Abstract text

An apparatus and process for producing a porous particulate media, such as nano-porous silicon (npSi). The apparatus has a rigid etching chamber configured to contain an etching reagent, an inlet for introducing the etching reagent into the etching chamber, and an outlet for outflow of the etching reagent from the etching chamber. One or more porous filter bags contain powders of a starting material for the porous particulate media, and are secured apart from each other within the etching chamber to enable contact between the etching reagent and the powders within the filter bags. Each filter bag is characterized by a pore size sufficiently small to confine the powders within the filter bag but sufficiently large to enable the etching reagent to flow through the filter bag. The etching reagent is flowed through the filter bags to etch the powders within each bag and produce the porous particulate media.