Purification of Hydrogen from CO with Cu/ZSM-5 Adsorbents.

The transition to a hydrogen economy requires the development of cost-effective methods for purifying hydrogen from CO. In this study, we explore the possibilities of Cu/ZSM-5 as an adsorbent for this purpose. Samples obtained by cation exchange from aqueous solution (AE) and solid-state exchange with CuCl (SE) were characterized by in situ EPR and FTIR, H 2 -TPR, CO-TPD, etc. The AE samples possess mainly isolated Cu 2+ cations not adsorbing CO. Reduction generates Cu + sites demonstrating different affinity to CO, with the strongest centres desorbing CO at about 350 °C. The SE samples have about twice higher Cu/Al ratios, as one H + is exchanged with one Cu + cation. Although some of the introduced Cu + sites are oxidized to Cu 2+ upon contact with air, they easily recover their original oxidation state after thermal treatment in vacuum or under inert gas stream. In addition, these Cu + centres regenerate at relatively low temperatures. It is important that water does not block the CO adsorption sites because of the formation of Cu + (CO)(H 2 O) x complexes. Dynamic adsorption studies show that Cu/ZSM-5 selectively adsorbs CO in the presence of hydrogen. The results indicate that the SE samples are very perspective materials for purification of H 2 from CO.