Nanostructured catalysts for oxygen electroreduction based on bimetallic monoethanolamine complexes of Co(III) and Ni(II)

Abstract

Oxygen reduction electrocatalysts based on the monoethanolmine complexes {(CoEtm)2(l-Etm)4Ni(NO3)2} and {(CoEtm)2(l-Etm)4Ni(NO3)2} ? activated carbon AG-3 have been obtained by high-temperature synthesis. The nature of active centers on the synthesized electro- catalysts was described. Using potentiostatic and cyclic potentiodynamic voltammetry, the kinetic characteristics of catalysts in the oxygen electroreduction reaction were determined. Thermal decomposition of the thermally unstable complexes was described and character of the active centers formed was discussed. The optimal synthesis temperature of electrocatalysts is 600 C in an inert atmosphere. The calculated exchange current densities for the oxygen electroreduction reaction at the catalysts in 1 M KOH at 20 C was j0 = 1.01 9 10 -3 Ag -1 -3.3 9 10 -3 Ag -1 . The Tafel slopes of stationary polarization curves are 0.054-0.063 V for b1 and 0.106-0.125 V for b2. The prepared electrocatalysts can be recommended only for electrochemical systems with alkaline electrolyte.