Abstract: A pressure swing adsorption process (PSA) comprising the following steps: feeding an input gas containing H2, CO2 and impurities through a CO2 adsorbent material in a pressure vessel under a high pressure; withdrawing a first H2-rich product gas due to adsorption of CO2 in the adsorbent material; setting the pressure to an intermediate pressure causing the adsorbent material release a second gas stream; passing a CO2-rich purge stream through the adsorbent material, obtaining a purge gas; setting the pressure to a sub-atmospheric low pressure, so that a CO2-rich product gas is released under vacuum by the adsorbent material; re-pressurizing the vessel to said high pressure; said steps being performed cyclically in a pressure vessel or in a plurality of parallel pressure vessels of a multiple vessel setup.