Abstract text

Processes and apparatuses for producing a porous material, such as nano-porous silicon (npSi) media suitable for storage and retrieval of elemental hydrogen. Processes of this invention generally entail applying a magnetic field to a substrate that contains charge carriers and is in contact with an etchant, and then etching the substrate with the etchant while relative movement occurs between the substrate and the magnetic field. During etching, the charge carriers move relative to the substrate and the magnetic field, and porosity forms at surfaces of the substrate contacting the etchant.