METALLOPHTHALOCYANINE CATALYZED ELECTROREDUCTION OF NITRATE AND NITRITE IONS IN ALKALINE MEDIA

The electrochemical reduction of nitrite and nitrate in alkaline solut ion has been studied on glassy carbon electrodes modified with phthalo cyanine complexes of Mn, Fe, Co, Ni, Cu and Zn (MnPc, FePc, CoPc, NiPc , CuPc and ZnPc, respectively, and Pc(-2) is phthalocyanine dianion). Voltammetry shows that the reduction of nitrite occurs at potentials s lightly less negative than for nitrate reduction. The MPc complexes lo wer the overpotential for the reduction of nitrite and nitrate as foll ows: CuPc > FePc > NiPc > CoPc > MnPc > ZnPc > glassy carbon electrode . The main product for the reduction of nitrite and nitrate is ammonia , with high yields of ammonia being obtained, depending on the choices of the electrolysis potential and MPc complex.