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The utilization of high‐sulfur coal, especially high‐organic coal, has always been a difficult hot spot in the energy field. To study the influence of sulfur in coal on coal‐based graphite products, a series of coal samples with different sulfur content and different degrees of coalification were collected for proximate analysis, ultimate analysis, and sulfur species analysis. The structural characteristics of coal‐based graphite products were analyzed by X‐ray diffraction (XRD). The relationships between the sulfur in coal and the yield (Y), graphitization degree (G), cell diameter (La), and stacking height (Lc) of coal‐based graphite products were explored. The yield of coal‐based graphite ranges from 8.92 % to 64.45 %, and it was found that the yield of coal‐based graphite is not only affected by the degree of coalification, fixed carbon content, and volatile matter content of coal but also significantly inhibited by organic sulfur in coal when the reflectance is less than 2.00 %. The graphitization degree (G) of coal‐based graphite is distributed between 76.02 % and 91.02 %, and positively related to the degree of coalification, and negatively related to the content of volatile matter. Organic sulfur in coal is an unfavorable factor for the graphitization degree (G) of coal‐based graphite. Both the cell diameter (La) and stacking height (Lc) of coal‐based graphite are positively correlated with the degree of coalification and negatively correlated with the volatile matter content in coal. Organic sulfur in coal plays an important inhibitory role on the cell diameter (La) of coal‐based graphite. Still, it has almost no effect on the stacking height (Lc) of coal‐based graphite, resulting in a low ratio of horizontal‐to‐vertical (La/Lc), which is not conducive to the horizontal development of coal‐based graphite cells. [ABSTRACT FROM AUTHOR]

Silicon oxycarbide (SiOC) is a promising anode material for lithium‐ion batteries, owing to the high capacity and superior structural stability. However, the application of SiOC anode is limited by its low conductivity and poor rate performance. Here, SiOC anodes were prepared by the pyrolysis of silicone resin (RSN‐217) at different temperatures (700, 850, 1000, and 1150° C), and the effect of graphitization degree and Si─O─C network on the electrochemical performance of SiOC anodes was investigated. The elemental and structural characteristics of the pyrolyzed SiOC ceramics at different temperatures were inspected using a broad spectrum of characterization techniques, and electrochemical performance testing methods, such as cyclic voltammetry and galvanostatic charge/discharge, were conducted on SiOC anode. SiOC‐1000 showed excellent electrochemical performance due to the highest graphitization degree of free carbon phase and the highest content of SiO2C2 and SiO3C units. Considerable research effort laid a foundation for exploring the lithium storage mechanism of SiOC anode. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to achieve the high-value utilization of heavy tar for the production of enhanced-performance graphite foam carbon, the carbon mesophase was ready from the heavy component of low-temperature coal tar, and the coal tar was modified by styrene-butadiene-styrene (SBS), polyethylene (PE) and ethylene-vinyl-acetate (EVA) copolymers. The order degree of the carbonite mesophase was analyzed using a polarizing microscope test, Fourier transform infrared spectroscopy and X-ray diffraction to screen out the most suitable copolymer type and addition amount. Furthermore, the mechanism of modification by this copolymer was analyzed. The results showed that adding SBS, PE and EVA to coal tar would affect the order of carbonaceous mesophase; however, at an addition rate of 10.0 wt.%, the linear-structure SBS copolymer with a styrene/butadiene ratio (S/B) of 30/70 exhibited the optimal degree of ordering in the carbonaceous mesophase. Its foam carbon prepared by polymer modification is the only one that forms a graphitized structure, with d002 of 0.3430 nm, and the maximum values of Lc and La are 3.54 nm and 2.22 nm, respectively. This is because, under elevated pressure and high-temperature conditions, SBS underwent chain scission, releasing a more significant number of methyl and other free radicals that interacted with the coal tar constituents. As a result, it reduced the affinity density of heavy coal tar molecules, enhanced fluidity, promoted the stacking of condensed aromatic hydrocarbons and increased the content of soluble carbonaceous mesophase, ultimately leading to a more favorable alignment of the carbonaceous mesophase. [ABSTRACT FROM AUTHOR]

To enhance the synergistic effect of phosphorus (P) and nitrogen (N) on flame retardant property, four different phytic acid-based NP flame retardants (FR-PAN) were manufactured using phytic acid and urea with various molar ratios, ranging from 1:3 to 1:12. The FR-PAN water solution was used to impregnate poplar wood under vacuum condition, and the thermal degradation performance of the FR-PAN treated wood were investigated. Compared to untreated wood, the PAN-6 (molar ratio is 1:6) group showed a reduction of 57.1% in total heat release and 80.0% in total smoke release. In the combustion, due to the introduction of P and N, FRPAN generates O=P/C-O/C-P/C-N bonds, forming highly graphitized char residues, which effectively isolate the entry of oxygen and heat and play a good protective role in the condensed phase. Morphological and chemical analysis of the residual char layer revealed that the introduction of P and N elements formed a more stable hybrid structure, significantly improving the thermal stability of the char layer. Among them, the PAN-6 group exhibited the highest char layer stability, indicating optimal synergistic effects of nitrogen and phosphorus under these conditions. [ABSTRACT FROM AUTHOR]

Using mesophase pitch based carbon fibers (CFMP) as reinforcement and pyrolytic carbon (PyC) and resin carbon as matrix, high thermal conductivity carbon fiber modified carbon/carbon (C/C) composites were prepared by chemical vapor deposition and liquid phase impregnation process. The micro-structure, mechanical and thermal conductivity properties of the modified C/C composites that heat treated at different temperature (2 000 and 3 000 °C) were investigated. The results show that the structure of CFMP and PyC is not changed obviously after 2 000 °C heat treatment, and the interface between PyC and carbon fiber is tightly bonded, with fewer micro-cracks observed at the interface. However, after 3 000 °C heat treatment, the graphitization degree of CFMP and PyC increases significantly, meanwhile, obvious micro-cracks are formed at the interface between CFMP and PyC. With 2 000 °C heat treatment, the average flexural strength and thermal conductivity of the modified C/C composites are 101.81 MPa and14.739 W/m·K, respectively. However, after 3 000 °C heat treatment, the average flexural strength is declined to 49.35 MPa, whereas the thermal conductivity is enhanced to 63.568 W/m·K. The declined flexural strength and enhanced thermal conductivity are mainly associated with the increased graphitization degree of different carbon phases after 3 000 °C heat treatment. [ABSTRACT FROM AUTHOR]

Two X-ray diffraction methods were chosen to determine the degree of structural order (degree of graphitization) of natural carbonaceous matter. Factors influencing the graphitization processes during the progressive and regressive stages of metamorphism are examined. The correlation of the degrees of structural order of the carbonaceous material with the sequence of mineral growth allows the metamorphic history of the graphite-bearing rocks to be traced. The obtained data can be used for the evaluation of graphite as a raw material. [ABSTRACT FROM AUTHOR]

Hydrovoltaic effect is an innovative route to acquire electric energy from low-quality energy of water. Carbonized wood has shown great potential in hydrovoltaic conversion for the natural directional microtube structure which can induce sustaining water flow. But the induced-current, key performance of the hydrovoltaic effect, was still limited by intrinsic resistance of carbonized wood. To reduce the intrinsic resistance and promote the carrier migration, graphitizing as a proved method is used to improve the hydrovoltaic current. In this work, the carbonized wood was graphitized in different degree through transition metal catalytic method to investigate the influence. Double influence of graphitizing modification on hydrovoltaic conversion was verified. Moderately graphitizing modification can simultaneously promote the carrier to migrate and accumulate at double electric layer (DEL) interface, which benefits hydrovoltaic effect. But excessive modification shows a negative effect on carrier accumulation and reduces the hydrovoltaic performance. Comparing to the untreated carbonized wood, the maximal open-circuit voltage of graphitized carbonized wood can reach ~2.4 times higher (~0.47 V), while short-circuit current can be further enhanced to a notable ~27 times increase (~35 μA), demonstrating the remarkable enhancement of graphitizing modification on induced current. [ABSTRACT FROM AUTHOR]

Mesocarbon microbead-silicon carbide (MCMB-SiC) composites were prepared by hot-press sintering (2100 °C/40 MPa/1 h) with two different graphitized MCMBs as the second phase, which exhibited good self-lubricating properties. The effects of the graphitization degree of the MCMBs on the microstructure and properties of the composites were investigated contrastively. The results showed that the composites that added raw MCMBs with a low degree of graphitization had excellent self-sintering properties, higher densities, and better mechanical properties; by comparison, the composites that added mature MCMBs with a high degree of graphitization, which has regular and orderly lamellar structures, not only had good mechanical properties but also exhibited a lower and more stable dry friction coefficient (0.35), despite the higher wear rate (2.66 × 10−6 mm3·N−1·m−1). Large amounts of mature MCMBs were peeled off during the friction process to form a uniform and flat graphite lubricating film, which was the main reason for reducing the dry friction coefficient of the self-lubricating composites and making the friction coefficient more stable. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The removal by adsorption of methylene blue dye from water using two‐dimensional (2D) (graphene oxide and reduced graphene oxide) and three‐dimensional (3D) (graphite and graphite oxide) carbon structures was studied. Two graphites with different degrees of graphitization were used to evaluate the significance of the carbon structural order in the adsorption efficiency, and therefore, the economic repercussions, because the degree of graphitization is related with the cost. Graphene oxides showed the best performance in methylene blue adsorption, with a removal of around 90%. The adsorption process was strongly influenced by the surface oxygenated groups, and electrostatic interaction was the main mechanism of adsorption. The degree of graphitization of the precursor does not have a strong influence on the adsorption results of methylene blue. Thus, graphene oxide with a lower degree of graphitization represents an economical and efficient adsorbent for the removal of methylene blue from water. The kinetic study was realized in pseudo‐first order, pseudo‐second order, and Elovich kinetic models in their linear and non‐linear forms. According to the determination coefficient and the standard deviation, the experimental data were best fitted to the Elovich model in its non‐linear form. [ABSTRACT FROM AUTHOR]

Grafting carbon nanotubes (CNTs) is one of the most commonly used methods for modifying carbon fiber surface, during which complex device is usually needed and the growth of CNTs is difficult to control. Herein, we provide an implementable and continuous chemical vapor deposition (CVD) process, by which the novel multiscale reinforcement of carbon nanotube (CNT)-grafted carbon fiber is prepared. After exploring the effects of the moving speed and growth atmosphere on the morphology and mechanical properties of carbon nanotubes/carbon fiber (CNTs/CF) reinforcement, the optimal CVD process conditions are determined. The results show that low moving speeds of carbon fibers passing through the reactor can prolong the growth time of CNTs, increasing the thickness and density of the CNTs layer. When the moving speed is 3 cm/min or 4 cm/min, the surface graphitization degree and tensile strength of CNTs/CF almost simultaneously reach the highest value. It is also found that H2 in the growth atmosphere can inhibit the cracking of C2H2 and has a certain effect on prolonging the life of the catalyst. Meanwhile, the graphitization degree is promoted gradually with the increase in H2 flow rate from 0 to 0.9 L/min, which is beneficial to CNTs/CF tensile properties. [ABSTRACT FROM AUTHOR]

Summary: In this paper, polyacrylonitrile‐based graphite felt (GF), carbon felt (CF) and the effect of thermal activation on them with or without the catalyst (BiCl3) are comprehensively investigated for iron‐chromium redox flow battery (ICRFB) application. The physical‐chemical parameters of GF and CF after the thermal activation is affected significantly by their graphitization degree, oxygen functional groups, and surface area. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results manifest that GF and CF before and after the thermal activation have different electrocatalytic activities owing to oxygen functional groups number increase and the graphitization degree decrease. In terms of the capacity decay rate, as oxygen functional groups provide shorter electrocatalytic pathways than bismuth ions, the performance of GF and CF after the thermal activation is more ideal. As a result, GF before and after the thermal activation exhibits higher efficiency (EE: 86%) and better stability at a charge‐discharge current density of 60 mA·cm−2 than those of CF during charge‐discharge cycling, as the dominant limitation in an ICRFB is ohmic and activation polarization. Therefore, GF after thermal activation together with the addition of BiCl3 in the electrolyte is a more promising electrode material for ICRFBs application than CF. [ABSTRACT FROM AUTHOR]

Nickel/scandia-ceria-stabilized-zirconia (Ni/10Sc1CeSZ) cermet is a potential anode for solid oxide fuel cells. The anode powder is prepared through a microwave-assisted glycine nitrate combustion process, and its properties, including phase and chemical composition as well as morphology, are characterized by XRD, TEM, and EDS techniques. The electrical conductivity and electrochemical behavior under low concentration of dry hydrogen (H2:N2 volume ratio = 10:90) and dry methane (CH4:N2 volume ratio = 50:50) fuels are determined. XRD results show two phases, namely, cubic NiO phase and cubic 10Sc1CeSZ phase, with the crystallite sizes of 67 and 40 nm, respectively. The area specific resistances (ASRs) of the prepared anode measured using a symmetrical cell of Ni/10Sc1CeSZ|10Sc1CeSZ|Ni/10Sc1CeSZ are 0.96 and 24.3 Ω cm2 observed at 800 °C in dry low hydrogen concentration (10 vol% hydrogen–90 vol% nitrogen) and dry methane (50 vol% methane–50 vol% nitrogen) fuels, respectively. The ASR in methane fuel is higher than that in hydrogen fuel at all operating temperatures (600–800 °C) because of carbon deposition. The amount of deposited carbon and degree of graphitization (IG/ID) of this anode after exposure in methane at 800 °C for 3 h are 4.34% and 2.1, respectively. Overall, Ni/10Sc1CeSZ cermet synthesized by glycine nitrate process assisted with microwave-heating technique exhibits acceptable electrochemical behavior even at low hydrogen concentration and also in dry methane. This can be related to the improved powder morphology as a result of uniform heating assisted by microwave energy. [ABSTRACT FROM AUTHOR]

In this work, bamboo-shaped, multi-walled carbon nanotubes were synthesized via methane decomposition over a Ni-Co-Fe tri-metallic catalyst at 1000 °C. The nitrogen absorption (BET), X-ray diffraction (XRD), and particle size analysis results of the catalyst were used to demonstrate the surface area, size distribution, and crystallinity of the sample. The scanning electron microscopy (SEM) micrographs of the nanocarbons deposited via methane decomposition indicated that highly uniform carbon nanotubes were grown on the surface of the tri-metallic catalyst. The transmission electron microscopy (TEM) images showed that the carbon nanotubes were multi-walled and bamboo-shaped with a diameter of ~20 nm. Raman spectra revealed the graphitization degree of the CNTs with an I/ I of 1.84, indicative of the crystallinity of CNTs with structural defects. The thermal analysis shows the high oxidation stability of the multi-walled carbon nanotubes. [ABSTRACT FROM AUTHOR]

The microstructure and texture of C/C composites with a resin-derived carbon, a rough laminar (RL) pyrocarbon and a smooth laminar pyrocarbon, before and after braking tests, were investigated by Raman spectroscopy. The full width at half maximum (FWHM) of the D-band indicates the amount of defects in the in-plane lattice, while the G-to-D band intensity (peak area) ratios ( I/ I) is used to evaluate the degree of graphitization. The results show that the FWHM of D-band of sample with RL pyrocarbon changes greatly from 36 cm to 168 cm after braking tests, which indicates that a large number of lattice defects are produced on its wear surface. However, the graphitization degree of resin-derived carbon sample rises significantly, because the I/ I increases from 0.427 to 0.928. Braking tests under normal loading conditions, involving high temperature and high pressure, produce a lot of lattice defects on the wear surface, and induce the graphitization of the surface. Sample with RL pyrocarbon having a low hardness is easy to deform, and has the most lattice defects on the wear surface after braking. While raw materials with resin-derived carbon have the lowest graphitization degree which rises greatly during braking. [ABSTRACT FROM AUTHOR]