Project |01 Energy
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Metal-hydride-based hydrogen storage: quantum mechanical method
0. Background: Metals can be utilized to store and release hydrogen through temperature dependent chemical reactions. In general, higher temperatures of metal hydrides increase the release of hydrogen gas. A metal hydride system that could release hydrogen gas at a mild reaction temperature would be required to be utilized in practical applications. However, the main challenge is that most of the metal hydrides and their mixtures slowly release at even high temperatures. To meet DOE guidelines on the reaction temperatures and hydrogen pressures as well as the hydrogen capacity, my research focuses on improving the reaction thermodynamics by reducing the reaction temperatures. A large-scale screening approach combined with the quantum mechanical method is employed in my research. I have interstigated these following topics in particular.
1. Particle size effect: Reducing a metal/metal hydride particle size will affect the metal hydride reaction thermodynamics either positively or negatively depending on the metal type.
2. Identifying promising metal hydride reaction candidates with favorable reaction thermodynamics (mild reaction temperatures) through a large-scale screening approach.
Lithium-ion batteries: quantum mechanical method, genetic algorithm, and deep learning approach
0. Background: Lithium-ion batteries consist of an anode, cathode, electrolyte, and separator. They can be charged and discharged by the lithium ions and electrons travelling between two electrodes supplied with a redox reaction on the electrode/electrolyte interfaces. Lithium-ion batteries need to have high energy, charge, and power densities for the use in practical applications. More importantly, such performance can be only sustained by high operating voltage conditions, which can be provided by high redox potentials. The maximum amount of the theoretically available energy, charge, and power densities can be determined by the operating voltage. My research focuses on fundamentally understanding the redox chemistry of promising electrode materials. Quantum mechanical methods are utilized for the investigation of the redox chemistry. More specifically, I have focused on the following topics.
1. Understanding the correlation between the redox property and structural-electronic properties.
2. Understanding the binding properties of lithium ions with promising electrode material candidates and resultant electronic properties.
3. Employing genetic algorithm and deep learning approach to construct a large-scale database and rapidly identify promising candidates.
Polymer solar cells: combined approaches of experiments and simulations
0. Background: A polymer solar cell is a type of flexible solar cell made with electron donating polymers and electron acceptors to produce electricity from sunlight by the photovoltaic effect. Polymer solar cells usually consist of an electron-blocking layer on top of an indium tin oxide (ITO) conductive glass followed by an active layer (consisting of an electron donor and an electron acceptor), a hole-blocking layer, and metal electrode on top. The polymer solar cell converts light into electricity, by converting a flux of photons (light) into a flux of charged particles (a current). The conversion process mainly follows the three main steps. First, a photon incident on a semiconductor, having an energy that exceeds the semiconductor band gap, excites an electron to an unoccupied state above the band gap, creating an electron-hole pair. Second, the electron-hole pair is subsequently separated over a built-in gradient in the electrochemical potential of the solar cell. Finally, the electron and hole are collected at opposite electrodes and led to recombine after being put to work in an external circuit.
1. Understanding the correlation between the solar cell performance and the microstructural properties of active layers (i.e., the domain sizes of electron donors, surface to volume ratios, and percolation ratios).
2. Understanding the correlation between the solar cell performance and the morphology of active layers.
Project |02 Environment
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Metal-organic frameworks (MOFs): toxic gas capture and gas separations
0. Background: Metal-organic frameworks (MOFs) are porous crystalline compounds consisting of metal oxide clusters coordinately linked by organic ligands generating regular pores. They can be synthesized by the self-assembly of nano-building blocks. MOFs are versatile materials with extremely high functionalized surface area and pore volume. MOFs can be easily tuned for different functionality due to the unlimited combination between the metal oxide clusters and organic ligands which makes MOFs an ideal candidate for a variety of applications such as toxic gas capture, energy storage, gas separations, and catalysis. My research particularly focuses on investigating the binding properties of gas molecules with MOF surfaces in an atomistic scale for selective toxic gas capture under humid conditions and gas separations. Quantum mechanical methods and grand-canonical Monte Carlo (GCMC) simulations are employed for this research. In particular, I have researched the following.
1. Identifying promising functional group candidates for selective toxic gas capture under humid conditions which would be possibly incorporated on MOF ligands.
2. Identifying promising MOFs for gas separations such as propylene/propane, CO2/CH4, CO2/N2, CO2/H2, etc.
Fullerenes
0. Background: Besides cells and MOFs, fullerene also known as bucky ball is another exciting material for the use in energy and environmental applications. For instance, one of the representative fullerene derivatives, PCBM, is a well-known electron acceptor for the polymer solar cell applications. In addition, oxygen molecules photoactivated on photosensitized fullerene surfaces are usually utilized for degrading micropollutants. However, the hydrophobic fullerenes in polar solvents tend to aggregate themselves and thereby lose their photoactivity. A possible solution to avoid this would be to functionalize the fullerenes with relevant polar functional groups. My molecular dynamics (MD) simulation approach allows us to understand the effect of the functionalization on the aggregating properties of the fullerenes. Specially, I have researched the following.
1. Understanding the aggregating properties of the fullerenes with two different functional groups in water solvents.
2. Understanding the time-evolved interaction between oxygen molecules and fullerenes with two different functional groups in water solvents.
Carbon dioxide capture
0. Background: Carbon dioxide is the most well-known greenhouse gas which contributes to global warming. The urgent need for strategies to reduce global atmospheric concentrations of the green house gases has prompted the development of a variety of relevant technologies including conventional chemical absorption, physical absorbents, and solid physical adsorbents. My research focuses on selectively capturing carbon dioxide from CO2-containing gas mixtures using porous crystalline compounds such as metal-organic frameworks, zeolites, and amorphous silica.
1. Metal-organic frameworks with open metal sites.
2. Impurity-embedded amorphous silica materials.
Project |03 Catalysis
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Aldol condensation reactions on alkylamine functionalized amorphous silica surfaces
0. Background: Aldol condensation reaction between 4-nitrobenzaldehyde and acetone can be accelerated by the cooperative catalytic activity between acidic silanols and basic amines on alkyl-amine functionalized amorphous silica surfaces. However, the cooperative catalytic activity is known to be dependent of the alkylamine length. Molecular dynamics (MD) simulations are employed to investigate how the backbone lengths and surface distributions of the incorporated alkyl-amine functional groups can affect the cooperative catalytic activity.
1. First factor: The length and flexibility of the alkyl linker.
2. Second factor: The competition between the amine and silanol to form a hydrogen bond with a reactant.
3. Third factor: The surface distribution of the alkylamines.
국가
대한민국
소속기관
건국대학교 (학교)
연락처
02-450-3741 https://kimkichul78.wixsite.com/kichul
책임자
김기출 kich2018@konkuk.ac.kr