Catalytic Activity of Multiwalled Carbon Nanotubes in Acetylene Hydrogenation

Graphical Abstract

Hydrogenation on carbon nanotubes: Multiwalled carbon nanotubes (MWCNTs) are used to catalyze the hydrogenation of acetylene to ethylene with high selectivity and no methane formation. The reaction takes place between adsorbed substrates through a Langmuir–Hinshelwood mechanism.

Abstract

The hydrogenation of acetylene was investigated on multiwalled carbon nanotubes (MWCNTs) with an average diameter of 35 nm and prepared by chemical vapor deposition from ethylene. The MWCNT structure and surface-oxygen-containing functional groups were verified by transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and Boehm titration. Significant differences in the surface functionalities of the MWCNTs were found before and after catalysis, but the morphology of the MWCNTs did not change. During catalysis, the MWCNTs are characterized by a large number of defects and the surface is functionalized with hydroxy and carbonyl groups. The MWCNTs demonstrated high selectivity towards ethylene formation. The formation of methane was not recorded. Our study indicates that acetylene hydrogenation proceeds according to a Langmuir–Hinshelwood mechanism.