Bimetallic Bismuth‐Based Nanoparticles From Pseudo‐Tetrahedral Zintl Anions

While Zintl compounds comprising Bi-based anions of p-block elements have been used as starting materials for larger bismuthbased clusters, their potential to form nanoparticles has not yet been explored. Here, bimetallic nanoparticles are synthesized from the oxidation of bismuth-based pseudo-tetrahedral Zintl anions (InBi3 ) 2−, (Sn 2 Bi 2 ) 2−, (TlBi 3 ) 2−, and (Pb 2 Bi 2 ) 2−. The anions rapidly oxidize at ambient conditions to form metallic seeds, with the mild oxidizing agent PVP (polyvinylpyrrolidone), which also serves as a stabilizing agent for nanoparticle growth. Each elemental combination behaves uniquely, resulting in bimetallic nanoparticles of varying forms (i.e., alloyed, core-shell, and Janus-type). The resulting nanoparticles show a relatively narrow size distribution with median diameters of ∼20–25 nm and exhibit ultraviolet (UV) absorption, with spectral features tunable by composition. The morphology and composition were analyzed by scanning transmission electron microscopy (STEM), highresolution transmission electron microscopy (HRTEM), micro-X-ray fluorescence spectroscopy (μ-XFS), powder X-ray diffraction (PXRD), synchrotron-based hard and soft X-ray photoelectron spectroscopy (HAXPES and PES), and attenuated total reflectance—Fourier transform infrared spectroscopy (ATR-FTIR). ... mehrThis approach demonstrates that binary Zintl anions can serve as versatile molecular precursors for designing heterometallic nanoparticles with controlled composition, morphology, and optical properties.