Al3+ Doping-Induced Electronic Structure Regulation in NiFeOx for Accelerated Oxygen Evolution Kinetics and Superior Stability

Abstract

Achieving enhanced efficiency and sustained stability of oxygen evolution reaction (OER) catalysts poses a considerable challenge, particularly for non-noble metal systems, where precise modulation of the electronic structure is essential for enhancing catalytic activity and durability. This study reveals that doping iron-nickel oxide catalysts supported on nickel foam (NF) with aluminum (Al³⁺) ions effectively modulates the material's electronic configuration, increases active site availability, and enhances charge transport properties. These synergistic effects lead to substantial enhancements in both OER activity and electrochemical stability. The optimized FeNiAl_0.5O/NF electrocatalyst displays remarkable OER performance in alkaline media, attaining 100 mA cm⁻² current density at 242 mV overpotential while maintaining an efficient Tafel slope of 48.0 mV dec⁻¹. Furthermore, the catalyst shows remarkable durability, maintaining stable performance without significant loss in current density over a 168-hour chronopotentiometry test. These results underscore the pivotal role of Al³⁺ doping in precisely tuning the electronic structure of iron-nickel oxide catalysts, leading to enhanced OER kinetics and extended operational durability. The findings from this research offer valuable insights for designing cost-effective, high-performance electrocatalysts based on non-noble metals for electrochemical water splitting.