A Hybrid Electrocatalyst with a Coordinatively Unsaturated Metal-Organic Framework Shell and Hollow Ni3S2/NiS Core for Oxygen Evolution Reaction Applications.

Metal-organic frameworks (MOFs) have emerged as a promising class of materials. However, their insulating nature has limited their application as electrocatalysts. Herein, we report a heterogeneous nanostructure of a Ni-based MOF-modified Ni3S2/NiS hollow nanoparticle. The Ni3S2/NiS hollow core is prepared by a sulfuration process from a colloidal nickel nanoparticle using dodecanethiol followed by a low-temperature heat treatment in air to remove the adsorbed organic ligands. The thin shell of the Ni-based MOF (Ni-BDC) is synthesized using an in situ method in which the nickel sulfides supply the metal source and the additional terephthalic acid serves as the linker. Serving as an oxygen evolution reaction catalyst, this hybrid nanocomposite shows superior electrocatalytic performance with a low overpotential of 298 mV at 10 mA·cm-2 without carbon addition and a long-time endurability with no detectable activity deterioration, which can be attributed to the synergistic effect of the advantageous heterogeneous structure, combining the good hydrophilicity and coordinative unsaturation of the Ni-BDC shell and the high conductivity and porosity of the Ni3S2/NiS core as well as the strongly coupled interface between them.