the complete disappearance of Cux(CO3)y(OH)z peaks f or all investigated catalyst materials af ter taking them out of the electrolyte even f or short time (<5 min). On the other hand, while remaining immersed these in-situ f ormed Cux(CO3)y(OH)z phases formed during CO2 electrolysis stay observable for some time (15-25 minutes) af ter the bias removal. Af ter that time, the equilibrium between Cu(OH)2 and basic copper carbonate (malachite/azurite) shifts towards basic copper carbonate with time, as demonstrated by the appearance of several new peaks which can be assigned to malachite/azurite phases. We theref ore conclude that while our quasi in-situ XPS approach does prevent the re-oxidation of catalyst surf aces af ter bias removal, it couldn't observe the Cu hydroxide/basic carbonate surf ace species since the presence of the local alkalization is essential f or the stability of those phases. Both of the two CO selective bimetallic systems (Cu85In15 and Cu85Sn15) showed a similar CO selectivity, despite showing significant differences f rom each other in the dominant copper active-surface species. Even the pure copper foam showed a similar surf ace Cu species to the Cu85In15 (CO selective). Thus, we do not f ind any clear relationship between these observed Cu hydroxide/carbonate surface species and the CO2ER to either CO or HCOO -of the different investigated catalyst materials.