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

Abstract

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_xO_y 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_x, demonstrate an overpotential of 328 ± 3 mV over a 2 h stability test at 10 mA cm^-2, 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.

Keywords: Oxygen evolution reaction; core−shell nanoparticles; electrocatalysts; nanostructures.