Cavity-Networked Copper Nanocatalysts with Acid-Tolerant Microenvironments for Efficient CO2 Electroreduction to Ethylene

Gasophilic/hydrophobic microstructured Cu nanomaterials address the multi-carbon (C₂₊) selectivity bottleneck in electrocatalytic CO₂ reduction reaction (CO₂RR), yet their morphological control is hindered by low reduction potentials and high surface atomic mobility. This study reports a bioinspired gas-trapping hydrophobic Cu nanostructure (BGH-Cu) via in situ electrochemical reconstruction, forming an interconnected cavity network that confers gasophilic/hydrophobic properties. Mechanistic studies reveal cavities act as dynamic electrolyte reservoirs, selectively retaining OH⁻/K⁺ to suppress proton transport and create a local micro-alkaline environment, while cavity-enhanced cation enrichment synergizes with C─C coupling. BGH-Cu achieves C₂H₄ Faradaic efficiency of 54.7% at current density of 600 mA cm⁻² in strongly acidic conditions (pH 1), with 63.7% single-pass carbon efficiency and 40 h stability in a membrane electrode assembly configuration. This work provides a non-extreme synthesis strategy for gasophilic/hydrophobic Cu nanomaterials, elucidates the “cavity microenvironment modulation” mechanism for C₂₊ selectivity, and offers a new paradigm for high-current-density acidic CO₂RR to C₂₊ products.