In H-2 production, the reformer downstream upgrading is a fundamental step for CO (ca. 10%) reduction. H-2 (ca. 50%) presence limits CO conversion (ca. 25%) significantly (by thermodynamics) in a traditional reactor (TR). A Pd-Ag membrane (60 mu m thick) removing H-2 from the reaction side shifted the water-gas shift reaction toward a further product formation, and a very high (ca. 90%) CO conversion was measured, significantly exceeding the TR equilibrium value. In the meantime, a pure H-2 stream, suitable for a proton-exchange membrane fuel cell (PEMFC), is recovered on the permeate side because no sweep gas is used. The H-2 permeation was driven by feed pressure.