Efficient reducibility of layered polysilane (SiH)n for selective recovery of platinum ions from aqueous media

Abstract

To achieve sustainable economic growth, it is essential to have a resource recycling system that uses energy and resources efficiently, eliminates waste, and maximizes their value. In particular, efficient recovery and recycling technology for scarce resources is extremely important because it leads to a stable supply of resources, environmental conservation, and reduction of mining energy. In this study, we demonstrate the one-pot and selective recovery of platinum (Pt) ions from aqueous media containing various coexisting ions using a two-dimensional silicon material. Specifically, Pt ions dissolved in artificial seawater were recovered using layered polysilane (SiH)_n (LpSi), which is a stacking of hydrogen-terminated monatomic silicon layers. Hydrosilyl groups (Si–H) in LpSi selectively reduced Pt ions to form Pt nanoparticles (Pt-NPs) on LpSi with a particle size less than 200 nm. The selective recovery of Pt ions using LpSi is effective even for low concentrations of Pt ions around 10 ppm, and Pt-NPs with sizes of less than 1 nm were recovered on LpSi. The formed Pt-NPs can be isolated from LpSi by simple treatment with an alkaline solution. Moreover, the resulting Pt-NP-loaded LpSi catalysed the hydrogen evolution reaction in water splitting as an electrocatalyst, and hydrogen evolution proceeded quantitatively for the supplied charges.