Revolutionizing CO 2 Electrolysis: Fluent Gas Transportation within Hydrophobic Porous Cu 2 O.

The success of electrochemical CO 2 reduction at high current densities hinges on precise interfacial transportation and the local concentration of gaseous CO 2 . However, the creation of efficient CO 2 transportation channels remains an unexplored frontier. In this study, we design and synthesize hydrophobic porous Cu 2 O spheres with varying pore sizes to unveil the nanoporous channel's impact on gas transfer and triple-phase interfaces. The hydrophobic channels not only facilitate rapid CO 2 transportation but also trap compressed CO 2 bubbles to form abundant and stable triple-phase interfaces, which are crucial for high-current-density electrocatalysis. In CO 2 electrolysis, in situ spectroscopy and density functional theory results reveal that atomic edges of concave surfaces promote C-C coupling via an energetically favorable OC-COH pathway, leading to overwhelming CO 2 -to-C 2+ conversion. Leveraging optimal gas transportation and active site exposure, the hydrophobic porous Cu 2 O with a 240 nm pore size (P-Cu 2 O-240) stands out among all the samples and exhibits the best CO 2 -to-C 2+ productivity with remarkable Faradaic efficiency and formation rate up to 75.3 ± 3.1% and 2518.2 ± 8.1 μmol h -1 cm -2 , respectively. This study introduces a novel paradigm for efficient electrocatalysts that concurrently addresses active site design and gas-transfer challenges.