Article
Chemistry, Multidisciplinary
Jungpil Kim, Jang-Woo Han, Yasuhiro Yamada
Summary: The presence of heptagons in graphene nanoflakes influences the XPS profiles, with isolated heptagons shifting peak positions towards higher binding energies and connected heptagons shifting peak positions towards lower binding energies. Additionally, the introduction of heptagons also affects the full width at half-maximum (FWHM) of the XPS profiles, with isolated heptagons leading to a larger increase in FWHM compared to connected heptagons.
Article
Chemistry, Multidisciplinary
Cesar D. D. Mendoza, F. L. Freire Jr
Summary: We investigated the interfacial electronic structure of single-layer graphene on a germanium substrate using UPS and XPS. The graphene was directly synthesized on (110) undoped Ge substrate via CVD. The study identified the main graphitic properties and showed that the Ge substrate affected the electronic structure of the graphene due to electronic coupling. The study also provided important information on the Schottky contact's nature and energy level alignments for potential integration of single-layer graphene on a Ge substrate with CMOS technology.
Article
Materials Science, Ceramics
Zexing Wang, Yunfeng Guo, Jiamao Li
Summary: In this paper, a series of Li2Zn[Ti1-x(Co1/3Nb2/3)x]3O8 ceramics were prepared via the conventional solid-state method. The influences of (Co1/3Nb2/3)4+ complex ions on the phase composition, spectral characteristics, microstructure, and microwave dielectric properties of Li2Zn[Ti1-x(Co1/3Nb2/3)x]3O8 ceramics were systematically studied. The study found that the presence of (Co1/3Nb2/3)4+ content affected the structure, performance, and microwave dielectric properties of Li2Zn[Ti1-x(Co1/3Nb2/3)x]3O8 ceramics.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Richard J. Wilbraham, Elizabeth A. Howett, Colin Boxall, David I. Hambley, Jessica K. Higgins
Summary: This paper presents a detailed study on the chemical and materials characterization of novel Simulated Spent Nuclear Fuels (SIMFuel) that replicate the state of Spent Nuclear Fuel (SNF) discharged from a UK Advanced Gas-cooled Reactor (AGR). The study evaluates the use of XPS, micro-Raman spectroscopy, and XRD in characterizing SIMFuels, and reveals the effects of lanthanide dopants on the UO2 bulk matrix. The findings suggest the presence of U(V) in the UO2 matrix as a means of charge compensation for the incorporation of Ln(III) states, and provide insights into the O/U ratios in SIMFuels.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Chemistry, Physical
Keishi Akada, Seiji Obata, Koichiro Saiki
Summary: In this study, plasma reduction and nitrogen doping were used to modify graphene oxide (GO), resulting in the removal of various functional groups and the introduction of a large amount of nitrogen content. The plasma treatment showed superior properties compared to thermal reduction, and it has the potential to improve device performance and open up new possibilities for GO applications.
Article
Materials Science, Multidisciplinary
Lijing Yang, Wenwen Du, Minghua Wu, Jin He, Guohong Yu, Shuchang Wang, Zhenlun Song
Summary: The corrosion behavior and passivation mechanism of S32750 super-duplex stainless steel exposed in a simulated marine atmosphere were investigated using electrochemical methods, XPS, and SEM. The results showed that the passivation film is composed of two chromium-enriched layers, and the specimen exposed for 24 days exhibited the best corrosion resistance.
Article
Chemistry, Multidisciplinary
Giovanni Chemello, Xenia Knigge, Dmitri Ciornii, Benjamen P. Reed, Andrew J. Pollard, Charles A. Clifford, Tom Howe, Neil Vyas, Vasile-Dan Hodoroaba, Joerg Radnik
Summary: The influence of the morphology of graphene particles on XPS results was studied. It was found that the size of the particles affects the degree of functionalization, and only the combination of XPS and HAXPES allows detection of the functionalization process and provides new insights.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
A. Sankar, S. Valli Chitra, M. Jayashree, M. Parthibavarman, T. Amirthavarshini
Summary: A simple hydrothermal approach was used to fabricate NiO/G nanocomposites, which exhibit hierarchical nanostructures with rich porosity and substantial specific surface area. The nanocomposites show excellent capacitance and cycle performance, making them suitable for high-geared reversible supercapacitors.
DIAMOND AND RELATED MATERIALS
(2022)
Article
Chemistry, Physical
Peng Lin, Yinggan Zhang, Zhou Cui, Rui Xiong, Cuilian Wen, Bo Wu, Qilang Lin, Baisheng Sa
Summary: By using Al4C3 as the precursor and growth environment, graphene nanosheets (GNs) can be efficiently derived from coal-tar pitch. The influence mechanism of Al-O and Al-C clusters on defects in the prepared GNs has been systematically investigated, and it was found that the existence of defects is beneficial for the further adsorption of Al-O and Al-C clusters in GNs.
Article
Chemistry, Physical
Ruo-Yu Wang, Huan-Yu Ji, Xiu-Neng Song, Yong Ma, Chuan-Kui Wang
Summary: By utilizing XPS and NEXAFS spectroscopy methods, different types of C-28 and C-30 isomers were successfully distinguished in the study, with NEXAFS spectroscopy showing better performance in identifying isomers. Additionally, the study also looked into the carbon atoms with different chemical environments in fullerene to determine the sources of characteristic peaks in the total spectra.
Article
Environmental Sciences
Gonzalo Bia, M. Gabriela Garcia, Nicolas J. Cosentino, Laura Borgnino
Summary: This study investigates the abundance, speciation, and dispersion of arsenic (As) in fresh volcanic ash from explosive Patagonian eruptions. Results show that the concentration, speciation, and mobility of As depend on the silica content of source magmas. Arsenic mainly accumulates on the surface of Al-silicate glass in volcanic ash. Atmospheric dispersion simulations reveal the impact of As-bearing ash on groundwater in Patagonia and surrounding areas.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Chemistry, Physical
Yogesh Kumar, S. Tripathi, Mangla Nand, R. Jangir, V. Srihari, A. Das, R. Singh, U. Deshpande, S. N. Jha, A. Arya
Summary: This study investigated the effect of Nd doping on the structural, optical, and electronic properties of lanthanum monazite structure. Pure and Nd-doped LaPO4 powders were prepared and analyzed for their composition, oxidation states, crystal structure, and bandgaps. The results confirmed the successful substitution of Nd in the LaPO4 matrix and provided insights into the local structure using extended X-ray absorption fine structure analysis.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Engineering, Chemical
Kiran, Nagesh Thakur
Summary: The study investigated the structural and microwave absorption properties of MFO@GO and MFO@rGO composites, with MFO@rGO showing the best absorption performance across the entire frequency range with excellent absorption efficiency and bandwidth.
Article
Chemistry, Physical
Mauricio Lopez Luna, Janis Timoshenko, David Kordus, Clara Rettenmaier, See Wee Chee, Adam S. Hoffman, Simon R. Bare, Shamil Shaikhutdinov, Beatriz Roldan Cuenya
Summary: The study investigates the structural and chemical evolution of oxide-supported iron nanoparticles during the activation stages and the CO2 hydrogenation reaction, revealing the preferential formation of iron surface oxides under reaction conditions. The results highlight the important role played by the oxide support in the final structure and composition of nanosized catalysts.
Article
Chemistry, Physical
Irene Ferrari, Alessandro Motta, Robertino Zanoni, Francesca Anna Scaramuzzo, Francesco Amato, Enrique A. Dalchiele, Andrea Giacomo Marrani
Summary: This study investigates the nature and interactions of oxygen functional groups in graphene oxide, providing insights into their electrochemical reduction energetics. Chemical modifications of graphene oxide under controlled electrochemical reduction conditions were studied to understand the contribution of single reactive oxygen functional groups. X-ray photoelectron spectroscopic analysis and theoretical modeling were used to characterize the various carbonaceous species involved in the rich chemistry of graphene oxide.
Article
Polymer Science
Junghoon Yang, Duyoung Choi, Kwang-Seok Kim, Dae Up Kim, Jungpil Kim
Summary: This study successfully synthesized a porous carbon network-Na3V2(PO4)(3) composite using a poly(vinylalcohol) assisted sol-gel method, which overcame the undesirable electrochemical performance caused by the low conductivity of Na3V2(PO4)(3). The composite exhibited excellent kinetic properties and stable cyclic stability.
Article
Materials Science, Multidisciplinary
Ryohei Kawai, Yasuhiro Yamada, Syun Gohda, Satoshi Sato
Summary: In this research, carbon materials with selectively introduced pyridinic nitrogen were synthesized through simple heat treatment, showing that dibenz[c,h]acridine had the highest pyridinic nitrogen content. The study results revealed the reasons behind the high pyridinic nitrogen content through experimental and computational methods.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Chemistry, Physical
Yasuhiro Yamada, Haruki Tanaka, Yosuke Tanaka, Shingo Kubo, Taisei Taguchi, Satoshi Sato
Summary: Selective doping of nitrogen in carbon materials is crucial for enhancing their properties, and this study discovered a simple preparation method without substrates to achieve high pyridinic nitrogen content.
Article
Materials Science, Multidisciplinary
Kumiko Mori, Jungpil Kim, Shingo Kubo, Yasuhiro Yamada
Summary: Nanocarbon materials like graphene and graphene nanoribbons (GNRs) have wide applications, but conventional analysis methods cannot accurately analyze their structures. This study reveals the impact of molecular shapes, sizes, and edge types on peak positions of C1s XPS spectra. By measuring combustion elemental analysis, mass spectrometry, and C1s XPS spectra, the structures of graphene-related materials can be estimated.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Chemistry, Physical
Yasuhiro Yamada, Hayato Sato, Syun Gohda, Taisei Taguchi, Satoshi Sato
Summary: Selective doping of nitrogen in the basal plane of carbon materials without substrates is achieved through simple heat treatment of indolizino[6,5,4,3-ija]quinoline (IQ) at 973 K, resulting in a carbon material with exceptionally high basal-nitrogen content (98-92%). Screening of precursors by molecular dynamic simulation reveals that IQ is the best precursor due to its high stability of C-N bonds, allowing for strategic synthesis.
Article
Chemistry, Physical
Harok Jeong, Sangmin Park, Junghoon Yang, Hye-Min Lee, Sangmin An, Yasuhiro Yamada, Jungpil Kim
Summary: Through simulation and experimental verification of XPS and Raman spectra of zigzag NBs, armchair NBs, and NHs, it was found that they have significant differences in spectral characteristics, so NBs and NHs can be distinguished using XPS and Raman spectroscopy.
Article
Chemistry, Analytical
Duyoung Choi, Ji-Yeon Shim, Sungwoong Choi, Sangmin Park, Harok Jeong, Min -Su Kim, Jungpil Kim, Junghoon Yang
Summary: Alkali vanadium phosphates are promising electrode materials for next-generation ion batteries, but suffer from low electronic conductivity due to phosphate group. In this study, a method of building an effective carbon backbone in alkali vanadium phosphate and carbon composite is proposed to overcome this issue. The carbon backbone not only provides electron pathways but also suppresses particle agglomeration, resulting in efficient ion diffusion and electron transfer. The importance of efficient carbon composite materials for phosphate-based electrode materials is demonstrated by investigating the rhombohedral Li3V2(PO4)3 material as a cathode and anode for lithium-ion batteries, which is a different phase from the well-known monoclinic Li3V2(PO4)3.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Physical
Junghoon Yang, Sungwon Park, Sungsik Lee, Jungpil Kim, Di Huang, Jihyeon Gim, Eungje Lee, Gilseob Kim, Kyusung Park, Yong-Mook Kang, Eunsu Paek, Sang-Don Han
Summary: Further development of electrochemical devices and electric vehicles requires advanced secondary batteries with higher energy density, longer lifetime and enhanced thermal safety. Increasing the cell operating voltage can extend the energy density but may lead to irreversible structural changes, mechanical failure, and parasitic reactions at the electrode-electrolyte interface, causing capacity fading, battery failure, and safety issues.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Chemistry, Physical
Naoto Ohtsubo, Syun Gohda, Kazuma Gotoh, Satoshi Sato, Yasuhiro Yamada
Summary: In this study, it was found that 1,5-naphthyridine had the highest percentage of pyridinic nitrogen (80%) and the highest pyridinic-nitrogen content (12.4 at%) after carbonization at 873 K among six relatively inexpensive precursors with pyridinic N and two-fused rings. Unlike precursors with three-or more-fused rings, 1,5-naphthyridine with two-fused rings retained C-H groups next to pyridinic nitrogen after carbonization, indicating different carbonization mechanisms.
Article
Engineering, Chemical
Sangmin Park, Junghoon Yang, Hye-Min Lee, Young-Seak Lee, Yoon Kyeung Lee, Yasuhiro Yamada, Nodo Lee, Jungpil Kim
Summary: CO2 separation from CO2/CH4 and CO2/H2 mixtures is crucial for H2 production from biogas. Amine-functionalized carbon materials show promising CO2 adsorption performance, but the impact of amine edge positions needs clarification. In this study, the adsorption abilities of 19 graphene nanoflakes (GNFs) with two amines at different edge positions were evaluated. All structures exhibited superior CO2 adsorption compared to CH4 and H2. The CO2 adsorption in GNFs with isolated amines was influenced by charge transfer, while GNFs with adjacent amines showed stronger hydrogen bonding. The presence of methyl groups on the nitrogen hindered CO2 adsorption, and the interaction between amines and CO2 was affected by the presence of H2O.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Taisei Taguchi, Syun Gohda, Kazuma Gotoh, Satoshi Sato, Yasuhiro Yamada
Summary: Selective doping of pyridinic nitrogen in carbon materials was achieved by carbonizing four precursors in the absence of catalysts, resulting in controlled edges and a high percentage of pyridinic nitrogen. Dibenzo[f,h]quinoline (DQ) showed the highest percentage of pyridinic nitrogen due to the formation of gulf edge structures. The study revealed three main factors required for maintaining pyridinic nitrogen in carbon materials with controlled edges.
Article
Nanoscience & Nanotechnology
Sangmin Park, Hye-Min Lee, Young-Seak Lee, Sangmin An, Junghoon Yang, Jungpil Kim
Summary: The CO2 adsorption performance of nanoporous graphene is influenced by the pore size and the type of nitrogen-containing functional groups introduced. Introducing nitrogen groups into graphene with appropriate pore size enhances CO2 adsorption through additional hydrogen bonds and Lewis acid-base interactions. Different nitrogen groups exhibit varying adsorption performances, with decreasing performance as pore size increases. This study emphasizes the importance of introducing nitrogen groups into the inner edges of nanoporous graphene.
ACS APPLIED NANO MATERIALS
(2023)
Article
Polymer Science
Jungpil Kim, Sang-Don Han, Bonwook Koo, Sang-Hyun Lee, Junghoon Yang
Summary: Hard carbons are a promising anode material for sodium-ion batteries, offering high reversible capacity, long cycle life, and low cost. Using cheaper resources like biomass waste as precursors can further improve their advantage in terms of price. This study investigates the structural properties of lignin-derived hard carbons and their impact on electrochemical performance. The results indicate that the production temperature influences the structure and contributes to the overall reversible capacity, rate capability, and cycling stability.
Article
Chemistry, Multidisciplinary
Dong Young Kim, Geonhee Lee, Gil Yong Lee, Jungpil Kim, Kwangu Jeon, Keun Soo Kim
Summary: This study developed a flexible nanocomposite based on polydimethylsiloxane (PDMS), incorporating highly conductive carbon nanotubes and reduced graphene oxide, for high-performance wearable electrocardiogram (ECG) electrodes. The optimized nanocomposite demonstrated uniform surface characteristics and low contact resistance, making it a promising material for expanding the application scope of wearable electronic devices and personal health monitoring systems.
NANOSCALE ADVANCES
(2022)