Ampere-level CO2 reduction to multicarbon products over a copper gas penetration electrode

Renewable energy-driven electrochemical CO2 conversion to value-added chemicals is a prospective strategy for addressing both carbon emission and energy consumption. Although considerable progress has been made in CO2 electroreduction, sustained production of multicarbon compounds at a high current density remains a challenge. Herein, we report a hierarchical micro/nanostructured Cu(100)-rich copper hollow fiber as a gas penetration electrode (GPE) that reduces CO2 to C2+ products with a faradaic efficiency of 62.8% and a current density of 2.3 A cm(-2) in 0.5 M KHCO3 solution at -1.94 V (vs. RHE), outperforming state-of-the-art Cu-based catalysts. Electrochemical results demonstrate that optimized mass transfer and an enhanced three-phase interface reaction synergistically promote CO2 activation and reduction kinetics. Theoretical calculations further suggest that the Cu(100) facet of the Cu GPE favors CO* intermediate adsorption and then facilitates C-C coupling, resulting in selective C2+ product formation. This work provides an attractive avenue to achieve industrial current densities to produce multicarbon products via rational electrode designs.