Engineering the Sandwich-Type Porphyrinic MOF-Ruthenium-Nickel Foam Electrode for Boosting Overall Water Splitting...

The rational construction of a hierarchical noble metal-metal-organic frameworks (MOFs) structure is anticipated to yield enduring and highly efficient performance in alkaline electrocatalytic water splitting. Herein, a sandwich construction strategy is employed to enhance the stability, wherein active RutheniRu (Ru) nanosheets are incorporated onto nickel foam (NF) and subsequently covered with porphyrinic MOFs (PMOFs). In addition, activated PMOF-NiOOH-Ru₂₀/NF-C/A electrodes are obtained by electrochemical self-reconstruction as cathode and anode, respectively. Density functional theory (DFT) calculations demonstrated that the resulting PMOF-NiOOH-Ru heterointerface effectively facilitated electron transfer, enhanced H₂O adsorption capacity, and optimized ΔG values for ^*H and ^*O to ^*OOH. Consequently, PMOF-NiOOH-Ru₂₀/NF-C/A exhibited low overpotentials for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), accompanied by minimal Ru leakage. Furthermore, stable overall water splitting can be achieved with a low voltage of 1.456 V@10 mA cm^-2 for over 120 h. Even when operated in simulated seawater, the prepared electrodes demonstrated similar activity and stability. This study contributes to a deeper understanding of the regulation mechanism for the performance and stability of active sites in the electrocatalytic self-reconstruction process.