The Electrochemical Behavior of Bifunctional Two-Dimensional VCo(Ni)-MOF for Alkaline Oxygen Evolution Reactions and Supercapacitor Applications.

Two-dimensional layered structures exhibit unique advantages in electrocatalysis and electrochemical energy storage systems due to their atomic-level thickness, short-range charge-ion transport paths, and highly exposed active sites. In this work, single-crystal 2D VCo-MOF and VNi-MOF were precisely constructed via a one-step hydrothermal method. The monoclinic C2/c space group endows the materials with regular interlayer pores and continuous conjugated planes, ensuring 100% accessibility of the catalytic sites. Electrochemical tests show that the two-dimensional VCo-MOF requires only 177 mV to drive a current density of 10 mA cm-2 for the oxygen evolution reaction in 1 M KOH, with a Tafel slope as low as 45.9 mV dec-1 and no activity decay after continuous operation for 20 h. DFT calculations confirm that the 2D confinement effect shifts the d-band center of Co to -1.126 eV, significantly reducing the energy barrier for the formation of *O intermediates to 1.88 eV and accelerating the OER kinetics. The interlayer fast electron/ion channels ensure the ultrahigh rate and long life of supercapacitors. This work clarifies the intrinsic correlation between the "two-dimensional structure-electronic regulation-interface reaction", providing a universal strategy for designing efficient, stable, and integrated two-dimensional MOF materials for catalysis and energy storage.