Rational construction of core-branch Co3O4@CoNi-layered double hydroxide nanoarrays as efficient electrocatalysts for oxygen evolution reaction

Electrocatalytic water oxidation is a crucial process for many conversion and storage systems. Developing noble-metal-free oxygen evolution reaction (OER) electrocatalysts with high activity and long durability thus becomes immensely vital yet challenging. In this work, core-branch Co3O4 @CoNi-layered double hydroxide nanoarrays are developed on nickel foam with the assistance of metal-organic-frameworks template and atomic layer deposition technology, acting as active and durable electrocatalysts for OER. The introduction of CoNi-LDH significantly regulates the morphological and electronic structure of Co3O4, giving rise to high surface-active sites exposure, accelerated electron transfer, and optimal interaction with intermediate products. Together with the 3D self-supported and binder-free structure, the optimized Co3O4@CoNi-LDH/NF exhibits remarkable OER performances in terms of low overpotential, high OER current density, and low Tafel slope, which are even better than the benchmark IrO2 electrocatalyst. This study provides a new horizon for exploring biphasic core-branch materials for electrocatalysis and other energy-related applications.