Two-dimensional bimetallic Fe/M- (Ni, Zn, Co and Cu) metal organic framework as efficient and stable electrodes for overall water splitting and supercapacitor applications

Abstract

2D based bimetallic MOFs have attracted significant attention for energy conversion and storage due to their synergistic effects and high electrocatalytic performance. However, the limited active sites and stability inhibit their multi-functional applicability in water electrolysis and supercapacitor applications. Herein, we report the 2D bimetallic Fe/M-BDC ((M-Ni, Zn, Co and Cu), BDC:1,4 benzene dicarboxylic acid) framework prepared by solvothermal and exfoliation condition, which exhibits excellent electrochemical performance. Electrochemical measurements and spectroscopic analysis establish that 2D Fe/M-BDC (M-Ni, Zn) contains a high surface area and abundant active sites that can accelerate the reaction kinetics. The as-prepared catalyst exhibits very low overpotentials of 78 mV for the hydrogen evolution reaction and 160 mV for the oxygen evolution reaction @ 10 and 20 mA cm−2, respectively. The bifunctional electrode assembly cell using anodic Fe/Zn-BDC and cathodic Fe/Ni-BDC couple provides the very low cell voltage of 1.35 V to drive current density of 10 mA cm−2. In addition, Fe/Zn-BDC and Fe/Ni-BDC exhibit high specific capacitances of 633.21 F/g and 1190.88 F/g at 1 mVs−1, respectively, with good stability when they are used as supercapacitor electrodes.