Fuels such as diesel contains different kinds of aromatic and poly aromatic compounds, which on their combustion emits environmental pollutants such as SOx, NOx, COx, and unburnt polycyclic aromatic hydrocarbons (PAH). These PAHs are not only environmental pollutants but are also increasingly associated with probable causes of several human diseases such as asthma and lung-cancer. Therefore, reducing the concentration of aromatic compounds in fuels during the refining process is of great importance. To attain this objective in this work, we would like to perform a detailed study on the fundamental interactions of benzene, cyclohexadiene, cyclohexene and cyclohexane on Ni as catalyst using Inelastic Neutron Spectroscopy (INS) and van der Waals Density Functional Theory (vdW-DFT). Here, we use the sequential hydrogenation of benzene as a relatively simple model for PAHs.