The hydrogen chemisorption process in metal hydrides and binary alloy systems of current interest for reversible hydrogen storage are dependent on the effective use of appropriate catalysts. To meet the current performance challenges, an understanding of the role of transition metal catalysts in the surface chemical reactions is crucial. To illustrate this point, experimental and theoretical results obtained from a study of hydrogen storage reactions in the sodium alanate system were presented. Reversible hydrogen storage in this material depended on the chemisorption of hydrogen that is catalytically assisted by 2-4% Ti dopant. The role of Ti could be linked entirely to the Ti-containing active sites on the surface of the metallic Al phase that is formed during the multi-step hydrogen depletion process. The Ti atoms had no long-range order beyond the second coordination sphere in the Al- phase, and it is located on or near the surface. This is an abstract of a paper presented at the 230th ACS National Meeting (Washington, DC 8/28/2005-9/1/2005)].
ASJC Scopus subject areas
- Chemical Engineering(all)