Bimetallic AgCu metal foams (15 at% Ag, 85 at% Cu) have been synthesized by means of an additive-assisted electrodeposition process using the dynamic hydrogen bubble template approach. Ag and Cu remain fully phase-segregated in the as deposited bimetallic foam exhibiting a high degree of dispersion of pure nm-sized Ag domains embedded in the Cu matrix. An activation of this bimetallic material towards ethanol formation is achieved by thermal annealing of the as deposited foam under mild conditions (200 °C for 12 h). Such annealing quantitatively transforms the Cu in the bimetallic system into a mixture of crystalline Cu₂O and amorphous CuO whereas the Ag remains in its metallic state due to the thermal instability of Ag₂O above temperatures of 180 °C. The selective oxidation of Cu in the bimetallic Ag₁₅Cu₈₅ catalyst goes along with an enrichment of Cu oxides on the surface of the formed mixed AgCu_xO foam.

Both operando X-ray diffraction and operando Raman spectroscopy demonstrate, however, that the oxide reduction is completed before the electrochemical CO₂ reduction sets in. The thus formed oxide-derived (OD) bimetallic Ag₁₅Cu₈₅ foam catalyst shows high selectivity towards alcohol formation with Faradaic efficiencies of FE_EtOH = 33.7% and FE_n-PrOH = 6.9% at −1.0 V and −0.9 V vs RHE, respectively. Extended electrolysis experiments (100 h) indicate a superior degradation resistance of the oxide-derived bimetallic catalyst which is ascribed to the effective suppression of the C1 hydrocarbon reaction pathway thus avoiding irreversible carbon contaminations appearing in particular during methane production.