Gold-Core Transition Metal Oxide-Shell Nanoparticle Electrocatalysts for Enhanced Oxygen Evolution

The oxygen evolution reaction (OER) is important for many renewable energy technologies, including electrolyzers, CO2 reduction, and metal-air batteries. Currently, the slow kinetics of this reaction limit efficiencies of many of these technologies, necessitating the development of high performance electrocatalysts. In recent reports, Au supports have been shown to enhance the OER catalytic activity of many 3d-transition metal thin films in alkaline conditions. Herein, we translate the beneficial impact of Au supports to high surface area core-shell nanoparticles, where a Au-core is surrounded by an OER-active transition metal oxide-shell (Au@MxOy where M=Ni, Co, Fe, and CoFe). This work presents the synthesis, characterization and electrochemical performance of Au@MxOy nanoparticles and demonstrates universal activity enhancement over Au-free oxide nanoparticles. Of all the materials tested, Au@CoFeOx particles demonstrate the highest activity and stability with an overpotential of 328 ± 3 mV over two hours at 10 mA cm-2. This illustrates that strategically coupling Au support and mixed metal-oxide effects in a core-shell nanoparticle morphology is a promising avenue to device-ready, high performance OER catalysts.