Title: Atomic-Scale Insights into Nickel Exsolution on LaNiO ₃ Catalysts via In Situ Electron Microscopy

Abstract

Using a combination of in situ bulk and surface characterization techniques, we provide atomic-scale insight into the complex surface and bulk dynamics of a LaNiO₃ perovskite material during heating in vacuo. Driven by the outstanding activity LaNiO₃ in the methane dry reforming reaction (DRM), attributable to the decomposition of LaNiO₃ during DRM operation into a Ni//La₂O₃ composite, we reveal the Ni exsolution dynamics both on a local and global scale by in situ electron microscopy, in situ X-ray diffraction and in situ X-ray photoelectron spectroscopy. To reduce the complexity and disentangle thermal from self-activation and reaction-induced effects, we embarked on a heating experiment in vacuo under comparable experimental conditions in all methods. Associated with the Ni exsolution, the remaining perovskite grains suffer a drastic shrinkage of the grain volume and compression of the structure. Ni particles mainly evolve at grain boundaries and stacking faults. Sophisticated structure analysis of the elemental composition by electron-energy loss mapping allows us to disentangle the distribution of the different structures resulting from LaNiO₃ decomposition on a local scale. Important for explaining the DRM activity, our results indicate that most of the Ni moieties are oxidized and that the formation of NiO occurs preferentially at grainmore » edges, resulting from the reaction of the exsolved Ni particles with oxygen released from the perovskite lattice during decomposition via a spillover process from the perovskite to the Ni particles. Correlating electron microscopy and X-ray diffraction data allows us to establish a sequential two-step process in the decomposition of LaNiO₃ via a Ruddlesden-Popper La₂NiO₄ intermediate structure. Exemplified for the archetypical LaNiO₃ perovskite material, our results underscore the importance of focusing on both surface and bulk characterization for a thorough understanding of the catalyst dynamics and set the stage for a generalized concept in the understanding of state-of-the art catalyst materials on an atomic level.« less

Authors:

Cao, Pengfei  ^[1];

• Search DOE PAGES for author "Cao, Pengfei"
• Search DOE PAGES for ORCID "0000-0002-8360-4541"

Tang, Pengyi ^[2]; Bekheet, Maged F. ^[3]; Du, Hongchu  ^[4];

• Search DOE PAGES for author "Du, Hongchu"
• Search DOE PAGES for ORCID "0000-0002-4661-4644"

Yang, Luyan ^[4]; Haug, Leander ^[5]; Gili, Albert ^[3]; Bischoff, Benjamin ^[3]; Gurlo, Aleksander  ^[3];

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• Search DOE PAGES for ORCID "0000-0001-7047-666X"

Kunz, Martin ^[6]; Dunin-Borkowski, Rafal E.  ^[4];

• Search DOE PAGES for author "Dunin-Borkowski, Rafal E."
• Search DOE PAGES for ORCID "0000-0001-8082-0647"

Penner, Simon  ^[5];

• Search DOE PAGES for author "Penner, Simon"
• Search DOE PAGES for ORCID "0000-0002-2561-5816"

Heggen, Marc ^[4]

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+ Show Author Affiliations

1. School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China, Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, Leo-Brandt-Strasse 1, D-52428 Jülich, Germany
2. Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, Leo-Brandt-Strasse 1, D-52428 Jülich, Germany, State Key Laboratory of Information Functional Materials, 2020 X-Lab, ShangHai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
3. Chair of Advanced Ceramic Materials, Institut für Werkstoffwissenschaften und -technologien, Technical University Berlin, Hardenbergstrasse 40, D-10623 Berlin, Germany
4. Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, Leo-Brandt-Strasse 1, D-52428 Jülich, Germany
5. Department of Physical Chemistry, University of Innsbruck, Innrain 52c, A-6020 Innsbruck, Austria
6. Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States

Publication Date:

Thu Dec 30 00:00:00 EST 2021

Research Org.:

Xi'an Jiaotong University, Shaanxi (China); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1837794

Alternate Identifier(s):

OSTI ID: 1839910; OSTI ID: 1958523

Grant/Contract Number:  

ALS-08865; AC02-05CH11231

Resource Type:

Published Article

Journal Name:

Journal of Physical Chemistry. C

Additional Journal Information:

Journal Name: Journal of Physical Chemistry. C Journal Volume: 126 Journal Issue: 1; Journal ID: ISSN 1932-7447

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Oxides; Grain; Organic reactions; Oxygen; Diffraction