(616c) Pt3Zn1 and Pt1Zn1 Intermetallic Nanocatalysts Synthesis and Characterization

Pt₃Zn₁ and Pt₁Zn₁ intermetallic nanoparticles supported on SiO₂ were synthesized by combining atomic layer deposition (ALD) of ZnO, incipient wetness impregnation (IWI) of Pt, and appropriate hydrogen reduction. The formation of Pt₁Zn₁ and Pt₃Zn₁ intermetallic nanoparticles was observed by X-ray diffraction (XRD) and synchrotron X-ray absorption spectroscopy (XAS). STEM images showed that the 2-3 nm Pt-based intermetallic nanoparticles were uniformly dispersed on SiO₂ support. The relationships between Pt-Zn intermetallic phases and synthesis conditions were established. The in situ XAS measurements at Pt L₃ and Zn K edges during hydrogen reduction provided a detailed image of surface species evolution. Due to a combined electronic and geometric effect, Pt₁Zn₁ exhibited much higher reactivity and stability than Pt₃Zn₁ and Pt in the direct dehydrogenation and oxidative dehydrogenation of ethane to ethylene reactions.