Improving the Electrocatalytic Activity of a Nickel-Organic Framework toward the Oxygen Evolution Reaction through Vanadium Doping.

ABSTRACT

Metal-organic frameworks (MOFs) have been considered as potential oxygen evolution reaction (OER) electrocatalysts owning to their ultra-thin structure, adjustable composition, high surface area, and high porosity. Here, we designed and fabricated a vanadium-doped nickel organic framework (V1-x -Nix MOF) system by using a facile two-step solvothermal method on nickel foam (NF). The doping of vanadium remarkably elevates the OER activity of V1-x -Nix MOF, thus demonstrating better performance than the corresponding single metallic Ni-MOF, NiV-MOF and RuO2 catalysts at high current density (>400 mA cm-2 ). V0.09 -Ni0.91 MOF/NF provides a low overpotential of 235 mV and a small Tafel slope of 30.3 mV dec-1 at a current density of 10 mA cm-2 . More importantly, a water-splitting device assembled with Pt/C/NF and V0.09 -Ni0.91 MOF/NF as cathode and anode yielded a cell voltage of 1.96 V@1000 mA cm-2 , thereby outperforming the-state-of-the-art RuO2 (+) ||Pt/C(-) . Our work sheds new insight on preparing stable, efficient OER electrocatalysts and a promising method for designing various MOF-based materials.