Asakura Laboratory
Catalyst Surface Research Division, Institute for Catalysis, Hokkaido University
- Synchrotron XAFS and nano-scope MICROSCOPY -
Research
Research triad
- Design and construct new catalysts regulated in nanosize on the basis of atomic scale understandings of catalytic activities, structures and physical properties.
- Develop new surface analysis methods to analyze surface structures and electronic properties.
- Construct new concept of surface chemistry and physics.
Our interest is to find a correlation of an atomic scale structure with catalytic activity on solid catalysts, especially focusing on metal oxides and other compounds surfaces. One of our approaches is to utilize the well-defined single crystal surface as a model catalyst.
We are challenging to develop new surface analysis methods with applying the accelerator based beam techniques such as synchrotron radiation, neutron, positron, muon and free electron laser by collaboration with High Energy Accelerator Research Organization (KEK), Institute for Molecular Science (IMS), Tokyo Medical and Dental University (TMDU), National Institute of Advanced Industrial Science and Technology (AIST), National Institute for Material Science (NIMS), and Spring-8.
CREATION - Control chemistry in nano world -
Single crystal surface is an ideal field to observe and control chemical reactions. We are creating series of atomically-controlled catalysts by chemical modification of single crystal TiO2 surface. TiO2(110) surface, on which carboxylic acid adsorbs stably in an ordered structure. We choose the surface as target. Our strategy is utilizing a molecule having b COOH group and b SH group. We adsorb Mercaptobenzoic Acid on TiO2(110) surface to stabilize metal atoms, such as Cu, Au and Ni, by b SH group. The characterization by Polarization dependent EXAFS shows atomically dispersed new chemical spices. In addition, the local structures of atomic metal spices is able to control by changing the position of SH group to use isomers, o-, m-, p- Mercaptobenzoic Acid.
DEVELOPMENT - Observe chemistry in nano world -
We are developing Surface nano analysis systems.
- Polarization-dependent Total Reflection Fluorescence X-ray Absorption Fine Structure (PTRF-XAFS)
- Energy-selected X-ray PhotoEmission Electron Microscopy (EXPEEM)
The PTRF-XAFS is capable to reveal three dimensional structure of dispersed metal clusters. Figure shown below shows the three dimensional Ni cluster dispersed on TiO2(110) surface in Figure.
DISCOVERY - To establish new concepts of the surface nano world -
Although Surface properties seem to be totally different from bulk properties, surface depends on the bulk and chemistry on surface can be explained in terms of solid state chemistry. We are struggling to understand the surface phenomena based on the classical bulk physics and chemistry. If not, we may discover a new phenomenon.
I welcome all of you to join us and to enjoy the science.