tThe introduction of organic additives, such as polyols, sugars or polyacids, in impregnation solutionshas been suggested to better control the size of nanoparticles on supported catalysts. The present paperfocuses on the roles played by three of these additives, sorbitol, glucose and citric acid, in the preparationof Ni/Al2O3catalysts. ATR-IR, circular dichroism spectroscopy and viscosity measurements show thatthe additives act as modifiers of the physical properties of the solutions, by increasing their viscosity viahydrogen bonding, rather than as stable ligands toward Ni2+ions. Recrystallization of the nickel precursorsalt is prevented upon drying. As a consequence, no population of large particles is evidenced by XRDand TPR on the catalysts prepared with additives, unlike reference catalysts prepared by conventionalimpregnation of nickel nitrate. Adding these organic molecules in the impregnation solution is thusan easy way to narrow the size distribution of NiO nanoparticles without significantly affecting theirreducibility.