A unique pathway of PtNi nanoparticle formation observed with liquid cell transmission electron microscopy

An understanding of nanoparticle growth is significant for controlled synthesis of nanomaterials with desired physical and chemical properties. Here we report the in situ study of platinum-nickel alloy nanoparticle growth using in situ liquid cell transmission electron microscopy (TEM). The observation revealed that Ni dendrites can form at the beginning and subsequently PtNi nanoparticles nucleate and grow by consumption of the Ni dendrites. The resulting PtNi alloy nanoparticles have a narrow size distribution with an average diameter of 3.7 nm, which are smaller than those obtained via classical solution growth. This work shed light on using such a unique growth pathway for the synthesis of novel nanoparticles.