Flow‐Through Hollow Fiber Gas Diffusion Electrodes with Morphology‐Controlled In Situ Galvanic Grown Silver Catalysts for Enhanced CO Selectivity in CO 2 Electroreduction

Electrochemical reduction of CO 2 (CO 2 RR) into value‐added products offers a promising strategy to reduce dependence on fossil fuels, particularly when powered by renewable electricity. However, CO 2 RR faces challenges, including high activation energy barriers, competing side reactions, and limited CO 2 mass transport. Addressing these limitations requires not only the development of advanced electrocatalysts to enhance CO 2 RR activity but also the design of electrodes to optimize gas‐catalyst‐electrolyte interfaces and facilitate efficient mass transport, thereby advancing CO 2 RR toward industrial‐scale applications. Herein, we developed flow‐through hollow fiber gas diffusion electrodes (HFGDEs) featuring in situ galvanic growth of flower‐like silver structures. The abundant ultrathin 2D nanosheets enhance active sites and CO 2 RR activity, and the resulting electrode achieves a high Faradaic efficiency of CO of 91% at −1.2 (V vs RHE). Furthermore, the HFGDE configuration ensured sufficient CO 2 delivery to the active sites, enabling a partial current density of CO of 280.8 mA cm −2 . In situ Raman spectroscopy revealed that the in situ‐grown silver flower structure promotes the adsorption of *COOH intermediate, thereby accelerating CO 2 RR kinetics. Moreover, the robust CO 2 supply afforded by the HFGDE configuration is crucial to suppress competitive hydrogen evolution reaction (HER) and maintain high CO 2 RR activity under industrially relevant current densities.