S. Sunohara et al., ELECTROCATALYSIS OF TRANSITION-METAL OXIDES FOR REDUCTION AND OXIDATION OF NITRITE IONS, Journal of electroanalytical chemistry [1992], 354(1-2), 1993, pp. 161-171
Electrodes of Mn, Fe, Co, Ni and Cu oxides supported on graphite subst
rates were prepared by pyrolysis of the metal nitrates. Ex situ X-ray
photoelectron spectroscopy (XPS) revealed that Mn, Fe and Ni oxides at
different chemical states were present at the electrode surfaces. The
electrodes catalyzed the reduction and oxidation of NO2- in a weakly
acidic medium (pH 2). All of the electrodes were deactivated by increa
sing the amount of metal oxide deposited, probably because of an incre
ase in electric resistance of the deposited electrodes. The Fe oxide e
lectrode with a small amount of deposited oxide exhibited the highest
activity for the reduction and oxidation of NO2-.