Active Site Tailoring of Metal‐Organic Frameworks for Highly Efficient Oxygen Evolution.

The direct correlation between active sites and catalytic activity in multiple‐component metal‐organic frameworks (MOFs) is key to understanding their mechanism of oxygen evolution reaction (OER) but remains vague. Herein, supported multiple‐site MOFs are adopted as model catalysts to quantitatively study the composition‐dependent OER performance. Ni MOFs on Fe metal substrate possess the highest intrinsic OER activity with the Ni/Fe ratio of 1:2 in the presence of metal leaching of the substrate during synthesis. Further introducing a proper amount of Cu further boosts the OER performance of Cu‐doped NiFe MOFs with an impressively low overpotential of 200 mV at 10 mA cm−2. Spectroscopic analysis with theoretical study indicates that the copper doping within the NiFe MOFs induces electron redistribution for high valence Fe sites with an optimized balance of OH/OOH adsorption and decreased energy barrier for improved OER. This work sheds light on the active site tailoring of MOFs which highly correlates with the OER activity. [ABSTRACT FROM AUTHOR]