Article
Chemistry, Analytical
Melih Besir Arvas, Metin Gencten, Yucel Sahin
Summary: The supercapacitor performances of chlorine-containing functional groups-doped graphene-based electrodes synthesized in one step by Yucel's method were investigated for the first time. It was found that doping chlorine-containing functional groups increased the capacitance values and cyclic stability of the electrodes. Increasing the number of cycles during synthesis also led to an increase in the quantity of different molecular functional groups on the electrode surface, resulting in higher areal capacitance of the electrodes.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2022)
Article
Chemistry, Physical
Rabi Khanal, Stephan Irle
Summary: We studied the electron transport within the MXene layers as a function of composition and found a linear relationship between current and voltage at lower potentials in all MXene compositions, indicating their metallic character. However, the conductivity varies among different compositions, with MXenes without surface terminations exhibiting higher conductivity compared to MXenes with surface functionalization. The conductivity also changes with the ratio of -O and -OH on the MXene surface. The surface composition-dependent conductivity of MXenes provides a way to enhance the pseudocapacitive performance.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Yuefei Zhang, Jiemin Wei, Tianyun Liu, Zheng Zhong, Zijiang Luo, Wenjun Xiao, Bing Lv, Xun Zhou, Xuefei Liu
Summary: The graphene-based Van der Waals heterostructures demonstrate great potential for the next generation of photoelectronic nanodevices. ZnSe is found to be a direct semiconductor with high electron mobility and the potential to achieve Schottky to Ohmic contact transformation. Furthermore, under light irradiation, hydrogen and oxygen evolution reactions can occur spontaneously in both acidic and alkaline media. Introducing 3d transition metal atoms significantly reduces the overpotential for the HER process of ZnSe monolayer.
APPLIED SURFACE SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
ZongXiang Wang, Kai Sun, YunPeng Qu, JinYuan Qin, Jiahong Tian, Yaping Li, XiaoFeng Li, Xuai Wang, RunHua Fan
Summary: In this study, titanium nitride/copper calcium titanate (TiN/CCTO) composites were prepared by low-temperature sintering. It was found that when the TiN content exceeded 50 wt%, the composites exhibited negative permittivity, which was attributed to plasma oscillation phenomenon. The AC conduction behavior transitioned from hopping to metal-like with increasing TiN content, and equivalent circuit analysis showed a relationship between positive reactance values and negative permittivity.
Article
Chemistry, Multidisciplinary
Hsin-Yi Liu, Jhao-Ying Wu
Summary: In this study, we used first-principles calculations to theoretically investigate the electronic properties of monolayer GaSe1-xTex alloys. Substituting Se with Te resulted in changes in the geometric structure, charge distribution, and bandgap. These changes were attributed to complex orbital hybridizations. This study highlights the strong dependence of energy bands, spatial charge density, and projected density of states (PDOS) on the concentration of substituted Te.
Article
Materials Science, Multidisciplinary
G. R. Berdiyorov, H. Hamoudi
Summary: Single-molecule quantum transport calculations were performed for biphenyl and phenyl-pyridine molecules asymmetrically anchored to gold electrodes via different edge groups, revealing clear current rectification depending on the edge group of the molecules. Among the considered structures, 4-mercaptophenyl-2,6-dithiolpyridine and 40-mercaptomethyl-4-thiol-biphenyl molecules showed the best diode parameters.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Chemistry, Physical
Ming -Zhu Liu, Xiao-Hong Li, Xing-Hao Cui, Hai-Tao Yan, Rui-Zhou Zhang, Hong -Ling Cui
Summary: Density functional theory was used to investigate the electronic properties, optical properties, and quantum capacitance of bare and functionalized Hf2C and Hf2CT2 MXenes. The introduction of functional groups can improve the stability of the system and modulate its properties and capacitance. The results of this study are important for the design and synthesis of new electrode materials.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Md. Sazzad Hossain, Adolfo I. B. Romo, Seth T. Putnam, Jahan Dawlaty, Veronica Augustyn, Joaquin Rodriguez-Lopez
Summary: Recently, non-Faradaic effects have been found to influence the electronic structure and reactivity of electrode-bound species. In this study, the near-electrode dissociation of N-heterocycle-BF3 Lewis adducts was investigated outside of the redox potential window. Through the use of scanning electrochemical microscopy and confocal fluorescence spectroscopy, a potential-dependent depletion of the adduct near the electrode was detected. This study suggests the presence of an electro-inductive effect on the N-heterocycle, and highlights the potential of electrostatics in field-driven electrocatalytic and electro-synthetic processes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Multidisciplinary Sciences
Liya Thurakkal, Pandurangan Nanjan, Mintu Porel
Summary: The design and synthesis of a versatile class of macrocycles with tunable functional groups and ring size are described. The synthesis approach allows for the production of macrocycles in large quantities and incorporates dithiocarbamates, an important functional group, into the macrocyclic backbone without the use of metals. The physicochemical properties of the macrocycles suggest their potential as drug candidates, as demonstrated by their interaction with a model protein.
SCIENTIFIC REPORTS
(2022)
Article
Energy & Fuels
Ahmed Fatah, Hisham Ben Mahmud, Ziad Bennour, Mofazzal Hossain, Raoof Gholami
Summary: The treatment of shales with supercritical CO2 can alter mineral composition, with an increase in quartz content and decrease in clay and carbonate minerals, providing benefits for long-term CO2 storage. Shales rich in clay are more susceptible to SCCO2 treatment, and the increase in oxygen-containing groups indicates a high adsorption capacity for CO2. The behavior of functional groups post-SCCO2 treatment varies depending on clay content, and quartz-rich shales may be more favorable for CO2 adsorption and storage capacity.
Article
Materials Science, Multidisciplinary
Jehad K. El-Demellawi, Ahmed E. Mansour, Ahmed M. El-Zohry, Mohamed N. Hedhili, Jun Yin, Abdul-Hamid M. Emwas, Partha Maity, Xiangming Xu, Osman M. Bakr, Omar F. Mohammed, Husam N. Alshareef
Summary: Due to their impressive electronic/optoelectronic properties, MXenes have attracted significant attention among researchers in the field of 2D materials. In this study, a surface-termination-independent method was introduced to tune the work function (WF) of Ti3C2Tx MXene through molecular doping. The achieved discrete control over the WF opens up new possibilities for MXene-based devices.
ACS MATERIALS LETTERS
(2022)
Article
Materials Science, Ceramics
Maria A. Gordeeva, Artem P. Tarutin, George N. Starostin, Gennady K. Vdovin, Dmitry A. Medvedev
Summary: In order to create efficient solid oxide fuel cells, suitable functional materials are needed to satisfy the requirements for both fuel and oxygen electrodes. By investigating the properties of La1-xBaxFeO3-delta materials, it was found that La0.6Ba0.4FeO3-delta exhibits the highest electrical conductivity and acceptable thermal expansion behavior, making it suitable as an oxygen electrode. However, the transport properties under reducing atmospheres need improvement for the successful use of La1-xBaxFeO3-delta as symmetrical electrodes.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
William R. Lake, Jinhui Meng, Jahan M. Dawlaty, Tianquan Lian, Sharon Hammes-Schiffer
Summary: Interfacial electric fields have a crucial role in electrocatalysis, and the impact of electrode potential on the vibrational probe frequency can be influenced by the molecular structure and the orientation of the probe.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Engineering, Mechanical
Hongxiang Yu, Haijie Chen, Zhiwen Zheng, Dan Qiao, Dapeng Feng, Zhenbin Gong, Guojun Dong
Summary: This study investigated the influence of functional groups on the tribological performances of lubricants using nine organic compounds as model lubricants. It was found that nonanoic acid with carboxyl showed the best lubrication properties, exhibiting a low friction coefficient and wear rate. Density functional theory (DFT) calculations revealed a positive correlation between low friction coefficient and high adsorption energy. Lubricant molecules with high adsorption energy tended to adsorb on substrates, maintaining a regular molecular brush structure during friction. Additionally, lubricant molecules with high surface energy were more prone to tribochemical reactions, resulting in the formation of a protective tribofilm and reduced wear rate.
Article
Polymer Science
Wee Siang Koh, Liang Fa Khaw, Swee Pin Yeap, Kiat Moon Lee, Jing Yao Sum, Pey Yi Toh
Summary: Polyaniline (PANI) is a conductive polymer that is currently receiving much attention for its applications in flexible supercapacitors and sensors. This study investigated the effects of polymerization time and dopant media on the morphological and electrical properties of PANI synthesized using chemical oxidative polymerization (COP). Extending the polymerization time in hydrochloric acid (HCl) medium resulted in the formation of regular flake- and globule-like structures, while changing the dopant media altered the PANI morphology to different shapes. The resistance of these PANIs could be tuned by changing the dopant media.
POLYMER INTERNATIONAL
(2023)
Article
Chemistry, Multidisciplinary
Do Hyung Cho, Zhou Shen, Yungok Ihm, Dae Han Wi, Chulho Jung, Daewoong Nam, Sangsoo Kim, Sang-Youn Park, Kyung Sook Kim, Daeho Sung, Heemin Lee, Jae-Yong Shin, Junha Hwang, Sung Yun Lee, Su Yong Lee, Sang Woo Han, Do Young Noh, N. Duane Loh, Changyong Song
Summary: The study utilizes X-ray free electron lasers and algorithms for multiple-model 3D imaging to investigate thousands of specimens in a short period of time and identify intrinsic heterogeneities with 3D structures. Quantitative analysis reveals various features of the 3D structures, providing quantitative information at the nanoscale.
Article
Chemistry, Physical
Young-Kwan Kim, Young-Jin Kim, Junbeom Park, Sang Woo Han, Seung Min Kim
Summary: This study explores the effects of purification on the mechanical and electrical properties of carbon nanotube (CNT) fibers, as well as the efficiencies of various surface modifications. Purification enhances the specific tensile strength and electrical conductivity of CNT fibers, and improves the efficiencies of surface modifications. Au nanoparticles grown on purified CNT fibers are denser, resulting in improved mechanical and physical properties for potential applications as fibrous catalysts.
Article
Chemistry, Analytical
Dionisio Del Orbe, Hyunwoo Yang, Incheol Cho, Jaeho Park, Jungrak Choi, Sang Woo Han, Inkyu Park
Summary: The thermocatalytic hydrogen gas sensor fabricated using electrodeposition of pseudo-porous networks of Pt crystals shows high sensitivity and selectivity, with low power consumption and fast response speed, making it suitable for industrial and personalized applications.
SENSORS AND ACTUATORS B-CHEMICAL
(2021)
Article
Biophysics
Seung Jun Lee, Hyeyeon Lee, Talshyn Begildayeva, Yiseul Yu, Jayaraman Theerthagiri, Yonghyeon Kim, Young Wook Lee, Sang Woo Han, Myong Yong Choi
Summary: Gold nanoparticles (Au NPs) were synthesized by pulsed laser ablation (PLA) in a mixed-phase solvent, and the surface-enhanced Raman scattering (SERS) activity was strongly dependent on the nanogaps between particles. Controlling the nanogaps by changing the amount of graphitic carbon (GC) layers resulted in significant SERS enhancement in Au NPs prepared in 30% acetonitrile.
BIOSENSORS & BIOELECTRONICS
(2022)
Review
Chemistry, Multidisciplinary
Younghyun Wy, Hayoon Jung, Jong Wook Hong, Sang Woo Han
Summary: This article reviews recent developments in the synthesis of gold nanostructures with multiple hot spots and Au-based heterostructures for plasmon-induced sensing and photocatalysis. Gold nanostructures with multiple hot spots exhibit enhanced molecular sensing and surface-enhanced Raman scattering performance, while Au-based heterostructures have shown great promise in photocatalytic reactions. The rational design of these nanostructures can lead to enhanced sensing and photocatalysis.
ACCOUNTS OF CHEMICAL RESEARCH
(2022)
Article
Chemistry, Multidisciplinary
Bon Seung Goo, Kyungrok Ham, Yeji Han, Seunghoon Lee, Hayoon Jung, Yongmin Kwon, Youngmin Kim, Jong Wook Hong, Sang Woo Han
Summary: This study developed a novel approach to investigate the intrinsic catalytic reactivity of edge and terrace atoms in nanocrystal catalysts. By comparing the catalytic behaviors of edge-covered Pd NCs with those of pristine Pd NCs, researchers successfully decoupled the activity of edge and {110}-plane atoms.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Mrinal Kanti Kabiraz, Bibi Ruqia, Jeonghyeon Kim, Haesol Kim, Hee Jin Kim, Youngmin Hong, Mi Ji Kim, Young Kyoung Kim, Chan Kim, Won-Jae Lee, Wonkyun Lee, Gyo Hyun Hwang, Hyeong Cheol Ri, Hionsuck Baik, Hyung-Suk Oh, Young Wook Lee, Lei Gao, Hongwen Huang, Seung Min Paek, Youn-Jung Jo, Chang Hyuck Choi, Sang Woo Han, Sang-Il Choi
Summary: Grain boundaries have adverse effects on bimetallic platinum-cobalt (Pt-Co) nanocatalysts in the oxygen reduction reaction (ORR), as they promote cobalt leaching and cause changes in the surface composition, leading to reduced catalytic activity.
Article
Multidisciplinary Sciences
Hyesung Jo, Dae Han Wi, Taegu Lee, Yongmin Kwon, Chaehwa Jeong, Juhyeok Lee, Hionsuck Baik, Alexander J. Pattison, Wolfgang Theis, Colin Ophus, Peter Ercius, Yea-Lee Lee, Seunghwa Ryu, Sang Woo Han, Yongsoo Yang
Summary: This study determines the 3D atomic structure of Pd@Pt core-shell nanoparticles and reveals the surface-interface strain relations. The strain distribution shows shape-dependent anisotropy, and the surface oxygen reduction reaction activity is predicted. These findings have important implications for understanding the structure-property relationships in strain-engineered core-shell systems and exerting direct control over catalytic properties.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Hojin Ahn, Hochan Ahn, Jihun An, Hyungjun Kim, Jong Wook Hong, Sang Woo Han
Summary: We have developed a synthesis method to study the surface strain-catalytic activity relationship of Pt{110} facets using rhombic dodecahedral Pd@Pt core-shell nanocrystals. The electrocatalytic activity of the Pd@Pt nanocrystals decreased as the Pt shells became thinner and applied more in-plane compressive surface strain. Density functional theory calculations revealed the characteristic strain-activity relationship of Pt{110} facets.
Article
Chemistry, Multidisciplinary
Younghyun Wy, Jaesung Park, Sung Huh, Hyuksang Kwon, Bon Seung Goo, Jung Young Jung, Sang Woo Han
Summary: A surface-enhanced Raman spectroscopy (SERS)-based in situ analytical tool is reported for the sensitive and rapid monitoring of hydrogen transport through graphene. The reduction of a Raman dye by hydrogen species transferred through graphene is monitored with SERS. The experimental results demonstrate the high sensitivity and rapid detection ability of SERS for the analysis of the hydrogen transport properties of graphene.
Article
Chemistry, Physical
Dae Han Wi, Hyunwoo Yang, Yonghyeon Kim, Hojin Ahn, Jong Wook Hong, Sang Woo Han
Summary: In this study, ternary heteronanocrystals composed of two different plasmonic metal nanocrystals (hexoctahedral Au and spherical Ag nanocrystals) and a semiconductor (Cu2O) were synthesized. These ternary heteronanocrystals exhibited enhanced photocatalytic H-2 evolution performance over a wide range of visible-light wavelengths compared to binary and monomeric counterparts. The improved photocatalytic function can be attributed to the combination of the distinct plasmonic properties of the two different metal nanocrystals with the semiconductor, enabling the promotion of both plasmon-induced charge and energy transfer processes.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Chemistry, Multidisciplinary
Hayoon Jung, Yongmin Kwon, Yonghyeon Kim, Hochan Ahn, Hojin Ahn, Younghyun Wy, Sang Woo Han
Summary: Conjugating plasmonic metals with catalytically active materials with controlled configurations can harness their light energy harvesting ability in catalysis. Herein, a well-defined core-shell nanostructure composed of an octahedral Au nanocrystal core and a PdPt alloy shell is presented as a bifunctional energy conversion platform for plasmon-enhanced electrocatalysis. The prepared Au@PdPt core-shell nanostructures exhibited significant enhancements in electrocatalytic activity for methanol oxidation and oxygen reduction reactions under visible-light irradiation. Our experimental and computational studies revealed that the electronic hybridization of Pd and Pt allows the alloy material to have a large imaginary dielectric function, which can efficiently induce the shell-biased distribution of plasmon energy upon illumination and, hence, its relaxation at the catalytically active region to promote electrocatalysis.
Article
Chemistry, Multidisciplinary
Yonghyeon Kim, Dae Han Wi, Jong Wook Hong, Sang Woo Han
Summary: Plasmonic metal-semiconductor hybrid nanostructures consisting of core-satellite assemblies and TiO2 show adjustable photocatalytic properties by controlling the distance between the Au nanocrystals, and exhibit high activity under visible to near-infrared light irradiation.
Review
Chemistry, Physical
Youngjoo Whang, Yongmin Kwon, Hojin Ahn, Jong Wook Hong, Sang Woo Han
Summary: This review highlights the importance of developing nanocrystal catalysts and presents two major strategies for engineering the surface structure of nanocrystals: controlling the atomic arrangement and composition. These methods enable efficient electrochemical reactions to be achieved.
CHEMICAL PHYSICS REVIEWS
(2023)
Article
Nanoscience & Nanotechnology
Dionisio Del Orbe Henriquez, Incheol Cho, Hyunwoo Yang, Jungrak Choi, Mingu Kang, Ki Soo Chang, Chan Bae Jeong, Sang Woo Han, Inkyu Park
Summary: Hollow, microrod-like Pt nanostructures are synthesized on a small, suspended microheater platform as the catalytic layer for a low-power hydrogen sensor. The highly localized Pt nanostructures and suspended microheater contribute to the sensor's high sensitivity, fast response and recovery speeds, as well as low-power consumption.
ACS APPLIED NANO MATERIALS
(2021)
