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Jeon H, Kim YH, Kim H, Jeong H, Won BR, Jang W, Park CH, Lee KT, Myung JH. Optimizing Reversible Exsolution and Phase Transformation in Double Perovskite Sr 2Fe 1.5-xCo xMo 0.5O 6-δ Electrodes for High-Performance Symmetric Solid Oxide Cells. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2401628. [PMID: 39248663 DOI: 10.1002/smll.202401628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Revised: 08/13/2024] [Indexed: 09/10/2024]
Abstract
Double perovskite (DP) oxides are promising electrode materials for symmetric solid oxide cells (SSOCs) due to their excellent electrochemical activity and stability. B-site cation doping in DP oxides affects the reversibility of phase transformation and exsolution, which plays a crucial role in the catalyst recovery. Yet, few studies have been conducted on this topic. In this study, the Sr2Fe1.5-xCoxMo0.5O6-δ (CSFM, x = 0, 0.1, 0.3, 0.5) DP system demonstrates modulated exsolution and phase transformation reversibility by manipulating the oxygen vacancy concentration. The correlation between Co-doping level and oxygen vacancy concentration is investigated to optimize the exsolution and phase transformation properties. Sr2Fe1.2Co0.3Mo0.5O6-δ (3CSFM) exhibits reversible transformation between DP and Ruddlesden-Popper phases with a high density of exsolved CoFe nanoparticles under redox atmospheres. The quasi-symmetric cell with 3CSFM shows a peak power density of 1.27 W cm-2 at 850 °C in H2 fuel cell mode and a current density of 2.33 A cm-2 at 1.6 V and 800 °C in H2O electrolysis mode. The 3CSFM electrode exhibits robust stability during continuous operation for ≈700 h. These results demonstrate the significant role of B-site doping in designing DP materials capable of dynamic phase transformation in diverse environments.
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Affiliation(s)
- Hyejin Jeon
- Department of Materials Science and Engineering, Incheon National University, Incheon, 22012, Republic of Korea
| | - Yo Han Kim
- Department of Materials Science and Engineering, Incheon National University, Incheon, 22012, Republic of Korea
| | - Hyeonggeun Kim
- Department of Mechanical Engineering, KAIST, Daejeon, 34141, Republic of Korea
| | - Hyeongwon Jeong
- Department of Materials Science and Engineering, Incheon National University, Incheon, 22012, Republic of Korea
| | - Bo-Ram Won
- Department of Materials Science and Engineering, Incheon National University, Incheon, 22012, Republic of Korea
| | - Wonjun Jang
- Department of Materials Science and Engineering, Incheon National University, Incheon, 22012, Republic of Korea
| | - Chan-Ho Park
- Department of Materials Science and Engineering, Incheon National University, Incheon, 22012, Republic of Korea
| | - Kang Taek Lee
- Department of Mechanical Engineering, KAIST, Daejeon, 34141, Republic of Korea
- KAIST Graduate School of Green Growth & Sustainability, Daejeon, 34141, Republic of Korea
| | - Jae-Ha Myung
- Department of Materials Science and Engineering, Incheon National University, Incheon, 22012, Republic of Korea
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López-García A, Remiro-Buenamañana S, Neagu D, Carrillo AJ, Serra JM. Squeezing Out Nanoparticles from Perovskites: Controlling Exsolution with Pressure. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2403544. [PMID: 39180444 DOI: 10.1002/smll.202403544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 06/25/2024] [Indexed: 08/26/2024]
Abstract
Nanoparticle exsolution has emerged as a versatile method to functionalize oxides with robust metallic nanoparticles for catalytic and energy applications. By modifying certain external parameters during thermal reduction (temperature, time, reducing gas), some morphological and/or compositional properties of the exsolved nanoparticles can be tuned. Here, it is shown how the application of high pressure (<100 bar H2) enables the control of the exsolution of ternary FeCoNi alloyed nanoparticles from a double perovskite. H2 pressure affects the lattice expansion and the nanoparticle characteristics (size, population, and composition). The composition of the alloyed nanoparticles could be controlled, showing a reversal of the expected thermodynamic trend at 10 and 50 bar, where Fe becomes the main component instead of Ni. In addition, pressure drastically lowers the exsolution temperature to 300 °C, resulting in unprecedented highly-dispersed and small-sized nanoparticles with a similar composition to those obtained at 600 °C and 10 bar. The mechanisms behind the effects of pressure on exsolution are discussed, involving kinetic, surface thermodynamics, and lattice-strain factors. A volcano-like trend of the exsolution extent suggests that competing pressure-dependent mechanisms govern the process. Pressure emerges as a new design tool for metallic nanoparticle exsolution enabling novel nanocatalysts and surface-functionalized materials.
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Affiliation(s)
- Andrés López-García
- Instituto de Tecnología Química (Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas), València, 46022, Spain
| | - Sonia Remiro-Buenamañana
- Instituto de Tecnología Química (Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas), València, 46022, Spain
| | - Dragos Neagu
- Department of Chemical and Process Engineering, University of Strathclyde, Glasgow, G1 1XQ, United Kingdom
| | - Alfonso J Carrillo
- Instituto de Tecnología Química (Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas), València, 46022, Spain
| | - José Manuel Serra
- Instituto de Tecnología Química (Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas), València, 46022, Spain
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Bonkowski A, Wolf MJ, Wu J, Parker SC, Klein A, De Souza RA. A Single Model for the Thermodynamics and Kinetics of Metal Exsolution from Perovskite Oxides. J Am Chem Soc 2024; 146:23012-23021. [PMID: 39116036 PMCID: PMC11345767 DOI: 10.1021/jacs.4c03412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 07/10/2024] [Accepted: 07/11/2024] [Indexed: 08/10/2024]
Abstract
Exsolution has emerged as an outstanding route for producing oxide-supported metal nanoparticles. For ABO3-perovskite oxides, various late transition-metal cations can be substituted into the lattice under oxidizing conditions and exsolved as metal nanoparticles after reduction. A consistent and comprehensive description of the point-defect thermodynamics and kinetics of this phenomenon is lacking, however. Herein, supported by hybrid density-functional-theory calculations, we propose a single model that explains diverse experimental observations, such as why substituent transition-metal cations (but not host cations) exsolve from perovskite oxides upon reduction; why different substituent transition-metal cations exsolve under different conditions; why the metal nanoparticles are embedded in the surface; why exsolution occurs surprisingly rapidly at relatively low temperatures; and why the reincorporation of exsolved species involves far longer times and much higher temperatures. Our model's foundation is that the substituent transition-metal cations are reduced to neutral species within the perovskite lattice as the Fermi level is shifted upward within the bandgap upon sample reduction. The calculations also indicate unconventional influences of oxygen vacancies and A-site vacancies. Our model thus provides a fundamental basis for improving existing, and creating new, exsolution-generated catalysts.
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Affiliation(s)
- Alexander Bonkowski
- Institute
of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52074 Aachen, Germany
| | - Matthew J. Wolf
- Institute
of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52074 Aachen, Germany
| | - Ji Wu
- Department
of Chemistry, University of Bath, Claverton Down, BA2 7AY Bath, U.K.
| | - Stephen C. Parker
- Department
of Chemistry, University of Bath, Claverton Down, BA2 7AY Bath, U.K.
| | - Andreas Klein
- Institute
of Materials Science, Technical University
of Darmstadt, Otto-Berndt-Str. 3, 64287 Darmstadt, Germany
| | - Roger A. De Souza
- Institute
of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52074 Aachen, Germany
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Zhu S, Fan J, Li Z, Wu J, Xiao M, Du P, Wang X, Jia L. Metal exsolution from perovskite-based anodes in solid oxide fuel cells. Chem Commun (Camb) 2024; 60:1062-1071. [PMID: 38167745 DOI: 10.1039/d3cc05688k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Solid oxide fuel cells (SOFCs) are highly efficient and environmentally friendly devices for converting fuel into electrical energy. In this regard, metal nanoparticles (NPs) loaded onto the anode oxide play a crucial role due to their exceptional catalytic activity. NPs synthesized through exsolution exhibit excellent dispersion and stability, garnering significant attention for comprehending the exsolution process mechanism and consequently improving synthesis effectiveness. This review presents recent advancements in the exsolution process, focusing on the influence of oxygen vacancies, A-site defects, lattice strain, and phase transformation on the variation of the octahedral crystal field in perovskites. Moreover, we offer insights into future research directions to further enhance our understanding of the mechanism and achieve significant exsolution of NPs on perovskites.
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Affiliation(s)
- Shasha Zhu
- School of Materials Science and Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
| | - Junde Fan
- Yueyang Yumeikang Biotechnology Co., Ltd., Yueyang, 414100, P. R. China
| | - Zongbao Li
- School of Materials Science and Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
| | - Jun Wu
- School of Materials Science and Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
| | - Mengqin Xiao
- School of Materials Science and Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
| | - Pengxuan Du
- School of Materials Science and Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
| | - Xin Wang
- School of Materials Science and Engineering, Wuhan Textile University, Wuhan 430200, P. R. China.
| | - Lichao Jia
- School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
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