visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2017-04-28 14:30 
일시 Apr. 28 (Fri.), 02:30 PM 
장소 E6-2. 1st fl. #1323 
연사 Dr. JeongYoung Park Graduate School of EEWS, KAIST 

 

Hot electron generation at surfaces and its impact to catalysis and renewable energy conversion

 

Dr. JeongYoung Park

Graduate School of EEWS, KAIST

Apr. 28 (Fri.), 02:30 PM

E6-2. 1st fl. #1323

 

 

Abstract: 

A pulse of high kinetic energy electrons (1–3 eV) in metals can be generated after surface exposure to external energy, such as the absorption of light or exothermic chemical processes. These energetic electrons are not at thermal equilibrium with the metal atoms and are called ‘‘hot electrons’’. The detection of hot electrons and understanding the correlation between hot electron generation and surface phenomena are challenging questions in the surface science and catalysis community. Hot electron flow generated on a gold thin film by photon absorption (or internal photoemission) appears to be correlated with localized surface plasmon resonance. 

In this talk, I will show strategy to quantify the non-adiabatic energy transfer and detect hot electron flux during the elementary steps of the energy conversion process and catalytic reaction processes occurring at both of solid-gas and solid-liquid interfaces. To detect and utilize the hot electron flows, the nanodiodes consisting of metal catalyst film, semiconductor layers, and Ohmic contact pads were constructed It was shown that the chemicurrent or hot electron flows were well correlated with the turnover rate of CO oxidation or hydrogen oxidation separately measured by gas chromatography, suggesting the intrinsic relation between catalytic reaction and hot electron generation. We show a novel scheme of graphene catalytic nanodiode composed of a Pt NPs array on graphene/TiO2 Schottky nanodiode, which allows detection of hot electron flows induced by hydrogen oxidation on Pt NPs. By analyzing the correlation between the turnover rate (catalytic activity) and hot electron current (chemicurrent) measured on the graphene catalytic nanodiodes, we demonstrate that the catalytic nanodiodes utilizing a single graphene layer for electrical connection of Pt NPs are beneficial for the detection of hot electrons due to not only atomically thin nature of graphene but also reducing the height of the potential barrier existing at the Pt NPs/graphene interface. I will show that hot electron flow generated on a gold thin film by photon absorption (or internal photoemission) is amplified by localized surface plasmon resonance. Finally, The effect of surface plasmons on the catalytic and photocatalytic activity on metal–oxide hybrid nanocatalysts is also highlighted. These phenomena imply the efficient energy conversion from the photon energy to the chemical energy, with the potential application of hot electron-based photocatalytic devices.

 

 

 

번호 날짜 장소 제목
227 2023-12-14 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  Superconducting qubits for large-scale quantum computers file
226 2023-04-13 11:00  Zoom  [High Energy Theory Seminar]Noninvertible Gauss Law and Axions
225 2015-12-01 16:00  E6-2, #1323  Introducing extra dimensions to spectroscopic studies of advanced quantum materials
224 2015-11-10 16:00  E6-2, #1323  Rapid heating of matter using high power lasers
223 2022-11-10 16:00  E6-2. 1st fl. #1323  Probing the Origin of Cosmic Infrared Background and Future Prospects with SPHEREx
222 2023-02-28 11:00  E6 Room(#1322)  Topotactic redox engineering toward novel material file
221 2018-10-16 10:00  #1323, E6-2  Capturing protein cluster dynamics and gene expression output in live cells file
220 2018-06-18 10:00  E6-2. 2nd fl. #2502  Rydberg electromagnetically induced transparency and microwave-to-optical conversion using Rydberg atoms file
219 2019-03-29 16:00  E6-2. 1st fl. #1323  Coherent Quantum Control and Magnetism on atoms – Trapped ion and ESR STM file
218 2023-09-26 16:00  E6-2, #2502  [High Energy Theory Seminar]A new step in interacting dark sector cosmologies
217 2016-03-11 16:00  E6-2. 1st fl. #1501  Jan. Switching handedness of of chiral solitons in Z4 topological insulators
216 2021-04-02 14:30  Online(Zoom)  Quantum computing and entanglement generation using trapped ions and photons
215 2021-05-14 14:30  Online seminar  Electrically tunable spin valve effect in vertical van-der-Waals magnetic tunnel junctions file
214 2015-11-28 10:00  E6-2, #1323  Electron Tunneling Spectroscopy of Single and Bilayer Graphene with Hexagonal Boron Nitride as Tunneling Barrier
213 2022-05-11 16:00  E6-2. #1323 & Zoom  Gravity as a phenomenon in quantum dynamics
212 2022-05-25 16:00  E6-2. 1st fl. #1323 / Zoom  Uncovering New Lampposts for Dark Matter: Continuum or Conformal
211 2019-05-01 16:00  #1323, E6-2  Raman and x-ray scattering study on correlated electron systems: two case examples file
210 2018-04-13 10:00  #1323 (E6-2, 1st fl.)  Quantum meets Mechanics: from Quantum Information to Fundamental Research file
209 2022-09-30 14:30  E6-2. 1st fl. #1323 & Zoom  Putting a spin on the Josephson effect file
208 2022-07-14 15:00  E6 #1501 & Zoom  Pure two-dimensional quantum electron liquid and its phase transition