Hydrogen Storage in Porous Single-Walled Carbon Nanohorns Dispersed with Pd-Ni Alloy Nanoparticles

摘要

Single-walled carbon nanohorns containing Pd—Ni alloy nanoparticles (Pd—Ni/SWCNHs) were prepared by the gas-injected arc-in-water method, and high-pressure H2 absorption by these nanoparticles was investigated using a magnetic suspension balance at 30 °C and 1.2 MPa. The amount of H2 absorbed by them was larger than the predicted combined absorption contributed by Pd—Ni alloy and pure-carbon SWCNHs. This synergetic H2 absorption was induced by the combination of Pd—Ni alloy nanoparticles and SWCNHs and occurred because of a spillover effect. Remarkably, H2 absorption occurred by diffusing into as-grown Pd—Ni/ SWCNHs. Opening the pores of Pd-Ni/SWCNHs by a mild oxidation treatment drastically improved the H2 absorption. Consequently, the diffusivity of H2 into Pd—Ni/SWCNHs was enhanced to the point where H2 absorption could reach saturation in an extremely short time.