Hierarchical carbon-supported iron carbide derived from zinc–iron bimetallic coordination polymer as an efficient electrocatalyst for alkaline oxygen evolution

Abstract

The development of non-precious metal catalysts with high activity, low cost and high stability represents one of the most effective strategies to tackle the prevailing challenges in the oxygen evolution reaction (OER), such as sluggish kinetics, heavy reliance on precious metals, and complex preparation protocols. Herein, a hierarchical carbon-supported iron carbide catalyst was fabricated using a zinc–iron bimetallic coordination polymer (ZnFe-CP) as the precursor, via a synergistic approach of self-assembly and controlled carbonization. Structural characterization, compositional analysis, and electrochemical measurements demonstrated that the zinc in ZnFe-CP not only facilitated the formation of active iron carbide phases but also enhanced the catalytic performance and kinetics toward alkaline OER. In addition, the optimized catalyst showed good OER catalytic activity in 1.0 M KOH solution, demonstrating an overpotential of 408 mV at a current density of 10 mA cm⁻², along with a Tafel slope of 76.1 mV dec⁻¹ and a long-term stability of approximately 15 h. This work offers valuable experimental insights for the rational design and in-depth exploration of carbon-supported metal-based catalysts for energy related applications.