Hierarchical porous CdS nanosheet-assembled flowers were synthesized by a simple ion-exchange strategy using morphology-analogous Cd(OH)(2) and Na2S as precursors. The prepared CdS flowers exhibited high visible-light photocatalytic H-2-production activity with a rate of 468.7 mu mol h(-1) and the corresponding apparent quantum efficiency (QE) of 24.7% at 420 nm, which exceeded that obtained on CdS nanoparticles by more than 3 times. This enhanced photocatalytic H-2-production activity was achieved because the hierarchical organization of nanosheets and porous nanosheet structures can efficiently enhance light-absorption ability and provide a greater number of active adsorption sites. This work shows a great potential of hierarchical porous CdS nanosheet-assembled flowers for photocatalytic H-2 production, and also demonstrates that the ion-exchange strategy of Cd(OH)(2) intermediates can be extended to the preparation of other porous oxides and sulfides with hierarchical nanostructures. (c) 2013 Elsevier B.V. All rights reserved.