A 2D metal-organic framework/Ni(OH)2 heterostructure for an enhanced oxygen evolution reaction
2D metal-organic frameworks (MOFs) are widely regarded as promising electrocatalysts for the oxygenevolution reaction (OER). This results from their inherent properties such as a large portion of surfacecoordinatively unsaturated metal atoms, rapid mass transfer and enhanced conductivity. However,2D MOFs have a strong tendency to aggregate, which severely limits their potential application in theOER. Here, novel 2D Ni-BDC/Ni(OH)2(BDC stands for 1,4-benzenedicarboxylate, C8H4O4) hybridnanosheets are synthesizedviaa facile sonication-assisted solution method. Because of the rationalmaterial design, the large surface area of Ni-BDC is maintained. Significantly, after coupling, the electronicstructure of Ni atoms in the Ni(OH)2component is well modified, leading to the generation of Ni cationswith higher oxidation states, which are desirable for the OER. As-prepared Ni-BDC/Ni(OH)2exhibits highactivity, favorable kinetics and strong durability towards the OER. Specifically, the OER current density ofNi-BDC/Ni(OH)2is 82.5 mA cm−2at 1.6 Vversusa reversible hydrogen electrode (RHE), which is signifi-cantly greater than those of Ni-BDC (5.5 times), Ni(OH)2(20.6 times) and Ir/C (3.0 times). Moreover, thesonication-assisted method developed in this work can be readily adapted for the preparation of various2D MOF-based hybrid functional materials.