Enhanced hydrogen adsorption on single-wall carbon nanotubes by sample reduction

Abstract

The effect of the reduction of single-wall carbon nanotubes (SWNTs) samples on the hydrogen adsorption is reported. Hydrogen adsorption isotherms have been performed at 77 K and until 300 Torr of hydrogen pressure on raw and modified SWNTs material produced by arc-discharge using Ni/Y as catalyst at different atomic percentages. The hydrogen adsorption isotherms of the samples after hydrogen reduction at 350 °C show around 40% of higher hydrogen adsorption than those of the unreduced material. This fact suggests hydrogen dissociation by the reduced metal nanoparticles and subsequent spillover to the SWNTs. The maximum hydrogen adsorption is low, around 3 wt.%, and higher pressures and temperatures at which spillover effect from metals to carbon surfaces has been probed have to be tested with carbon nanostructures. The samples have been characterized by ICPS and Raman Spectroscopy and the porous structure by using standard BET methods from nitrogen adsorption isotherms at 77 K.