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Dynamics of Supported Noble metal Nanoparticles in the Presence of Oxidizing Environment: Application of Compressive Sensing in ETEM

EMSL Project ID


Direct atomic level visualization of structural and surface transformations of nanoparticles during exposure to oxidizing environment is critical for developing a structure-property relationship in catalytic research. The specific aim of this project is to apply novel acquisition approaches in Environmental Transmission Electron Microscopy (ETEM) to directly visualize at the atomic level the structural and surface transformation of noble metal nanoparticles during exposure to oxidizing environment with the aim to 1) Establish structural nature od surface oxide under their reversible formation in CO oxidizing conditions 2) Identify the chemical and crystallographic factors that dictates the kinetics of oxide transformation for nanoparticles supported on various reducible and no reducible oxides. To achieve this task, we will employ direct detection camera and novel compressive sensing acquisition techniques, which are expected to improve the sensitivity and acquisition rate by an order of magnitude compared to conventional acquisition techniques. Due to the complexity of addressing the structure of surface oxides, selected samples will also be studied using aberration corrected Scanning TEM in combination with compositional mapping using Electron Energy Loss Spectroscopy (EELS). An important aspect of this work will be the validation of the bonding environment on surfaces, and derivation of surface energies with the use of Density Functional Theory (DFT) methods.

Project Details

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Principal Investigator

Libor Kovarik
Pacific Northwest National Laboratory

Team Members

Andrew Stevens
Pacific Northwest National Laboratory

Nigel Browning
University of Liverpool

Andrey Liyu
Environmental Molecular Sciences Laboratory

Janos Szanyi
Pacific Northwest National Laboratory

Related Publications

Kovarik L, AJ Stevens, AV Liyu, and ND Browning. 2016. "Implementing an Accurate and Rapid Sparse Sampling Approach for Low-Dose Atomic Resolution STEM Imaging." Applied Physics Letters 109(16):Article No. 164102. doi:10.1063/1.4965720
Kovarik L., M.E. Bowden, D. Shi, J. Szanyi, and C.H. Peden. 2019. "Structural Intergrowth in delta-Al2O3." Journal of Physical Chemistry C 123, no. 14:9454-9460. PNNL-SA-138049. doi:10.1021/acs.jpcc.8b10135
Mehdi B.L., A. Stevens, L. Kovarik, N. Jiang, H.S. Mehta, A.V. Liyu, and S.M. Reehl, et al. 2019. "Controlling the Spatio-Temporal Dose Distribution During STEM Imaging by Subsampled Acquisition: In-Situ Observations of Kinetic Processes in Liquids." Applied Physics Letters 115, no. 6:Article Number 063102. PNNL-SA-145156. doi:10.1063/1.5096595