In situ semi-etching of bimetallic LDH nanosheet arrays into FeNi-LDH/MOF to boost oxygen evolution reaction

The inherent sluggish kinetics of water oxidation is the core issue for electrochemical hydrogen production from water splitting. Metal organic frameworks (MOFs) with tunable porous structures, abundant coordination metal centers and large specific surface area are expected as efficient electrocatalysts. In this paper, FeNi-LDH/MOF composite nanostructures were successfully constructed on carbon cloth (CC) through partially converting iron-nickel layered double hydroxide (FeNi-LDH) into FeNi-MOF (NiFe(CN)5NO) by an in-situ semi-etching method. The MOF nanocrystals in this material are in-situ decorated on the surface of FeNi-LDH nanosheets, providing abundant open active sites and mass transfer channels for electrocatalysis. Thanks to the synergistic effect of the LDH and MOF, as well as the exceptional hierarchical architecture, the FeNi-LDH/MOF/CC as a self-supported electrode exhibits distinguished electrocatalytic OER performance, with a low overpotential of 263 mV@100 mA cm−2 and a small Tafel slope of 50.2 mV dec-1 in 1.0 M KOH. In addition, the catalyst exhibits good durability with almost constant current density during 24 h OER test. This work provides an effective way to design high-performance MOFs-based composite electrocatalytic materials.