The Investigation of Well-Defined Structure and Grain Boundary on Nanocrystals Using Atomic Resolution TEM

In past, identifying the mechanism of particle formation nearby ordered structures has been a challenge because there was no way to control the GB on nanocrystals. Recently our research group developed a process to control the grain boundary and defects on nanocrystals. Within these nanocrystals, we have succeeded in controlling the number, size, and orientation of the individual GBs, which is distinguished from disordered defects in polycrystalline materials. Therefore, observation of a responsive material to which energy is transferred and capturing the unknown variables according to the existence of defects/grain boundaries is essential to find out noble reaction pathways.<br/><br/>Herein, we study the grain boundary (GB) phase transition of nanocrystals with real-time monitoring atomic resolution TEM imaging. We aim to fabricate a well-defined core-shell structure sample capable of being a phase transition (ordered structure from disordered) by an external source (e.g. electron beam, heat), and enough to be confirmed atomic dynamics during TEM imaging. The formation of GB can be the matrix in which the reaction takes place. Observation of phase transformations according to external sources in GB can serve as a fundamental model for understanding nanostructure–property relationships. From this perspective, capturing unknown variables in defects/grain boundary formation enables the exploration of catalytic activity and noble reaction pathways for the electrochemical CO2 reduction reaction using TEM.