Mechanochemical Post-Synthesis of Metal-Organic Framework-Based Pre-Electrocatalysts with Surface Fe-O-Ni/Co Bonding for Highly Efficient Oxygen Evolution

Rational surface engineering of metal-organic frameworks (MOFs) provide potential opportunities to address the sluggish kinetics of oxygen evolution reaction (OER). However, the development of MOF-based materials with low overpotentials remains a great challenge. Herein, a post-synthesis strategy to prepare highly efficient MOF-based pre-electrocatalysts via all-solid-phase mechanochemistry is demonstrated. The surface of a Fe-based MOF (MIL-53) can be reconstructed and anchored with atomically dispersed Ni/Co sites. As expected, the optimized M-NiA-CoN exhibits a very low overpotential of 180 mV at 10 mA cm(-2) and a small Tafel slope of 41 mV dec(-1) in 1 m KOH electrolyte. The superior electrocatalytic OER activity is mainly due to the formation of surface Fe-O-Ni/Co bonding. Furthermore, density functional theory calculations reveal that the transformation from *OH to *O is the rate-determining step and the electrocatalytic OER activity trend at different metal sites is Co > Ni approximate to Fe.