Interface engineering and heterometal-doped FeOOH/Ga-Ni3S2 nanosheet arrays for efficient electrocatalytic oxygen evolution

Abstract

The exploration of highly efficient and stable non-noble metal electrocatalysts for oxygen evolution reaction (OER) is a crucial challenge. Herein, we demonstrate the design and fabrication of three-dimensional (3D) gallium-doped FeOOH/Ni₃S₂ nanosheet arrays on a Ni foam (denoted as FeOOH/Ga-Ni₃S₂) via a facile hydrothermal synthesis and their subsequent electrodeposition. Benefiting from the strong interfacial coupling effects between FeOOH and Ni₃S₂, Ga doping in Ni₃S₂ creates exposed active sites, and the optimal 3D FeOOH/Ga-Ni₃S₂ electrocatalyst exhibits outstanding electrocatalytic performance towards OER, while requiring a low overpotential of 274 mV at 100 mA cm⁻². In addition, it possesses impressive durability of up to 24 h even at 100 mA cm⁻². Furthermore, density functional theory (DFT) calculations validate the improved conductivity and binding energy of oxygen-containing intermediates due to synergistic effects among multiple components and the optimised electronic structure of Ni₃S₂ ascribed to Ga doping, which boosts the OER performance. This study provides new insight into the fabrication of highly active, stable, and cost-effective electrocatalysts.