Activated Gas Diffusion Layers as Electrocatalysts for Sustainable Anion Exchange Membrane Water Electrolysis

ABSTRACT Anion exchange membrane water electrolysis (AEMWE) has emerged as a next‐generation water electrolysis technology for sustainable hydrogen production. Despite extensive research on electrocatalysts, scaling and retaining half‐cell–level performance in large‐area stack systems remains a major challenge. Recently, increasing attention has turned toward engineering gas diffusion layers (GDLs) to serve directly as catalytic substrates, providing a scalable and cost‐effective route by eliminating the need for additional catalyst layers. In this review, we present an overview of recent advances in activating and modifying GDLs for use as standalone electrocatalysts in AEMWE systems. We highlight diverse activation strategies for Ni‐ and stainless steel‐based GDLs commonly employed under alkaline conditions, as well as in situ electrochemical activation approaches applicable at high current densities. Finally, we discuss key challenges and future opportunities for designing effective GDL modification strategies, outlining potential pathways toward more efficient, durable, and economically viable AEMWE technologies.