Co Single Atom Coupled with 3D-Printed Electrodes for High-Efficiency Solar-Driven Oxygen Evolution

The development of highly efficient electrocatalysts for the oxygen evolution reaction (OER) is essential to overcome the efficiency limitations of water electrolysis. In this study, the CN^– and NH₂^– provided by the amide, along with 2-methylimidazole as the coordination anchor points for the metal, lock the excess Co²⁺ into a cyanide-bridged bimetallic structure of Co₂(CN)₅NH₂, spontaneously achieving single-atom dispersion. A self-supported Co₂(CN)₅NH₂/Ni-3D electrode with high catalytic activity and stability is developed as a versatile platform for large-scale water electrolysis and oxygen production. The Co₂(CN)₅NH₂ catalyst demonstrates exceptional OER performance, achieving an overpotential of 218.5 mV at 10 mA cm^–2 in 1.0 M KOH. The Co₂(CN)₅NH₂/Ni-3D electrode maintains stable operation for over 110, 100, and 140 h at current densities of 20, 50, and 100 mA cm^–2, respectively. Notably, the electrode features unique interconnected pore structure, enabling the rapid bubble release and determining the long-term performance of OER catalysts. We achieve the synergistic optimization of the macrostructural morphology of the electrode and the microscale catalytic activity, thereby endowing the electrode with excellent adaptability for long-term OER applications outdoors.