Poly(N-vinyl-2-pyrrolidone) (PVP) was successfully grafted onto silica by a two-step method developed in this work. The Ru nanoparticles/silica composites were fabricated using the PVP-modified silica. Nitrogen adsorption, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques were used to characterize the nanocomposites. The results showed that Ru nanoparticles with the size of about 2-5 nm that possessed high crystallinity were immobilized on the silica grafted by PVP. The hydrogenation of aromatics was studied using the nanocomposites as the catalyst. It was found that the catalyst was very active for the reactions, and was very stable due to the stabilizer PVP grafted on the surface of the silica. (C) 2009 Elsevier B.V. All rights reserved.