Electrodeposited Ni–Fe–P–FeMnO3/Fe multi-stage nanostructured electrocatalyst with superior catalytic performance for water splitting.

It is very important to design and prepare low-cost and high-efficiency electrocatalysts for water splitting in alkaline solution. In this study, Ni–Fe–P and Ni–Fe–P–FeMnO₃ electrocatalysts are developed using a facile electrodeposition method. Transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) characterization studies show that FeMnO₃ particles are successfully composited into the Ni–Fe–P amorphous matrix, and multi-stage nanostructures are obtained which enable the exposure of more active sites for the hydrogen evolution reaction. The Ni–Fe–P electrocatalyst prepared at a deposition current density of 150 mA cm⁻² exhibits remarkable hydrogen evolution reaction catalytic activity, and only requires 39.7 mV overpotential at 10 mA cm⁻² current density. Compared with the Ni–Fe–P electrode, the Ni–Fe–P–FeMnO₃ electrode shows more outstanding electrocatalytic properties requiring only 13.5 mV overpotential at 10 mA cm⁻² current density. The fabricated Ni–Fe–P–FeMnO₃ electrode is able to sustain a current density of 10 mA cm⁻² with negligible increase in overpotential in 24 h which shows remarkable electrochemical stability. [ABSTRACT FROM AUTHOR]