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장소 E6-2. 1st fl. #1323 
일시 Apr. 28 (Fri.), 02:30 PM 
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 일시 장소 연사 제목
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106 May 1 (Wed), 4:00 PM  #1323, E6-2  Dr. Sungkyun Choi  Raman and x-ray scattering study on correlated electron systems: two case examples file
105 May 11 (Wed.), 4 PM  E6-2. #1323(1st fl.)  Dr. Bumjoon Kim, Max Planck Institute for Solid State Research  The quest for novel high-temperature superconductors---Prospects and progress in iridates
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103 May 13 (Fri.), 1:30 PM  E6. #1501(1st fl.)  Dr. Young-Woo Son, Dept. of Physics, KIAS  Aperiodic crystals in low dimensions
102 May 16, 2016 (Mon) 4PM  #1323(E6-2, 1st Fl.)  Dr. Daniel Bowring , Fermi National Accelerator Laboratory  Tuning microwave cavities with biased nonlinear dielectrics for axion searches
101 May 19 (Thu) 4PM  #1323(E6-2, 1st fl.)  Dr. Heedeuk Shin, POSTECH  Nonlinear/quantum optical effect in silicon nano-photonics
100 May 19, 2016 (Thur.) 3PM  May 19, 2016 (Thur.) 3PM,  Dr. Michael Betz, CERN  The CERN Resonant WISP Search: Development, Results and Lesson-Learned
99 May 2 (Thu.), 4:00 PM  #1323, E6-2  Prof. Joon Ik Jang  Anomalous optical properties of halide perovskites file
98 May 21 (Tue.), 4:00 PM  #5318, E6-2  임준원 박사  Classification of flat bands according to the band-crossing singularity of Bloch wave functions file
97 May 24 (Fri.), 16:00 PM  #1323, E6-2  Prof. Soonjae Moon  Infrared spectroscopy study on metal-insulator transitions in layered perovskite iridates file
96 May 24 (Tue) 4 PM  E6-2. #1323(1st fl.)  Dr. Euyheon Hwang, SKKU Advanced Institute of Nanotechnology, Sung Kyung Kwan University  Electronic and magnetic properties of 2D transition-metal thiophosphates and tunability of magnetic order with carrier density
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