Highly Efficient Acidic Oxygen Evolution Electrocatalysis Enabled by Porous Ir–Cu Nanocrystals with Three-Dimensional Electrocatalytic Surfaces

The design of efficient Ir-based catalyst for oxygen evolution reaction (OER) in acidic conditions is the key for realizing the commercialization of polymer electrolyte membrane technology. This study reports a class of highly porous Ir–Cu nanocrystals (P-IrCux NCs) through a facile chemical dealloying strategy. Featuring the increased active surface area and plenty of defects, the newly generated P-IrCux NCs are highly active and stable toward OER in acidic conditions. The optimized P-IrCu1.4 NCs exhibit the current density of 12.8 mA cm–2 at the potential of 1.55 V (vs RHE), presenting 3.5-fold improvement in mass activity and 1.8-fold improvement in specific activity over the pristine solid IrCu1.4 NCs (S-IrCu1.4 NCs). Moreover, the obtained P-IrCu1.4 NCs also show excellent OER stability with negligible potential shift after continuous electrolysis in 0.05 M H2SO4 for 10 h. Further analysis reveals that the coordinatively unsaturated atoms at defects result in the higher oxidation state of iridium, which promotes the optimized intrinsic activity of P-IrCux NCs. This work highlights a promising strategy to create three-dimensional porous Ir-based catalysts for enhancing OER electrocatalysis.