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Arimura S, Matsumoto I, Sekiya R, Haino T. Intermediate Color Emission via Nanographenes with Organic Fluorophores. Angew Chem Int Ed Engl 2024; 63:e202315508. [PMID: 38191241 DOI: 10.1002/anie.202315508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 12/19/2023] [Accepted: 01/05/2024] [Indexed: 01/10/2024]
Abstract
Photoluminescence (PL) color can be tuned by mixing fluorophores emitting the three primary colors in an appropriate ratio. When color tuning is achieved on a single substrate, we can simplify device structures. We demonstrated that nanographenes (NGs), which are graphene fragments with a size of tens of nanometers, could be utilized as carriers of fluorophores. The addition of red- and blue-light-emitting fluorophores on the edge successfully reproduced the purple light. The relative PL intensities of the fluorophores could be regulated by the excitation wavelength, enabling multicolor emission between blue and red light. Owing to the triphenylamine units of the fluorophores, the NGs showed PL enhancement due to aggregation. This characteristic was valuable for the fabrication of solid polymer materials. Specifically, the functionalized NGs can be dispersed into polyvinylidene difluoride. The resultant polymer films emitted red, blue, and purple color. Our study demonstrated the potential applicability of NGs for fluorophore carriers capable of reproducing intermediate colors of light.
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Affiliation(s)
- Saki Arimura
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Ikuya Matsumoto
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Ryo Sekiya
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Takeharu Haino
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
- International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM2), Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8527, Japan
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2
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Sekiya R, Haino T. Application of Exciton Coupling for Characterization of Nanographene Edge. Chemphyschem 2024; 25:e202300740. [PMID: 38226791 DOI: 10.1002/cphc.202300740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/18/2023] [Accepted: 01/15/2024] [Indexed: 01/17/2024]
Abstract
The structural characterization of nonstoichiometric nanographene (NG)-organic hybrid materials is usually difficult. The number of substituents on the edge and their arrangements are frequently questioned but are difficult to answer. Since the number of functional groups is closely related to the distance between the nearest neighbors (dISD ), the extraction of dISD from spectroscopic data could provide important information on their structural characterization. We show that exciton coupling, which is a theoretical prediction of the absolute structures of discrete molecules, is a possible candidate to address this issue. The comparison of the calculated CD spectra of the chiral chromophores extracted from the model NG edge with the observed edge spectra indicated a dISD of ca. 8 Å; this corresponded to substitution on every other armchair edge. Furthermore, an up-up-down-down alternate orientation was found to be a possible edge structure. Although the procedure was limited to NGs carrying chiral substituents, our method could facilitate the detailed structural characterization of NG-organic hybrid materials.
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Affiliation(s)
- Ryo Sekiya
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Takeharu Haino
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
- International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM2), Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8527, Japan
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3
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Wakizaka M, Gupta S, Wan Q, Takaishi S, Noro H, Sato K, Yamashita M. Spin qubits of Cu(II) doped in Zn(II) metal-organic frameworks above microsecond phase memory time. Chemistry 2024; 30:e202304202. [PMID: 38146235 DOI: 10.1002/chem.202304202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 12/25/2023] [Indexed: 12/27/2023]
Abstract
With the aim of creating Cu(II) spin qubits in a rigid metal-organic framework (MOF), this work demonstrates a doping of 5 %, 2 %, 1 %, and 0.1 % mol of Cu(II) ions into a perovskite-type MOF [CH6 N3 ][ZnII (HCOO)3 ]. The presence of dopant Cu(II) sites are confirmed with anisotropic g-factors (gx =2.07, gy =2.12, and gz =2.44) in the S=1/2 system by experimentally and theoretically. Magnetic dynamics indicate the occurrence of a slow magnetic relaxation via the direct and Raman processes under an applied field, with a relaxation time (τ) of 3.5 ms (5 % Cu), 9.2 ms (2 % Cu), and 15 ms (1 % Cu) at 1.8 K. Furthermore, pulse-ESR spectroscopy reveals spin qubit properties with a spin-spin relaxation (phase memory) time (T2 ) of 0.21 μs (2 %Cu), 0.39 μs (1 %Cu), and 3.0 μs (0.1 %Cu) at 10 K as well as Rabi oscillation between MS =±1/2 spin sublevels. T2 above microsecond is achieved for the first time in the Cu(II)-doped MOFs. It can be observed at submicrosecond around 50 K. These spin relaxations are very sensitive to the magnetic dipole interactions relating with cross-relaxation between the Cu(II) sites and can be tuned by adjusting the dopant concentration.
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Affiliation(s)
- Masanori Wakizaka
- Department of Applied Chemistry and Bioscience, Faculty of Science and Technology, Chitose Institute of Science and Technology, 758-65 Bibi, Chitose, 066-8655, Japan
| | - Shraddha Gupta
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Qingyun Wan
- Department of Chemistry, State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, The University of Hong Kong
| | - Shinya Takaishi
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Honoka Noro
- Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan
| | - Kazunobu Sato
- Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan
| | - Masahiro Yamashita
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
- School of Chemical Science and Engineering, Tongji University, Siping Road 1239, Shanghai, 200092, P. R. China
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4
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Toyota Y, Sagawa M, Yamashita S, Okayasu Y, Nagai Y, Okada Y, Kobayashi Y. Effect of the bulkiness of alkyl ligands on the excited-state dynamics of ZnO nanocrystals. RSC Adv 2024; 14:2796-2803. [PMID: 38234874 PMCID: PMC10792356 DOI: 10.1039/d3ra05166h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 01/10/2024] [Indexed: 01/19/2024] Open
Abstract
Organic ligands on the surface of nanocrystals (NCs) are extremely important in influencing various physical properties, such as dispersibility, electrical properties, and optical properties. Recent studies have revealed that a slight difference in the molecular structure of aliphatic organic ligands significantly affects the dispersibility of the NCs. On the other hand, the effects of the difference in the molecular structure of ligands on the excited-state dynamics of NCs remain elusive. In this study, we synthesized a series of colloidal ZnO NCs capped with different alkyl phosphonic acids and investigated their photophysical properties using emission decay measurements and transient absorption spectroscopy. The spectral shape and lifetime of the emission originating from the surface oxygen defects of ZnO NCs are almost the same irrespective of the alkyl phosphonic ligands used, indicating that the electronic states of the surface oxygen defects are not affected by the bulkiness of the ligand. On the other hand, the emission quantum yield correlates with the rate of carrier trapping by oxygen defects, suggesting that the rate of carrier trapping reflects the number of oxygen defects. Revealing the detailed relationship between molecular structures of organic ligands and the optical properties of NCs is important for advanced photofunctional superstructures using semiconductor NCs.
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Affiliation(s)
- Yuto Toyota
- Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University Kusatsu Shiga 525-8577 Japan +81-77-561-3915
| | - Masahiko Sagawa
- Department of Applied Biological Science, Tokyo University of Agriculture and Technology Tokyo 183-8509 Japan
| | - Shohei Yamashita
- Department of Applied Biological Science, Tokyo University of Agriculture and Technology Tokyo 183-8509 Japan
| | - Yoshinori Okayasu
- Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University Kusatsu Shiga 525-8577 Japan +81-77-561-3915
| | - Yuki Nagai
- Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University Kusatsu Shiga 525-8577 Japan +81-77-561-3915
| | - Yohei Okada
- Department of Applied Biological Science, Tokyo University of Agriculture and Technology Tokyo 183-8509 Japan
| | - Yoichi Kobayashi
- Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University Kusatsu Shiga 525-8577 Japan +81-77-561-3915
- Precursory Research for Embryonic Science and Technology (PRESTO), Science and Technology Agency (JST) 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
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5
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Ikegawa D, Fukatsu A, Okada K, Takahashi M. Accelerated Water Desorption of Oligomeric Poly(ethylene glycol) by Addition of Poly(propylene glycol) for Energy-Efficient Water Recovery Systems. ACS Omega 2024; 9:1084-1091. [PMID: 38222510 PMCID: PMC10785649 DOI: 10.1021/acsomega.3c07310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 01/16/2024]
Abstract
Adsorbents are used to recover water vapor from the atmosphere in desiccant air conditioning (DAC) and atmospheric water harvesting (AWH) systems. Solid adsorbents have been conventionally used in these systems, though liquid adsorbents are considered to be more effective for energy-efficient fluidic thermosystems because of their low regeneration temperatures (45-70 °C). While most previous studies have focused on improving the adsorption performance, the desorption performance of adsorbents can also be a critical factor in improving the energy efficiency of these systems. Thus, this study aimed to improve the water desorption efficiency, focusing on the liquid adsorbents. We found that mixing hydrophobic molecules into a liquid adsorbent decreases the desorption temperature and increases the water-desorption efficiency. Oligomeric poly(ethylene glycol) (PEG), a common moisture-adsorbing liquid oligomer used in detergents and cosmetics, was selected as the liquid adsorbent. Oligomeric poly(propylene glycol) (PPG), which has a structure analogous to PEG and lower hygroscopicity, was selected as the hydrophobic molecule. Water adsorption and desorption experiments showed that the mixture of PPG with PEG promoted the desorption of water molecules beyond that of PEG, while thermogravimetric differential thermal analysis revealed a decrease in the water desorption temperature with increasing PPG content. The improved desorption efficiency was ascribed to the likely water adsorption equilibrium between PEG and PPG in the blend; water molecules are preferentially desorbed from PPG, which has weaker water-adsorbate interactions. The proposed concept is expected to be incorporated into various hygroscopic liquids to develop energy-efficient liquid adsorbents for DAC and AWH.
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Affiliation(s)
- Daisuke Ikegawa
- Department of Materials Science,
Graduate School of Engineering, Osaka Metropolitan
University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Arisa Fukatsu
- Department of Materials Science,
Graduate School of Engineering, Osaka Metropolitan
University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Kenji Okada
- Department of Materials Science,
Graduate School of Engineering, Osaka Metropolitan
University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Masahide Takahashi
- Department of Materials Science,
Graduate School of Engineering, Osaka Metropolitan
University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
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6
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Uchiyama H, Tachibana S. Hydrothermal synthesis of dittmarite-group NH 4(Co 1-xMn x)PO 4·H 2O particles as inorganic violet pigments. RSC Adv 2024; 14:1939-1943. [PMID: 38192309 PMCID: PMC10772953 DOI: 10.1039/d3ra07387d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 12/28/2023] [Indexed: 01/10/2024] Open
Abstract
Dittmarite-group NH4(Co1-xMnx)PO4·H2O particles were prepared via a hydrothermal route. Single-phase platelike NH4(Co1-xMnx)PO4·H2O particles were obtained from aqueous solutions containing MnCl2·4H2O, CoCl2·6H2O, and (NH4)2HPO4, where the [Mn2+]/([Co2+] + [Mn2+]) mole ratios in the products were controlled by changing the MnCl2 and CoCl2 concentrations of the precursor solutions. The vivid violet colour of the ammonium cobalt phosphate (NH4CoPO4·H2O) particles was maintained upon substitution of Co2+ with Mn2+ ions up to x = 0.8, thus achieving an 80% saving of cobalt in the preparation of violet pigments.
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Affiliation(s)
- Hiroaki Uchiyama
- Department of Chemistry and Materials Engineering, Kansai University 3-3-35 Yamate-cho Suita 564-8680 Japan +81-6-6368-1121 ext. 6131
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7
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Shuang Y, Chen Q, Kim M, Wang Y, Saito Y, Hatayama S, Fons P, Ando D, Kubo M, Sutou Y. NbTe 4 Phase-Change Material: Breaking the Phase-Change Temperature Balance in 2D Van der Waals Transition-Metal Binary Chalcogenide. Adv Mater 2023; 35:e2303646. [PMID: 37338024 DOI: 10.1002/adma.202303646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/13/2023] [Indexed: 06/21/2023]
Abstract
2D van der Waals (vdW) transition metal di-chalcogenides (TMDs) have garnered significant attention in the nonvolatile memory field for their tunable electrical properties, scalability, and potential for phase engineering. However, their complex switching mechanism and complicated fabrication methods pose challenges for mass production. Sputtering is a promising technique for large-area 2D vdW TMD fabrication, but the high melting point (typically Tm > 1000 °C) of TMDs requires elevated temperatures for good crystallinity. This study focuses on the low-Tm 2D vdW TM tetra-chalcogenides and identifies NbTe4 as a promising candidate with an ultra-low Tm of around 447 °C (onset temperature). As-grown NbTe4 forms an amorphous phase upon deposition that can be crystallized by annealing at temperatures above 272 °C. The simultaneous presence of a low Tm and a high crystallization temperature Tc can resolve important issues facing current phase-change memory compounds, such as high Reset energies and poor thermal stability of the amorphous phase. Therefore, NbTe4 holds great promise as a potential solution to these issues.
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Affiliation(s)
- Yi Shuang
- WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, 980-8577, Japan
| | - Qian Chen
- New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Mihyeon Kim
- Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11 Aoba-yama, Sendai, 980-8579, Japan
| | - Yinli Wang
- Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11 Aoba-yama, Sendai, 980-8579, Japan
| | - Yuta Saito
- Device Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, Umezono 1-1-1, Tsukuba, 305-8568, Japan
| | - Shogo Hatayama
- Device Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, Umezono 1-1-1, Tsukuba, 305-8568, Japan
| | - Paul Fons
- Department of Electronics and Electrical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan
| | - Daisuke Ando
- Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11 Aoba-yama, Sendai, 980-8579, Japan
| | - Momoji Kubo
- New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Yuji Sutou
- WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, 980-8577, Japan
- Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11 Aoba-yama, Sendai, 980-8579, Japan
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Saw MJ, Nguyen MT, Kunisada Y, Tokunaga T, Yonezawa T. Anisotropic Growth of Copper Nanorods Mediated by Cl - Ions. ACS Omega 2022; 7:7414-7420. [PMID: 35252731 PMCID: PMC8892852 DOI: 10.1021/acsomega.2c00359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 02/03/2022] [Indexed: 06/14/2023]
Abstract
Anisotropic growth to form Cu particles of rod and wire shapes has been obtained typically in a complex system that involves both organic capping agents and Cl- ions. However, the sole effect of Cl- ions on the formation of Cu wires has yet to be fully understood, especially in an organic system. This present work determines the effect of Cl- ions on the morphologies of Cu particles in an organic phase without any capping agents. The results revealed that anisotropic Cu rods could be grown with the sole presence of Cl- ions. The rods have the (011) facets as the long axis, the (111) facets as the tip, and the (100) facets as the side surface. By increasing the Cl- ion concentration, more Cu atoms contributed to the formation of Cu rods and the kinetic growth of the length and the diameter of the rods varied. This suggests that Cl- ions have preferential adsorption on the (100) Cu surfaces to promote the anisotropic growth of Cu. Meanwhile, the adsorption of Cl- to the (111) and (100) surfaces at high Cl- concentrations regulates the relative growth of the particle length and diameter.
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Affiliation(s)
- Min Jia Saw
- Division
of Materials Science and Engineering, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan
| | - Mai Thanh Nguyen
- Division
of Materials Science and Engineering, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan
| | - Yuji Kunisada
- Center
for Advanced Research of Energy
and Materials, Faculty of Engineering, Hokkaido
University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan
| | - Tomoharu Tokunaga
- Department
of Materials Science and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
| | - Tetsu Yonezawa
- Division
of Materials Science and Engineering, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan
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Yamamoto T, Tsutsumi K. Decomposing Oil-Soluble Initiators in Particles: A Template-Free Method for the Preparation of Hollow Polymer and Silica Particles. ACS Omega 2021; 6:31677-31682. [PMID: 34869991 PMCID: PMC8637971 DOI: 10.1021/acsomega.1c04197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 11/05/2021] [Indexed: 06/13/2023]
Abstract
Nanovoids contained in hollow particles render them potential drug carriers. However, conventional methods for the synthesis of these particlhes involve complex processes. In this study, we developed a template-free method for the synthesis of hollow polymer and silica particles by initially preparing polystyrene core particles containing 2,2'-azobis(2-methylbutyronitrile) (V-59) through soap-free emulsion polymerization. The subsequent generation of nitrogen gas inside these particles upon the decomposition of V-59 at 70 °C led to the formation of voids. In addition, silica shells were synthesized on the surfaces of the V-59-containing polystyrene core particles through a sol-gel reaction at 40 °C, following which voids were formed by the decomposition of V-59 at 70 °C. The developed method involves straightforward steps and is environmentally friendly, as it does not require the use of surfactants, organic solvents, or templates.
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Affiliation(s)
- Tetsuya Yamamoto
- Department
of Chemical Systems Engineering, Nagoya
University, Furo-cho, Chikusa-ku, Nagoya-shi 464-8603, Japan
| | - Kazuya Tsutsumi
- Department
of Materials and Design Innovation Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya-shi 464-8603, Japan
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Hasegawa T, Yamasaki N, Asakura Y, Ueda T, Yin S. Ce(iv)-centered charge-neutral perovskite layers topochemically derived from anionic [CeTa 2O 7] - layers. Chem Sci 2021; 12:15016-15027. [PMID: 34909142 PMCID: PMC8612395 DOI: 10.1039/d1sc03053a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 10/13/2021] [Indexed: 11/30/2022] Open
Abstract
Layered perovskites have been extensively investigated in many research fields, such as electronics, catalysis, optics, energy, and magnetics, because of the fascinating chemical properties that are generated by the specific structural features of perovskite frameworks. Furthermore, the interlayers of these structures can be chemically modified through ion exchange to form nanosheets. To further expand the modification of layered perovskites, we have demonstrated an advance in the new structural concept of layered perovskite "charge-neutral perovskite layers" by manipulating the perovskite layer itself. A charge-neutral perovskite layer in [CeIVTa2O7] was synthesized through a soft chemical oxidative reaction based on anionic [CeIIITa2O7]- layers. The Ce oxidation state for the charge-neutral [CeIVTa2O7] layers was found to be tetravalent by X-ray absorption fine structure (XAFS) analysis. The atomic arrangements were determined through scattering transmission electron microscopy and extended XAFS (EXAFS) analysis. The framework structure was simulated through density functional theory (DFT) calculations, the results of which were in good agreement with those of the EXAFS spectra quantitative analysis. The anionic [CeIIITa2O7]- layers exhibited optical absorption in the near infrared (NIR) region at approximately 1000 nm, whereas the level of NIR absorption decreased in the [CeIVTa2O7] charge-neutral layer due to the disappearance of the Ce 4f electrons. In addition, the chemical reactivity of the charge-neutral [CeIVTa2O7] layers was investigated by chemical reduction with ascorbic acid, resulting in the reduction of the [CeIVTa2O7] layers to form anionic [CeIIITa2O7]- layers. Furthermore, the anionic [CeIIITa2O7]- layers exhibited redox activity which the Ce in the perovskite unit can be electrochemically oxidized and reduced. The synthesis of the "charge-neutral" perovskite layer indicated that diverse features were generated by systematically tuning the electronic structure through the redox control of Ce; such diverse features have not been found in conventional layered perovskites. This study could demonstrate the potential for developing innovative, unique functional materials with perovskite structures.
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Affiliation(s)
- Takuya Hasegawa
- Institute of Multidisciplinary Research for Advanced Material (IMRAM), Tohoku University 2-1-1 Katahira, Aoba-ku Sendai 980-8577 Japan +81-22-217-5598 +81-22-217-5598
| | - Naoki Yamasaki
- Department of Marine Resource Science, Faculty of Agriculture and Marine Science, Kochi University Nankoku 783-8502 Japan
| | - Yusuke Asakura
- Institute of Multidisciplinary Research for Advanced Material (IMRAM), Tohoku University 2-1-1 Katahira, Aoba-ku Sendai 980-8577 Japan +81-22-217-5598 +81-22-217-5598
| | - Tadaharu Ueda
- Department of Marine Resource Science, Faculty of Agriculture and Marine Science, Kochi University Nankoku 783-8502 Japan
- Center for Advanced Marine Core Research, Kochi University Nankoku 783-8520 Japan
| | - Shu Yin
- Institute of Multidisciplinary Research for Advanced Material (IMRAM), Tohoku University 2-1-1 Katahira, Aoba-ku Sendai 980-8577 Japan +81-22-217-5598 +81-22-217-5598
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11
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Ferry MA, Maruyama J, Asoh TA, Uyama H. Fused sphere carbon monoliths with honeycomb-like porosity from cellulose nanofibers for oil and water separation. RSC Adv 2021; 11:2202-2212. [PMID: 35424147 PMCID: PMC8693729 DOI: 10.1039/d0ra08950h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 12/26/2020] [Indexed: 11/21/2022] Open
Abstract
Carbon monoliths with a unique hierarchical surface structure from carbonized cellulose nanofibers were synthesized in pursuit of developing carbon materials from sustainable natural resources. Through a 2-step hydrothermal - carbonization method, TEMPO-oxidized cellulose nanofibers were turned into carbon-rich hydrochar embedded with polystyrene latex as template for 80 nm-sized pores in a honeycomb pattern, while the triblock copolymer Pluronic F-127 was used for a dual purpose not reported before: (1) an interface between the cellulose nanofibers and polystyrene particles, as well as (2) act as a secondary template as ∼1 μm micelles that form hollow carbon spheres. The use of nanofibers allowed more contact between the carbon spheres to coalesce into a working monolith while optimizing the pore structure. Oil-water separation studies have shown that carbon monoliths have high adsorption capacity due to surface area and hydrophobicity. Testing against commercially available activated carbon pellets show greater performance due to highly-developed macropores.
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Affiliation(s)
- Mark Adam Ferry
- Osaka University Graduate School of Engineering, Division of Applied Chemistry 2-1 Yamadaoka Suita, Osaka 565-0871 Japan
| | - Jun Maruyama
- Osaka Research Institute of Industrial Science and Technology, Research Division of Environmental Technology 1-6-50 Morinomiya Osaka 536-8553 Japan
| | - Taka-Aki Asoh
- Osaka University Graduate School of Engineering, Division of Applied Chemistry 2-1 Yamadaoka Suita, Osaka 565-0871 Japan
| | - Hiroshi Uyama
- Osaka University Graduate School of Engineering, Division of Applied Chemistry 2-1 Yamadaoka Suita, Osaka 565-0871 Japan
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12
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Abstract
A solid-phase photochemical method produces Au-Ag alloy nanoparticles (NPs) with a sharp size distribution and varying composition in AgBr crystals (Au-Ag@AgBr). These features render Au-Ag@AgBr promising as a material for the plasmonic photocatalyst further to provide a possibility of elucidating the action mechanism due to the optical tunability. This study shows that the visible-light activity of Au-Ag@AgBr for degradation of model water pollutant is very sensitive to the alloy composition with a maximum at the mole percent of Au to all Ag in AgBr (y) = 0.012 mol%. Clear positive correlation is observed between the photocatalytic activity and the quality factor defined as the ratio of the peak energy to the full width at half maximum of the localized surface plasmon resonance band. This finding indicates that Au-Ag@AgBr works as a local electromagnetic field enhancement-type plasmonic photocatalyst in which the Au-Ag NPs mainly promotes the charge separation. This conclusion was further supported by the kinetic analysis of the light intensity-dependence of external quantum yield.
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Affiliation(s)
- Shin-Ichi Naya
- Environmental Research Laboratory, Kindai University, 3-4-1, Kowakae, Higashi-Osaka, Osaka, 577-8502, Japan
| | - Hiroaki Tada
- Department of Applied Chemistry, Faculty of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashi-Osaka, Osaka, 577-8502, Japan.
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