New Development Studies on Synthesis and Hydrogenation Behaviourof Graphitic Nanofibres

摘要

The nano-variants of carbon including graphitic nanofibres (GNF) have recently beenconsidered to be exotic (light weight, high storage capacity) hydrogen storage materials.Earlier we have studied hydrogenation behaviour of GNF grown from acetylene gas inpresence of Cu + Ni (2% Cu, 98% Ni) as catalysts. The present study is aimed atsynthesis, structural as well as microstructural characterization and hydrogenationbehaviour of graphitic nanofibres prepared by hydrocarbon gas (ethylene, benzene,acetylene). In the present investigations, we report growth of aligned bundles of GNFprepared by thermal decomposition of acetylene employing palladium (Pd) sheet ascatalyst. This represents a new form of catalyst. The structural and microstructuralcharacteristics have been evaluated by X-ray diffraction and scanning as well astransmission electron microscopy. Exploration through SEM (secondary electron images)has revealed that the typical length and width of cross section of bundles is ～50 μm and ～25 μm respectively.The length of individual GNF is ～50 μm and diameters individual～250nm. The microstructural characteristics of the dehydrogenated samples has beendone /studied employing TEM. This reveals presence of curved void spaces in thedehydrognated sample. This possibly reveals the sites of hydrogen storage. The GNFbundles grown by the present method are easier to hydrogenate, thus they absorbhydrogen at lower pressure of ～80 atm. As against ～120 atm for the GNF grown in the ourearlier studies. The reproducible hydrogen storage capacity of the GNF grown in thepresent studies is ～17wt%. This is one of the high hydrogen storage capacities of theGNF samples.