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Hydrogen is gaining a great deal of attention as an energy carrier as well as an alternative fuel. However, in order to fully implement the so called 'hydrogen economy' significant technical challenges need to be overcome in the fields of production and storage of hydrogen and its point of use especially in fuel cells for the automotive industry. The purpose of this review is to present and discuss recent advances in the use of nanomaterials for solar hydrogen production and on-board solid state storage of hydrogen. The role of nanotechnology in enhancing the efficiency of fuel cells and reducing their cost is also discussed.

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Silver particles grown on silicon in a galvanic displacement process undergo Ostwald ripening in which small particles merge into bigger ones. In this process the particles are shown by scanning electron microscopy to become smoother. Even though the surface area of the nanoparticles is halved on ripening, the Raman enhancement provided by them is at least five times higher than of the particles that did not undergo the ripening. In several regions, transmission electron microscopy (TEM) images show that the ripened particles resemble agglomerated colloids. In these regions the signal due to surface-enhanced Raman scattering (SERS) is greatly enhanced, suggesting that they are the SERS "hot spots". The importance of boundaries formed between silver particles to the increased Raman signal is suggested.

Pure Sn films deposited on Cu and Cu alloys are prone to spontaneous whisker formation. One way of preventing whisker formation is to alloy Pb into Sn coatings. However, restriction on the use of Pb demands the development of alternative methods for preventing whisker growth. The present work reports the effect of substrate composition on whisker formation and morphology. Despite employing identical plating conditions, long filament-like whiskers grew only on Sn-plated Cu samples and not on brass. The presence or lack of Sn whiskers has been explained via the thermodynamic stability of various intermetallic compounds at the Sn/substrate interface.

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