Ta-Doped NiFe Layered Double Hydroxide for Efficient Alkaline Water Oxidation at Ampere-Level Current with 2000 h Durability †

Abstract

Electrochemical water splitting offers a sustainable strategy for hydrogen production, yet the kinetic sluggishness of the oxygen evolution reaction (OER) due to high activation barriers remains a critical challenge. NiFe layered double hydroxide (NiFe LDH) is a promising OER catalyst in alkaline media, but its performance suffers from limited active site exposure and insufficient durability. Herein, the rational design of a Ta-doped NiFe LDH (NiFeTa LDH) were achieved via a facile hydrothermal method. Ta incorporation results in basal spacing expansion, and induction of electronic redistributionprimarily electron transfer from Fe 3+ to Ta 5+ -thus enhancing OER intermediate adsorption. Consequently, NiFeTa LDH exhibited superior OER activity, delivering a low overpotential of 200 mV at a current density of 10 mA•cm -2 . Remarkably, it sustains long-term operation at 1 A•cm -2 for over 2000 hours, demonstrating exceptional durability under industrially relevant conditions. Complementary DFT + U calculations reveal that Ta doping induces an upshift of the d-band center at the active sites, thereby contributing to the optimized OER intermediate adsorption. This electronic modulation is identified as the key factor underlying the observed catalytic enhancement. This work highlights the effectiveness of high-valence ion doping for tuning LDH-based electrocatalysts toward practical water electrolysis applications.