Core–Shell Au@Metal-Oxide Nanoparticle Electrocatalysts for Enhanced Oxygen Evolution

Enhanced catalysis for electrochemical oxygen evolution is essential for the efficacy of many renewable energy technologies, including water electrolyzers and metal–air batteries. Recently, Au supports have been shown to enhance the activity of many 3d transition metal-oxide thin films for the oxygen evolution reaction (OER) in alkaline media. Herein, we translate the beneficial impact of Au supports to high surface area, device-ready core–shell nanoparticles consisting of a Au-core and a metal-oxide shell (Au@M<sub><i>x</i></sub>O<sub><i>y</i></sub> where M = Ni, Co, Fe, and CoFe). Through a systematic evaluation, we establish trends in performance and illustrate the universal activity enhancement when employing the Au-core in the 3d transition metal-oxide nanoparticles. The highest activity particles, Au@CoFeO<sub><i>x</i></sub>, demonstrate an overpotential of 328 ± 3 mV over a 2 h stability test at 10 mA cm<sup>–2</sup>, illustrating that strategically coupling Au support and mixed metal-oxide effects in a core–shell nanoparticle morphology is a promising avenue to achieve device-ready, high-performance OER catalysts.