The catalyst support also plays an important role in the CO2RR process. State-of-the-art, conductive, carbon-based GDEs frequently suffer from flooding, i.e., the electrolyte penetrates deep into the channels of the porous substrate and impedes the transport of the gaseous CO2 reactant to the catalytic active sites, hence leading to a decrease in performance with time on stream. To prevent this, the surface of the GDE is usually treated to render it hydrophobic. However, this hydrophobicity slowly decreases, gradually limiting the access of the CO2 reactant, favoring the HER against the CO2RR to CO. A major step in the prevention of flooding has been reported with the use of the intrinsically hydrophobic PTFE as GDE. In contrast to carbon-based GDEs, porous polymer substrates are nonconductive, serving therefore only for gas diffusion, while the electrically conductive catalyst layers, in combination with current collectors, secure a high and uniform current for the CO2RR. This paper reports on the development of a highly efficient, sputtered Ag catalyst, directly on porous PTFE substrate, allowing for decreased Ag loading compared to commercial catalyzed GDEs. The higher PTFE hydrophobicity drastically decreases the flooding, contributing to higher stability with comparable current density for the CO2RR to CO. The sputtered Ag films have been subjected to an oxygen plasma treatment, causing a change of the oxidation state and increase in porosity, leading to increased catalytic performance in the CO2RR compared to the untreated catalyst. Plasma-treated, sputtered Ag catalysts yield higher current density at low overpotential, >90% faradaic efficiency for CO and prolonged stability when compared to the pristine Ag.