Bimetallic NiCo-NiCoO2 nano-heterostructures embedded on copper foam as a self-supported bifunctional electrode for water oxidation and hydrogen production in alkaline media

Earth-abundant, non-precious metal-based bifunctional electrocatalysts with efficient water splitting activity are of valuable importance in the limitation of energy losses in an alkaline environment. Herein, we report NiCo-NiCoO2 nano-heterostructures embedded on the oxidized surface of copper foam (NiCo-NiCoO2@Cu2O@CF) as an efficient bifunctional electrocatalyst for overall water splitting in 1 M KOH electrolyte solution. In this study, metallic Ni and Co interlinkage with NiCoO2 nanoparticles (NPs) are suggested to form by thermal decomposition of nickel-cobalt hydroxide precursors embedding on copper foam under a nitrogen environment. Bimetallic thin layered nano-heterostructures of NiCo-NiCoO2@Cu2O@CF exhibits a synergic effect of doubly active metals Ni and Co to achieve remarkable small overpotentials of 133 and 327 mV to achieve a current density of 10 mA cm(-2) for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The influential synergetic and structural effects have been extensively discussed to understand the overall water splitting for designing an efficient electrocatalyst. Hence, this phenomenon for surface modification of conductive substrate (CF) with a suitable combination of metal/metal oxide alloying as catalytic material helps us to design and synthesize low cost, highly efficient, non-precious metal-based electrocatalysts for overall water splitting. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The study presents NiCo-NiCoO2 nano-heterostructures embedded on copper foam as an efficient bifunctional electrocatalyst for water splitting. The synergic effect of Ni and Co metals results in remarkable small overpotentials for hydrogen evolution and oxygen evolution reactions. This surface modification strategy with metal/metal oxide alloying on a conductive substrate helps design low cost, highly efficient non-precious metal-based electrocatalysts.