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
191 2018-10-25 16:00  #1323, E6-2  Abelian and non-Abelian dark photons file
190 2018-10-24 10:30  E6-1, Lecture Room 1501(1F)  Photonic integration of next-generation clocks and Hertz-absolute-accuarcy optical frequenncy synthesizers file
189 2018-10-19 10:00  #1323, E6-2  Energy conversion processes during magnetic reconnection in a laboratory plasma file
188 2018-10-18 16:00  #1323, E6-2  Applications of nonlinear optics for condensed matter researches file
187 2018-10-18 10:00  #1323, E6-2  Understanding membrane protein folding using single-molecule force techniques file
186 2018-10-16 10:00  #1323, E6-2  Capturing protein cluster dynamics and gene expression output in live cells file
185 2018-10-15 16:00  #1323, E6-2  Universal properties of macroscopic current-carrying systems file
184 2018-10-12 16:00  E6-2. 1st fl. #1323  Direct observation of a two-dimensional hole gas at oxide interfaces file
183 2018-10-12 14:30  E6-2. 1st fl. #1323  Quantum Advantage in Learning Parity with Noise file
182 2018-10-11 16:00  #1323, E6-2  Dirac electrons in a graphene quasicrystal file
181 2018-10-04 16:00  #1323, E6-2  Engineering light absorption in an ultrathin semiconductor metafilm file
180 2018-09-20 16:00  #1323, E6-2  Toward Cancer Treatment Using Terahertz Radiation: Demethylation of Cancer DNA file
179 2018-09-07 15:00  학술문화관 (E9), 2층 양승택 오디토리움  Recent developments in density functional theory: From new functionals to the nature of the chemical bond file
178 2018-09-05 16:00  #1323, E6-2  Shining a light on fractional excitations file
177 2018-09-04 14:30  E6-2. 2st fl. #2502  Ultrafast time- and angle-resolved photoemission spectroscopy (tr-ARPES) with extreme ultraviolet laser pulses file
176 2018-08-01 11:00  양분순 빌딩 (E16-1) 207호  Future of AI: Is the brain a computer? file
175 2018-07-27 15:00  Room 5318, KAIST Natural Sciences Lecture Hall(E6).  Muon g-2 in the 2HDM and MSSM: comprehensive numerical analysis and absolute maxima file
174 2018-07-27 13:30  #1323, E6-2  Magnetic reversal of artificial spin ice file
173 2018-07-26 14:00  Room 5318, KAIST Natural Sciences Lecture Hall(E6).  Inflation in String Theory and Backreaction file
172 2018-07-13 14:00  Room 5318, KAIST Natural Sciences Lecture Hall(E6).  Loop Induced Single Top Partner Production and Decay at the LHC