Although hydrogen is produced on a rather large scale, only 62% of the output is attained as a target product; the balance is a by-product of oil refining, coking, and other facilities. To be utilised in a way, alternative to conventional on-site burning, this hydrogen has to be separated from industrial gas streams, and availability of this huge resource for hydrogen energy and technology is directly connected to the development of efficient methods for hydrogen extraction and purification. Metal hydrides (MH) are very promising for this application, as they exhibit high selectivity towards hydrogen. The main problem is in the deterioration of the MH performances caused by their poisoning with gas impurities (H2S, CO, CO2, O2, H2O) and slow activation kinetics after exposure to the non-inert environments. This problem can be addressed using surface engineering approaches, in particular, by deposition of Platinum Group Metals (PGM) onto the core material, increasing surface catalytic activity towards hydrogen dissociation and the poisoning tolerance.

This report presents results illustrating the improvement of hydrogen absorption performances of the MH surface-modified by electroless deposition of PGM. It was found that Pd and Pd+Ni encapsulation improves the hydrogenation kinetics of the AB5-type core in the absorption of hydrogen at low pressure (5 bar) and room temperature, after long-term pre-exposure to air and without activation by vacuum heating (Figure 1).

An experimental approach for the accurate study of kinetics of hydrogen extraction from gas mixtures by MH (running-flow technique combined with Sieverts apparatus) is discussed as well.