Layer-structured FeCo bihydroxide as an ultra-stable bifunctional electrocatalyst for water splitting at high current densities

Abstract

The development of stable bifunctional electrodes capable of operation at high current densities is a key requirement for large scale hydrogen generation by water electrolysis. Herein, amorphous FeCo hydroxides are controllably electroplated onto nickel mesh to produce binder-free bifunctional FeCo-LDH/NM electrodes for water splitting. In an alkaline electrolyte, the hydrogen evolution reaction on FeCo-LDH/NM requires an overpotential of only 311 mV to deliver a current density of 1000 mA cm⁻², and the same current density is achieved in the oxygen evolution reaction at 300 mV. Notably, in a real electrolyzer setup, a current density of 1000 mA cm⁻² is realized at 1.82 V and remains unchanged for 150 h. The study demonstrates promising bifunctional electrocatalytic properties of the FeCo-LDH/NM electrode material making it a suitable candidate for practical applications in large-scale water electrolysis systems.