In Situ Liquid Cell Transmission Electron Microscopy Observations of Growth and Anticorrosion Behaviors of AuCl3 Shell on Au Nanobipyramids

Comprehensive Summary Designing new materials and architectures to maintain activity and stability requires a better understanding on the anticorrosion dynamics of nanoparticles. Under‐coordinated atoms on the surface of nanoparticles can be protected by deposited shells. Real‐time observation on how protective shells grow and play a role is challenging but worthwhile. Here, protective effects of AuCl 3 shells on Au nanobipyramids (NBPs) are studied in HAuCl 4 aqueous solutions by in‐situ liquid cell transmission electron microscopy (LCTEM). This study is the first to observe the formation of Au‐AuCl 3 core‐shell nanostructure and the corresponding anticorrosion behaviors of AuCl 3 deposited shell. The presence of CTAB can substantially influence the growth mode and structure of AuCl 3 shell, by a direct or indirect way, intervene the dissolution of Au NBP. These growth or dissolution kinetics here revealed at the nanoscale provide insights towards engineering of the surface anticorrosion to pursue Au nanoparticles with improved stability in acidic environment.