoPCNF) film. Cyclic voltammetry (CV) of the CoPCNFonto the GC(CoPCNF/GC) shows a redox couple (Fe~(III)/Fe~(II)) with a standard potential (E~(0')) of 580 mV. The current ratio I_(pa)/I_(pc) remains almost 1, and a peak separation (ΔE_p) of 106 mV is observed in 0.5 M KNO_3 as the supporting electrolyte. Anodic peak currents were found to be linearly proportional to the scan rate between 10 and 200 mVs~(-1), indicating an adsorption-controlled process. The redox couple of the CoPCNF film presents an electrocatalytic response to sulfide in aqueous solution. The analytical curve was linear in the concentration range of 7.5 × 10~(-5) to 7.7 × 10~(-4) M with a detection limit of 4.6 × 10~(-5) M for sulfide ions in 0.5 M KNO_3 solution.