Organics- and Surfactant-Free Molten Salt Medium Controlled Synthesis of Pt-M (M = Cu and Pd) Bi- and Trimetallic Nanocubes and Nanosheets

We present a novel synthetic strategy for the shape-controlled synthesis of Pt-based alloy nanoparticles (NPs) in inorganic molten salt without using any organic surfactants or capping agents. Graphene oxide (GO) was chosen as the stabilizer in the inorganic molten salt synthetic strategy, due to the existence of various oxygen-containing functional groups on its surface, which adsorb, anchor, and stabilize the metal ions or NPs. After GO was added in molten salt, the PtPd nanosheets were formed on its surface in H₂ atmosphere. In addition, when KI was chosen as the shape-inducing agent to selectively adsorb on and fully protect the (100) facets of alloys, PtPd nanocubes with core-shell structure, PtCu nanohemicubes, and PtPdCu nanocubes were prepared successfully on the surface of GO in molten salt. Introduction of GO as the stabilizer in molten salt proves a new approach in synthesis of Pt-based nanocrystals with controlled morphologies.