Synergistic electronic interaction between ruthenium and nickel-iron hydroxide for enhanced oxygen evolution reaction

The efficiency of electrochemical water splitting is extremely hampered by the sluggish oxygen evolution reaction (OER) occurred at the anode. Therefore, developing high-performance OER electrocatalysts is crucial for realizing the industrialized application of water splitting. Herein, a high-efficiency electrocatalyst of ruthenium-decorated nickel-iron hydroxide (10Ru-NiFe LDH) supported on Ni foam is successfully synthesized for OER. Modifying NiFe LDH with ruthenium can optimize the electronic density to form high valences of metal sites, which is beneficial to promote its OER performance. Consequently, the 10Ru-NiFe LDH only needs a low overpotential of 222 mV to achieve a current density of 50 mA·cm⁻², which exhibits fast OER kinetics with a small Tafel slope of 58 mV·dec⁻¹. Moreover, this electrocatalyst shows high stability over 20 h at a high current density of 100 mA·cm⁻² without obvious decay. The decent OER performances can be ascribed to the increased active sites and the synergistic electronic interactions among Ni, Fe and Ru. This work provides an effective approach for designing desirable electrocatalysts for OER.