Post‐Selenium‐Leaching Induced Fast Micro‐Bubble Detachment on Nickel‐Iron‐Based OER Catalyst for Efficient AEM‐WE

Abstract Developing efficient and durable oxygen evolution reaction (OER) catalysts is critical for advancing anion exchange membrane water electrolysers (AEM‐WE) for green hydrogen production driven by solar or wind power. This study explored the impact of the selenium (Se) modification on the OER performance of nickel‐iron layered double hydroxide‐based catalysts (i.e., NiFeSe), focusing on micro‐bubble formation/detachment and its role in optimizing mass transport. The introduction of Se influenced the surface and interface properties of the NiFeSe, including enhanced surface roughness, facilitated rapid nucleation and detachment of smaller oxygen bubbles, and reduced bubble‐induced diffusion limitations. As a result, the NiFeSe catalyst achieved a low overpotential of 190 mV at 1000 mA cm −2 and demonstrated a high durability beyond 2000 h in 1 M KOH. In the practical AEM‐WE device, it reached 8800 mA cm −2 at 2.0 V and worked continuously for over 3000 h at 1000 mA cm −2 . These findings highlight the crucial role of selenium‐induced micro‐bubble formation/detachment in improving mass transport and catalytic efficiency, providing new insights for next‐generation OER catalysts in industrial water electrolysis.