Single\nWalled Carbon Nanotube–Metal Oxide Nanocomposites for Reversible\nand Reproducible Storage of Hydrogen

Abstract

Composite material consisting of\nsingle walled carbon nanotubes (SWCNTs) and metal oxide nanoparticles\nhas been prepared and their hydrogen storage performance is evaluated.\nMetal oxides such as tin oxide (SnO₂), tungsten trioxide\n(WO₃), and titanium dioxide (TiO₂) are chosen\nas the composite constituents. The composites have been prepared by\nmeans of ultrasonication. Then, the composite samples are deposited\non alumina substrates and at 100 °C in a Sieverts-like hydrogenation\nsetup. Characterization techniques such as transmission electron microscopy\n(TEM), Raman spectroscopy, scanning electron microscopy (SEM), powder\nX-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy,\nenergy dispersive spectroscopy (EDS), CHN elemental analysis, and\nthermogravimetric (TG) measurements are used to analyze the samples\nat various stages of experiments. Hydrogen storage capacity of the\ncomposites namely, SWCNT–SnO₂, SWCNT–WO₃, and SWCNT–TiO₂ are found to be 1.1, 0.9,\nand 1.3 wt %, respectively. Hydrogenated composite samples are stable\nat room temperature and desorption of hydrogen is found to be 100%\nreversible. Desorption temperature ranges and binding energy ranges\nof hydrogen have been measured from the desorption studies. The hydrogenation,\ndehydrogenation temperature, and binding energy of hydrogen fall\nin the recommended range of a suitable hydrogen storage medium applicable\nfor fuel cell applications. Reproducibility and deterioration level\nof the composite samples have also been examined.