Enhanced Electrocatalytic Oxygen Evolution by Exfoliation of a Metal–Organic Framework Containing Cationic One-Dimensional [Co₄(OH)₂]⁶⁺ Chains

Metal–organic frameworks (MOFs) are an emerging class of heterogeneous electrocatalyst, though the focus for the vast majority of them has been on employing them as a precursor for carbon materials or as a host material for encapsulating catalytically active species. Herein, we report the preparation of a metal–organic nanosheet with one-dimensional (1-D) [Co4(OH)2]6+ chains via delamination of a 3-D MOF. The resultant atomically thin nanosheets are highly active, robust, and recyclable oxygen evolution reaction (OER) electrocatalysts with a low overpotential 318 mV (without iR compensation) to achieve a current density of 10 mA cm–2. These values along with the small Tafel slope (54 mV dec–1) exhibit a superior performance to the bulk MOF precursor and the benchmark RuO2 catalyst under the identical condition. The electrochemical studies ascribe the excellent OER activity to the high surface area, accessible CoII sites, and good charge transfer of the nanosheets.