Reevaluation of the Suitability of Xe Nuclear Magnetic Resonance Spectroscopy for Pore Size Determination in Porous Carbon Materials.

Xenon isotope nuclear magnetic resonance (Xe-NMR) spectroscopy has been widely used to evaluate the pore structure of materials. However, determining how to apply this technique to investigate porous carbon materials is sometimes challenging, partly due to the structural disorder and heterogeneity of the surface properties of these materials, and partly due to the lack of reliable methods for controlling and assessing the density of adsorbed Xe. In this study, we designed and constructed a temperature- and pressure-controllable Xe-NMR system to evaluate the interaction between activated carbon (AC) and adsorbed Xe molecules.

Qualitative Analysis of Nitrogen and Sulfur Compounds in Vacuum Gas Oils via Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry.

Analysis of the heavy fractions in crude oil has been important in petroleum industries. It is well known that heavy fractions such as vacuum gas oils (VGOs) include heteroatoms, of which sulfur and nitrogen are often characterized in many cases. We conducted research regarding the molecular species analysis of VGOs.

Effective Removal of Acetaldehyde Using Piperazine/Nitric Acid Co-Impregnated Bead-Type Activated Carbon.

Acetaldehyde (CHCHO) in the atmosphere is associated with adverse health effects. Among the various options for use in removing CHCHO, adsorption is often employed because of its convenient application and economical processes, particularly when using activated carbon. In previous studies, the surface of activated carbon has been modified with amines to remove CHCHO from the atmosphere via adsorption.

Study on the applicability of pressurized physically activated carbon as an adsorbent in adsorption heat pumps.

Activated carbon is a suitable adsorbent for adsorption heat pumps (AHPs) with ethanol refrigerants. Although chemically activated carbon with highly developed pore structures exhibits good ethanol adsorption, the associated high production costs inhibit its practical application as an AHP adsorbent. Moreover, although physical activation can produce inexpensive activated carbon, the limited pore development limits the ethanol uptake.

Preparation of Isotropic Carbon Fibers from Kerosene-Purified Coal Tar Pitch by Co-Carbonization with Pyrolysis Fuel Oil.

An inexpensive and general-purpose carbon fiber was prepared using coal tar pitch. In contrast to the solvent extraction process employing expensive solvents, a low-cost centrifugal separation method facilitated the reduction of loss due to the pitch purification and an overall yield increase. The coal tar pitch purified by centrifugation and subsequently co-carbonized with pyrolysis fuel oil improved in spinnability.

Highly Chlorinated Polyvinyl Chloride as a Novel Precursor for Fibrous Carbon Material.

Pure, highly chlorinated polyvinyl chloride (CPVC), with a 63 wt % of chlorine, showed a unique-thermal-pyrolytic-phenomenon that meant it could be converted to carbon material through solid-phase carbonisation rather than liquid-phase carbonisation. The CPVC began to decompose at 270 °C, with a rapid loss in mass due to dehydrochlorination and novel aromatisation and polycondensation up to 400 °C. In this study, we attempted to prepare carbon fibre (CF) without oxidative stabilisation, using the aforementioned CPVC as a novel precursor.

Evolution of Phosphorus-Containing Groups on Activated Carbons during Heat Treatment.

Two types of activated carbons have been prepared by HPO activation of lignocellulose and by HPO modification of activated carbon, and then heat-treated at temperatures from 400 to 900 °C in an atmosphere of N or H to investigate the evolution of phosphorus-containing groups. Elemental analysis, X-ray photoelectron spectroscopy, P nuclear magnetic resonance, nitrogen adsorption, and scanning electron microscopy have been used to analyze the physicochemical properties of the activated carbons. The results show that C-O-P linkages of phosphorus-containing groups can progressively evolve into C-P-O, C-P═O, C-P, and eventually elemental phosphorus as a result of heat treatment.

Fast Water Relaxation through One-Dimensional Channels by Rapid Energy Transfer.

Water in carbon nanotubes is surrounded by hydrophobic carbon surfaces and shows anomalous structural and fast transport properties. However, the dynamics of water in hydrophobic nanospaces is only phenomenologically understood. In this study, water dynamics in hydrophobic carbon nanotubes is evaluated based on water relaxation using nuclear magnetic resonance spectroscopy and molecular dynamics simulations.

Methanol-Tolerant Platinum-Palladium Catalyst Supported on Nitrogen-Doped Carbon Nanofiber for High Concentration Direct Methanol Fuel Cells.

Pt-Pd catalyst supported on nitrogen-doped carbon nanofiber (N-CNF) was prepared and evaluated as a cathode electrode of the direct methanol fuel cell (DMFC). The N-CNF, which was directly synthesized by the catalytic chemical vapor deposition from acetonitrile at 640 °C, was verified as having a change of electrochemical surface properties such as oxygen reduction reaction (ORR) activities and the electrochemical double layer compared with common carbon black (CB). To attain the competitive oxygen reduction reaction activity with methanol tolerance, the Pt and Pd metals were supported on the CB or the N-CNF.

Formation of single-layered Pt islands on Au(111) using irreversible adsorption of Pt and selective adsorption of CO to Pt.

This communication compares two different multiple deposition routes of Pt on Au(111), using irreversible adsorption of Pt precursor ions and selective adsorption of CO. A scanning tunneling microscopy study revealed that the conventional route, not utilizing CO, produced multiple-layered Pt cluster islands, while the CO route, employing CO, formed single-layered Pt islands exclusively. The role of CO selectively adsorbed on pre-existing Pt islands was to prevent additional irreversible adsorption of Pt precursor ions onto Pt islands.

Chemoselective hydrogenation of functionalized nitroarenes and imines by using carbon nanofiber-supported iridium nanoparticles.

The reaction of three types of carbon nanofibers (CNFs; platelet: CNF-P, tubular: CNF-T, herringbone: CNF-H) with Ir4(CO)12 in mesitylene at 165 °C provided the corresponding CNF-supported iridium nanoparticles, Ir/CNFs (Ir content=2.3-2.6 wt.

Hollow fibers networked with perovskite nanoparticles for H2 production from heavy oil.

Design of catalytic materials has been highlighted to build ultraclean use of heavy oil including liquid-to-gas technology to directly convert heavy hydrocarbons into H2-rich gas fuels. If the H2 is produced from such heavy oil through high-active and durable catalysts in reforming process that is being constructed in hydrogen infrastructure, it will be addressed into renewable energy systems. Herein, the three different hollow fiber catalysts networked with perovskite nanoparticles, LaCr(0.

Toward an effective adsorbent for polar pollutants: formaldehyde adsorption by activated carbon.

Due to increasing concerns about environmental pollutants, the development of an effective adsorbent or sensitive sensor has been pursued in recent years. Diverse porous materials have been selected as promising candidates for detecting and removing harmful materials, but the most appropriate pore structure and surface functional groups, both important factors for effective adsorbency, have not yet been fully elucidated. In particular, there is limited information relating to the use of activated carbon materials for effective adsorbent of specific pollutants.

Pt nanoparticle-reduced graphene oxide nanohybrid for proton exchange membrane fuel cells.

A platinum nanoparticle-reduced graphene oxide (Pt-RGO) nanohybrid for proton exchange membrane fuel cell (PEMFC) application was successfully prepared. The Pt nanoparticles (Pt NPs) were deposited onto chemically converted graphene nanosheets via ethylene glycol (EG) reduction. According to the powder X-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) analysis, the face-centered cubic Pt NPs (3-5 nm in diameter) were homogeneously dispersed on the RGO nanosheets.

Synthesis of silicon monoxide-pyrolytic carbon-carbon nanofiber composites and their hybridization with natural graphite as a means of improving the anodic performance of lithium-ion batteries.

Novel composites of silicon monoxide, pyrolytic carbon and carbon nanofiber (SiO/PyC/CNF) were hybridized with natural graphite (NG) as a means of improving the anodic performance of Li-ion batteries. Samples were made with hybridization levels of 10-30 wt% of NG exhibited excellent cyclability with a discharge capacity of 389-522 mAh g(-1) in a Li-ion battery system. SiO/PyC/CNF composite hybrids showed better cyclability than other carbon composites containing SiO/PyC and SiO/CNF.

Structure and electrochemical applications of boron-doped graphitized carbon nanofibers.

Boron-doped graphitized carbon nanofibers (CNFs) were prepared by optimizing CNFs preparation, surface treatment, graphitization and boron-added graphitization. The interlayer spacing (d₀₀₂) of the boron-doped graphitized CNFs reached 3.356 Å, similar to that of single-crystal graphite.

High magnetic field solid-state NMR analyses by combining MAS, MQ-MAS, homo-nuclear and hetero-nuclear correlation experiments.

A general strategy of structural analysis of alumina silicate by combining various solid-state NMR measurements such as single pulse, multi-quantum magic angle spinning, double-quantum homo-nuclear correlation under magic angle spinning (DQ-MAS), and cross-polarization hetero-nuclear correlation (CP-HETCOR) was evaluated with the aid of high magnetic field NMR (800 MHz for (1) H Larmor frequency) by using anorthite as a model material. The high magnetic field greatly enhanced resolution of (27) Al in single pulse, DQ-MAS, and even in triple-quantum magic angle spinning NMR spectra. The spatial proximities through dipolar couplings were probed by the DQ-MAS methods for homo-nuclear correlations between both (27) Al-(27) Al and (29) Si-(29) Si and by CP-HETCOR for hetero-nuclear correlations between (27) Al-(29) Si in the anorthite framework.

Electrochemical catalytic activity for oxygen reduction reaction of nitrogen-doped carbon nanofibers.

The electrocatalytic activity of nitrogen-doped carbon nanofibers (N-CNFs), which are synthesized directly from vaporized acetonitrile over nickel-iron based catalysts, for oxygen reduction reaction (ORR), was investigated. The nitrogen content and specific surface area of N-CNFs can be controlled through the synthesis temperature (300-680 degrees C). The graphitization degree of N-CNFs also are significantly affected by the temperature, whereas the chemical compositions of nitrogen species are similar irrespective of the synthesis conditions.

IVS6+5G>A found in Wiskott-Aldrich syndrome and X-linked thrombocytopenia in a Korean family.

Wiskott-Aldrich syndrome (WAS) and X-linked thrombocytopenia (XLT) are caused by a mutation in the WAS gene on Xp11.22. We report two patients with IVS6+5G>A of WAS in a Korean family.

Graphitization behaviour of chemically derived graphene sheets.

Graphene sheets were prepared via chemical reduction of graphite oxides and then graphitized at 2800 °C. The structure changes from pristine graphite to graphitized graphene sheets were monitored using X-ray diffraction and Raman spectroscopy. It was found that the graphitized graphene sheets exhibited relatively low degree of graphitization and high level of structural defects.

Partially unzipped carbon nanotubes as a superior catalyst support for PEM fuel cells.

Partially unzipped carbon nanotubes prepared by strong oxidation and thermal expansion of carbon nanotubes were explored as an advanced catalyst support for PEM fuel cells. The unique hybrid structure of 1D nanotube and 2D double-side graphene resulted in an outstanding electrocatalytic performance.

Fabrication of uniform graphene discs via transversal cutting of carbon nanofibers.

The graphene discs with well-defined shape are successfully fabricated using a simple oxidation and exfoliation process of high-crystalline carbon nanofibers (CNFs). To control the shapes of graphene discs, two different types of CNFs (platelet and herringbone-type) are used as starting materials. The CNFs are formed by the perpendicular stacking of graphene discs, resulting in free edges on the external surface and ready access to interlay spaces.

Preparation of nitrogen-doped graphene sheets by a combined chemical and hydrothermal reduction of graphene oxide.

Nitrogen-doped graphene sheets were prepared through a hydrothermal reduction of colloidal dispersions of graphite oxide in the presence of hydrazine and ammonia at pH of 10. The effect of hydrothermal temperature on the structure, morphology, and surface chemistry of as-prepared graphene sheets were investigated though XRD, N(2) adsorption, solid-state (13)C NMR, SEM, TEM, and XPS characterizations. Oxygen reduction and nitrogen doping were achieved simultaneously under the hydrothermal reaction.