The direct doping of small Pd cluster on IRMOF-1 and its influence on H-2 adsorption were investigated using periodic density functional methods. Our calculations indicate that the Pd cluster prefers to be deposited on the linker. The doped Pd cluster can not only play the important role for dissociating H-2 molecules, but also enhance the H interaction with IRMOF-1 by altering its electronic structures. As a result, hydrogen spillover in IRMOF-1 by directly doping Pd catalysts is thermodynamically feasible and the odd numbered H bottlenecks on undoped IRMOF-1 are eliminated. In addition, we discuss a working mechanism for releasing H-2 from the chemisorbed states. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.