Jeehye Byun
KAIST
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Publication
Featured researches published by Jeehye Byun.
Chemsuschem | 2017
Hasmukh A. Patel; Jeehye Byun; Cafer T. Yavuz
Excess carbon dioxide (CO2 ) emissions and their inevitable consequences continue to stimulate hard debate and awareness in both academic and public spaces, despite the widespread lack of understanding on what really is needed to capture and store the unwanted CO2 . Of the entire carbon capture and storage (CCS) operation, capture is the most costly process, consisting of nearly 70 % of the price tag. In this tutorial review, CO2 capture science and technology based on adsorbents are described and evaluated in the context of chemistry and methods, after briefly introducing the current status of CO2 emissions. An effective sorbent design is suggested, whereby six checkpoints are expected to be met: cost, capacity, selectivity, stability, recyclability, and fast kinetics.
Nature Communications | 2016
Jeehye Byun; Hasmukh A. Patel; Damien Thirion; Cafer T. Yavuz
Molecular architecture in nanoscale spaces can lead to selective chemical interactions and separation of species with similar sizes and functionality. Substrate specific sorbent chemistry is well known through highly crystalline ordered structures such as zeolites, metal organic frameworks and widely available nanoporous carbons. Size and charge-dependent separation of aqueous molecular contaminants, on the contrary, have not been adequately developed. Here we report a charge-specific size-dependent separation of water-soluble molecules through an ultra-microporous polymeric network that features fluorines as the predominant surface functional groups. Treatment of similarly sized organic molecules with and without charges shows that fluorine interacts with charges favourably. Control experiments using similarly constructed frameworks with or without fluorines verify the fluorine-cation interactions. Lack of a σ-hole for fluorine atoms is suggested to be responsible for this distinct property, and future applications of this discovery, such as desalination and mixed matrix membranes, may be expected to follow.
Journal of Materials Chemistry | 2016
Paul D. Mines; Jeehye Byun; Yuhoon Hwang; Hasmukh A. Patel; Henrik Rasmus Andersen; Cafer T. Yavuz
Nanoscale zero-valent iron (nZVI), with its reductive potentials and wide availability, offers degradative remediation of environmental contaminants. Rapid aggregation and deactivation hinder its application in real-life conditions. Here, we show that by caging nZVI into the micropores of porous networks, in particular Covalent Organic Polymers (COPs), we dramatically improved its stability and adsorption capacity, while still maintaining its reactivity. We probed the nZVI activity by monitoring azo bond reduction and Fenton type degradation of the naphthol blue black azo dye. We found that depending on the wettability of the host COP, the adsorption kinetics and dye degradation capacities changed. The hierarchical porous network of the COP structures enhanced the transport by temporarily holding azo dyes giving enough time and contact for the nZVI to act to break them. nZVI was also found to be more protected from the oxidative conditions since access is gated by the pore openings of COPs.
Journal of Materials Chemistry | 2015
Jeehye Byun; Hasmukh A. Patel; Dong Jun Kim; Chan Ho Jung; Jeong Young Park; Jang Wook Choi; Cafer T. Yavuz
We report a new, surfactant-free method to produce Co3O4 nanocrystals with controlled sizes and high dispersity by caging templation of nanoporous networks. The morphologies of Co3O4 nanoparticles differ from wires to particulates by simply varying solvents. The composites of nanoparticles within network polymers are highly porous and are promising for many applications where accessible surface and aggregation prevention are important. The electrochemical performance of the composites demonstrates superior capacity and cyclic stability at a high current density (∼980 mA h g−1 at the 60th cycle at a current density of 1000 mA g−1). In a catalytic oxidation reaction of carbon monoxide, the composites exhibit a remarkable stability (in excess of 35 hours) and catalytic performance (T100 = 100 °C).
RSC Advances | 2016
Youngho Sihn; Jeehye Byun; Hasmukh A. Patel; Woojin Lee; Cafer T. Yavuz
Seawater contains uranium in surprisingly high quantities that can supply vast energy, if recovered economically. Attempts to design effective sorbents led to the identification of organic functional groups such as amidoximes. Here we report a porous polymer, a polymer of intrinsic microporosity (PIM) with permanent pores that feature amidoxime pendant groups, which is capable of removing more than 90% uranyl [U(VI)] from seawater collected from the Ulleung basin of the East Sea of the Republic of Korea. From this uptake, over 75% was collected in less than six hours, leading to highly feasible field applications. When the seawater was acidified by bubbling CO2 (pH = 5.4), the uptake increased dramatically. Regeneration studies showed full recovery of sorbents and no loss in capture capacity. Our results indicate that successful uranium recovery can be realized by scalable applications of porous polymeric networks and when low cost CO2 is co-administered, uptake can be significantly enhanced.
ACS Applied Materials & Interfaces | 2018
Saravanan Subramanian; Joonho Park; Jeehye Byun; Yousung Jung; Cafer T. Yavuz
Cyclic carbonates as industrial commodities offer a viable nonredox carbon dioxide fixation, and suitable heterogeneous catalysts are vital for their widespread implementation. Here, we report a highly efficient heterogeneous catalyst for CO2 addition to epoxides based on a newly identified active catalytic pocket consisting of pyridine, imine, and phenol moieties. The polymeric, metal-free catalyst derived from this active site converts less-reactive styrene oxide under atmospheric pressure in quantitative yield and selectivity to the corresponding carbonate. The catalyst does not need additives, solvents, metals, or co-catalysts, can be reused at least 10 cycles without the loss of activity, and scaled up easily to a kilogram scale. Density functional theory calculations reveal that the nucleophilicity of pyridine base gets stronger due to the conjugated imines and H-bonding from phenol accelerates the reaction forward by stabilizing the intermediate.
Advanced Functional Materials | 2013
Hasmukh A. Patel; Ferdi Karadas; Jeehye Byun; Joonho Park; Erhan Deniz; Ali Canlier; Yousung Jung; Mert Atilhan; Cafer T. Yavuz
Physical Chemistry Chemical Physics | 2016
Damien Thirion; Vepa Rozyyev; Joonho Park; Jeehye Byun; Yousung Jung; Mert Atilhan; Cafer T. Yavuz
Journal of Nanoparticle Research | 2012
Hasmukh A. Patel; Jeehye Byun; Cafer T. Yavuz
Polymer | 2017
Jeehye Byun; Hasmukh A. Patel; Damien Thirion; Cafer T. Yavuz