Publications by authors named "Jimin Kwag"

Electrochemical liquid-cell transmission electron microscopy (e-LCTEM) offers great potential for investigating the structural dynamics of nanomaterials during electrochemical reactions. However, challenges arise from the difficulty in achieving the optimal electrolyte thickness, leading to inconsistent electrochemical responses and limited spatial resolution. In this study, we present advanced e-LCTEM techniques tailored for tracking Pt/C degradation under electrochemical polarization at short intervals with high spatial resolution.

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Metal nanoclusters (NCs), an important class of nanoparticles (NPs), are extremely small in size and possess quasi-molecular properties. Due to accurate stoichiometry of constituent atoms and ligands, NCs have strong structure-property relationship. The synthesis of NCs is seemingly similar to that of NPs as both are formed by colloidal phase transitions.

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Unit-cell-thick MoS is a promising electrocatalyst for the hydrogen evolution reaction (HER) owing to its tunable catalytic activity, which is determined based on the energetics and molecular interactions of different types of HER active sites. Kinetic responses of MoS active sites, including the reaction onset, diffusion of the electrolyte and H bubbles, and continuation of these processes, are important factors affecting the catalytic activity of MoS . Investigating these factors requires a direct real-time analysis of the HER occurring on spatially independent active sites.

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Active sites and catalytic activity of heterogeneous catalysts is determined by their surface atomic structures. However, probing the surface structure at an atomic resolution is difficult, especially for solution ensembles of catalytic nanocrystals, which consist of heterogeneous particles with irregular shapes and surfaces. Here, we constructed 3D maps of the coordination number (CN) and generalized CN () for individual surface atoms of sub-3 nm Pt nanocrystals.

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