B-Cu-Zn Gas Diffusion Electrodes for CO₂ Electroreduction to C₂₊  Products at High Current Densities

Electroreduction of CO₂ to multi-carbon products has attracted considerable attention as it provides an avenue to high-density renewable energy storage. However, the selectivity and stability under high current densities are rarely reported. Herein, B-doped Cu (B-Cu) and B-Cu-Zn gas diffusion electrodes (GDE) were developed for highly selective and stable CO₂ conversion to C₂₊  products at industrially relevant current densities. The B-Cu GDE exhibited a high Faradaic efficiency of 79 % for C₂₊  products formation at a current density of -200 mA cm^-2 and a potential of -0.45 V vs. RHE. The long-term stability for C₂₊ formation was substantially improved by incorporating an optimal amount of Zn. Operando Raman spectra confirm the retained Cu⁺ species under CO₂ reduction conditions and the lower overpotential for *OCO formation upon incorporation of Zn, which lead to the excellent conversion of CO₂ to C₂₊ products on B-Cu-Zn GDEs.