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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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공지 2019/09/02 - 12/09  Seminar Room 1501  이호성 박사 (한국표준과학연구원) and etc.  Fall 2019: Physics Colloquium
144 July 25(Thur.),4:00PM  E6-2, #1323  Prof.Bohm-Jung Yang  Band topology of twisted bilayer graphene file
143 July 21 - August 2  E6-2,# 5318  Junmou Chen/Thomas Flacke/Kaoru Hagiwara/Junichi Kanzaki/Chris Kelso/Jeong Han Kim/Kyoungchul Kong/Gabriel Lee/Hye-Sung Lee/Ian Lewis  Challenges and Opportunities in Theoretical Particle Physics 2019 file
142 July 2. 2018 (Monday) 3:00 PM  Seminar Room (C303), Creation Hall (3F), KAIST Munji Campus  Dr. Peter Winter (Argonne National Laboratory)  High Precision Magnetic Field Measurement for the Muon g-2 Experiment file
141 July 13, 2018 at 14:00  Room 5318, KAIST Natural Sciences Lecture Hall(E6).  Prof. Ian Lewis (The University of Kansas, Department of Physics & Astronomy)  Loop Induced Single Top Partner Production and Decay at the LHC
140 July 10 (Wed.), 04:00 PM-  Academic Cltural Complex (E9) 5층 스카이라운지  Prof. Sidney Nagel/Young-Kee Kim  Public Lectures file
139 Jul. 28 (Thu.) 4PM  #1323(E6-2. 1st fl.)  Prof. Johannes Pollanen, Jerry Cowen Chair of Experimental Physics at Michigan State University  Low Dimensional Electrons: On the Road to Hybrid Quantum Systems
138 Jul. 08 (Fri.) 2PM  #1323(E6-2. 1st fl.)  Dr. Junhyun Lee, Harvard University  Electronic quasiparticles in the quantum dimer model
137 Jul. 08 (Fri.) 11:00 AM  #1323(E6-2. 1st fl.)  Dr. Michael Lawler(Binghampton Univ. / Cornell Univ.)  Isostatic magnetism
136 Jul. 07 (Thu.) 2PM  #1323(E6-2. 1st fl.)  Dr. Eun Ah Kim, CORNELL UNIV.  Let there be topological superconductors
135 Jul 3rd, 2019 (Wed)  E6-2, 2501  Kyung Soo Choi  Many-body quantum electrodynamis (QED) with atoms and photons: A new platform for quantum optics" file
134 January 23, 2019  Rm. C303, Creation Hall (3F), Munji Campus  Mikko Mottonen  Ultrasensitive Microwave Bolometer: Opportunity for Axion Detectors file
133 Jan.9 (Wed.), 04:00 PM  E6-2. 2nd fl. #2501  Dr. Heung-Sik Kim  Molecular Mott state in the deficient spinel GaV4S8 file
132 JAN. 7 (Mon), 03:00 PM  E6-2. 2st fl. #2501  Dr. Byoung min Kang  Many-Body Invariants for Multipoles in Higher-Order Topological Insulators file
131 February 21 (Thu.), 16:00 PM  #5313, E6-2  Prof. Diptimoy Ghosh  B-meson charged current anomalies - Theoretical status file
130 Feb. 25 - Jun 3  Rm. 1501 (E6)    Spring 2019: Physics Colloquium file
129 Feb. 12 (Mon), 3:00pm  #C303, (Creation Hall 3F, KAIST Munji Campus)  Dr. Byeongsu Yang, Kamioka Observatory, Univ. of Tokyo  The recent result of XMASS Experiment
128 Feb. 1 (Wed.), 2p.m.  #1323(E6-2. 1st fl.)  Dr. Michihisa Yamamoto, Department of Applied Physics, The University of Tokyo  Quantum electron optics using flying electrons
127 December 5 (Thu.), 16:00 PM  #1323, E6-2  Prof. Soon-Hong Kwon  Subwavelenth Photonic Devices: From Single Photon Sources to Solar Cell file
126 December 3 (Tue.), 4:00 PM  #1323, E6-2  Dr. Jong Mok Ok  Toward Quantum Materials with Correlated Oxides file
125 Dec. 9(Fri), 4p.m.  #1323(E6-2. 1st fl.  Dr. Kun Woo Kim, KIAS  Shift Charge and Spin Photocurrents in Dirac Surface States of Topological Insulator