Magnesium-doped Nickel-iron (Hyro)oxides-based Catalyst for Efficient and Stable Hydrogen Evolution

NiFe-based materials offer tailorable electronic structure and exhibit promising performance in alkaline hydrogen evolution reaction (HER). Electron-rich earth metals as doping species can regulate the local electronic configuration of NiFe-based catalysts towards improved HER activity. Herein, a low electronegative Mg dopant strategy is utilized to prepare Mg-FeOOH/NiFeO x electrocatalyst for HER. The introduction of Mg improves the bonding strength of Fe-O bond in FeOOH active species, resulting in rapid H 2 O dissociation and improved stability. Meanwhile, Mg-dopant induces a downshift in the d -band center of FeOOH, which weakens the hydrogen adsorption for promoted H 2 production. The Mg-FeOOH/NiFeO x catalyst shows an ultra-low HER overpotential of 18 mV at 10 mA cm -2 and excellent stability in 1.0 M KOH. Moreover, the anion-exchange membrane water electrolyzer reaches 500 mA cm -2 at 1.70 V. This study provides a practical strategy to synthesise high-efficiency NiFe-based HER catalysts.