RESEARCH TOPICS
Detection of hot electrons during catalytic reactions
Catalysis is more active when the system is moved to a beneficial energy landscape through electron transfer between the catalyst surface and a reaction intermediate. Charge transfer in a metal on oxide system, which is the main component of industrial catalysts, plays a crucial role since it leads to the enhancement of catalytic performance. This knowledge serves as the foundation for discussing electron transfer at metal-oxide junctions as a separate subject. Our SCAN group tries to detect the hot electrons excited in various catalytic reactions using 'hot electron detectors' and demonstrate the correlation between electron transfer and reactivity. A catalytic nanodiode must be coupled with metal-oxide heterogeneous catalysts to study the surface dynamics of hot electrons on metal surfaces.
[Related Publications]
Lee, S. W. et al., Nat. Commun. 2021, 12 (1), 40. [Link]
Lee, S. W. et al., Trends Chem. 2023, 5 (7), 561-571. [Link]
Lee, S. W. et al., ACS Catal. 2019, 9 (9), 8424-8432. [Link]
Hot electron phenomena at solid-liquid interfaces
Interface between solid and liquid plays a critical role in energy technologies, such as rechargeable batteries, electrochemical reaction, photocatalytic reaction, and biochemical reaction. Hence, a comprehensive understanding of surface dynamics at solid-liquid interfaces is of major interest in heterogeneous catalysis. Our SCAN group aims to observe the hot electron transfer at the solid-liquid interface by developing cutting-edge technologies with metal-semiconductor Schottky nanodiodes. By employing advanced methodologies combining the energy dissipation from the chemical reaction (i.e., chemicurrent) and photon-to-electric signal (i.e., photocurrent), a fundamental understanding of hot electron flows at solid-liquid interfaces may provide new insight into the future development for energy technologies.
[Related Publications]
Lee, S. W. et al., Nano Lett. 2023, 23 (11), 5373-5380. [Link]
Lee, S. W. et al., J. Phys. Chem. Lett. 2022, 13 (40), 9435-9448. [Link]
Lee, S. W. et al., Appl. Surf. Sci. Adv. 2023, 16, 100428. [Link]
Hot electron-based hybrid nanocatalysts
Excited electrons with an energy of 1-3 eV that are not in thermal equilibrium in metal surfaces are called "hot electrons". Significantly, it has been reported that several surface reactions can be driven and enhanced by the transfer of hot electrons to the catalyst surface ("hot electron-driven chemical reaction"). Our SCAN group aims to electronically control chemical reactions via hot electron transfer on metal-semiconductor hybrid nanocatalysts. The strong correlation between hot electron transfer and turnover rates proposed that excited electrons can be utilized for controlling catalytic performance. Therefore, the dissipation from photon to electrical energy, photon-driven hot electron excitation, enables to give further insight into energy conversion, considering hot electrons as a major candidate.
[Related Publications]
Lee, S. W.* et al., ACS Catal. 2024, 14 (8), 5520-5530. [Link]
Lee, S. W. et al., Nanoscale 2018, 10 (23), 10835-10843. [Link]
Lee, S. W. et al., Nanoscale 2018, 10 (8), 3911-3917. [Link]
Operando ("operating condition") surface science
Since a chemical reaction in heterogeneous catalysis occurs on the catalyst surface, many catalyst studies using surface-sensitive characterization techniques have been reported. Most surface science studies have been performed under low pressure conditions at cryogenic temperatures, however, studies in these rarefied conditions may not be representative of the catalyst surfaces since real catalysts operate from mbar to atmosphere regions at high temperature. Therefore, our SCAN group aims to utilize in-situ NAP-STM and NAP-XPS, which can make possible to understand the chemical and structural evolution of catalyst surfaces under more "realistic" chemical reaction conditions. By means of these operando surface science configurations, we are able to reveal reaction mechanism and active sites under catalytic reactions.
[Related Publications]
Lee, S. W. et al., Nat. Commun. 2023, 14 (1), 4649. [Link]
Lee, S. W. et al., J. Phys. Chem. C 2023, 127 (42), 20700-20709. [Link]
Lee, S. W. et al., Surf. Sci. Rep. 2021, 76 (3), 100532. [Link]
