Interfacial interaction induced OER activity of MOF derived superhydrophilic Co3O4–NiO hybrid nanostructures

Abstract

Electrocatalytic water splitting is one of the key technologies for future energy systems envisioned for the storage of energy obtained from variable renewables and green fuels. The development of efficient, durable, Earth-abundant and cheap electrocatalysts for the oxygen evolution reaction is a scorching area of research. The oxygen evolution reaction has huge potential for fuel cell and metal–air battery applications. Herein, we reported interfacially interacted and uniformly decorated Co₃O₄–NiO hybrid nanostructures formed by a metal–organic framework (Co₂–BDC(OH)₂) using BDC as a linker to the metal center. The fine nanosheets of Co₂–BDC(OH)₂ were first uniformly grown over the honeycomb-like structure of nickel foam (NF). After controlled calcination of these nanosheets/NF composites, a uniformly decorated, binder-free Co₃O₄–NiO/NF electrocatalyst was synthesized. The transformation of Co₂-BDC(OH)₂/NF into Co₃O₄–NiO/NF was characterized by several techniques such as powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy, transmission electron microscopy, etc. The catalyst exhibits a low overpotential of 311 mV vs. RHE at 10 mA cm⁻² current density. The catalyst also shows long-term stability (24 h) with a Tafel slope value of 90 mV dec⁻¹. The obtained experimental results are also in-line with the theoretical data acquired from model systems.