Hydrogen storage properties of Pd-doped thermally oxidized single wall carbon nanohorns

Single wall carbon nanohorns as well as their thermally oxidized derivatives were decorated with Pd nanoparticles and their H-2 sorption performance was examined at 298 K up to 20 bar. The specific surface area of the nanohorns was increased through air oxidation, while both the thermal treatment and the metal doping led to the enhancement of the H-2 uptake. The higher uptake of the hybrid materials could not be attributed only to the additive effect of the carbon support and Pd content suggesting the existence of a cooperative mechanism between the metal particles and the carbon surface. This weak chemisorption process was found to be fully reversible after mild heating; still, its contribution to the overall H-2 uptake was not found to be of great significance. (C) 2014 Elsevier B.V. All rights reserved.