Sponge crystals based on a novel formation principle and their functional development

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K21239
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 36:Inorganic materials chemistry, energy-related chemistry, and related fields
• Research Institution: Hiroshima University
• Principal Investigator: INUMARU Kei 広島大学, 先進理工系科学研究科(工), 教授 (80270891)
• Project Period (FY): 2020-07-30 – 2023-03-31
• Keywords: 多孔体 / sponge crystal / epitaxial self assembly / mesocrystal

Outline of Final Research Achievements

A quarter-century ago we have found a phenomenon in which crystalline nanoparticles self-assemble to form aggregates and the entire aggregate acquires order as a single crystal (Epitaxial Self-Assembly) (Chem. Lett., 1996; J. Phys. Chem., 1997). This was a discovery that preceded the well-known concept of "mesocrystal" (Colfen et al., 2005). Furthermore, we proposed a novel concept of porous single crystals “sponge crystals” (Catal. Surv. Asia, 2006). In this study, a quarter century after our discovery, the pore structure of (NH4)4SiW12O40 sponge crystals was elucidated at the atomic- and molecular-level.

Free Research Field

無機材料化学

Academic Significance and Societal Importance of the Research Achievements

我々の発見後，Cs4SiW12O40の構造に関する報文がいくつか報告されているが，スポンジ結晶の細孔構造そのものを原子・分子レベルで明らかにするには，細孔径分布を直接捉え，結晶構造と比較して議論することが必須であった．本研究では，長年未踏であったこの課題にスポンジ結晶の発見者である我々が自ら到達することができた．
以上，本研究により，ゼオライトやALPOに代表される多孔質単結晶の科学に，スポンジ結晶の科学と化学が，原子・分子レベルのより詳細な理解とともに書き加えれられ，全体が単結晶の秩序を持ちながら内部に柔軟な細孔構造をもつ「スポンジ結晶」の新たな物質・材料科学のさらなる展開の端緒が得られた．