2022 Fiscal Year Annual Research Report
| Project/Area Number |
22F22348
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| Allocation Type | Single-year Grants |
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| Research Institution | Tokyo University of Science |
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Principal Investigator |
田村 隆治 東京理科大学, 先進工学部マテリアル創成工学科, 教授 (50307708)
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| Co-Investigator(Kenkyū-buntansha) |
JIN HUIXIN 東京理科大学, 先進工学部, 外国人特別研究員
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| Project Period (FY) |
2022-11-16 – 2025-03-31
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| Keywords | Quasicrystals / Catalytic / Frank-Kasper phases |
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| Outline of Annual Research Achievements |
The purpose of this study is to prepare a multifunctional gradient structure (gradient membrane or nanostructured alloy-metal oxide coupling) and explore the influence of icosahedral structure (Frank-Kasper phases and quasicrystals) on catalytic properties of different Oxidation-Reduction Reactions.
The main work of this year is divided into three parts. The first part is to study the catalytic properties of Tsai-type 1/1 approximant crystals (ACs) such as Al-Pd-Sc, Ga-Pd-Sc. The activity of these catalysts and their selectivity for C2H4 were evaluated using simple C2H2 hydrogenation reactions with no surface oxidation. It can be found that substituting Ga with Al greatly improves the catalytic activity. DFT calculation shows that the adsorption energy of C2H2 on Al-Pd-Sc surface is higher, indicating that Al-Pd-Sc is more likely to adsorb gas molecules and promote the reaction. These findings can provide guidance for the selection of components in the preparation of gradient structures.
In the second part, the Frank-Kasper phases (TCPs) related to quasicrystals is studied. There is a great number of icosahedral clusters in TCPs, and these clusters are aperiodic in IQC, but three-dimensionally periodical in TCPs. Our research indicate that TCPs (icosahedral clusters) are prone to generate stacking fault during formation, which provides a basis for the frequently found IQC structure in the TCPs.
The third part explores whether Ga/In-Co-Ni/Cu can form quasicrystals. At present, there is no possibility of quasicrystals in these alloys with different compositions.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
At present, although the above important progress has been made in the catalytic properties of Tsai type 1/1 approximant crystals and the structure and defects of Frank-Kasper phases, the research on the gradient quasicrystal structure is still mainly stalled in the exploration of the quasicrystal composition. Since the components of the quasicrystals reported in the past are very easy to oxidize and cannot be reduced at temperatures below 1000 degrees Celsius. So, whether sputtering the film or making nanocrystalline particles by ball milling, the oxidation problem on the surface of the particles and the film is the key problem that affects the catalyst performance. We are exploring solutions to this problem in two ways. One is thinking about how to make new quasicrystals without using the easily oxidized metals. The other one is to prevent oxidation in the process of sputtering (or ball milling) and catalytic performance testing.
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| Strategy for Future Research Activity |
Nanomaterials play an important role in catalysis because of their excellent surface area and small-size effect. We want to make a nano-sized Frank-Kasper phases or 1/1 ACs or quasicrystals by means of metal salts and study their catalytic properties for different Oxidation-Reduction reactions. The main methods are as follows: First, add water to mix and stir the three metal salts evenly followed by aging at ambient temperature overnight and further dry at 100 degrees Celsius. The obtained samples are calcined in static air at a specific temperature to obtain three metal oxide mixtures as precursors. It is directly reduced in a quartz tube in H2 flow at atmospheric pressure and specific temperature. Finally, the heat treatment process required for the desired structure (quasicrystals or TCPs) is performed to obtain nanoscale intermetallic compounds and test their catalytic properties.
In addition, we will continue to try to prepare gradient TCP phase/quasicrystal membranes by using sputtering and explore their effect on catalytic performance.
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