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
223 2019-04-26 16:00  #1323, E6-2  Robust Quantum Metrology using Strongly Interacting Spin Ensembles and Quantum Convolutional Neural Network file
222 2019-04-23 16:00  #1323, E6-2  From Mott physics to high-temperature superconductivity file
221 2019-04-19 16:00  E6-2. 1st fl. #1323  Graphene and hBN heterostructures file
220 2019-04-19 14:30  E6-2. 1st fl. #1323  A family of finite-temperature electronic phase transitions in graphene multilayers file
219 2019-04-19 11:00  #1323, E6-2  First-principles studies of semiconductors for solar cell applications file
218 2019-04-11 16:00  #1323, E6-2  Massive screening for cathode active materials using deep neural network file
217 2019-04-04 16:00  #1323, E6-2  Chiral spin-photon interaction at nanoscale file
216 2019-03-29 16:00  E6-2. 1st fl. #1323  Coherent Quantum Control and Magnetism on atoms – Trapped ion and ESR STM file
215 2019-03-29 14:30  E6-2. 1st fl. #1323  Epitaxial Multifunctional Oxide Thin Films for Novel Electronics file
214 2019-03-26 15:00  E6-2. 2st fl. #2501  Consideration of thermal Hall effect in frustrated and un-frustrated quantum magnets file
213 2019-03-21 16:00  RM. 1323, E6-2  Spring 2019: Physics Seminar Serises file
212 2019-02-25 16:00  Rm. 1501 (E6)  Spring 2019: Physics Colloquium file
211 2019-02-21 16:00  #5313, E6-2  B-meson charged current anomalies - Theoretical status file
210 2019-01-23 16:00  Rm. C303, Creation Hall (3F), Munji Campus  Ultrasensitive Microwave Bolometer: Opportunity for Axion Detectors file
209 2019-01-09 16:00  E6-2. 2nd fl. #2501  Molecular Mott state in the deficient spinel GaV4S8 file
208 2019-01-07 15:00  E6-2. 2st fl. #2501  Many-Body Invariants for Multipoles in Higher-Order Topological Insulators file
207 2018-12-27 16:00  E6-2. 1st fl. #1323  Quantum Innovation (QuIN) Laboratory file
206 2018-12-26 16:00  E6-1. 3rd fl. #3434  Informal Workshop on Topology and Correlation file
205 2018-12-26 16:00  E6-2. 1st fl. #1323  Brane-like defect in 3D toric code file
204 2018-12-16 16:00  E6-2. 1st fl. #1323  Lectures on 2d Conformal Field Theory file