Friction-Assisted Electrochemical Oxidation of Iridium Surfaces for Enhanced Catalysis

Abstract

Iridium oxide (IrOx) has emerged as a prominent catalyst for acidic oxygen evolution reactions (OER), yet its direct preparation on the surface of Ir remains rare, severely restricting its applications in catalysis and sensing technologies. In this work, we report an innovative method to locally generate amorphous IrOx layers on Ir surfaces through the synergistic action of friction and anodic potentials. This approach enables the rapid preparation of sub-micrometer-thick IrOx layers within 200 seconds. The microscopic topography of Ir substrate has a significant impact on local reactant surface excess. Additionally, friction not only lowers the surface potential required for the oxidation of Ir but also introduces defects that enhance the electrocatalytic activity of the oxide. The resulting IrOx characterized by unique nanostructures demonstrates significant OER activity in acidic environments, significantly surpassing that of metallic Ir. These findings highlight the great potential of friction-assisted anodization for advancing micro-reactors and micro-sensor arrays.