Layered Nickel-Cobalt Oxide Coatings on Stainless Steel as an Electrocatalyst for Oxygen Evolution Reaction

In this work, we have obtained spinel-type nickel-cobalt oxide nanostructures on low-cost and easy-handling AISI304-type stainless steel substrate via simple potentiostatic electrodeposition. Nickel and cobalt hydroxide layers were formed by varying the deposition potential at the same time intervals (-1.15V for Ni(OH)(2) and -0.85V for Co(OH)(2)). An electrolyte bath containing 0.05M Ni(NO3)(2), 0.05M Co(NO3)(2), and 0.1M KNO3 was used for the electrodeposition. Structural analysis confirmed the formation of a spinel NiCo2O4 after thermal treatment. The influence of annealing temperature in the range of 473-1073K on the films activity in OER has been investigated using 0.1M NaOH. Nickel-cobalt oxide coatings demonstrated OER activity close to the benchmark IrO2 with the onset potential value of +1.6 (vs. RHE), overpotential of 530mV at 10mAcm(-2), and Tafel slope of 49mVdec(-1). Meanwhile, the electrocatalytic activity of separate Co3O4 and NiO is far smaller.