Tracking the Evolution of Iridium Nanocatalysts During Acidic Oxygen Evolution Reaction by Substrate‐Stabilized Identical‐Location Transmission Electron Microscopy

), which obscure the identification of genuine Ir reconstruction. By coating the Au grid with Pt to form a stabilized working electrode, these artifacts are effectively suppressed for up to 2.5 h, enabling direct visualization of the nanoscale evolution of Ir nanocatalysts. Control measurements further confirm that the electrochemical response of Ir nanocatalysts on Pt-coated grids is dominated by the Ir catalysts rather than the Pt support. This study demonstrates that IL-TEM provides a practical approach for probing catalyst evolution in harsh, prolonged acidic environments by tracking the same nanocatalysts over extended reaction times, complementing in situ and operando TEM techniques.