Pyridine-modulated Ni/Co bimetallic metal-organic framework nanoplates for electrocatalytic oxygen evolution

Two-dimensional (2D) metal-organic frameworks (MOFs) are promising for electrocatalysis with high performance, as they possess large surface areas and high densities of exposed active sites. It attracts tremendous attention to obtain 2D nanostructures via simple preparation methods. Herein, a facile pyridine-modulated solvothermal synthesis of Ni/Co bimetallic MOF nanoplates (NixCoy-bpy (PyM)) is reported with well-defined 2D morphology with a thickness as thin as 20 nm and an aspect ratio larger than 50. These nanoplates possess oxygen evolution reaction activity as electrocatalysts in alkaline conditions. Specifically, Ni0.5Co1.5-bpy(PyM) exhibits excellent OER electrocatalytic activity with a low overpotential of 256 mV at 10 mA cm−2 and a small Tafel slope of 81.8 mV dec−1 in 1.0 mol L−1 KOH with long-term electrochemical stability for 3000 cyclic voltammetry cycles. The high catalytic activity of Ni0.5Co1.5-bpy(PyM) can be attributed to the in situ formed active hydroxide and oxyhydroxide species within the inherited 2D morphology and the optimized bimetallic ratio.