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.