2025-09-19 神奈川大学
図1. 熱安定性に優れたストロンチウム・ガリウム酸水酸化物と新しいプロトン機能性材料の応用展開
＜関連情報＞
- https://www.kanagawa-u.ac.jp/news/details_29491.html
- https://www.kanagawa-u.ac.jp/cr_att/0011/29491_105512_010.pdf
- https://pubs.acs.org/doi/10.1021/acs.inorgchem.5c02586
高熱安定性Sr–Gaオキシ水酸化物：その特徴的な水素結合ネットワークの解明 A Sr–Ga Oxy-Hydroxide with High Thermal Stability: Unraveling Its Characteristic Hydrogen-Bond Network
Yusuke Asai,Yuto Nishihara,Yoko Kokubo,Kenji Arai,Kosaku Ohishi,Satoshi Ogawa,Miwa Saito,Yusuke Nambu,Maxim Avdeev,Koji Kimoto,Zi Lang Goo,Kunihisa Sugimoto,Miki Inada,Katsuro Hayashi,and Teruki Motohashi
Inorganic Chemistry Published August 31, 2025
DOI:https://doi.org/10.1021/acs.inorgchem.5c02586
Abstract
Oxy-hydroxides represent potential proton carriers for solid acid catalysts and proton conductors owing to their hydroxide-rich compositions. However, their applications in high-temperature environments are limited due to thermal instability associated with dehydration at moderate to high temperatures. Therefore, the development of oxy-hydroxides with enhanced thermal stability is of critical importance. Herein, we report the discovery of a strontium–gallium oxy-hydroxide, Sr2Ga3O6(OH), with exceptional thermal stability. The Sr–Ga oxy-hydroxide was successfully synthesized via an unconventional synthesis route, “vapor hydroxidation”, involving high-temperature heat treatment in highly concentrated water vapor. Structural characterization employing X-ray diffraction, neutron diffraction, and transmission electron microscopy revealed that the Sr–Ga oxy-hydroxide crystallizes in a trigonal structure (R3̅ space group) with lattice parameters a = 18.1904(2) Å and c = 7.2693(1) Å. Notably, OH– anions are nonuniformly distributed within the crystal structure and are confined to a narrow space between two strontium sites. Thermogravimetry combined with desorption gas analysis indicated that OH– anions are retained in the crystal structure up to approximately 850 °C. In situ infrared spectroscopy upon heating demonstrated proton redistribution via multilinked hydrogen bonds at elevated temperatures, which likely contributes to the excellent thermal stability.
