Boosting Oxygen Evolution Reaction Induced by Carbon Sacrificial Strategy Based on FeNi2B@C/NF Core-shell Electrocatalyst

Abstract

Developing highly efficient and low-cost oxygen evolution reaction (OER) electrocatalysts under large current densities is attractive but challenging. To address this, we designed a novel Fe-doped carbon shell encapsulated nickel-boron core-shell heterostructure electrocatalyst (Fe-Ni₂B@C/NF) on nickel foam. The electronic structure of Ni₂B is effectively modulated by Carbon Sacrificial Strategy and the electron-donating characteristics of Fe, resulting in an upward shift of the d-band center. This modulation enhances the catalytic activity for OER by weakening the adsorption of oxygen-containing intermediates. In 1 M KOH solution, the Fe-Ni₂B@C/NF catalyst demonstrates remarkable performance with an overpotential of 208 mV at 10 mA cm⁻² and excellent durability, outperforming commercial IrO₂. Additionally, when integrated into an anion exchange membrane (AEM) electrolyzer, the catalyst achieves a current density of 2000 mA cm⁻² at a low voltage of 1.59 V, maintaining stability for over 1000 hours. Density functional theory (DFT) calculations further reveal that the core-shell heterostructure facilitates charge transfer between the carbon shell and Fe-Ni₂B core, reducing the energy barrier for OER intermediates and enhancing catalytic efficiency. This study provides a novel approach to developing efficient electrocatalysts with high catalytic activity and long-term durability at a large current density.