Multimetallic nanostructure spinels composed of nickel, cobalt, and manganese ions were synthesized and their bifunctional catalytic activity towards oxygen evolution and oxygen reduction reaction in alkaline pH is reported. Three different compositions, namely, NiCoMnO 4 Ni 1.5 Co 0.75 Mn 0.75 O 4 and Ni 2 Co 0.5 Mn 0.5 O 4 were prepared by a simple template-free hydrothermal route followed by a thermal treatment in air at 600 °C. The ORR/OER activity and the stability of these ternary metal oxides strongly depend on the composition of transition metals. The best performing Ni 1.5 Co 0.75 Mn 0.75 O 4 catalyst exhibits modest OER and ORR activity with an overpotential difference (ΔE = E ORR -E OER ) of 0.79 V vs. RHE between two reactions in alkaline solution, comparable to expensive and supported IrO 2 Pt catalysts. Electrochemical studies and extensive physical characterizations indicated that amount of nickel substituted in the crystal lattice influence the bifunctional catalytic activity of the studied ternary metal oxide compositions.
Bibliographical noteFunding Information:
P. Sivakumar thanks the Council for Higher Education, State of Israel for the PBC scholarship for outstanding postdoctoral researchers from China and India. Palaniappan Subramanian acknowledge the support of INREP and Ariel University postdoctoral fellowship program for providing the research scholarship. Alex Schechter would like to thank the Israel Science Foundation (ISF) for funding the research work through the Israel National Research Center for Electrochemical Propulsion (INREP) and I-CORE Program (number 2797/11 ).
© 2019 Elsevier B.V.
- Oxygen evolution
- Oxygen reduction
- Spinel oxides