Assessment of oxide nanoparticle stability in liquid phase transmission electron microscopy

Studying liquid phase nanoscale dynamic processes of oxide nanoparticles is of considerable interest to a wide variety of fields. Recently developed liquid phase transmission electron microscopy (LP-TEM) is a promising technique, but destabilization of oxides by solid-liquid-electron interactions remains an important challenge. In this work we present a methodology to assess LP-TEM oxide stability in an aqueous phase, by subjecting several oxides of technological importance to a controlled electron dose in water. We show a correlation based on the Gibbs free energy of oxide hydration that can be used to assess the stability of oxides and demonstrate the existence of several remarkably stable oxides, with no observable structural changes after one hour of electron beam irradiation in LP-TEM. Rationalizing such destabilization phenomena combined with the identification of stable oxides allows for designing LP-TEM experiments free from adverse beam effects and thus investigations of numerous relevant nanoscale processes in water.