[ 原子をまぜる ] 山元公寿(化学生命科学研究所/アトムハイブリッドマテリアル研究ユニット)
当研究室の研究紹介ビデオがYouTubeのTokyoTech IIRチャンネルで公開されています。ぜひご覧ください。
当研究室の研究紹介ビデオがYouTubeのTokyoTech IIRチャンネルで公開されています。ぜひご覧ください。
第12回 CSJ化学フェスタにてアウギ君、飯塚君、飯塚さん が優秀ポスター賞をしました。おめでとうございます!
Augie Atqa (D2)
発表タイトル「Designing ultra-small Mo-Pt subnanoparticles for room temperature reverse water-gas shift reaction」
飯塚 忠寿 (D1)
発表タイトル「水素発生反応におけるサブナノ粒子の原子組成依存性」
飯塚 麗奈 (M2)
発表タイトル「ボロフェン類似2次元構造体の制御合成」
Q. Zou, Y. Akada, A. Kuzume, M. Yoshida, T. Imaoka, K. Yamamoto
Angew. Chem. Int. Ed. 2022, 61, e202209675.
Bonding dissimilar elements to provide synergistic effects is an effective way to improve the performance of metal catalysts. However, as the properties become more dissimilar, achieving synergistic effects effectively becomes more difficult due to phase separation. Here we describe a comprehensive study on how subnanoscale alloying is always effective for inter-elemental synergy. Thirty-six combinations of both bimetallic subnanoparticles (SNPs) and nanoparticles (NPs) were studied systematically using atomic-resolution imaging and catalyst benchmarking based on the hydrogen evolution reaction (HER). Results revealed that SNPs always produce greater synergistic effects than NPs, the greatest synergistic effect was found for the combination of Pt and Zr. The atomic-scale miscibility and the associated modulation of electronic states at the subnanoscale were much different from those at the nanoscale, which was observed by annular-dark-field scanning transmission electron microscopy (ADF-STEM) and X-ray photoelectron spectroscopy (XPS), respectively.
M. Inazu, Y. Akada, T. Imaoka, Y. Hayashi, C. Takashima, H. Nakai, K. Yamamoto
Nature Commun. 2022, 13, 2968.
従来の化学は、化学反応によって熱力学的に安定で分離可能な化合物(分子や固体)を得ることを目指して発展してきた。しかし、計算化学の最近の発展により、その場で形成される原子や分子の動的な集合と解離の研究の重要性が増している。本研究では、元素同定を伴う原子分解能で、不安定な二量体および三量体の形成および解離の動態を直接可視化する。多くの同種および異種金属二量体のビデオ記録は、Zコントラスト原理に基づく元素同定と組み合わせた走査透過型電子顕微鏡(STEM)を使用して行われる。AuAg、AgCu、およびAuAgCuなどの存在確率が低い短命な分子でさえ、低電子線量での原子の動きを識別することによって直接可視化される。
Traditionally, chemistry has been developed to obtain thermodynamically stable and isolable compounds such as molecules and solids by chemical reactions. However, recent developments in computational chemistry have placed increased importance on studying the dynamic assembly and disassembly of atoms and molecules formed in situ. This study directly visualizes the formation and dissociation dynamics of labile dimers and trimers at atomic resolution with elemental identification. The video recordings of many homo- and hetero-metallic dimers are carried out by combining scanning transmission electron microscopy (STEM) with elemental identification based on the Z-contrast principle. Even short-lived molecules with low probability of existence such as AuAg, AgCu, and AuAgCu are directly visualized as a result of identifying moving atoms at low electron doses.