In this study, multiwalled carbon nanotube (CNT)-nickel hybrid materials were prepared from CNTs by the impregnation of nickel at various CNT/nickel mass ratios. The presence of nickel nanoparticles on CNTs influences the spillover effect on hydrogen storage capacity. A thermal reduction method was employed to increase the contacts between the nickel metal particles and the carbon support, thus facilitating hydrogen spillover. The as-obtained nickel-decorated CNTs exhibited a high hydrogen storage capacity of 0.87 wt.% at 298 K and 100 bar, resulting in an enhancement factor of 2.5 relative to the untreated CNTs. These experimental results demonstrate that the presence of nickel creates hydrogen-favorable sites that can lead to improved hydrogen storage capacities based on the spillover effect. (C) 2016 Elsevier B.V. All rights reserved.