Imaging, Understanding, and Engineering of Nanoscale Materials Transformations via Liquid Phase Electron Microscopy

Nanoscale materials often change morphology, structure, or chemical states, especially in solution processes, which impact properties of the materials. Thus, an understanding of nanoscale materials transformations is significant to the synthesis and various applications of materials, such as batteries, catalysis, and so on. We have developed an in-situ liquid phase transmission electron microscopy (TEM) platform to investigate materials transformation dynamics at the atomic level and to elucidate how atomic scale heterogeneity and fluctuations at solid-liquid interfaces influence the transformation pathways. In this talk, I will highlight some of our recent work on revealing atomic evolution of nanoscale materials transformation by developing high resolution liquid phase TEM. For example, by tracking single particle growth trajectories our in-situ studies reveal the significance of heterogeneity and defects, as well as kinetic factors, in the formation of nanoscale materials. I will also show the direct observation of dynamic phenomena at electrified solid-liquid interfaces, such as catalyst evolution during electrocatalytic reactions. With our development of novel electrochemical liquid cell TEM, we track Cu-based catalysts evolution and atomic dynamics of electrified solid-liquid interfaces during CO₂ reduction reaction (CO₂RR). Intermediate structures, mass loss of Cu, and unique transformation pathways of the Cu-based catalysts have been captured. Control experiments have also demonstrated that intermediates can be utilized for enhanced carbon-carbon coupling, thus improving the catalytic performance.