Abstract: The fabrication of highly active and low cost bifunctional oxygen electrodes is a bottleneck for wide-spread utilization of renewable energy technologies such as unitized regenerative fuel cells (URFC) and metal-air batteries, such as Zn-air, Al-air and Li-air among others. The main challenge is to achieve high performance and reversibility of the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR), that are both kinetically sluggish and possess numerous intermediates. Moreover, the pH of the electrolyte drastically influences the performance of the catalyst due to shift in the potentials of the underlying intermediate reactions. Only a few metals like Pt are active for the ORR at low pH conditions as they can provide the high free energy for O2 adsorption [1]. Other compounds such as transition metal oxides possess promising ORR activity in basic electrolytes due to the easier activation of oxygen molecules in alkaline media [2]. The combination of ORR and OER catalysts into a composite aims at producing materials that can retain their individual properties or even slightly alter their activity due to a synergetic effect [3]. However, to date most bifunctional catalytic systems suffer from lack of activity of one of the reactions leading to a wide gap between overpotentials for the OER and ORR, along with low stability or high cost.

Cite: Kazakova M.A. , Elumeeva K.V. , Morales D. , Medina D. , Kuznetsov V.L. , Schuhmann W. , Masa J.
Bifunctional Oxygen Reduction/Evolution Activity of Fe/Сo/Ni Mixed Oxide Nanoparticles Supported on Oxidized Carbon Nanotubes
VIII International Symposium on Carbon for Catalysis 26-29 Jun 2018