Catalyst Metal Deposition into Porous Silicon Layer

In order to prevent catalyst layer collapse formed onto a porous silicon layer, a new method was developed. We have proposed a novel miniaturized fuel cell using monolithically fabricated silicon electrodes and power generation was verified though the output was small. Pore diameter and porosity of the porous silicon layer which works as a diffusion layer and a catalyst support layer was enlarged for easy penetration of electrolyte and fuel, but the porous layer was collapsed when the catalyst metals were deposited onto the porous layer. It is assumed that the porous layer shrinks because platinum, whose atomic size is smaller than the size of silicon, replaces silicon at equal stoichiometric ratio in a plating bath using Pt4+ ion. Pt2+ ion was mixed into the plating bath and the collapse of the porous layer was prevented.

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