Аннотация:The effect of quinoline additions and amount of the sulfiding agent added on the activity of the in situ prepared NiWS catalyst in naphthalene hydrogenation was studied. In the presence of 1 wt % quinoline, the obtained catalyst shows high activity (>95% naphthalene conversion). The physicochemical properties of the catalyst were studied by XPS, X-ray diffraction analysis, and TEM. At the W : substrate molar ratio of 1 : 40 and 360°С, an increase in the amount of the sulfiding agent from 1 to 5 wt % leads to a decrease in the selectivity with respect to decalins from 68 to 39%, respectively. The degree of decoration with nickel on adding 1 wt % sulfiding agent is 0.1. As the amount of the sulfiding agent added is increased to 5 wt %, the degree of decoration with nickel increases to 0.3.