Abstract <p>Liquid-phase hydrogenation of styrene at the atmospheric pressure in aqueous media was studied on a series of Ni/SiO₂ supported nickel catalysts containing various nickel amounts (from 6 to 28 wt %). The effects of textural characteristics of the catalysts and its controlled deactivation with sulfide ions on the catalytic activity were studied. The dispersion increased in response to decreasing nickel content, but the active surface area of the reduced metal decreased. Partial deactivation was simulated by addition of a controlled amount of Na₂S in order to quantify the density and activity of various types of catalytic centers. The complete deactivatation of one Ni⁰ atom on the surface required 0.6 to 1.2 S^2– ions on the average, depending on the morphology of the catalyst. The poison resistance of the catalyst was analyzed in terms of the turnover frequency (TOF) and turnover number (TON_deact). Our results expand the understanding of deactivation schemes and can be used to develop new-generation catalysts that would be resistant to sulfur-containing impurities in hydrogenation reactions.</p>