Ni0.9co2.1o4 mixed valence oxide nanoparticules composite electrode catalysts for oxygen reduction in alkaline solutions

Nickel cobalt mixed valence oxide nanoparticles composite Ni0.9Co2.1O4 was prepared by sol-gel method via propionic acid. The cell parameter and the average crystallite size of the Ni0.9Co2.1O4 composite are 8.102 Å and 49.57 nm, respectively. The composition and spinel type structure of the binary mixed oxide were characterized by X-ray photoelectron spectroscopy (XPS) combined with cyclic voltammetry (CV). It was found that the as-synthesized composite has a mixed spinel structure. Cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and chronopotentiometry measurements were performed to investigate the electrochemical properties of the composite. The results indicate that Ni0.9Co2.1O4 oxide composite offer high electrical reactivity, good stability in alkaline media, and that increasing the polarization potential leads to the decrease in catalytic performance.