The effect of Ni addition on the structure of Pt-Sn/C nanoparticles by electron microscopy

Carbon supported bimetallic Pt-Sn and trimetallic Pt-Sn-Ni nanoparticles were synthesized by Bönnemann's colloidal precursor method and characterized by high-resolution transmission electron microscopy (HR-TEM) and energy dispersive X-ray analysis (EDX) techniques. HR-TEM and EDX results demonstrated that SnO₂ nanoparticles tend to form clusters in Pt-Sn/C; however, the presence of Ni in the Pt-Sn/C gives rise to an induced interaction between SnO₂ and Pt nanoparticles. Electron diffraction patterns of Pt-Sn-Ni/C showed that either cubic Pt or PtSn₂ structures are present. From the selected area EDX analysis, it was found that both of these structures contain Sn. This suggests that Pt-Sn-Ni/C nanoparticles may be partially covered by Sn-richer PtSn₂ alloyed structure.