In the present work, we investigated the influence of the increase of Ni/W ratio by the addition of nickel nitrate on heteropolycompound (HPC) based catalysts. Synthesized catalysts were characterized by Raman, XPS and HRTEM techniques and were examined in the model reaction of toluene hydrogenation. The Ni2SiW12O40 based catalyst with a ratio of 0.36 obtained by addition of nickel nitrate was found to have the best catalytic activity compared to the most efficient of the HPC based catalysts with a stoichiometric Ni/W ratio of 0.36. Raman spectroscopy showed that the SiW12O40 (4-) HPA was decomposed during the drying step in SiW11O39 (8-) species.