Ru and S co-modification-induced synergistic morphology and electronic engineering of nickel-iron hydroxide with efficient oxygen evolution

Abstract

Synchronously achieving morphological and electronic engineering control is crucial but challenging for enhancing the oxygen evolution reaction (OER) performance of nickel-iron based catalysts. Herein, a ruthenium and sulfur co-modified nickel-iron hydroxide (S_ARu_T-FeNiOH_x-5h) was synthesized by a distributed room-temperature impregnation method. It was found that the solubility product difference between ruthenium and nickel-iron hydroxide can promote the rapid nucleation of the catalyst and form finer nanosheet structures, thereby increasing 1.25 times for the contact area between the catalyst and the electrolyte. Meanwhile, the subsequent deposition of sulfur can act as an electronic modulator, promoting the transfer of surface charge at nickel sites and increasing the oxidation state of nickel. Theoretical calculations indicate that the combination of ruthenium and sulfur can effectively optimize the OER reaction pathway and lower the activation energy barrier of the rate-determining step, endowing S_ARu_T-FeNiOH_x-5h an excellent OER performance with a low overpotential of 253 mV at 1000 mA/cm² and long-term stability (500h). In the future, it is hoped that this strategy of synergistic control of morphology and electronic structure can be applied to the development of other highly active catalysts.