Prof. Hong Seok Kang
Jeonju University, Republic of Korea
Title: Electronic Structures and Energy Applications of Layered Materials
Abstract:
Based on a combination of various first-principles methods, we propose various kinds of layered materials. One is tetragonal GeP2, which has optimal band offset for photocatalyzed CO2 decomposition at wide pH range. The second one TeSe2, which exhibits phase polymorphism and interesting spin texture depending upon the presence or absence of centrosymmetry. Others are orthorhombic BP3 and hexagonal GeX (X=P,As), which are charactierized by high carrier mobility and high interlayer Li diffusion rate, respectively. I also describe my recent collaborations with an experimental group. First, combined experimental and theoretical effort is described for an efficient photoelectrochemical (PEC) water splitting of p-GeAs/n-Si heterojunction based on the band alignment, buildup of space charge in the junction, and the band bending of the n-Si at the electrolyte interface. Second, our extensive DFT calculation complemented by analyses of charge transfer, band structure analyses, and Volmer-Heyrovsky reactions give a deep insight into our experimental results, which has shown that the 1T'-phase guest-intercalated MoS2 nanosheets synthesized by one-step hydrothermal reaction exhibit excellent stability as well as higher catalytic activity toward the hydrogen evolution reaction. Finally, our extensive ab initio molecular dynamics simulations not only reproduce collaborative experimental voltage-charge capacity curves for WS2@graphite and WS2@nitrogen-doped graphite composites in lithium ion battery but also gives us a detailed picture on the structural evolution in the charge-discharge process.
Biography:
I
was graduated from the Department of Chemistry, Seoul National University.
After that, I got my Ph. D from the Department of Chemistry, KAIST in 1986,
Korea. Using various first-principles methods, I have recently been involved in
research for designing and understanding electronic and chemical properties of various
low dimensional nanomaterials. Although my research in this area has been
activated relatively late due to the change of major field, I have recently published many papers in ACS Nano, J. Am. Chem. Soc, and J. Mater. Chem. A & C, etc as
the corresponding author. In 2008, I was awarded Ipjae Physical Chemistry Prize from the Division of Physical Chemistry, Korean Chemical Society for
outstanding research. In 2018, I was also awarded an excellent research prize from the vice prime minister of Government of Korea.
From
2017, my interest has moved to the energy applications of those
materials in secondary battery and photocatalytic CO2/H2O
decompositions. For that
purpose, I have been actively involved in collaboration with a highly
sophicated scientist in Korea University. In addition we are at the stage of
establishing new collaborations with another highly sophiscated scientists in Korea.
Very recently, my purely theoretical papers were selected as cover articles in Journal of Materials Chemistry C (2018) and Journal of Materials Chemistry A (2017).