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
367 2019-07-30 16:00  #1323, E6-2  Dirac fermions and flat bands in correlated kagome metals file
366 2023-07-11 11:00  E6-2, #1323  Ordered phases, non-Fermi liquid, and quantum criticality driven by entanglement between multipoles and conduction electrons
365 2017-04-28 16:00  #1323 (E6-2. 1st fl.)  Carbon nanotubes coupled to superconducting impedance matching circuits
364 2016-09-29 16:00  E6-2. #2501(2nd fl.)  Exploring the phase diagram of BaBiO3: epic voyage of just another bad trip?
363 2019-06-12 15:00  Rm# 1323, E6-2  The relation between free and interacting fermionic SPT phases file
362 2022-10-06 13:00  E6 #1323  Counting States with Global Symmetry
361 2022-08-12 10:00  E6-1 #1323  Twisted Bilayer Magnets file
360 2022-08-12 10:00  E6-1 #1323  Twisted Bilayer Magnets file
359 2016-04-26 16:00  #1323(1st Floor. E6-2)  Transport spectroscopy for electronic bands in carbon-based nanomaterials with weak-bond contacts
358 2018-05-11 16:00  E6-2. 1st fl. #1323  암페어 단위 재정의와 단전자 펌프 소자 개발 file
357 2016-06-01 10:30  BK21 Conference Room (#1318, E6-2)  Welcome to Nature Photonics
356 2018-07-02 15:00  Seminar Room (C303), Creation Hall (3F), KAIST Munji Campus  High Precision Magnetic Field Measurement for the Muon g-2 Experiment file
355 2015-10-16 15:00  E6-2, 5th fl. #5318  High Magnetic Fields to Probe the sub-eV range of Particle/Astroparticle Physics - From the OSQAR experiments at CERN up to new perspectives at LNCMI-Grenoble
354 2018-11-09 14:30  E6-2. 1st fl. #1323  Moiré superlattices – from twisted bilayer graphene to quasicrystal file
353 2022-03-29 10:00  E6 #1501/zoom, E6 #2502/zoom  Non-reciprocal phase transitions file
352 2022-03-31 10:00  E6 #1501/zoom  Weiss fields for Quantum Spin Dynamics file
351 2020-10-15 17:00  https://bit.ly/3ndIiJn  Time crystals, quasicrystals, and time crystal dynamics in the superfluid universe file
350 2023-05-03 16:00  E6-2, #2502  Probing microscopic origins of axions by the chiral magnetic effect
349 2022-11-09 16:00  E6-2. 1st fl. #1323  Radio Astronomy, Radio Interferometry, and Multi-wavelength Studies on Relativistic Jets
348 2017-06-02 16:00  #1323 (E6-2. 1st fl.)  Maxwell's demon in quantum wonderland file