Interfacial Electron Coupling in Au Nanoparticle/CoFe Layered Double Hydroxide Nanosheet Heterostructures as Water Oxidation Catalysts

Abstract

Cobalt−iron layered double hydroxide (CoFe LDH) is considered an advanced electrocatalyst toward the alkaline oxygen evolution reaction (OER), yet its poor stability is still a huge challenge. Here, based on an innovative spontaneous redox reaction (SRR) method, we synthesize a gold-nanoparticle-decorated CoFe LDH heterostructure on nickel foam (Au/CoFe LDH/NF) at room temperature. The heterostructure catalyst not only exhibits a low overpotential of 233 mV at 10 mA cm −2 but also displays 400 h stability without any degradation at ∼200 mA cm −2 . The experimental and density functional theory (DFT) calculations validate that Au/CoFe LDH/NF with strong electronic coupling at the interface optimizes the electronic structure, reducing the OER energy barrier. In situ Raman spectra demonstrate that the transfer of electrons from Au nanoparticles to CoFe LDH alleviates the structural distortion of the catalyst during the OER, which is responsible for the strengthened stability.