Thermal Catalysts

The rational design of catalytic systems enables the production of valuable chemical compounds. Our research focuses on designing catalytic materials with a high synthetic precision of controlling constituent atoms and applying them to carbon dioxide utilization and renewable energy production.
 
The synthetic development of the catalytic systems is based on high-end characterization techniques such as atomic resolution S/TEM, cryogenic S/TEM, in situ Raman, and in situ S/TEM techniques, which provide unique information for further improvement and development of catalytic systems. Systems we are interested in include single atoms, clusters, two-dimensional structures, and three-dimensional site modulations.

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Atomically Controlled Catalyst for Liquid Organic Hydrogen Carrier (LOHC)

For using hydrogen as an energy source for sustainable future, liquid organic hydrogen carrier (LOHC) material has been proposed as an efficient hydrogen transport material. However, the major hurdle in utilizing LOHC is the low stability of catalysts. They are sintered and differentiated under hydrogen production condition in LOHC, and thus the development of a highly active catalyst system with suppressed deactivation is required. We found that active metal atoms can be selectively supported at points where metal-support interactions are maximized by using a mild reduction method. We develop synthetic strategy whereby such selective metal-support interactions can be manipulated to make stable catalysts for hydrogenation and dehydrogenation reactions of LOHC.

Chemical Design for Utilizing Metal-Support Interactions

Supported metal catalysts are widely used in industrial processes. Their catalytic properties can be improved by controlling the size and structure of the metal particles while achieving high metal dispersion. We aim to achieve this goal by using strong metal-support interaction (MSI), whereby the metal precursors are efficiently anchored onto the support and atomic migration can be suppressed during a typical thermal treatment. Our strategy includes the fabrication of highly dispersed catalysts by tailoring the chelate ligand of the metal ion and the treatment of the support materials to have proper surface structures to anchor the metal precursor. We aim to apply as-synthesized catalyst systems for hydrogen storage system and CO2 utilization.

Formation Mechanism and Synthetic Design of

Heterogeneous Catalyst with Atomic Scale Precision

 
It is now generally accepted that even an addition (or an elimination) of a single atom on a catalytically active site can significantly alter its interaction with the reactant molecule, and thereby change its catalytic performance. Therefore, fine control of the active site, such as the isolation of single atoms or the creation of desired metal-support interface, is needed to further advance the performance of heterogeneous catalysts. We seek to directly understand the atomic-scale formation mechanism of catalytic active sites by utilizing an advanced microscopic method of in situ TEM and atomic-resolution low-dose imaging. Based on our understanding, we develop synthetic methods that generate structurally homogeneous active sites such as single-atom catalysts and epitaxial metal-support structures. Our goal is to utilize our atomically precise catalysts to tackle global challenges, including carbon dioxide utilization and renewable energy production.