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Gyan-Barimah C, Mantha JSP, Lee HY, Wei Y, Shin CH, Maulana MI, Kim J, Henkelman G, Yu JS. High vacancy formation energy boosts the stability of structurally ordered PtMg in hydrogen fuel cells. Nat Commun 2024; 15:7034. [PMID: 39147744 PMCID: PMC11327255 DOI: 10.1038/s41467-024-51280-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 07/31/2024] [Indexed: 08/17/2024] Open
Abstract
Alloys of platinum with alkaline earth metals promise to be active and highly stable for fuel cell applications, yet their synthesis in nanoparticles remains a challenge due to their high negative reduction potentials. Herein, we report a strategy that overcomes this challenge by preparing platinum-magnesium (PtMg) alloy nanoparticles in the solution phase. The PtMg nanoparticles exhibit a distinctive structure with a structurally ordered intermetallic core and a Pt-rich shell. The PtMg/C as a cathode catalyst in a hydrogen-oxygen fuel cell exhibits a mass activity of 0.50 A mgPt-1 at 0.9 V with a marginal decrease to 0.48 A mgPt-1 after 30,000 cycles, exceeding the US Department of Energy 2025 beginning-of-life and end-of-life mass activity targets, respectively. Theoretical studies show that the activity stems from a combination of ligand and strain effects between the intermetallic core and the Pt-rich shell, while the stability originates from the high vacancy formation energy of Mg in the alloy.
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Affiliation(s)
- Caleb Gyan-Barimah
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, Republic of Korea
| | | | - Ha-Young Lee
- Energy Science and Engineering Research Center, DGIST, Daegu, Republic of Korea
| | - Yi Wei
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, Republic of Korea
| | - Cheol-Hwan Shin
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, Republic of Korea
| | - Muhammad Irfansyah Maulana
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, Republic of Korea
| | - Junki Kim
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, Republic of Korea
| | - Graeme Henkelman
- Department of Chemistry, The University of Texas at Austin, Austin, TX, USA.
| | - Jong-Sung Yu
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, Republic of Korea.
- Energy Science and Engineering Research Center, DGIST, Daegu, Republic of Korea.
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Gloriozova N, Prots Y, Jach F, Krnel M, Bobnar M, Ormeci A, Grin Y, Höhn P. Nitridochromate(IV): LiSr 2[CrN 3]. Inorg Chem 2023; 62:12940-12946. [PMID: 37534772 PMCID: PMC10428211 DOI: 10.1021/acs.inorgchem.3c01697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Indexed: 08/04/2023]
Abstract
The quaternary nitridochromate(IV) LiSr2[CrN3] crystallizes in a new structure type with the non-centrosymmetric space group P21 (no. 4) with a = 5.5685(7) Å, b = 5.3828(8) Å, c = 7.5381(1) Å, and β = 92.291(8)°. Predominant structural features of the compound are slightly nonplanar trigonal units [CrN3]5-, which are connected by three-fold coordinated lithium to form slabs in the (001) plane. Shorter Cr-N bond lengths in comparison with reported nitridochromates(III), as well as diamagnetic behavior and vibrational spectroscopy data indicate Cr(IV), which is in a good agreement with the charge balance. According to electronic structure calculations, the compound is a semiconductor with a band gap of 1.19 eV.
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Affiliation(s)
- Natalia Gloriozova
- Max-Planck-Institut
für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Yurii Prots
- Max-Planck-Institut
für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Franziska Jach
- Max-Planck-Institut
für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany
- Faculty
of Chemistry and Food Chemistry, Technische
Universität Dresden, 01062 Dresden, Germany
| | - Mitja Krnel
- Max-Planck-Institut
für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Matej Bobnar
- Max-Planck-Institut
für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Alim Ormeci
- Max-Planck-Institut
für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Yuri Grin
- Max-Planck-Institut
für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Peter Höhn
- Max-Planck-Institut
für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany
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Shin CH, Lee HY, Gyan-Barimah C, Yu JH, Yu JS. Magnesium: properties and rich chemistry for new material synthesis and energy applications. Chem Soc Rev 2023; 52:2145-2192. [PMID: 36799134 DOI: 10.1039/d2cs00810f] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Magnesium (Mg) has many unique properties suitable for applications in the fields of energy conversion and storage. These fields presently rely on noble metals for efficient performance. However, among other challenges, noble metals have low natural abundance, which undermines their sustainability. Mg has a high negative standard reduction potential and a unique crystal structure, and its low melting point at 650 °C makes it a good candidate to replace or supplement numerous other metals in various energy applications. These attractive features are particularly helpful for improving the properties and limits of materials in energy systems. However, knowledge of Mg and its practical uses is still limited, despite recent studies which have reported Mg's key roles in synthesizing new structures and modifying the chemical properties of materials. At present, information about Mg chemistry has been rather scattered without any organized report. The present review highlights the chemistry of Mg and its uses in energy applications such as electrocatalysis, photocatalysis, and secondary batteries, among others. Future perspectives on the development of Mg-based materials are further discussed to identify the challenges that need to be addressed.
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Affiliation(s)
- Cheol-Hwan Shin
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea.
| | - Ha-Young Lee
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea.
| | - Caleb Gyan-Barimah
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea.
| | - Jeong-Hoon Yu
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea.
| | - Jong-Sung Yu
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea.
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Energy Electronegativity and Chemical Bonding. Molecules 2022; 27:molecules27238215. [PMID: 36500308 PMCID: PMC9737094 DOI: 10.3390/molecules27238215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 11/29/2022] Open
Abstract
Historical development of the concept of electronegativity (EN) and its significance and prospects for physical and structural chemistry are discussed. The current cutting-edge results are reviewed: new methods of determining the ENs of atoms in solid metals and of bond polarities and effective atomic charges in molecules and crystals. The ENs of nanosized elements are calculated for the first time, enabling us to understand their unusual reactivity, particularly the fixation of N2 by nanodiamond. Bond polarities in fluorides are also determined for the first time, taking into account the peculiarities of the fluorine atom's electronic structure and its electron affinity.
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Verchenko VY, Tsirlin AA. Semiconducting and Metallic Compounds within the IrIn 3 Structure Type: Stability and Chemical Bonding. Inorg Chem 2022; 61:3274-3280. [PMID: 35138836 DOI: 10.1021/acs.inorgchem.1c03843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Narrow-gap semiconductors are very rare among intermetallic compounds. They appear only when two factors come together: strong hybridization of valence orbitals in the vicinity of the Fermi level and an appropriate number of valence electrons. Surprisingly, the IrIn3 family of intermetallics contains a number of semiconductors, including 17 e- FeGa3, RuGa3, OsGa3, and RuIn3, for which the d-p hybridization gap opens at the Fermi energy. We present comprehensive total energy electronic-structure calculations and crystal orbital Hamilton population analysis of the stable IrIn3-type compounds with semiconducting and metallic properties. The calculated electronic structures possess two pseudogaps and one real gap at the magic valence electron count of 15, 17, and 18 e- per formula unit. When the Fermi level is located in these gaps, the antibonding states are minimized. Total energies calculated for the isomorphous compounds suggest that the metallic state with 18 e- leads to a comparable or even higher thermodynamic stability than the semiconducting state with 17 e-.
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Affiliation(s)
- Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.,National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
| | - Alexander A Tsirlin
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany
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