Sputter deposition is a state-of-the-art industrial technique for batch-to-batch and roll-to-roll production, offering a wide range of advantages for the catalyst fabrication. These include uniform catalyst distribution on the electrode, easy control of the catalyst's thickness, morphology, porosity and chemical composition, high reproducibility, and strong adherence of the catalyst to the substrate. Sputtering of Ag on carbon-based gas diffusion electrodes (GDEs) and polytetrafluoroethylene (PTFE) has recently been reported by Monti et. al. and Sargent et al., respectively, and shown promising results in the electrocatalytic reduction of CO2 to CO. The porosity and accessible active sites are fundamental to boost the CO2RR. To this end, plasma treatment is an effective method to modify the surface of the electrodes chemically and morphologically. Plasma oxidation treatment and pretreatment in O3 were recently reported to increase the activity and selectivity of Ag-based catalysts towards CO. However, the mechanisms responsible for this beneficial effect of plasma oxidation for an electrode that is reduced during CO2RR, are not yet elucidated.