Nanocages: Metal–Organic Polyhedra (MOPs) to Form M/MO Embedded Carbon Polyhedra

ABSTRACT

Metal–organic polyhedra (MOPs) are discrete and intrinsically porous molecular self‐assemblies. MOPs exhibit rich surface chemistry; the existence of peripheral reactive sites is exploited by post‐synthetic covalent and/or coordination‐based polymeric structures by maintaining MOP identities. By further treatment, the dimensions of cuboctahedral MOPs are manipulated in an unprecedented manner into next‐generation metal/metal oxides‐doped carbon polyhedron nanocages/nanospheres. Herein, the predesigned mixed metal and metal oxides dopped carbon nanopolyhedral spheres/cages (M/MO@CNS) are obtained through the pyrolysis of MOPs. These composites are characterized by FTIR, Raman, PXRD, BET, ICP, XPS, FE‐SEM, and TEM techniques. The spherical morphology of the nanomaterial is preserved as carbon spheres doped with metal‐based nanoparticles (Cu ⁰ Co ⁰ /Cu ₂ OCoO@CNS), demonstrating excellent electrocatalytic performance. Compared to commercial iridium oxide, the carbon nanospheres incorporating metals/metal oxides presented a high activity profile for alkaline water oxidation. Catalysts prepared at 600°C and 1000°C revealed maximum current densities, as compared to the commercial IrO ₂ benchmark catalyst. The current densities of 10 mA/cm ² recorded low overpotentials/η ₁₀ and Tafel slopes than IrO _2, with lower charge transfer resistance. Combined post‐catalysis analyses and DFT calculations demonstrate that the synergistic interaction within Cu ₂ O/CoO@CNS optimizes the electronic structure and promotes electron transfer. It also balances the free energies of key intermediates and reduces the energy barrier of the OER rate‐determining step, resulting in enhanced catalytic performance. The MOPs derived next‐generation carbon‐nanocages are tested for catalytic stability via chronopotentiometry, which shows that these composites remained stable during several hours of electrolysis.