Electrochemical Detection and Catalytic Oxidation of Phenolic Compounds Over Nickel Complex Modified Graphite Electrode

A Novel Ni(II) mixed ligand complex modified graphite electrode is developed for detection and oxidation of the phenolic compounds based on simple cyclic voltammetric technique. The Ni(II) mixed ligand complex with thiocyanate and macro cyclic ligand 1, 4, 8, 11 tetraaza cyclotetradecane (cyclam) was synthesised and used for catalytic oxidation of phenolic compounds viz. phenol, nitro-phe-nol and chloro-phenol etc. The Ni(II)-cyclam-thiocyanate mixed ligand complex was synthesised in typ-ical molar ratio of 1:2:5:: Ni(II):cyclam:thiocyanate and crystallized followed by characterization and catalytic applications. The electrochemical study of the complex mediated graphite electrode revealed its fast electron-transfer property, as formation of higher oxidation state of central Ni(II) metal ion as Ni(III) on applying a positive potential, which catalyses the oxidation of the target species. The Ni(II) complex modified graphite paste electrode enhanced the oxidation current of phenolic compounds many times rel-atively at lower oxidation potential in comparison to simple graphite paste electrode. It is also found to be sensitive for the detection of various phenolic compounds in the range of 20 mg/L to 0.5mg/L in aque-ous solution. The Ni(II)-complex stability at higher potential and ambient condition proved its potential for sensing and detoxification of phenolic compounds released in the ecosystem from polluting indus-tries.