A cobalt hydroxide coated metal-organic framework for enhanced water oxidation electrocatalysis

Although metal–organic frameworks (MOFs) with coordinatively unsaturated metal centers have been regarded as promising electrocatalysts towards oxygen evolution reaction (OER), few reports focus on MOFs with inactive coordinative-saturated metal centers. Herein, we report a universal strategy to generate a layer of Co(OH)2 coating on the surface of Co-MOFs (Co(OH)2/Co-MOF) through an in situ cathodic electro- transformation approach. Experimental analysis and density functional theory (DFT) calculations reveal that electrons transfer from Co(OH)2 to Co-MOF could synergistically tailor the adsorption free energy of oxygenic intermediates in the OER pathways, which together with the unique structure of Co-MOF, contribute to the outstanding OER performance and long-term stability, with overpotential of 196 mV to achieve the current density of 10 mA cm−2.