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
251 2019-12-13 13:30  #1323, E6-2  Biophysics Mini-symposium at KAIST file
250 2019-12-18 16:00  #1323, E6-2  Road to Higher Tc Superconductivity file
249 2019-12-27 15:00  #5318, E6-2  The superconducting order parameter puzzle of Sr2RuO4 file
248 2019-12-27 15:00  E6-2,#5318  The superconducting order parameter puzzle of Sr2RuO4 file
247 2020-01-17 16:00  #1323, E6-2  Symmetry Breaking and Topology in Superfluid 3He file
246 2020-02-12 13:00  E6-2, #5318  From inflation to new weak-scale file
245 2020-02-13 16:30  E6-6, #119  Enhanced Light-Matter Interactions in Graphene with Noble Metal Plasmonic Structures file
244 2020-02-20 16:00  #1323, E6-2  Unconventional superconductivity in the locally non-centrosymmetric heavy-fermion CeRh2As2 file
243 2020-07-02 16:00  Zoom Video Conference Seminar  An irreversible qubit-photon coupling for the detection of itinerant microwave photons file
242 2020-08-17 20:00  Zoom webinar  Using magnetic tunnel junctions to compute like the brain file
241 2020-08-25 20:00  Zoom webinar  KAIST Global Forum for Spin and Beyond (Second Forum) file
240 2020-09-11 14:00  zoom  SRC Seminar file
239 2020-09-14 17:30  Zoom webinar  KAIST Global Forum for Spin and Beyond (Third Forum) file
238 2020-09-22 09:30  Zoom webinar  Physics and applications of soliton microcombs(Quantum- & Nano-Photonics) file
237 2020-09-24 09:00  Zoom Video  (CAPP/IBS)Searching for Dark Matter with a Superconducting Qubit , Cryogenic Microwave Circuit Development at the NSTU file
236 2020-09-28 17:30  Zoom webinar  KAIST Global Forum for Spin and Beyond(Fourth Forum) file
235 2020-10-09 09:00  https://kaist.zoom.us/j/85161896513?pwd=U3pwWFFZaWVRamxDZUR5REhNeVk0UT09  Quantum Many-Body Simulation file
234 2020-10-15 16:00  CAPP Seminar Room #C303, Creation Hall (3F), KAIST Munji Campus  Graphene-based Josephson junction microwave bolometer file
233 2020-10-15 16:00  (https://kaist.zoom.us/j/93997220310)  Towards resource-efficient and fault-tolerant quantum computation with nonclassical light
232 2020-10-15 17:00  https://bit.ly/3ndIiJn  Time crystals, quasicrystals, and time crystal dynamics in the superfluid universe file