Surface-modified advanced hydrogen storage alloys for hydrogen separation and purification

This paper summarises collaborative activities of South African and Norwegian groups in the development and characterisation of the advanced hydride-forming materials obtained by surface modification of AB(5)-type substrate by fluorination and/or electroless deposition of single-or mixed-metal coatings on the basis of palladium. The surface modification was shown to significantly improve activation performance and poisoning tolerance of the hydride-forming materials. In particular, hydrogen absorption rate, after long-term pre-exposure to air, was shown to be increased by similar to 100 times for the surface-modified materials, as compared to the unmodified alloy. It was shown that the surface modification route significantly influenced surface morphology and rate of hydrogenation. Finally, feasibility of application of the surface-modified hydride-forming materials for efficient hydrogen separation from gas mixtures containing CO(2) and CO has been demonstrated. The approach undertaken has the potential in tailoring of new classes of highly efficient and robust composite H storage materials for hydrogen separation and purification. (C) 2010 Elsevier B.V. All rights reserved.