yrammuS 要概molecular design, the potential of spontaneous self-assembly from more than thousands of molecules toward designed microstructures, which is similar to non-covalent bond formation via a reaction, was exemplified by the present study.マイクロ波は，急速成長や単分散ナノ粒子が得られることから，ナノ粒子合成で幅広く使用されている．しかし，粒子が生成されるときのスーパーヒートのメカニズムは未解明のままである．本研究では，これらの現象を防ぐために，マイクロ波2段照射を提案した．例えば，粒子径やバブル径，懸濁液の輝度などマイクロ波照射中のin-situのデータから，1段目の高出力照射によって核生成が促進されることを示した．この高懸濁密度化によって，マイクロ波の吸収エネルギー各粒子に分配されることになる．その結果，粒子の発熱は抑えられ，バブル径が小さくなる．このように，2段照射は連続照射よりも，微細粒子を得るために有効であり，過加熱の抑制等，安定化にも寄与することが期待される．Microwave has been widely used for nano-particle synthesis because rapid growth and mono-dispersed parti-cle size can be obtained. However, the mechanism of superheat behavior caused by the higher power has not been clearly understood when colloidal particle of ferric hydroxide was produced by heating ferric chloride solution under the irradiation. In this study, to prevent superheat behavior, two-stage irradiation was proposed in nano-particle formation process. Based on in-situ measurement data, such as the profiles of bubble size, fi-nal particle size and brightness of scattering light of suspension, it is evident that nucleation of nano-particle is promoted by higher power of the first irradiation. As a result, particle number density became higher, and then microwave absorbance energy was evenly distributed to each particle. Due to suppression of heat gener-ation in a particle, bubble size became smaller. Two-stage irradiation became more advantageous in obtaining smaller particle than continuous irradiation because lower power of the second irradiation prevents superheat behavior. Finally, this method can contribute stable operation for nano-particle synthesis.本研究の目的は，電子相関の強い良導体をベースに酸素発生反応(OER)と酸素還元反応(ORR)の両方に優れた二元機能触媒を設計することにある．そこで，高い電気伝導性を有する(Ca1-xSrx)RuO3に対して系統的に電気化学測定を行い，電子相関が強ければ強いほどOER活性が増強されることを明らかにした．特筆すべきは，(Ca1-xSrx)RuO3が金属-絶縁体転移の近傍に位置した時(x〜0.1)にOER活性が著しく増強されたことである．さらに，(Ca1-xSrx)RuO3はx 〜0.1でOERとORRに対して高い二元機能性を示すことを明らかにした．この成果によって金属-絶縁体転移の近傍の良導体が金属空気電池の空気極触媒として有望であることを示した．The purpose of this study is to design bifunctional electrocatalysts with high oxygen evolution (OER) and oxygen reduction (ORR) activity on the basis of conducting materials with strong electron correla-tion. Therefore, systematic electrochemical study was conducted on (Ca1-xSrx)RuO3 with high conduc-朝熊 裕介27Yusuke ASAKUMA平井 慈人28Shigeto HIRAI単分散ナノ粒子生成プロセスの新展開〜マイクロ波2段階照射による核生成・成長過程の分離〜 (2017年採択)New development of mono-dispersed nano-particle formation process - separation of nucleation and growth processes by two-stage microwave irradiation - (Project 2017)半永久的に充電可能な金属空気電池を実現する二元機能触媒の開発 (2017年採択)Development of bifunctional catalysts for realizing long-term rechargeable metal-air batteries (Project 2017)35Rep. Grant. Res., Asahi Glass Foundation (2019)
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