Co (II) Boron Imidazolate Framework with Rigid Auxiliary Linkers for Stable Electrocatalytic Oxygen Evolution...

Metal-organic frameworks (MOFs) have significant potential for practical application in catalysis. However, many MOFs are shown to be sensitive to aqueous solution. This severely limits application of MOFs in electrocatalytic operations for energy production and storage. Here, a Co (II) boron imidazolate framework CoB(im)₄(ndc)_0.5 (BIF-91, im = imidazolate, ndc = 2,6-naphthalenedicarboxylate) that is rationally designed and successfully tested for electrocatalytic application in strong alkaline (pH ≈ 14) solution is reported. In such a BIF system, the inherent carboxylate species segment large channel spaces into multiple domains in which each single channel is filled with ndc ligands through the effect of zeolite channel confinement. These ligands, with strong C-H···π interaction, act as a rigid auxiliary linker to significantly enhance the structural stability of the BIF-91 framework. Additionally, the π-conjugated effect in BIF-91 stabilizes dopant Fe (III) at the atomic scale to construct Fe-immobilized BIF-91 (Fe@BIF-91). Due to the synergistic effect between Fe (III) guest and Co (II) in the framework, the Fe@BIF-91 acts as an active and stable electrocatalyst for the oxygen evolution reaction in alkaline solution.