Electrodeposition of hierarchically structured three-dimensional nickel-iron electrodes for efficient oxygen evolution at high current densities.

Xunyu Lu,Chuan Zhao

doi:10.1038/ncomms7616

Abstract

Large-scale industrial application of electrolytic splitting of water has called for the development of oxygen evolution electrodes that are inexpensive, robust and can deliver large current density (>500 mA cm−2) at low applied potentials. Here we show that an efficient oxygen electrode can be developed by electrodepositing amorphous mesoporous nickel–iron composite nanosheets directly onto macroporous nickel foam substrates. The as-prepared oxygen electrode exhibits high catalytic activity towards water oxidation in alkaline solutions, which only requires an overpotential of 200 mV to initiate the reaction, and is capable of delivering current densities of 500 and 1,000 mA cm−2 at overpotentials of 240 and 270 mV, respectively. The electrode also shows prolonged stability against bulk water electrolysis at large current. Collectively, the as-prepared three-dimensional structured electrode is the most efficient oxygen evolution electrode in alkaline electrolytes reported to the best of our knowledge, and can potentially be applied for industrial scale water electrolysis.

Highlights

Large-scale industrial application of electrolytic splitting of water has called for the development of oxygen evolution electrodes that are inexpensive, robust and can deliver large current density (4500 mA cm À 2) at low applied potentials
In an electrolytic water splitting cell, the production of H2 at the cathode is severely constrained by the sluggish kinetics of the oxygen evolution reaction (OER) on the anode[1,2]
The metallic NiFe films deposited via galvanostatic reduction of Ni2 þ and Fe2 þ are relatively thick (2B8 mm) with high degree of discontinuities, and the electrodes are unstable under long term, large current density operation for water electrolysis[26]