The reaction of ethylene molecules with a Ni cluster was investigated by ab initio molecular
simulations. We found that hydrogen atoms on the Ni cluster hamper dehydrogenation of
ethylene molecules, which implies that carbon atoms are not supplied into the Ni cluster when
the number of the hydrogen atoms is saturated. However, the hydrogen atoms were removed
from the cluster by producing hydrogen molecules and carbon atoms are continuously supplied.
This fact suggests that the production of the hydrogen molecules determines the rate of
supplying carbon atoms. We investigated activation energies to form the hydrogen molecules on
the Ni cluster, and discussed the mechanism of efficient removal of the hydrogen atoms.
Key words: ethylene molecule, nickel cluster, carbon nanotube, dehydrogenation, hydrogen molecule