Hydrogen reservoirs based on porous silicon (PS) nanostructures are considered. Silicon-based hydrogen tanks are believed to be applicable for portable device energy supply and compatible with micro-sources of energy of new generation. Stain etching of silicon powder to produce PS is studied as a technology alternative to conventional electrochemical etching and application of the PS powder for hydrogen production is also described. Size selection of initial Si micro-particles constituting the powders was carried out by sedimentation technique. Hydrogen content in PS was investigated by FTIR spectroscopy. Extraction of hydrogen in water environment in presence of small amount of NH3 as catalyst was shown to have advantages such as safety and tunability, additional production of hydrogen from water dissociation, and a possibility to characterize PS as a hydrogen source material in terms of hydrogen effective shell and crystalline core conception. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.