Enhanced electrocatalytic performance of FeNiCoP amorphous alloys as oxygen-evolving catalysts for electrolytic water splitting application

Abstract

Low cost and efficient oxygen-evolving electrocatalyst with excellent catalytic activity and long-term stability are urgently required for primary application in electrolytic water splitting. In the present work, novel quaternary FeNiCoP amorphous alloys as self-supports electrocatalysts have been synthesized by a facile melt-spinning technique to investigate the oxygen evolution reaction (OER) performances. In the case of acidic solutions, the most active electrode requires only an overpotential of 497 mV at a current density of 10 mA cm−2 with a Tafel slope of 79 mV dec−1 and exhibits long term stability of approximately 20 h. Further, the material achieves a low overpotential of 281 mV at 10 mA cm−2 with a Tafel slope of 38 mV dec−1, being comparable to IrO2 in alkaline solutions. Mössbauer spectroscopy analyses prove that the density of Fe-centered clusters with low coordination numbers is increased remarkably after the Co addition, resulting in enriched active sites and an enhancement in OER activity. In addition to this, there is a distinct increase in reaction kinetics with an advance in electrical conductivity. Furthermore, a synergistic effect between Fe (Ni or Co) oxide/hydroxide and phosphate species contributes to expediting of the OER process. This study will offer a cost-effective transition-metal material as robust electrodes for efficient OER.