Despite the quasi in-situ XPS and XAS results indicating the full reduction of Cu under all the applied potentials, operando surface enhanced Raman spectroscopy measurements indicate the formation of a thin surface layer of Cu(OH)2/malachite mixture during CO2 electrolysis f or all the studied catalyst materials (pure Cu and bimetallic f oams). The Cu(OH)2/malachite equilibrium depends on the local alkalinity developed under CO2 electrolysis conditions. Operando SERS enables us to follow the transformation of the copper surface oxides into metallic copper and then into mixture of Cu(OH)2/malachite during the activation step (applying -2 mA/cm 2 ).