Green reaction engineering towards an iron-based nanostructured hybrid as an electrocatalyst for oxygen evolution reaction

Abstract

Developing robust electrocatalysts based on nonprecious metals with high activity in the sluggish oxygen-evolution reaction (OER) is crucial for achieving large-scale hydrogen production. We present a novel approach to design a molecular iron-based hybrid composed of Fe₃O₄, Fe, and FeNi₃ with a sphere-like structure deposited on a flaky substrate. Our optimized catalyst, denoted as Fe/Ni_450C, demonstrates superior electroactivity with a low overpotential of 307 mV, and a minimal Tafel slope of 42 mV dec⁻¹. The material demonstrates ultra-high durability in a 425 h stability test, retaining 86.80% of initial potential at 10 mA cm⁻², and exhibits outstanding resistance to high currents (450 mA). The ex situ XRD, XPS, and Mössbauer spectroscopy analyses shed light on the underlying mechanism. Utilizing low-temperature operational conditions, environmentally friendly substrates, cost-effectiveness, high abundance, and impressive stability at high current density collectively position our findings as a pivotal step toward practical applications in the industry associated with electrochemical water decomposition.