Pd on three dimensional (3D) porous carbon (Pd/PC) has been one-pot synthesized via in situ potassium hydroxide activation of PdCl62--exchanged resin for the first time. The anion-exchange resin not only anchors PdCl62- ions to obtain uniformly dispersed Pd nanoparticles but also acts as a carbon source. The Pd/PC composites exhibit an ultrahigh surface areas (2734-3316 m(2) g(-1)) and large pore volumes (1.789-1.991 cm(3) g(-1)). The excess hydrogen uptake of Pd/PC-850 reaches 4.6 wt% at 77 K and 20 bar. At room temperature, the hydrogen spillover process from Pd nanoparticles to the 3D activated porous carbon has been clearly observed. The 1.86 wt% Pd-containing composite (Pd/PC-850) displays a high hydrogen spillover enhancement (154%) at 298 K. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.