A two-dimensional zeolitic imidazolate framework loaded with an acrylate-substituted oxoiron cluster as an efficient electrocatalyst for the oxygen evolution reaction

Abstract

An acrylate-substituted oxoiron cluster {Fe₂₈}, with acidity and poor solubility, has been loaded with 2D zeolitic imidazolate frameworks (ZIF)-L. The obtained composite ZIF-L@Fe₂₈ (120 mg) affords the best oxygen evolution reaction (OER) activity and stability with an overpotential of 312 mV at 10 mA cm⁻², and a Tafel slope of 78 mV dec⁻¹, compared with ZIF-L@Fe₂₈ (80, 160 mg), ZIF-67@Fe₂₈, the pristine 2D ZIF-L and 3D ZIF-67. These controls suggest that the superior performance is attributable to the {Fe₂₈} ↔ ZIF bidirectional synergistic effect and the etching effect of {Fe₂₈} in aqueous solution on the ZIF-L. Therefore, we propose that the strategy of preparing ZIF composites loaded with polynuclear metal-oxo clusters fully composed of OER-active metal sites (Fe, Co and Ni) may open up new avenues for the design of novel non-noble electrocatalysts for the OER.