In situ formation of amorphous Fe-based bimetallic hydroxides from metal-organic frameworks as efficient oxygen evolution catalysts

Oxygen evolution from water driven by electrocatalysis or photocatalysis poses a significant challenge as it requires the use of efficient electro-/photo-catalysts to drive the four-electron oxygen evolution reaction (OER). Herein, we report the development of an effective strategy for the in situ chemical transformation of Fe-based bimetallic MIL-88 metal-organic frameworks (MOFs) into corresponding bimetallic hydroxides, which are composed of amorphous ultrasmall nanoparticles and afford an abundance of catalytically active sites. Optimized MOF-derived NiFe-OH-0.75 catalyst coated on glassy carbon electrodes achieved a current density of 10 mA cm(-2) in the electrocatalytic OER with a small overpotential of 270 mV, which could be decreased to 235 mV when loading the catalysts on a nickel foam substrate. Moreover, these MOF-derived Fe-based bimetallic hydroxides can be used as efficient cocatalysts when combined with suitable photosensitizers for photocatalytic water oxidation. (C) 2021, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

The study presents a strategy for transforming Fe-based bimetallic MOFs into corresponding bimetallic hydroxides, which offer abundant catalytically active sites. The optimized NiFe-OH-0.75 catalyst exhibited good performance in electrocatalytic oxygen evolution reactions and could serve as an efficient cocatalyst for photocatalytic water oxidation.