N-Doped carbon coated NiCo2O4 nanorods for efficient electrocatalytic oxygen evolution

Abstract

The oxygen evolution reaction (OER) is considered an imperative step in the electrocatalytic water splitting process to obtain clean hydrogen fuel. The scarcity of noble metals impedes the practice of such technology at a commercial scale. To replace noble metal electrocatalysts with non-expensive and abundant materials is critical for the practical application of this technology. Herein, we report a novel approach to fabricate 1D nitrogen-doped carbon coated ternary NiCo₂O₄ nanorods (NiCo₂O₄@NC) derived from metal–organic frameworks (MOFs), which display a low overpotential (η ≈ 296 mV @10 mA cm⁻²), a small Tafel slope (53 mV dec⁻¹) and excellent durability for OER in an alkaline medium, which is higher than for a commercially available Ir/C electrocatalyst (η ≈ 350 mV @10 mA cm⁻²). Such higher electrochemical properties can be primarily attributed to the high electrochemical surface area, the synergistic effect from chemical compositions and the unique mesoporous architecture with a support of nitrogen-doped carbon species. The proposed strategy for the controlled design and fine-tuning of MOF derived functional materials provides projections for producing remarkably active and stable electrocatalysts in electrochemical energy devices. This work presents a meaningful approach to understanding the effect of morphological engineering on electrocatalytic OER activity.