The fabrication of core-shell nanocrystals by incorporating microporous UiO-66 into mesoporous MIL-101 is reported. The growth of the core-shell MIL-101@UiO-66 nanocrystals was observed and supported by TEM and PXRD. The accessible pore volumes of the individual metal-organic framework (MOF) components and the core-shell hybrid crystals were also characterized. The hydrogen storage capacity exhibited by the resulting core -shell nanocrystals was 26% and 60% higher than those of pure phase MIL-101 and UiO-66, respectively. Finally, the fabricated core-shell MIL-101@UiO-66 structure exhibited a high degree of moisture tolerance. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.