Synthesis of Intermetallic Pt-Based Catalysts by Lithium Naphthalenide-Driven Reduction for Selective Hydrogenation of Cinnamaldehyde

Intermetallic nanoparticles (NPs) with a well-defined atom binding environment and a long-range ordering structure can be used as ideal models to understand their physical and catalytic properties. In this work, several kinds of nanostructured and carbon nanotube (CNT)-supported Pt-based intermetallic compounds (IMCs) have been synthesized by one-step lithium naphthalenide-driven reduction at room temperature without the use of surfactants in light of the reduction potential of metals. In the chemoselective hydrogenation of cinnamaldehyde, the second metal in Pt-M IMCs significantly creates a suitable reaction environment through construction of a good geometric and electronic structure. The Pt₃Sn/CNT catalyst presents highly efficient and good chemoselective hydrogenation of cinnamaldehyde to cinnamyl alcohol. This can be attributed to the fact that the incorporated Sn atoms effectively dilute large Pt ensembles and increase the electron density of Pt. The in situ-formed SnO_x interfaces as Lewis acid sites facilitate the coordination of C═O bonds, enhancing the selectivity to cinnamyl alcohol. In addition, the SnO_x interface as the joint between Pt₃Sn IMCs NPs and CNTs significantly improves the stability of the catalyst in the reaction environment.