Solution and surfactant-free growth of supported high index facet SERS active nanoparticles of rhenium by phase demixing

Abstract

Stable, high-index facet Re nanoparticles have been grown by a solid state synthetic method, negating the need for solutions or surfactants to control seeding, supracrystallization and NP shape. By using mixtures of K[ReO₄] and the cyclic triphosphazene [NP(O₂C₁₂H₈)]₃, high-index facet nanoparticles and nanocrystals ∼3 nm in size can be seeded and grown from drop-cast films and powders due to phase demixing of the metallopolymer. NP dispersions are formed directly within a carbon support that liquefies, allowing NP coarsening and ripening, and the eventual formation of a solidified graphitic support filled with crystals. Successful growth of mesoscale supracrystals of Re also occurs from ripening of nucleated NP seeds, incubated within a solidified and partially dewetted solid support that patterns the surface. The supported Re NP dispersions also exhibit surface enhanced Raman scattering within a graphitic matrix.