Synergism induced multifunctional electroactivity of Co-Ni bimetallic metal-organic frameworks towards oxygen evolution reaction and supercapacitors
Nikhil Kumar, Pallab Bhattacharya, Animesh Jana, Sunil Kumar
Abstract
Energy generation through oxygen evolution reaction (OER) and storage is the cornerstone for numerous prominent energy conversion devices, encompassing metal–air battery, water splitting and supercapacitors. Herein, two single metals Co (I) and Ni (II) and one optimized CoNi-based (III) metal–organic frameworks are designed, characterized by Single crystal and powder X-ray diffraction, Scanning and transmission electron microscopy with energy dispersive spectroscopy, TGA , X-ray photoelectron spectroscopy and employed as remarkable efficient active material for OER and supercapacitor . The bi-metallic coupling of CoNi-based material just prerequisites a low over potential of 290 mV to deliver a current density of 100 mA cm −2 with a favourable Tafel slope of 55 mV dec −1 in 1 M KOH electrolyte and achieved excellent specific capacitance 318 Fg −1 at a current density of 1 Ag −1 in 6 M KOH. The proficiency towards electrocatalytic activity is owing to assimilation of CoNi with organic ligands could benefit the charge transfer efficiency and reaction kinetics, resulting in the excellent OER activity. Furthermore, the synergistic role of metal ions with orbital couplings and mechanistic pathway is investigated by Density Functional Theory (DFT) and Reactive Molecular Dynamics (RMD) simulations. Besides, the as-synthesized material demonstrates decent specific capacitance with good stability, signifying the potential results for sustainable electrochemical energy devices.