Hydrogen storage of multi-walled carbon nanotubes obtained by decomposition of hydrocarbon over Ni-Li/SiO₂

Hydrogen storage into multi-walled carbon nanotubes obtained by the decomposition of hydrocarbons using Ni-Li/SiO₂ was investigated. The optimized reaction conditions for the synthesis of carbon nanotubes were 873K and W/F = 40 g-cat.h/mol, and carbon nanotubes obtained by C₂H ₆ decomposition were found to exhibit fairly large H₂ storage capacity of 1 wt% at room temperature. The storage capacity increased with decreasing temperature and a capacity of 5 wt% was achieved at 77K, with 66% of adsorbed hydrogen being desorbable. Hydrogen adsorption by π orbital in C-C bond coordination is proposed, observing both weakened Raman adsorption C-C peaks and the thermal release of CH₄ after H₂ storage.