Impact of morphology on the oxygen evolution reaction of 3D hollow Cobalt-Molybdenum Nitride

The oxygen evolution reaction (OER) is an essential process for water electrolysis and to realize the scalability of renewable energy sources. In this work, a strategy is developed to fabricate anisotropic metallic Cobalt-Molybdenum Nitride materials combining hollow 3D structures and 2D nanosheets which result highly active OER electrocatalysts. The sample structure and morphology is investigated to derive its formation process following the synthesis strategy relying on the ligand-metal interactions of metal-organic framework (ZIF-67 and Mo-aMOF). Three different sample morphologies with large specific surface areas are obtained by changing the water and 2-methylimidazole contents. After ammonification in NH₃, the morphologies and the specific surface areas of the samples are preserved. The electronic structure can also be adjusted to regulate electron density of Co and Mo by N-doping. These Co-Mo binary metals offer a viable way for realizing the electronic transfer between the different components, as demonstrated by XPS. Taking advantage from the above features, the as-obtained electrocatalyst exhibits a high catalytic activity and long-term cyclic stability for OER with low overpotential (η₁₀ is 294 mV).