Synthesis of a Paddlewheel-Based 3D Co-MOF and Its Co3Se4-Derived Composite as an Electrocatalyst for Water Oxidation.

Cobalt selenides, such as Co3Se4, are promising electrocatalysts for the oxygen evolution reaction (OER), but their synthesis via pyrolysis is hindered by the redox sensitivity of selenium. Here, we report a strategy to overcome this challenge by employing a three-dimensional (3D) metal-organic framework (MOF), [Co3(BTC)2(Ade)2]·DMF·H2O (Co-BTC-Adenine MOF), as a precursor. The Co-BTC-Adenine MOF, synthesized solvothermally, featured a paddlewheel-type network with one-dimensional (1D) channels and was characterized by single-crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). Upon pyrolysis at 600 °C, a Co3Se4-based composite (Co3Se4@600) embedded in an N-doped carbon matrix was obtained. This composite exhibited a low overpotential of 235 mV at 10 mA cm-2, a Tafel slope of 61 mV dec-1, and excellent durability for over 68 h in alkaline media. The enhanced OER performance is attributed to the porous hybrid architecture, improved conductivity, and synergistic interactions between Co3Se4 and the carbon support. This work presented a temperature-controlled route for fabricating robust, nonprecious OER electrocatalysts from MOF precursors.