Gas diffusion electrodes (GDEs) are emerging as a transformative platform for electrochemical energy conversion and sustainable chemical synthesis. By enabling efficient electrochemical reactions involving gaseous species, such as CO 2 , CO, N 2 , O 2 , and H 2 , at well-defined gas-liquid-solid interfaces, GDEs fundamentally overcome the intrinsic mass-transport constraints inherent to conventional aqueous electrodes, thereby enabling industrially relevant current densities unattainable in traditional configurations. Structurally, GDEs integrate a functional catalyst layer with a porous gas diffusion layer (GDL), allowing continuous and regulated delivery of gaseous reactants to active sites while stabilizing three-phase interfaces and tailoring local reaction microenvironments. These features collectively enhance reaction kinetics, product selectivity, and energy efficiency across diverse applications, including CO 2 electroreduction, water electrolysis, fuel cells, and electrochemical H 2 O 2 synthesis. This Perspective provides a critical analysis of recent progress in GDE materials, architectures, and interface engineering, with an emphasis on uncovering the mechanistic foundations of their operation. On this basis, we highlight unresolved challenges and propose emerging design principles aimed at realizing adaptive, durable, and scalable GDE platforms. We further discuss key research directions necessary to translate fundamental advances into practical, industrially relevant electrochemical technologies that support a carbon-neutral energy and chemical economy. This perspective introduced the structure and working principles of GDEs, and their frontier applications, as well as key challenges and future design directions for sustainable electrochemical technologies. • GDEs overcome mass transport limits for gas-involving electrosynthesis. • Engineered three-phase interfaces enable high current density and selectivity. • Design principles guide scalable and durable electrochemical systems.
Zhang et al. (Wed,) studied this question.