Dynamic Reconstructed RuO2/NiFeOOH with Coherent Interface for Efficient Seawater Oxidation

Developing efficient oxygen evolution reaction (OER) electrocatalysts for seawater electrolysis is still a big challenge. Herein, a facile one-pot approach is reported to synthesize RuO2 -incorporated NiFe-metal organic framework (RuO2 /NiFe-MOF) with unique nanobrick-nanosheet heterostructure as precatalyst. Driven by electric field, the RuO2 /NiFe-MOF dynamically reconstructs into RuO2 nanoparticles-anchored NiFe oxy/hydroxide nanosheets (RuO2 /NiFeOOH) with coherent interface, during which the dissolution and redeposition of RuO2 are witnessed. Owing to the synergistic interaction between RuO2 and NiFeOOH, the as-reconstructed RuO2 /NiFeOOH exhibits outstanding alkaline OER activity with an ultralow overpotential of 187.6 mV at 10 mA cm-2 and a small Tafel slope of 31.9 mV dec-1 and excellent durability at high current densities of 840 and 1040 mA cm-2 in 1 m potassium hydroxide (KOH). When evaluated for seawater oxidation, the RuO2 /NiFeOOH only needs a low overpotential of 326.2 mV to achieve 500 mA cm-2 and can continuously catalyze OER at 500 mA cm-2 for 100 h with negligible activity degradation. Density function theory calculations reveal that the presence of strong interaction and enhanced charge transfer along the coherent interface between RuO2 and NiFeOOH ensures improved OER activity and stability.