Electro-synthesis of 3D porous hierarchical Ni–Fe phosphate film/Ni foam as a high-efficiency bifunctional electrocatalyst for overall water splitting

Abstract

A highly efficient bifunctional electrocatalyst of nickel–iron phosphates for hydrogen and oxygen evolution reactions (HER and OER) was designed and prepared via a simple electrodeposition method. The as-obtained catalyst presents remarkable catalytic activities for both the HER and OER, which requires overpotentials of 87 mV to reach −10 mA cm⁻² for the HER and 204 mV to generate 20 mA cm⁻² for the OER in 1 M KOH. Employed as both the anode and cathode for full water splitting, the electrodeposited catalyst also exhibits excellent activity, which requires an overpotential of only 326 mV to attain 10 mA cm⁻² and yields a faradic efficiency close to 100%.