Hong Seok Kang,Department of Nano & Adv. Mater., Jeonju University, Korea
Using various first-principles methods, I have been involved in research for designing and understanding electronic, optical, and chemical properties of various low dimensional nanomaterials. Very recently, i.e., in 2017, my interest has moved to the energy applications of those materials such as secondary battery and photocatalytic CO2/H2O decompositions.
In this regard, my purely theoretical papers were selected as cover articles in Journal of Materials Chemistry C (2018) and Journal of Materials Chemistry A (2017).
I have been 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 other Universities in Korea upon their requests for theoretical design of artificial photosynthesis based on semiconductors. I believe that my group is one of a few leaders for semiconductor-based theoretical photosynthesis in Korea.
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, ferroelectricity, and interesting spin texture depending upon the presence or absence of centrosymmetry.[2,3] 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 ofspace 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 nanosheetssynthesized by one-step hydrothermal reactionexhibit excellent stability as well as higher catalytic activity toward the hydrogen evolution reaction.[6-8] Finally, our extensive ab initio molecular dynamics simulations not only reproduce collaborative experimental voltage-charge capacity curves for WS2@graphite and WS2@nitrogen-doped graphitecomposites in lithium ion battery but also gives us a detailed picture on the structural evolution in the charge-discharge process.
1.Debela, T. T.; Kang, H. S. “Phase Polymorphism and Electronic Structures of TeSe2,” J. Mater. Chem. C 2018, 2018, 6, 10109-10378. (Selected as cover article)
2.Shojaei, F.; Hahn, J. R.; Kang, H. S. “Electronic Structure and Photocatalytic Band Offset of Few-layer GeP2,” J. Mater. Chem. A.2017, 5, 22146 (IF=9.931; Selected as Cover article).
3.Debela, T. T.; Kang, H. S. in submission.
4.Shojaei, F.; Kang, H. S. “Partially planar BP3 with high electron mobility as a phosphorene analog,” J. Mater. Chem. Chem. C.2017, 5, 11267.
5.Jung, C. S.; Kim, D.; Cha, S.; Myung, Y.; Shojaei, F.; Abbas, H. G.; Lee, J. A.; Cha, E. H.; Park, J.; Kang, H. S. “Two-dimensional GeAs with a Visible Range Band Gap,” J. Mater. Chem. A.2018, 6, 9089-9098.
6.Kwak, I. H.; Kwon, I. S.; Abbas; Jung, G.; Yoo, Lee, Y.; Debela T. T.; Yoo, S. J.; Kim, J.-G.; Park, J.; Kang, H. S. “Nitrogen-Rich 1T'-MoS2 Layered Nanostructures Using Alkyl Amines for High Catalytic Performance Toward Hydrogen Evolution,” Nanoscale2018, 10, 14726-14735.
7.Kwon, I. K.; Kwak, I. H.; Abbas, H. G.; Lee, Y.; Jung, G.; Yoo, S. J.; Kim, J.-G.; Park, J.; Kang, H. S. “Intercalation of Aromatic Amines for the 2H-1T’ Phase Transition of MoS2 by Experiments and Calculations,” Nanoscale2018, 10, 11349-11356.
8.Kwak, I. H.; Kwon, I. S.; Ghulam Abbas, H.; Jung, G.; Lee, Y.; Park, J.; Kang, H.S. “Stable Methylammonium-Interalated 1T’-MoS2 for Efficient Electrocatalytic Hydrogen Evolution,” J. Mater. Chem. A.2018, 6, 5613.
9.Debela, T. T.; Lim, Y. R.; Seo, H. W.; Kwon, I. S.; Kwak, I. H.; Park, J.; Cho, W. I.; Kang, H. S. “Two-Dimensional WS2@Nitrogen-Doped Graphite for High-Performance Lithium Ion Battery: Experiments and Molecular Dynamics Simulations,” ACS Appl. Mater. Interfaces2018, 10, 37928−37936.