@article{e2baef70413e46ab96dc4d2594dcc278,
title = "Revealing high-temperature reduction dynamics of high-entropy alloy nanoparticles via in situ transmission electron microscopy",
abstract = "Understanding the behavior of high-entropy alloy (HEA) materials under hydrogen (H2) environment is of utmost importance for their promising applications in structural materials, catalysis, and energy-related reactions. Herein, the reduction behavior of oxidized FeCoNiCuPt HEA nanoparticles (NPs) in atmospheric pressure H2 environment was investigated by in situ gas-cell transmission electron microscopy (TEM). The reduction reaction front was maintained at the external surface of the oxide. During reduction, the oxide layer expanded and transformed into porous structures where oxidized Cu was fully reduced to Cu NPs while Fe, Co, and Ni remained in the oxidized form. In situ chemical analysis showed that the expansion of the oxide layer resulted from the outward diffusion flux of all transition metals (Fe, Co, Ni, Cu). Revealing the H2 reduction behavior of HEA NPs facilitates the development of advanced multicomponent alloys for applications targeting H2 formation and storage, catalytic hydrogenation, and corrosion removal.",
keywords = "High-entropy alloys, In situ TEM, Nanoparticles, Phase segregation, Reduction",
author = "Boao Song and Yong Yang and Yang, {Timothy T.} and Kun He and Xiaobing Hu and Yifei Yuan and Dravid, {Vinayak P.} and Zachariah, {Michael R.} and Saidi, {Wissam A.} and Yuzi Liu and Reza Shahbazian-Yassar",
note = "Funding Information: R.S.-Y. is thankful to National Science Foundation (NSF) for Award No. DMR-1809439. W.S. is thankful to NSF for Award No. DMR-1809085. Part of the computational work is supported by the University of Pittsburgh Center for Research Computing. Part of this work is performed at the Center for Nanoscale Materials (CNM), which is a U.S. Department of Energy Office of Science User Facility, and supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. We utilized JEOL JEM-ARM 200CF and JEOL JEM-3010 available at Electron Microscopy Center as part of RRC shared facility at UIC. The UIC JEOL JEM-ARM 200CF was obtained by a MRI-R2 grant from the NSF Award DMR-0959470. We are thankful to Dr. F. Shi from UIC for assisting and facilitating electron microscopy efforts. Some of the electron microscopy experiments were performed at the EPIC facility of Northwestern University{\textquoteright}s NUANCE Center with support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. Also, M.Z. appreciates the support of an ONR award through MURI program. Publisher Copyright: {\textcopyright} 2021 American Chemical Society",
year = "2021",
month = feb,
day = "24",
doi = "10.1021/acs.nanolett.0c04572",
language = "English (US)",
volume = "21",
pages = "1742--1748",
journal = "Nano Letters",
issn = "1530-6984",
publisher = "American Chemical Society",
number = "4",
}