Heterostructural CoFe2O4/CoO nanoparticles-embedded carbon nanotubes network for boosted overall water-splitting performance

Development of inexpensive and highly efficient bifunctional electrocatalysts for overall water-splitting is of great significance to produce sustainable hydrogen fuel from a renewable water source. Particularly, the sluggish oxygen evolution reaction kinetics limit the overall efficiency of water-splitting catalysis. Although, precious metal-based catalysts can reduce the energy barrier and drive the reaction at low overpotentials, their scarcity and high cost limit the commercialization. In order to address the aforementioned issues, we present a metal-organic framework (MOF)-derived CoFe2O4/CoO heterostructure-embedded carbon nanotubes (CNT)-network with exceptional water-splitting performance. Due to the collective advantages related to MOF-derived porous carbon with abundant oxygen-vacancies, CoFe2O4/CoO heterostructure-embedded CNT-networks with largely exposed catalytic sites, and their synergistic interactions, the hybrid catalyst (CoFe/C-650) delivers superior performance for oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and overall water-splitting: it requires a low overpotential of 246 mV (for OER) and 164 mV (for HER) at 10 mA/cm2 (ƞ10) with low Tafel slopes of 45.27 and 86.38 mV/dec, respectively. Interestingly, it requires an overpotential of 1.614 V (ƞ10) for full water-splitting catalysis, which is comparable to that of benchmark Pt/C (Cathode) and RuO2 (Anode) combination. This work presents a novel approach towards nanostructure design and facile production of transition metal-based oxide heterostructures to achieve the superior bifunctional activity.