Noble Metal Recovering by Electroless Displacement Deposition on Silicon Powder

Noble metal is not only precious but also crucial for industries, such as electronics, catalyst, automotive, and electrolysis. Recycling of noble metal from scrap electronics and industrial waste is important for saving natural resources and environment. In the conventional recycling process, the scraps and waste are dissolved in aqueous solution and refined chemically. For recovering from low concentration waste solution, ion-exchange resin or electrolysis is used. We have been studying electroless displacement deposition of noble metal nanoparticles on silicon (Si) substrates (1) for efficient solar cell production (2) and metal film formation (3). This deposition is a local galvanic reaction expressed by followings.