Nanoporosities and catalytic activities of Pd-tailored single wall carbon nanohorns

Abstract

The nanoporosities and catalytic activities of Pd nanoparticles dispersed on single wall carbon nanohorns (Pd-SWCNHs) and oxidized single wall carbon nanohorns (Pd-ox-SWCNHs) were examined. A transmission electron microscopy (TEM) observation indicated that Pd nanoparticles of 2–3 nm size were highly dispersed on both the SWCNHs. X-ray photoelectron spectra and N 2 adsorption isotherms at 77 K illustrated the differences in the deposition process mechanisms of the Pd-SWCNHs and Pd-ox-SWCNHs; the deposition process depended on the surface functional groups. The supercritical H 2 adsorption isotherms at 77 K suggested the relationships between the interaction of Pd-SWCNHs and Pd-ox-SWCNHs with H 2 and the catalytic activities for a water formation reaction in a gas phase at 273 or 298 K. The catalytic activity measurement and TEM observation of the catalysts after the reactions demonstrated that the Pd-SWCNHs and Pd-ox-SWCNHs are promising catalysts.