Synthesis of surfactant-free Pt concave nanoparticles in a freshly-made or recycled molten salt

This paper reports the synthesis of platinum concave nanoparticles (NPs) using a freshly-made or recycled KNO₃-LiNO₃ molten salt (MS). The products obtained from the freshly-made and four-times recycled MSs have similar size and morphology distributions, indicating that the MS can be recycled and reused without any detrimental effect on the character of the particles. Noticeably, no organic capping agents are used in the reaction system. Therefore the as-prepared NPs have a very "clean" surface. Furthermore, the exposed surface steps and high index facets existing on the edges of the as-prepared Pt concave NPs enable them to exhibit a much enhanced electrocatalytic oxidation performance toward methanol. Thus, the MSs have potential to be used as green solvents for the preparation of surfactant or capping agent-free platinum nanostructures.