Hydrogen storage on Ni/Al/sub 2/O/sub 3/ nano-composite for fuel application

Nanomaterials are now emerging as an alternative to the conventional bulk materials due to their unprecedented physical and chemical properties. A material is said to be nano if the particle size is less than 100 nm in at least one dimension. From the great many advantages of nanomaterials one is the opportunity to control the microstructure (composition, structure, shape and size) at nano-meter level scale. The properties of nanomaterials change as a function of size of the particles. The smaller size allows large specific surface area which enables them excellent candidates for adsorption applications. This presentation highlights the synthesis of Ni/Al/sub 2/O/sub 3/ nano-composite and its application for hydrogen adsorption (storage), one of the burning topics of the present times. A dynamic chemical vapor deposition (CVD) technique was used for the synthesis of Ni/Al/sub 2/O/sub 3/ nano-composite. The material was achieved by reducing Ni+2 to Ni0 under the steady stream of hydride-modified aluminum alkoxides ((H2Al(OtBu)2). The CVD reactor has the advantage of dynamic vacuum removing the byproduct as soon as produced and thus hindering the contamination of the resulting Ni/Al/sub 2/O/sub 3/ nano-composite. The physical (analytical) characterization techniques revealed the formation of metallic nickel dispersed in alumina (Ni/Al/sub 2/O/sub 3/) matrix. The material has sufficient porosity which is revealed by the scanning electron microscopic photographs. The material was tested for possible hydrogen storage using homemade Sievert's type apparatus and it was found that approximately 2.9 wt.% (w/w %) hydrogen can be stored upon the Ni/Al/sub 2/O/sub 3/ nano-composite. Although the amount of hydrogen stored is below of the required amount for onboard applications. However, the study will open new dimension in terms of hydrogen storage materials. (author)