A nanosize Zr-metal organic framework (Zr-MOF, UiO-66) with a uniformed particle size around 100 nm was solvothermally synthesized and activated by solvent exchange method, vacuum drying and heating. The activation process with an exchangeable guest solvent produced the Zr-MOF with a high surface area by removal almost all guest and free terephthalic acid molecules from the pores enhancing its capacity for adsorption. The nanosize Zr-MOF also showed strong thermal stability up to 753 K. The Zr-MOF was tested for hydrogen and carbon dioxide adsorption at varying pressures and temperatures and it exhibited adsorption capacity of 1.6 wt% (H-2) at 1 atm. 77 K and 79 cc (CO2) g(-1) at 1 atm, 273 K, respectively. The heat of H-2 adsorption was estimated to be 6-12 kJ molt while the heat of CO2 adsorption was determined to be around 28 kJ mol(-1). (C) 2012 Elsevier B.V. All rights reserved.