With the recent emergence of future mobility developments such as Urban Air Mobility (UAM), there has been an increasing interest in the development of materials suitable for these advancements. What might the specific requirements be for materials used in future mobility? Firstly, lightweight materials will be...
* This seminar will be held in Korean. ...
Electro-Mechanically Responsive Ionoelastomer Heterojunctions Hyeong Jun Kim Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, South Korea Soft solids capable of conducting ions offer promise for the design of entirely new classes of highly deformable and bio-inspired devices. While resistive and capacitive ionic circuit elements are...
When shape optimization of engineering objects is conducted in the aerodynamic prospective, it is necessary to examine objects’ performance at various designs. One of the most widely used shape design methods in this purpose is to parameterize the given shape (frequently called the baseline design or...
* This seminar will be held in Korean. ...
Electrocatalysis on Atom-Precise Metal Nanoclusters Dongil Lee Yonsei University, Seoul 03722, Republic of Korea dongil@yonsei.ac.kr Accurate identification of active sites is critical for elucidating catalytic reaction mechanisms and developing highly efficient and selective electrocatalysts. In the first part of my presentation, I will talk about atomic-level identification of active sites for the electrochemical CO2 reduction reaction (CO2RR) using atomically well-defined metal nanoclusters (NCs) Au25(SR)18 and Ag25(SR)18 (SR = thiolate). While both NCs produced CO as a main CO2RR product, the Au25 NC exhibited a significantly higher CO2RR activity than the Ag25 NC. Theoretical and operando studies revealed that the CO2RR limiting potential for the Au25 NC was significantly smaller than that for the Ag25 NC, while both NCs contained the partially dethiolated metal sites as the active sites. Active-site engineering was performed by replacing the Ag12(SR)18 shell of the Ag25(SR)18 NC with the Au12(SR)18 shell to generate a core-shell AuAg12@Au12(SR)18 NC, which exhibited stable CO2-to-CO electroreduction at a commercially relevant current density of 200 mA/cm2 and a full-cell potential of 2.1 V in a zero-gap CO2 electrolyzer. In the second part, I will discuss the effects of metal doping and ligand engineering on the hydrogen evolution reaction (HER) activities of gold and silver NCs. Studies of electrocatalysis by the rationally engineered NCs provide many important design principles for the development of electrocatalysts with tailored structure and adsorption energy. These principles are illustrated with NC-based electrocatalysts for water splitting and CO2 conversion. ...
Observing atmospheric chemical components from space: applications to air pollution and climate studies Rokjin Park School of Earth and Environmental Sciences, Seoul National University Observing the earth’s radiances from space can be an effective approach to monitoring atmospheric chemical composition, which changes cause various environmental issues, including local air pollution and global climate changes. Low-orbiting satellites have been widely used to provide global-scale information and are often limited by their infrequent overpass times, which could be hampered by clouds. Since the first geostationary environmental monitoring spectrometer (GEMS) has been successfully launched by the Korean Ministry of Environment, we are in a new era of satellite observations. This talk mainly focuses on developing GEMS retrieval algorithms to observe volatile organic compounds (VOCs) column concentrations in East Asia and the first evaluation of GEMS VOCs observations. Furthermore, I will talk about some issues related to greenhouse gas concentrations whose emissions are highly uncertain, which are diagnosed by satellite observations....
