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301. Atomic-scale combination of germanium-zinc nanofibers for structural and electrochemical evolution

Author

Song, Gyujin, primary, Cheong, Jun Young, additional, Kim, Chanhoon, additional, Luo, Langli, additional, Hwang, Chihyun, additional, Choi, Sungho, additional, Ryu, Jaegeon, additional, Kim, Sungho, additional, Song, Woo-Jin, additional, Song, Hyun-Kon, additional, Wang, Chongmin, additional, Kim, Il-Doo, additional, and Park, Soojin, additional

Published
2019
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335. A hierarchical carbon nanotube-loaded glass-filter composite paper interlayer with outstanding electrolyte uptake properties for high-performance lithium–sulphur batteries

Author

Id Kim Il-Doo Kim and Cl Lee Cho-Long Lee

Subjects
Materials science, Sonication, Composite number, chemistry.chemical_element, Carbon nanotube, Electrolyte, Sulfur, law.invention, Filter (aquarium), chemistry, law, General Materials Science, Lithium, Composite material
Abstract

A hierarchical CNT-loaded GF composite paper interlayer was fabricated by a sonication method. In this study, the GF paper offers outstanding electrolyte uptake, which is essential for preserving dissolved polysulphides, and the CNT networks provide a fast electron pathway for insulating the active materials. The GF/CNT interlayer-loaded Li-S cell exhibited a high capacity and long-term cycling performance.

Published
2015

337. Unravelling high volumetric capacity of Co3O4 nanograin-interconnected secondary particles for lithium-ion battery anodes.

Author

Chang, Joon Ha, Cheong, Jun Young, Shim, Yoonsu, Park, Jae Yeol, Kim, Sung Joo, Lee, Jiyoung, Lee, Ho Jun, Lim, Haeseong, Liu, Weiyan, Zhang, Qing, Terasaki, Osamu, Lee, Chan-Woo, Kim, Il-Doo, and Yuk, Jong Min

Abstract

The development of high-tap density electrode materials that can simultaneously achieve stable electrochemical performance at high charge/discharge rates is critically in demand. Herein, we propose an innovative material design that can offer high tap density and excellent rate capabilities by using Co3O4 nanograin-interconnected secondary particles (Co3O4 NISPs). By taking advantage of a conversion reaction that forms Co from Co3O4, we demonstrate that Co3O4 NISPs are capable of creating a number of metallic Co sites along with a number of vacant sites in-between nanograins. Electrochemical tests that reveal reduced internal cell resistance and more accessible Li diffusion are achieved for Co3O4 NISPs compared with Co3O4 nanoparticles (NPs). Additionally, in situ X-ray diffraction (XRD) analyses, electron energy loss spectroscopy (EELS), and density functional theory (DFT) calculations reveal that the insulating intermediate product (CoO) is formed less on the Co3O4 NISPs, which can enhance the charge transport. Attributed to the combinatorial effects of Co3O4 nanograins that form metallic Co upon conversion and secondary particles that enable high tap density, Co3O4 NISPs show the most outstanding volumetric capacity (2167.3 mA h cm−3 at a current density of 500 mA g−1) among spinel-type metal oxide electrode materials researched so far. [ABSTRACT FROM AUTHOR]

Published
2021
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338. CD36 deficiency reduces chronic BBB dysfunction and scar formation and improves activity, hedonic and memory deficits in ischemic stroke.

Author

Balkaya, Mustafa, Kim, Il-doo, Shakil, Faariah, and Cho, Sunghee

Abstract

Ameliorating blood–brain barrier disruption and altering scar formation dynamics are potential strategies that may improve post-stroke recovery. CD36 is a class B scavenger receptor that plays a role in innate immunity, inflammation and vascular dysfunction and regulates post-stroke injury, neovascularization, reactive astrogliosis and scar formation. By subjecting WT and CD36KO mice to different MCAo occlusion durations to generate comparable acute lesion sizes, we addressed the role of CD36 in BBB dysfunction, scar formation and recovery. The majority of stroke recovery studies primarily focus on motor function. Here, we employed an extensive behavioral test arsenal to evaluate psychological and cognitive endpoints. While not evident during the acute phase, CD36 deficient mice displayed significantly attenuated BBB leakage and scar formation at three months after stroke compared to wild-type littermates. Assessment of motor (open field, rotarod), anxiety (plus maze, light-dark box), depression (forced swim, sucrose preference) and memory tests (water maze) revealed that CD36 deficiency ameliorated stroke-induced behavioral impairments in activity, hedonic responses and spatial learning and strategy switching. Our findings indicate that CD36 contributes to stroke-induced BBB dysfunction and scar formation in an injury-independent manner, as well as to the chronic motor and neurophysiological deficits in chronic stroke. [ABSTRACT FROM AUTHOR]

Published
2021
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341. Quality Characteristics and Antioxidant Activity of Unripe Peach (Prunus Persica L. Batsch) Extracts with Distilled Water Coupled with Ultrasonication and Prethanol-A.

Author

Jung, Kyung-Mi, Kim, San-Yeong, Lee, Gi-Woo, Kim, Il-Doo, Park, Yong-Sung, Dhungana, Sanjeev Kumar, Kim, Jeong-Ho, and Shin, Dong-Hyun

Subjects
PEACH, DISTILLED water, PRUNUS, SONICATION, PLANT health, EXTRACTS
Abstract

Peach, an important fruit crop for its health benefits, is grown in different parts of the world. A huge amount of unripe peaches, which are obtained during fruit thinning or as natural fruit drop, are generally discarded as waste. It would be very fortunate for the fruit growers if the thinned out or naturally dropped peaches could be utilized as valuable resources. The objective of this study was to evaluate the quality characteristics and antioxidant potential of unripe peach of two cultivars, Changhowon Hwangdo and Kanoiwa Hakuto extracted with distilled water coupled with ultrasonication or prethanol-A, an ethanol-based food preservative. The physicochemical characteristics (pH, titratable acidity, soluble solid content, color value, mineral content, DPPH radical scavenging potential, and total phenol content) of the extracts significantly varied with cultivar, extracting solvent and/or their interaction. The results of this experiment showed that unripe peach fruits could be used as an inexpensive source of antioxidants and phenolic compounds, which could even be extracted with distilled water, and possess a big potential to be used in food and cosmetic industries. [ABSTRACT FROM AUTHOR]

Published
2020
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342. Single-Atom Catalysts in Conductive Metal–Organic Frameworks: Enabling Reversible Gas Sensing at Room Temperature

Author

Park, Chungseong, Shin, Hamin, Jeon, Mingyu, Cho, Su-Ho, Kim, Jihan, and Kim, Il-Doo

Abstract

Conductive metal–organic frameworks (cMOFs) offer high porosity and electrical conductivity simultaneously, making them ideal for application in chemiresistive sensors. Recently, incorporating foreign elements such as catalytic nanoparticles into cMOFs has become a typical strategy to enhance their sensing properties. However, this approach has led to critical challenges, such as pore blockage that impedes gas diffusion, as well as limited improvement in reversibility. Herein, single-atom catalyst (SAC)-functionalized cMOF is presented as a robust solution to the current limitations. Facile functionalization of SACs in a cMOF can be achieved through electrochemical deposition of metal precursors. As a proof of concept, a Pd SAC-functionalized cMOF is synthesized. The Pd SACs are stabilized at the interplanar sites of cMOF with Pd–N4coordination while preserving the porosity of the MOF matrix. Notably, the microenvironment created by Pd SACs prevents irreversible structural distortion of cMOFs and facilitates a reversible charge transfer with NO2. Consequently, the cMOF exhibits a fully recoverable NO2response, which was not previously attainable with the nanoparticle functionalization. Additionally, with the combination of preserved porosity for gas diffusion, it demonstrates the fastest level of response and recovery speed compared to other 2D-cMOFs of this class.

Published
2024
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343. Cobalt-Doped Ceria Sensitizer Effects on Metal Oxide Nanofibers: Heightened Surface Reactivity for High-Performing Chemiresistive Sensors

Author

Baek, Jong Won, Han, Seunghee, Lee, Sang Eun, Ahn, Jaewan, Park, Chungseong, Nam, Jong Seok, Kim, Yoon Hwa, Shin, Euichul, Kim, Minhyun, Jang, Ji-Soo, Kim, Jihan, Park, Hee Jung, and Kim, Il-Doo

Abstract

Chemiresistive gas sensors based on semiconducting metal oxides typically rely on noble metal catalysts to enhance their sensitivity and selectivity. However, noble metal catalysts have several drawbacks for practical utilization, including their high cost, their propensity for spontaneous agglomeration, and poisoning effects with certain types of gases. As such, in the interest of commercializing the chemiresistive gas sensor technology, we propose an alternative design for a noble-metal-free sensing material through the case study of Co-doped ceria (Co–CeO2) catalysts embedded in a SnO2matrix. In this investigation, we utilized electrospinning and subsequent calcination to prepare Co–CeO2catalyst nanoparticles integrated with SnO2nanofibers (NFs) with uniform particle distribution and particle size regulation down to the sub-2 nm regime. The resulting Co–CeO2@SnO2NFs exhibited superior gas sensing characteristics toward isoprene (C5H8) gas, a significant biomarker for monitoring the onset of various diseases through breath diagnostics. In particular, we identified that the Co–CeO2catalysts, owing to the transition metal doping, facilitated the spillover of chemisorbed oxygen species to the SnO2sensing body. This resulting in the sensor having a 27.4-fold higher response toward 5 ppm of C5H8(compared to pristine SnO2), exceptionally high selectivity, and a low detection limit of 100 ppb. The sensor also exhibited high stability for prolonged response–recovery cycles, attesting to the strong anchoring of Co–CeO2catalysts in the SnO2matrix. Based on our findings, the transition metal-doped metal oxide catalysts, such as Co–CeO2, demonstrate strong potential to completely replace noble metal catalysts, thereby advancing the development of the commercially viable chemiresistive gas sensors free from noble metals, capable of detecting target gases at sub-ppm levels.

Published
2024
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344. Unmatched Redox Activity of the Palladium-Doped Indium Oxide Oxygen Carrier for Low-Temperature CO2Splitting

Author

Park, Seyeon, Oh, DongHwan, Jang, Myeong Gon, Seo, Hwakyoung, Kim, Uisik, Ahn, Jaewan, Choi, Yoonseok, Shin, Dongjae, Han, Jeong Woo, Jung, WooChul, and Kim, Il-Doo

Abstract

The chemical conversion of CO2into value-added products is the key technology to realize a carbon-neutral society. One representative example of such conversion is the reverse water–gas shift reaction, which produces CO from CO2. However, the activity is insufficient at ambient pressure and lower temperatures (<600 °C), making it a highly energy-intensive and impractical process. Herein, we report indium oxide nanofibers modified with palladium catalysts that exhibit significantly potent redox activities toward the reduction of CO2splitting via chemical looping. In particular, we uncover that the doped palladium cations are selectively reduced and precipitated onto the host oxide surface as metallic nanoparticles. These catalytic gems formed operando make In2O3lattice oxygen more redox-active in H2and CO2environments. As a result, the composite nanofiber catalysts demonstrate the reverse water–gas shift reaction via chemical looping at record-low temperatures (≤350 °C), while also imparting high activities (CO2conversion: 45%). Altogether, our findings expand the viability of CO2splitting at lower temperatures and provide design principles for indium oxide-based catalysts for CO2conversion.

Published
2024
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345. Three-Dimensional Nanofibrous Air Electrode Assembled With Carbon Nanotubes-Bridged Hollow Fe2O3Nanoparticles for High-Performance Lithium–Oxygen Batteries

Author

Jung, Ji-Won, Jang, Ji-Soo, Yun, Tae Gwang, Yoon, Ki Ro, and Kim, Il-Doo

Abstract

Lithium–oxygen batteries have been considered as one of the most viable energy source options for electric vehicles due to their high energy density. However, they are still faced with technical challenges, such as low round-trip efficiency and short cycle life, which mainly originate from the cathode part of the battery. In this work, we designed a three-dimensional nanofibrous air electrode consisted of hierarchically structured carbon nanotube-bridged hollow Fe2O3nanoparticles (H-Fe2O3/CNT NFs). Composite nanofibers consisted of hollow Fe2O3NPs anchored by multiple CNTs offered enhanced catalytic sites (interconnected hollow Fe2O3NPs) and fast charge-transport highway (bridged CNTs) for facile formation and decomposition of Li2O2, leading to outstanding cell performance: (1) Swagelok cell exhibited highly reversible cycling characteristics for 250 cycles with a fixed capacity of 1000 mAh g–1at a current density of 500 mA g–1. (2) A module composed of two pouch-type cells stably powered an light-emitting diode lamp operated at 5.0 V.

Published
2024
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349. A Critical Review on Functionalization of Air‐Cathodes for Nonaqueous Li–O2 Batteries.

Author

Balaish, Moran, Jung, Ji‐Won, Kim, Il‐Doo, and Ein‐Eli, Yair

Subjects
LITHIUM-air batteries, SURFACE chemistry, ELECTRIC batteries, CHEMICAL stability, SURFACE structure, NONAQUEOUS phase liquids, NITRIDES, METALLIC oxides
Abstract

This review reports on the most updated technological aspects of Li–air battery cathode materials. It provides the reader with recent developments, alongside critical views. The requirements for air‐cathodes, as well as the classification and characterization of carbon‐based and carbon‐free air cathodes, are listed. The effects of two major substituent groups of materials, namely carbon and advanced materials (metals, metal‐oxides, metal‐carbides, and metal‐nitrides) aimed at replacing carbon, are discussed in terms of their chemical and electrochemical stability. The report covers aspects of surface chemistry and structure influence on the electrolyte and discharge products stability. The review also reports on the efforts to suppress side reactions and deterioration of the polymeric binders (if a composite electrode is being considered). This is recognized as a means to enhance Li–air battery performance. The report concludes with an outlook and perspective, providing the readers with some insight on other factors and their impact on the long road toward a viable air‐cathode suitable for Li–air battery operations. [ABSTRACT FROM AUTHOR]

Published
2020
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