Pyrimidine-Functionalized Covalent Organic Framework and its Cobalt Complex as an Efficient Electrocatalyst for Oxygen Evolution Reaction

A pyrimidine-modified covalent organic framework (COF-Pyr) was designed to be synthesized via the Povarov reaction. The nitrogen atom on the pyrimidine showed excellent coordination ability to metal ions. Their stable metal composite material (Co@COF-Pyr) exhibited remarkable performance for electrocatalytic oxygen evolution reaction (OER) in 1.0 m KOH aqueous solution. The overpotential was 450 mV at 10 mA cm^-2 . The Co@COF-Pyr with large specific surface area (392 m²  g^-1 ) and regular crystal structure provided free passage for H₂ O to move and make them fully contact with the uniformly dispersed cobalt ions on the surface. Thus, the turnover frequency of Co@COF-Pyr was 0.1 s^-1 at the overpotential of 370 mV, which was higher than most reported OER catalysts. This work provided a new way to design and prepare nitrogen-containing heterocyclic functionalized COFs. They can be combined with metal ions to expand the application of COFs in the field of electrocatalysis.