Leveraging Metal Nodes in Metal-Organic Frameworks for Advanced Anodic Hydrazine Oxidation Assisted Seawater Splitting

Metal-organic frameworks (MOFs) show great promisefor electrocatalysisowing to their tunable ligand structures. However, the poor stabilityof MOFs impedes their practical applications. Unlike the general pathwayfor engineering ligands, we report herein an innovative strategy forleveraging metal nodes to improve both the catalytic activity andthe stability. Our electrolysis cell with a NiRh-MOF||NiRh-MOF configurationexhibited 10 mA cm(-2) at an ultralow cell voltageof 0.06 V in alkaline seawater (with 0.3 M N2H4), outperforming its counterpart benchmark Pt/C||Pt/C cell (0.12V). Impressively, the incorporation of Rh into a MOF secured a robuststability of over 60 h even when working in the seawater electrolyte.Experimental results and theoretical calculations revealed that Rhatoms serve as the active sites for hydrogen evolution while Ni nodesare responsible for the hydrazine oxidation during the hydrazine oxidationassisted seawater splitting. This work provides a paradigm for greenhydrogen generation from seawater.

Automated summary

Metal-organic frameworks (MOFs) have potential in electrocatalysis due to their adjustable ligand structures, but their poor stability hinders practical applications. This study introduces an innovative strategy of leveraging metal nodes to enhance both the catalytic activity and stability. The NiRh-MOF||NiRh-MOF configuration in the electrolysis cell achieved a current density of 10 mA cm(-2) at an ultralow voltage of 0.06 V in alkaline seawater, outperforming the Pt/C||Pt/C benchmark cell (0.12 V). Additionally, the incorporation of Rh into the MOF enabled a robust stability of over 60 hours in seawater electrolyte.