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Mesoscale Materials Chemistry Group

Research Activities

Rational design of nanoporous materials (Dr. Yusuke Yamauchi)

Our work focuses on the synthesis of novel inorganic nanoporous materials by utilizing various self-assembly processes of atoms/molecules. Especially, research on nanoporous materials, conducted mainly by using surfactant assemblies as templates, has been increasing rapidly. The specific features of regular pore arrangement, uniform pore size, and high surface area make these materials very promising for various applications. Especially, nanoporous “metals” with high electroconductivity have attracted particular interest for their very wide range of applications in such items as batteries, fuel cells, solar cells, chemical sensors, field emitters, and photonic devices. Our research target is rational design of nanoporous metals with controlled compositions and morphologies, which is very attractive and challenging objective.
 
We are always interested in many scientific aspects ranging from fundamental chemistry to industrial-scale production. Toward practical use, we have developed some prototypes (e.g., low-k materials, low thermal expansion materials, E-papers, antibacterial films, electrocatalysts) by using nanoporous materials which are produced in a large-scale industrial operation. In addition, we are currently exploring new chemical and physical properties originated from the nanoporous structures with extensive collaborations with many research groups all over the world.


Functionalization of 0D-3D inorganic materials (Dr. Yusuke Ide)

In the field of materials chemistry, extensive effort has been spent synthesizing high-performance materials that often rely on noble and precious metals. We focus on the design and development of new materials and operating environments to attain these high performances, but using cheap and Earth abundant materials like SiO2 and TiO2. Our materials design approach includes the dissolution/recrystallization of conventional materials, deposition of functional particles like MOFs in solids, and simple integration of conventional materials. We are using these materials to investigate multiple applications including: 
1. Photocatalysis. We develop materials for the removal of organic pollutants, fine chemical synthesis and photochemical water-splitting. 
2. Separation. New materials can assist in the recovery of useful elements and removal of toxic elements in environments. 
3. UV shielding. New TiO2 with no photocatalytic activity and extremely low refractive index can be used as UV-protective transparent coatings. Typical examples of our work on operating environments include using CO2 atmosphere to enhance the photocatalytic synthesis of fine chemicals on TiO2, and using seawater for selective and effective cation exchange in layered silicates.

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Synthesis of nanocrystals and the creation of functional porous nanocrystalline architectures (Dr. Joel Henzie)

The role of nanoparticle shape can be as important as crystal chemistry in determining the electronic and catalytic properties of inorganic clusters and nanoparticles. Yet the chemistry governing shape at this length scale is not well understood, especially in binary and ternary materials. We are using a combination of simulation, structural analysis and high-precision synthetic techniques to discover a common origin of shape in different nanomaterials systems, with special attention on classes of materials useful for enhanced light absorbance and catalysis. 
We treat these nanocrystals as “building blocks” for a new class of functional, porous architectures that can be completely assembled from the bottom up. Over the years many synthetic methods have been developed to generate particles with exquisite control of shape and size in metal, dielectric and semiconductor materials. Our focus is on arranging these building blocks into precisely ordered lattices, where they become the component "atoms" of new, functional porous materials with unusual physical and chemical properties that cannot be found in nature. We are interested in both the fundamental science of self-assembly, and diverse applications including bio-molecular sensing, metamaterials and plasmon-enhanced catalysis.

"Fig. By tuning interparticle forces in octahedral Ag nanocrystals, we can create a material that is ~12% more porous than its densest packing (SEM: Left, Middle). Monte Carlo modeling can show how these particles assemble, and what forces are required (Right)." Image

Fig. By tuning interparticle forces in octahedral Ag nanocrystals, we can create a material that is ~12% more porous than its densest packing (SEM: Left, Middle). Monte Carlo modeling can show how these particles assemble, and what forces are required (Right).




Structural & electrochemical analyses of mesoscale materials (Dr. Satoshi Tominaka)

Mesoscale materials are of great importance for electrochemical applications, especially for applications such as fuel cells and batteries. Our research group combines mesoscale materials chemistry with rigorous atomic-scale structural analysis to explain the origin of materials properties.
Synthesis: We synthesize materials via solvothermal reactions (e.g., for metal organic frameworks), low temperature reduction reactions (e.g., for conductive oxides) and electrochemical reactions (e.g., for metal nanostructures) 
Analysis: We analyze atomic structures by general technique such as IR spectroscopy and X-ray diffraction as well as X-ray pair distribution functions (PDFs). In addition to the laboratory X-ray measurements, we often use synchrotron facilities. The data is analyzed using in-house programs as well as other major programs for the real-space Rietveld analysis and the Reverse Monte Carlo method. The structures are modeled via molecular mechanics simulations as well as density-functional theory (DFT) calculations.
Properties: We measure electrochemical properties using a range of setups including general techniques such as rotating disk electrode (RDE) and electrochemical impedance spectroscopy (EIS), in addition to more exotic methods such as measuring the ion/electron conductivities for single crystals. In addition to these property measurements and structure analysis, we carry out a variety of technique such as synchrotron X-ray photoelectron spectroscopy to understand the mechanism.

"Fig. Atomic structures of mesoscale materials may be different from bulk materials due to surface effect and quantum effect, resulting in unique properties including catalytic activities. Short range ordering in materials affect physical properties including ion conduction, electrical conductivity and electrocatalytic activities. We use techniques like pair distribution function (PDF) analysis to help explain the impact of short-range ordering on materials properties." Image

Fig. Atomic structures of mesoscale materials may be different from bulk materials due to surface effect and quantum effect, resulting in unique properties including catalytic activities. Short range ordering in materials affect physical properties including ion conduction, electrical conductivity and electrocatalytic activities. We use techniques like pair distribution function (PDF) analysis to help explain the impact of short-range ordering on materials properties.




Group Leader

"Yusuke YAMAUCHI" Image

Yusuke YAMAUCHI


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Mesoscale Materials Chemistry Group
1-1 Namiki, Tsukuba, Ibaraki, 305-0044
JAPAN
TEL: 029-854-9061
E-Mail: YAMAUCHI.Yusuke=nims.go.jp(Please change "=" to "@")
National Institute for Materials Science (NIMS)
1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, JAPAN
TEL.+81-(0)-29-859-2000
FAX.+81-(0)-29-859-2029