Demonstration of a micro-fabricated hydrogen storage module for micro-power systems.

The objective of this work was to demonstrate a micro-fabricated hydrogen storage module for micro-power systems. Hydrogen storage materials were developed as thin-film inks to be compatible with an integrated manufacturing process. Performance and durability of storage modules were evaluated. Further, applications were demonstrated for a nickel-hydrogen battery and a micro-fabricated hydrogen-air PEM fuel cell. The ink making process, in which polymer binders and solvents were added to the palladium-treated alloys, slightly decreased the storage capacities, but had little effect on the activation properties of the treated alloys. After 5000 absorption/desorption cycles under hydrogen, the hydrogen storage capacities of the thin-film inks remained high. Absorption/desorption behavior of the ink was tested in the environment of a new type nickel-hydrogen battery, in which it would in contact with 26wt% KOH solution, and the ink showed no apparent degradation. Storage modules were used as the successfully as hydrogen source for PEM fuel cell.

A Micro-fabricated Hydrogen Storage Module with Sub-atmospheric Activation and Durability in Air Exposure.

The objective of this work was to develop a hydrogen storage module for onboard electrical power sources suitable for use in micro power systems and micro-electro-mechanical systems (MEMS). Hydrogen storage materials were developed as thin-film inks to be compatible with an integrated manufacturing process. Important design aspects were (a) ready activation at sub-atmospheric hydrogen pressure and room temperature and (b) durability, i.e. capable of hundreds of absorption/desorption cycles and resistance to deactivation on exposure to air. Inks with palladium-treated intermetallic hydrogen storage alloys were developed and are shown here to be compatible with a thin-film micro-fabrication process. These hydrogen storage modules absorb hydrogen readily at atmospheric pressure, and the absorption/desorption rates remained fast even after the ink was exposed to air for 47 weeks.

Solar-light photoamperometric and photocatalytic properties of quasi-transparent TiO2 nanoporous thin films.

Transparent photocatalytic surfaces are of ever increasing importance for many applications on self-cleaning windows and tiles in everyday applications. Here, we report the formation and photocatalytic testing of a quasi-transparent thin and nanoporous titania films deposited on glass plates. Sputtered Ti thin films were anodized in fluoride-ion-containing neutral electrolytes to form optically semitransparent nanoporous films, which transformed to be completely transparent after thermal annealing. The nanoporous films were studied at different stages, such as before and after anodization, as well as after thermal annealing using scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-vis and Raman spectroscopy. It was observed that anodization at 20 V of high-temperature deposited titanium films resulted in regular nanopore films with pore diameters of 30 nm. Structural investigations on the transparent nanopore arrays reveal the presence of anatase phase TiO(2) even after annealing at 500 °C, which was confirmed by XRD and Raman spectroscopy measurements. The solar-light induced photocatalytic decomposition of stearic acid and photoconductivity characteristics of these nanoporous thin films are also presented.