Revolutionizing CO₂ Electrolysis: Fluent Gas Transportation within Hydrophobic Porous Cu₂O

The success of electrochemical CO₂ reduction at high current densities hinges on precise interfacial transportation and the local concentration of gaseous CO₂. However, the creation of efficient CO₂ transportation channels remains an unexplored frontier. In this study, we design and synthesize hydrophobic porous Cu₂O 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 CO₂ transportation but also trap compressed CO₂ bubbles to form abundant and stable triple-phase interfaces, which are crucial for high-current-density electrocatalysis. In CO₂ 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 CO₂-to-C₂₊ conversion. Leveraging optimal gas transportation and active site exposure, the hydrophobic porous Cu₂O with a 240 nm pore size (P-Cu₂O-240) stands out among all the samples and exhibits the best CO₂-to-C₂₊ 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.