Three-Dimensional Ordered Macroporous NiFe₂O₄ Self-Supporting Electrode with Enhanced Mass Transport for High-Efficiency Oxygen Evolution Reaction

Despite that nickel–iron spinel (NiFe₂O₄) exhibits excellent oxygen evolution catalytic activity, its unsatisfactory mass transport limits further improvement in catalytic performance. Herein, we report an electrode with three-dimensional ordered macroporous NiFe₂O₄ on carbon cloth (3DOM-NiFe₂O₄/CC) for oxygen evolution reaction (OER). The ordered macropores endow the electrode with high porosity and short diffusion passages, which facilitate fast electrolyte flow and gas spillage, thereby enhancing the mass transport capability. Meanwhile, the highly conductive carbon cloth substrate enables the electrons to transfer rapidly through the electrode. Benefited from the excellent mass transport and electron mobility, the as-prepared electrode exhibited high catalytic activity with a small overpotential of 238 mV for a driving current density of 10 mA cm^–2 and a small Tafel slope of 57.2 mV dec^–1 for OER.