Uniform and well-dispersed Ru nanoparticles with a diameter of 4-6 nm supported on chromium oxide (Cr2O3) nanoparticles have been prepared via the impregnation method. The catalytic activity of the Ru/Cr2O3 catalyst in ammonia decomposition and the rate of hydrogen generation are evaluated. The physical and chemical properties of Ru/Cr2O3 catalysts were characterized by N-2 sorption, XRD, TEM, H-2-TPR and XPS. The analysis data show that Ru nanoparticles are well dispersed on mesoporous Cr2O3 supports and have strong interactions with the Cr2O3 support. Ru/Cr2O3 catalysts show good catalytic performance. Complete ammonia decomposition was achieved at 600 C even at high space velocity (30,000 ml/(h g(cat))). 2013 Elsevier B.V. All rights reserved.