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

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.