Nickel nanoparticles (2–6 nm) were successfully deposited on MOF-5 (Zn4O(BDC)3, BDC=1,4-benzenedicarboxylate) by a facile wet impregnation strategy to prepare Ni@MOF-5 employing Ni(acac)2 (acac = acetylacetonate) as the precursor in absolute ethanol solvent owing to the sensitivity to the moisture of MOF-5.