Hierarchical iron-phosphide@NiCo2O4 nanoneedle arrays for high performance water splitting

A recent approach for hydrogen production has been electrolysis of water using stable and efficient bifunctional electrocatalysts. Herein, we report a hierarchical FePx-NiCo2O4 nanoneedle arrays with core-shell structure grown on nickel foam (FeP-NCO@NF), which acts as a superior bifunctional electrocatalyst for water electrolysis. Benefiting from the synergetic effects between crystalline NiCo2O4 and amorphous FePx, the binder-free FeP-NCO@NF electrode delivers an oxygen hydrogen production with an overpotential of 220 mV for the oxygen evolution reaction and 82 mV for the hydrogen evolution reaction at 10 mA cm(-2) in 1 M KOH electrolyte. In addition, the overall water splitting based on FeP-NCO@NF as anode/cathode can be performed with a low voltage of 1.523 V to deliver 10 mA cm(-2), which is 14 mV lower than that for the commercial Pt/C-IrO2 electrocatalyst. The developed materials combine the catalytic activity with working stability, which paves a new way for exploring transition metal oxides based overall water splitting electrocatalysts.

Automated summary

The study presents a bifunctional electrocatalyst based on hierarchical FePx-NiCo2O4 nanoneedle arrays, which shows superior performance in water electrolysis. The electrode exhibits low overpotentials and voltage, outperforming commercial electrocatalysts, paving a new way for developing transition metal oxides-based overall water splitting electrocatalysts.