Improved oxygen evolution activity of IrO2 by in situ engineering of an ultra-small Ir sphere shell utilizing a pulsed laser

Abstract

Noble metal-based catalysts are vital electrocatalysts for the oxygen evolution reaction (OER), which is a half reaction among multiple renewable energy-related reactions. To fully exploit their potential as efficient OER catalysts, we developed a fast one-step strategy to engineer a unique nanostructure for the benchmark catalyst IrO₂ utilizing an ultra-fast pulse laser, through which a shell of ultra-small Ir spheres with a diameter of ca. 2 nm is in situ engineered around the IrO₂ core. The creation of the Ir sphere shell not only increases the electrochemical surface area, but also improves the electrical conductivity of the electrocatalyst. The as-engineered IrO₂@Ir architecture exhibits extremely high electrocatalytic activity towards the OER, revealing an overpotential of 255 mV at 10 mA cm⁻² and Tafel slope of 45 mV dec⁻¹. These values are much lower than those observed for the unmodified structure. Furthermore, the catalytic performance is the best among all the noble metal-based OER catalysts. This work may open a new avenue to efficiently improve the catalytic activity of noble metal-based catalysts and significantly advance the development in the energy industry.