Dmitri N. Zakharov

Denoising Machine Learning Model for Out-of-distribution Transmission Electron Microscopy Datasets

B Lee, Rohin Harikumar, M Li, Susan E Minkoff et autres

High-resolution transmission electron microscopy (HRTEM) enables the observation of structural and morphological evolution of materials at Angstrom scales. However, the high temporal resolution and low electron dosage required to observe atomic scale events with minimal perturbation often result in low signal-to-noise ratio …

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Real-time Observation of Redox Reaction Induced Fragmentation Dynamics

Xiaobo Chen, M Li, Sabrina M Gericke, Seunghwa Hong et autres

Fragmentation represents a key atomic redistribution mechanism in single-atom catalysis, playing a critical role in modulating catalytic reactivity and selectivity. Elucidating its underlying mechanisms is therefore essential for the rational design of single-atom catalysts with precisely controlled activity. In general, nanoparticle (NP) …

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Imaging Oxidation and Catalytic Reactions Under Realistic Conditions Using In Situ Environmental TEM

M Li, B Lee, Dmitri N. Zakharov, Wissam A. Saidi et autres

Direct observation of nano-to-atomic scale structural evolution is critical for understanding the mechanisms governing oxidation, reduction, corrosion, and catalytic reactions. While conventional transmission electron microscopy (TEM) studies often rely on idealized model samples under high vacuum, realistic reaction environments introduce significant experimental …

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Machine learning pipeline for denoising low signal-to-noise ratio and out-of-distribution transmission electron microscopy datasets

Brian Lee, Meng Li, Judith C. Yang, Dmitri N. Zakharov et autres

Abstract High-resolution transmission electron microscopy (HRTEM) is crucial for observing material’s structural and morphological evolution at Angstrom scales, but the electron beam can alter these processes. Devices such as CMOS-based direct-electron detectors operating in electron-counting mode can be utilized to substantially reduce …

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Oxide nucleation via threshold-driven volume instability in Ni oxidation

Linna Qiao, Hehe Zhang, Jianyu Wang, X Y Chen et autres

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Structural characterization of neutron irradiated hexagonal boron-10 nitride-15 single crystals

Thomas Poirier, Josh Avery, Dmitri N. Zakharov, Kim Kisslinger et autres

The negatively charged boron vacancy (VB−) in hexagonal boron nitride (hBN) is a promising quantum defect that can be used to sense pressure, temperature, and magnetic field with high spatial resolution. hBN enriched with the boron-10 and nitrogen-15 isotopes, denoted h10B15N, has …

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Substrate-Mediated Evaporation and Stochastic Evolution of Supported Au Nanoparticles

Dmitri N. Zakharov, Xiaohui Qu, Hong Wang, Yuewei Lin et autres

We use in situ transmission electron microscopy with automated tracking to study supported gold nanoparticles (NPs) during high-temperature vacuum annealing. \rev{The average mass loss per NP is governed by a flat, nearly size-independent substrate-mediated evaporation profile.} On top of \rev{this mean shrinkage}, …

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Oxidation pathway selection directed by atomic surface steps

Hehe Zhang, Ke Tong, Dmitri N. Zakharov, Min Wang et autres

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Visualizing metal-mediated nucleation and growth of GaN

A. Liu, Zhucong Xi, Xiaobo Chen, Catherine Huang et autres

Understanding the atomic-scale mechanisms governing metal-mediated nucleation and growth of gallium nitride (GaN) and related alloys is critical for tailoring their structural and functional properties in advanced electronic, optoelectronic, and quantum devices. Using real-time environmental transmission electron microscopy (E-TEM) in conjunction with …

In-situ monitoring of atomically dispersed Pt sites supported on OMS-2 during CO2 activation

Scott Bamonte, Harshul S. Khanna, Inosh Perera, Meilin Li et autres

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Atomically Revealing Bulk Point Defect Dynamics in Hydrogen‐Driven γ‐Fe 2 O 3 → Fe 3 O 4 → FeO Transformation

Yupeng Wu, Dongxiang Wu, Wenhui Zhu, Xiaobo Chen et autres

Abstract Understanding how point defects in the bulk govern redox transformations is essential for advancing hydrogen‐based metal production and designing high‐performance oxide materials. This study reveals the atomic‐scale mechanisms driving hydrogen‐induced reduction of γ‐Fe 2 O 3 to Fe 3 O 4 …

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Nanometer-scale resolution in an ultra-high pressure environmental TEM holder

George G. Hollyer, Dmitri N. Zakharov, Daan Hein Alsem, Calvin Parkin et autres

Abstract Environmental Transmission Electron Microscopy gas holders are vital for studying catalyst nanostructures in reactive gases. Although there are existing methods to understand the behavior of catalysts during reaction, a “pressure gap” exists. Pressures of up to 4.5 bar have been demonstrated, …

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