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Purpose: To demonstrate improved frequency selective fat suppression in MRI using a magnetic susceptibility matching foam by reducing B0 inhomogeneities induced within the body by air-tissue interfaces., Materials and Methods: Flexible pyrolytic graphite (PG) composite foam was tailored to match the magnetic susceptibility of human tissue and was shaped to surround the cervical spine region. Field maps and frequency selective fat suppressed T1 -weighted FLASH images were acquired at 3 Tesla in both phantoms and six healthy necks., Results: B0 field uniformity was shimmed to a target critical threshold of 1 ppm for fat suppression. The percentage of voxels in the phantom that did not achieve the critical threshold was reduced from 64% without the PG foam to only 1% with the foam. A similar decrease from 16% to 2% was observed in the in vivo region of interest., Conclusion: PG foam improved B0 field uniformity by moving air-tissue field gradients outside of the neck where they cannot cause MRI artifacts. The PG foams consistently mitigated signal dropout, improved overall SNR, and enabled more robust frequency selective fat suppression., (© 2014 Wiley Periodicals, Inc.)

Additive micro/nano‐manufacturing of polymeric precursors combining with a subsequent pyrolysis step enables the design‐controlled fabrication of micro/nano‐architected 3D pyrolytic carbon structures with complex architectural details. Pyrolysis results in a significant geometrical shrinkage of the pyrolytic carbon structure, leading to a structural dimension significantly smaller than the resolution limit of the involved additive manufacturing technology. Combining with the material properties of carbon and 3D architectures, architected 3D pyrolytic carbon exhibits exceptional properties, which are significantly superior to that of bulk carbon materials. This article presents a comprehensive review of the manufacturing processes of micro/nano‐architected pyrolytic carbon materials, their properties, and corresponding demonstrated applications. Acknowledging the "young" age of the field of micro/nano‐architected carbon, this article also addresses the current challenges and paints the future research directions of this field. [ABSTRACT FROM AUTHOR]

Highly portable nanoelectronics and large-scale electronics rely on lithium-ion batteries (LIBs) as the most reliable energy storage technology. This method is thought to be both environmentally friendly and cost-effective. We provide a study of a low-cost, abundant, and renewable supply of carbon-based biomass with potential uses in LIBs. Renewable feedstocks have received significant attention in recent decades as promising tools for efficient and alternative anode materials for LIBs. Researchers can synthesise carbon-rich biochar through the pyrolytic process of biomass. Depending on the synthetic process, precise surface chemistry, and textural qualities such as specific surface area and porosity, this material can be customised to favour application-specific properties with a preferred application. In this research, we look at the performance of biochar in LIBs, its properties, and the biomass supply, and we discuss the prospects for these biomass-derived materials in energy storage devices. [ABSTRACT FROM AUTHOR]

The carbon phase diagram is rich with polymorphs which possess very different physical and optical properties ideal for different scientific and engineering applications. An understanding of the dynamically driven phase transitions in carbon is particularly important for applications in inertial confinement fusion, as well as planetary and meteorite impact histories. Experiments on the Z Pulsed Power Facility at Sandia National Laboratories generate dynamically compressed high-pressure states of matter with exceptional uniformity, duration, and size that are ideal for investigations of fundamental material properties. X-ray diffraction (XRD) is an important material physics measurement because it enables direct observation of the strain and compression of the crystal lattice, and it enables the detection and identification of phase transitions. Several unique challenges of dynamic compression experiments on Z prevent using XRD systems typically utilized at other dynamic compression facilities, so novel XRD diagnostics have been designed and implemented. We performed experiments on Z to shock compress carbon (pyrolytic graphite) samples to pressures of 150–320 GPa. The Z-Beamlet Laser generated Mn-Heα (6.2 keV) X-rays to probe the shock-compressed carbon sample, and the new XRD diagnostics measured changes in the diffraction pattern as the carbon transformed into its high-pressure phases. Quantitative analysis of the dynamic XRD patterns in combination with continuum velocimetry information constrained the stability fields and melting of high-pressure carbon polymorphs. [ABSTRACT FROM AUTHOR]

In this work, X-ray photoelectron spectroscopy (XPS) was used to study the effect of preliminary oxidative treatment of a carbon support surface on the results of NO2 interaction with model systems prepared by palladium deposition onto highly oriented pyrolytic graphite (HOPG). It was found that, in Pd/HOPG samples with the atomic ratios [O]/[C] ≤ 0.0035, the carbon support was oxidized with the destruction of its structure to a depth of 10–15 graphene layers. In this case, the palladium particles remained in a metallic state, and they penetrated into the near-surface layer of the support due to the deep oxidation of adjacent carbon atoms. At the atomic ratio [O]/[C] ≈ 0.01–0.02, the result of the interaction changed dramatically. In this case, the support remained stable, and the palladium particles were oxidized to form an oxide. This finding explained the high stability of supported palladium catalysts prepared on Sibunit carbon supports in oxidative catalysis reactions. [ABSTRACT FROM AUTHOR]

This review focuses on techniques for modifying the surface of carbon that is produced from sustainable resources, such as pyrolytic carbon. Many of these materials display high specific surface area and fine particle distribution. Functionalization of a surface is a commonly used approach in designing desired surface properties of the treated material while retaining its bulk properties. Usually, oxidation is a primary step in carbon functionalization. It can be performed as wet oxidation, which is a type of chemical surface modification. Wet oxidation is usually performed using nitric acid and hydrogen peroxide, as well as using hydrothermal and solvothermal oxidation. On the other side, dry oxidation is representative of physical surface modification. This method is based on corona discharge and plasma oxidation which are promising methods that are in line with green chemistry approaches. Whilst the oxidation of the carbon surface is a well-known method, other chemical modification techniques, including cycloadditions and various radical reactions on graphene layers, are presented as an alternative approach. Regarding secondary functionalization, coupling organosilanes to activated carbon is a common technique. Organosilanes bearing reactive groups present a bridge between inorganic species and polymer systems, e.g., epoxy and polyurethane resins, and facilitate the use of carbonaceous materials as reinforcing components for polymers and thermosetting resins. Along with the presented functionalization methods, this review also provides an overview of new applications of modified (i.e., functionalized) carbon materials, e.g., for the building industry, wastewater treatment, semiconducting materials and many more. [ABSTRACT FROM AUTHOR]

Carbon-fiber-reinforced polymers (CFRP), being conductive, are capable of supporting cathodic oxygen reduction reactions (ORR) and thus promote galvanic corrosion when coupled to many metallic materials. Hence, understanding cathodic processes at carbon surfaces is critical to developing new strategies for the corrosion protection of multi-material assemblies. In the present work, the electrochemical responses of CFRP, glassy carbon, and HOPG (Highly Ordered Pyrolytic Graphite) have been evaluated in a quiescent 50 mM NaCl solution, and their respective activities towards ORR have been ranked. Employing the averages of the specific charges (CFRP, 129.52 mC cm−2; glassy carbon, 89.95 mC cm−2; HOPG, 60.77 mC cm−2) passed during 1 h polarization of each of the 3 carbon surfaces at −1000 mVSCE in the test media as a ranking criterion, the propensities of the 3 carbon surfaces (CFRP, GC, and HOPG) to support cathodic activities that can lead to anodic metal dissolution on galvanic coupling to metallic materials are ranked thusly; CFRP > GC > HOPG. This ranking is consistent with the trend of capacitance values obtained in this work: CFRP (19.5 to 34.5 μF cm−2), glassy carbon (13.6 to 85.5 μF cm−2), and HOPG (1.4 to 1.8 μF cm−2). A comparison of electrochemical data at potentials relevant to galvanic coupling to metals indicated that at these cathodic potential(s) the CFRP surface is the most electrochemically active of the studied carbon surfaces. On the basis of the values and trends of the electrochemical parameters evaluated, it is postulated that the observed differences in the electrochemical responses of these 3 carbon-rich surfaces to ORR are significantly due to differences in the proportions of edge sites present on each carbon surface. These results could provide valuable insights on plausible strategies for designing carbon surfaces and carbon fiber composites with reduced activity toward ORR for corrosion protection applications or enhanced activity towards ORR for energy applications. [ABSTRACT FROM AUTHOR]

Radiocarbon (14 C) analysis of carbonaceous aerosols is used for source apportionment, separating the carbon content into fossil vs. non-fossil origin, and is particularly useful when applied to subfractions of total carbon (TC), i.e. elemental carbon (EC), organic carbon (OC), water-soluble OC (WSOC), and water-insoluble OC (WINSOC). However, this requires an unbiased physical separation of these fractions, which is difficult to achieve. Separation of EC from OC using thermal–optical analysis (TOA) can cause EC loss during the OC removal step and form artificial EC from pyrolysis of OC (i.e. so-called charring), both distorting the 14 C analysis of EC. Previous work has shown that water extraction reduces charring. Here, we apply a new combination of a WSOC extraction and 14 C analysis method with an optimised OC/EC separation that is coupled with a novel approach of thermal-desorption modelling for compensation of EC losses. As water-soluble components promote the formation of pyrolytic carbon, water extraction was used to minimise the charring artefact of EC and the eluate subjected to chemical wet oxidation to CO 2 before direct 14 C analysis in a gas-accepting accelerator mass spectrometer (AMS). This approach was applied to 13 aerosol filter samples collected at the Arctic Zeppelin Observatory (Svalbard) in 2017 and 2018, covering all seasons, which bear challenges for a simplified 14 C source apportionment due to their low loading and the large portion of pyrolysable species. Our approach provided a mean EC yield of 0.87±0.07 and reduced the charring to 6.5 % of the recovered EC amounts. The mean fraction modern (F14 C) over all seasons was 0.85±0.17 for TC; 0.61±0.17 and 0.66±0.16 for EC before and after correction with the thermal-desorption model, respectively; and 0.81±0.20 for WSOC. [ABSTRACT FROM AUTHOR]

Fast charging capability is highly desired for new generation lithium-ion batteries used in consumer-grade electronic devices and electric vehicles. However, currently used anodes suffer from sluggish ion kinetics due to limited interlayer distance. Herein, the coal-based semicoke was chosen as precursor to prepare cost-effective carbon anodes with high-rate performance through a facile pyrolytic strategy. The evolution of microstructure and its effect on electrochemical performance are entirely studied. The results show that large number of short-ordered defective structures are generated due to the occurrence of turbostatic-like structures when pyrolyzed at 900 °C, which are propitious to large interlayer distance and developed porous structure. High accessible surface area and large interlayer spacing with short-ordered defective domains endow the sample treated at 900 °C under argon (A900) with accelerated ion dynamics and enhanced ion adsorption dominated surface-induced capacitive processes. As a result, A900 delivers high capacity (331.1 mAh g−1 at 0.1 A g−1) and long life expectancy (94.8% after 1000 cycles at 1 A g−1) as well as good rate capability (153.2 mAh g−1 at 5 A g−1). This work opens a scalable avenue to fabricating cost-effective, high-rate, and long cycling life carbon anodes. [ABSTRACT FROM AUTHOR]

A surface science based approach was applied to model carbon supported Pd nanoparticle catalysts. Employing physical vapour deposition of Pd on sputtered surfaces of highly oriented pyrolytic graphite (HOPG), model catalysts were prepared that are well-suited for characterization by X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). Analysis of the HOPG substrate before and after ion-bombardment, and of Pd/HOPG before and after annealing, revealed the number of "nominal" HOPG defects (~ 1014 cm−2) as well as the nucleation density (~ 1012 cm−2) and structural characteristics of the Pd nanoparticles (mean size/height/distribution). Two model systems were stabilized by UHV annealing to 300 °C, with mean Pd particles sizes of 4.3 and 6.8 nm and size/height aspect ratio up to ~ 10. A UHV-compatible flow microreactor and gas chromatography were used to determine the catalytic performance of Pd/HOPG in ethylene (C2H4) hydrogenation up to 150 °C under atmospheric pressure, yielding temperature-dependent conversion values, turnover frequencies (TOFs) and activation energies. The performance of Pd nanocatalysts is compared to that of polycrystalline Pd foil and contrasted to Pt/HOPG and Pt foil, pointing to a beneficial effect of the metal/carbon phase boundary, reflected by up to 10 kJ mol−1 lower activation energies for supported nanoparticles. [ABSTRACT FROM AUTHOR]

The high crystallinity structure endows carbon materials with exceptional electrical and thermal conductivity, making them suitable for high-end industrial applications, such as graphite for lithium-ion battery. However, the non-graphitizable carbons are hardly converted to graphite even at 3000 °C due to their highly disordered nanotexture. Herein, we propose that re-structuring non-graphitizable carbons through ball-milling can significantly boost their crystallinity after 2800 °C treatment using a activated carbon as a research model. Ball milling-induced order rearrangement of carbon layers promotes the development of the large graphenic crystallites toward graphite structure during the subsequent heat treatment. As a utilization exemplification for lithium storage, the optimal sample shows a greatly improved plateau capacity (<0.2 V, 194.8 vs. 155.1 mAh g−1) compared to the one obtained without ball-milling pre-modulation. Furthermore, the same approach was also applied to three typical non-graphitizable carbons derived from polymers and biomass, showing a similar result. This indicates that ball-milling may be a universal pre-treatment strategy for boosting the high-temperature "graphitization" of non-graphitizable carbon materials for advanced applications. The order rearrangement of carbon layers in non-graphitizable carbons through ball-milling promotes the development of their graphenic crystallite toward graphite structure during the 2800 °C treatment. [Display omitted] • Ball-milling endows activated carbon with a significant propensity to graphitizability. • The plateau capacity for lithium storage increases from 155.1 to 194.8 mAh g−1. • This phenomenon is universal for polymers and biomass derived non-graphitizable carbons. [ABSTRACT FROM AUTHOR]

The synthesis of carbon onions in the laboratory by various methods is common; however, naturally occurring carbon onions have only been found in a few geological samples on Earth. This study used high-resolution transmission electron microscopy to identify natural carbon onions in seven intrusion-affected coal samples collected from Permian coal-bearing strata in the Yongan Coalfield, Fujian Province, South China. This study identified the largest natural carbon onions ever recorded on Earth; their outer diameter was ∼55 nm. Granite porphyry intrusions and quartz hydrothermal veins are abundant in the Permian coal-bearing strata in this coalfield. All samples collected were tectonically deformed coals with highly developed structural fractures, friction mirror planes, and maximum vitrinite reflectance values of 4.0–9.5%. Natural carbon onions observed in the coal samples had single or multiple cores, with 24–46 graphitic shells characterized by outer diameters of 24–55 nm. The maximum vitrinite reflectance, outer diameter, and graphitic shell number of carbon onions in the intrusion-affected coal were positively correlated, indicating that the carbon onions were secondary products formed during coal metamorphism owing to magmatic intrusion. Our results suggest that carbon onions in intrusion-affected coal are synthesized by chemical vapor deposition. We speculate that natural carbon onions exist mainly in fractures or cavities, similar to vapor-deposited pyrolytic carbon, which is the leading cause of the uneven distribution of carbon onions in intrusion-affected coals in the study area. [ABSTRACT FROM AUTHOR]

The influence of different conductive additives (carbon nanofibers (CNFs), carbon nanoplatelets, and pyrolytic carbon from sucrose (Sucr) or polyvinylidene fluoride) on the morphology, electron conductivity, and electrochemical performance of LiFePO4-based cathodes was investigated to develop the most efficient strategy for the fabrication of high-rate cathodes. Pyrolytic carbon effectively prevents the growth of LiFePO4 grains and provides contact between them, CNFs provide fast long-range conductive pathways, while carbon nanoplatelets can be embedded in carbon coatings as high-conductive "points" which enhance the rate capability and decrease the capacity fading of LFP. The LiFePO4/CSucr/CNF showed better performance than the other cathodes due to the synergy of the high-conductive CNF network (the electronic conductivity was 1.3 × 10−2 S/cm) and the shorter Li+ ion path (the lithium-ion diffusion coefficient was 2.1 × 10−11 cm2/s). It is shown that the formation of composites based on LFP and carbon nanomaterials via mortar grinding is a more promising strategy for electrode material manufacturing than ball milling. [ABSTRACT FROM AUTHOR]

SiC ceramic coatings were reactively sintered on carbon/carbon composites with two representative textures, rough laminar (RL) and smooth laminar (SL), pyrolytic carbon matrices by pack cementation. The ablation test results showed that RL-SiC (RLS) coating exhibited much lower linear ablation rate (−0.30 × 10−3 mm s−1) than SL-SiC (SLS) coating (3.25 × 10−3 mm s−1) under a 2.4 MW m−2 heat flux oxyacetylene flame for 30 s. The high thermal conductivity, the stable structure of 4H–SiC and large crystalline size were considered to be mainly responsible for the low ablation rate of RLS coating. Moreover, anisotropic etching resulted in distinctly hexagon pattern of V-shaped etch pits on ablated central region. [ABSTRACT FROM AUTHOR]

Vanadium redox flow batteries (VRFBs) have attracted much attention in the field of energy storage systems owing to their safety, long‐cycle life, and feasible scalability. However, the market penetration of VRFBs is still hindered by the poor performance of current carbon‐based electrodes. Herein, spent asphalt is employed as an efficient and low‐cost precursor to generate carbon decorating carbon felt for VRFB applications. By thermal decomposition treatment, the spent asphalt is converted into highly active pyrolytic carbon and deposited on surfaces of carbon felt. The as‐prepared carbon felt with increased active sites and improved hydrophility displays superior performance towards redox reactions of VO2+/VO2+ in terms of better electrochemical reversibility and faster reaction kinetics. Therefore, the VRFB cell with the carbon felt decorated with carbon derived from spent asphalt as cathode shows 85% energy efficiency which is higher than the pristine carbon felt cathode by 9%. Meanwhile, the energy efficiency and voltage efficiency are both stable during the cell cycling. This strategy can raise the value of the spent asphalt and improve the performance of VRFBs with the decorated carbon felt electrode shedding light on their commercial applications for large‐scale energy storage. [ABSTRACT FROM AUTHOR]

• In-situ grafting method is developed to tun the defects of coal-derived hard carbon. • Coal-derived hard carbon with low defects exhibits obviously improved initial Coulombic efficiency (ICE). • High capacity, outstanding rate performance and excellent capacity retention are demonstrated for coal-derived hard carbon anode. • The "adsorption-intercalation/filling" sodium ion storage mechanism in hard carbon is also confirmed. Sodium-ion batteries is not essential but also potential to support energy storage system due to the low cost. It's worth noting that low price and high carbon production helps coal extraordinary promise as hard carbon precursor. However, low initial coulombic efficiency (ICE) and practical Na+ storage specific capacity barrier their application owing to lots of defects. Herein, a grafting method is proposed to decrease defects, introducing glucose with simple one step carbonization process. Utilizing the reaction between glucose and coal reduces the defects, which generates a high ICE with less irreversible sodium ion consumption. Meanwhile the expanded carbon layer spaces enable the fast sodium ions transfer, leading to an optimized sodium storage performance. The grafted glucose obviously decreases the defects during the carbonization process and contributes extra sodium storage capacity. The optimal CG0.1 exhibits higher reversible capacity of 293 mAh∙g−1 and ICE of 84 % than pristine coal pyrolytic carbon (250 mAh∙g−1 and 79 %). Besides, it also delivers outstanding capacity retention with 95.3 % and 95.8 % after 1000 cycles at 0.3 A∙g−1 (240 mAh∙g−1) and at 1 A∙g−1 (207 mAh∙g−1). [ABSTRACT FROM AUTHOR]

Catalytic membrane process, which combines membrane filtration and advanced oxidation, has promising application prospects in water decontamination. In this work, a novel metal-free coal-based catalytic carbon membrane (PPy/CCM-800) was developed and applied for the typical EDC-bisphenol A (BPA) removal from water via activating peroxymonosulfate (PMS). Morphology investigation manifested that the N-doped carbon nanospheres derived from the pyrolytic PPy particles distributed evenly on the surface of coal-based carbon membrane (CCM). In contrast to bare CCM, catalytic performance of PPy/CCM-800 was significantly enhanced by the anchoring of N-doped carbon nanospheres, and 97.89 % of BPA and 60.83 % of total organic carbon (TOC) can be removed by PPy/CCM-800 during catalytic filtration treatment. Catalytic mechanism investigations confirmed that the excellent decontamination performance of PPy/CCM-800 was attributed to the synergistic effects of radical and non-radical oxidation pathway, and the non-radical pathway (1O 2 and direct electron transfer) played the dominant role. Moreover, the possible BPA degradation pathways were proposed based on the density functional theory (DFT) calculations and HPLC-MS results. [Display omitted] • N-doped carbon nanospheres functionalized coal-based catalytic carbon membrane was developed. • The deposition of N-doped carbon nanospheres significantly improve the catalytic performance of CCM. • Non-radical mechanism played the dominant role in BPA removal during the treatment. • PPy/CCM-800 exhibits excellent applicability for BPA removal in different water matrixes. [ABSTRACT FROM AUTHOR]

• An original ICVI algorithm reproducing the pyrolytic carbon deposition process is proposed. • The relationship between the process parameters and mechanical properties of unidirectional carbon/carbon composites is investigated. • The transverse modulus and tensile strength increase with an increase of the infiltration time, pressure, and temperature. • Interfacial debonding and propagation of multiple cracks result in the complete failure of unidirectional carbon/carbon composites. This paper proposes an innovative algorithm derived from the isothermal chemical infiltration process to generate quasi-real microstructures of unidirectional carbon/carbon composites. This algorithm, which can predict the relationship between the composite density and infiltration time, is termed the isothermal chemical infiltration algorithm. To further evaluate the relationship between the process parameters and the mechanical properties, a mesoscale finite element model of the unidirectional carbon/carbon composite is established based on the isothermal chemical infiltration algorithm. After validation, the developed numerical model is employed to study the effects of the infiltration time, pressure, and temperature on the effective mechanical properties. The results show that the transverse modulus and tensile strength increase with an increase in the infiltration time, pressure, and temperature, with the effect of temperature being the most significant. In parallel, it is revealed that the complete failure of unidirectional carbon/carbon composites results from interfacial debonding and propagation of multiple cracks during transverse tension. The proposed model has potential applications in the process design and optimization of high-performance carbon/carbon composites. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The two-step carbonization approach gave improved carbon properties of OTR. • KOH activation improved the properties of carbon from pyrolytic tyre solid residue. • Si, Zn, Fe and KCl are effectively recovered for reuse in industrial processes. • Recovered SiO 2 has an exceptionally high cross-linking ratio. • Functionalized carbon can be used for energy storage and catalyst applications. This study aims to identify suitable processing conditions for converting pyrolytic solid residue from off-the-road tyres (OTR) to improve carbon materials properties that can be used in multiple applications and the recovery of minerals from OTR. Pyrolysis of OTR at 800 °C and a heating rate 2 °C.min−1 gave a carbon material with the highest surface area, most defective carbon structures, and the highest micro-porosity. This operating condition was used to compare the conventional three-step carbonization approach, which involves a demineralization stage that produces high volumes of toxic wastewater, with a two-step approach that bypasses this stage. Analysis of the carbon structures showed that the quality of the carbon material from the two-step approach is similar to the three-step approach. This two-step approach resulted in a solid and a liquid phase, in which ∼ 93.4% of Zn was selectively fractionated to the liquid phase. The wastewater from the acid wash of the carbonized OTR was neutralized to recover the SiO 2 , of which 55.5% was reactive SiO 2. The SiO 2 was found to have an exceptionally high cross-linking ratio of 5.94, achievable only when SiO 2 is reacted with silane groups. The study demonstrated that the engineered carbon material from OTR has a H 2 uptake of 1.03 wt% at 77 K and 1.2 bar, and the sulfonated counterpart was an effective catalyst (64% conversion) for the Aldol condensation of levunilic acid to two dimer products [tetrahydro-2- methyl-5,γ-dioxo-2-furanpentanoic acid (TMDFA) and 3-(2-methyl-5-oxo- tetrahydrofuran-2-yl)-4-oxopentanoic acid (MOTOA)] that are precursors for fuels and chemicals. [ABSTRACT FROM AUTHOR]

Summary: The nanocrystalline material LiMn0.8Fe0.2PO4/C was prepared by the solvothermal method using the toluene‐soluble component of pitch or sucrose as a carbon source. The effects of carbon source types and contents, and the carbonization‐heating rate between 350°C and 500°C on the physicochemical and electrochemical properties of the obtained materials were investigated. When the carbonization heating rate was between 350°C and 500°C is 0.5°C·min−1, cathode TS‐200‐0.5 coated by 200 mg toluene‐soluble component of pitch showed the optimum electrochemical performance with discharge specific capacity of 156.4, 149.2, and 116.4 mAh·g−1 at 0.1, 1, and 5 C, respectively. After 150 cycles at 1 C, the specific discharge capacity was still 135.1 mAh·g−1, and the capacity retention rate was 92.7%. Compared with sucrose, the toluene‐soluble component of pitch is an aromatic compound, and its pyrolytic carbon has streamlined structure with high graphitization. Moreover, small amounts of sulfur and nitrogen doped exist in pyrolysis carbon of the toluene‐soluble component of pitch. Cathode TS‐200‐0.5 exhibits high ionic and electronic conductivity and stability. [ABSTRACT FROM AUTHOR]

We demonstrated the relationships between elemental carbon (EC) and EC fractions during evolved gas analysis (EGA) for PM2.5 sampled at KOREATECH from 29 March 2018 to 12 May 2018. The EC concentrations were compared to the concentrations of equivalent black carbon to confirm that the level of EC concentrations analyzed in this study was valid. Among various EC fractions and their combination, EC1+EC3 fractions were best correlated with the EC concentrations. Especially, dominant EC fraction was related with the dependence of carbon oxidation quantity on the oxidation temperature. We also examined the relationships between pyrolytic carbon (PyC) and EC concentration with respect to the split time. PyC was correlated with the split time in the phase of oxygen-helium mixture. PyC was close to zero for the split time in the helium phase. It is novel, as far as the authors know, that the correlation between PyC and the split time under NIOSH 5040 protocol was reported with regard to EGA. We believe that our study helps to identify what causes uncertainty in the quantification of PyC. [ABSTRACT FROM AUTHOR]

In this work we compare seven different types of natural and synthetic graphite particles and examine how their integration into the cathode of carbon-based perovskite solar cells (C–PSCs) is influencing their opto-electronic properties. By combining x-ray diffraction, Raman spectroscopy and 4-point probe measurements we show that the differences in graphite crystallinity significantly affect the sheet resistance of the carbon-based cathode. The most conductive carbon-based film with an exceptional sheet resistance of 4 Ω/sq. have been produced from scaly graphite with the crystallite dimensions of L a = 60.6 nm and L c = 28.6 nm. Electrochemical Impedance Spectroscopy further revealed that charge transfer resistance at the perovskite/carbon contact differ for each graphite type. Overall, the pyrolytic graphite was found to be the best compromise between high conductivity and low charge transfer resistance leading to least series resistance losses and a fill factor (FF) above 74% (in perovskite solar cells with area of 0.64 cm2). However, an overall efficient hole extraction and lower non-radiative charge recombination in C–PSCs with scaly graphite resulted in the highest average power conversion efficiency and a champion device reaching 14.63%. All the C–PSCs show exceptional moisture stability for 5,000 h under ambient condition, with a PCE decrease of less than 3%. [Display omitted] [ABSTRACT FROM AUTHOR]

In recent years the most studied carbon allotrope has been graphene, due to the outstanding properties that this two-dimensional material exhibits; however, it turns out to be a difficult material to produce, pattern, and transfer to a device substrate without contamination. Carbon microelectromechanical systems are a versatile technology used to create nano/micro carbon devices by pyrolyzing a patterned photoresist, making them highly attractive for industrial applications. Furthermore, recent works have reported that pyrolytic carbon material can be graphitized by the diffusion of carbon atoms through a transition metal layer. In this work we take advantage of the latter two methods in order to produce multilayer graphene by improving the molecular ordering of photolithographically-defined pyrolytic carbon microstructures, through the diffusion (annealing) of carbon atoms through nickel, and also to eliminate any further transfer process to a device substrate. The allotropic nature of the final carbon microstructures was inspected by Raman spectroscopy (Average ID/IG of 0.2348 ± 0.0314) and TEM clearly shows well-aligned lattice planes of 3.34 Ĺ fringe separation. These results were compared to measurements made on pyrolytic carbon (Average ID/IG of 0.9848 ± 0.0235) to confirm that our method is capable of producing a patterned multilayer graphene material directly on a silicon substrate. [ABSTRACT FROM AUTHOR]

The design of solid-state materials whose properties and functions can be manipulated in a controlled manner by the application of electron beam irradiation is important in modern materials chemistry and physics. In this paper, we present a progress in the development of scalable electron beam irradiation platform to obtain innovative materials for technological and industrial applications, since one of the problems to be solved in this research area is the scalability of these new nanomaterials induced by electron beam irradiation (EBI). In particular, we focus on carbon structures due to its excellent and exciting properties applied in the technological area in the last years, where we show for the first time a new strategy for carbon allotropic transformation through the portable EBI. This new platform is particularly effective, fast, versatile, clean and easy-to-use, facilitating the preparation of many types of nanomaterials that cannot be obtained by conventional chemical and physical methods. The EBI on flat graphite pellets resulted in a covering of it surface with rod-like particles composed of different allotropic forms of carbon. Furthermore, the developed system allowed the implantation of the Fe as a catalytic material through steel sputtering of the high voltage acceleration anode during the EBI process. It was observed by HRTEM analyses that the rod-like particles are preferentially composed of highly oriented graphite in its bottom, polycrystalline graphite in its middle and magnetite nanoparticles in its top. Image 1 [ABSTRACT FROM AUTHOR]

Selecting suitable precursor and exploring controllable carbonization process is crucial to carbon materials, especially for carbon-based material in electromagnetic interference shielding application. However, carbon materials are primarily used in the forms of powders, which remains big challenge in developing continuous ones. Herein, large-scale aramid nanofibers (ANFs)-derived carbon membrane was developed for the first time. Influence of pyrolysis temperature on chemical constitution and crystalline structure during carbonization process was investigated. The results showed that the decomposition stage of ANFs freestanding membrane begun at ~ 474 °C, while the reconstruction stage begun at ~ 600 °C. Besides, the rupture of amide bonds occurred around 500 °C, which was validated by disappearance of C=O groups. Moreover, the declining integrated intensities ID/IG, and the sharp rising electrical conductivity of demonstrated progressive aromatization and ring condensation. In addition, the microgrooves with an average diameter of ~ 40 nm were formed during the carbonization. Subsequently, the ANFs-derived carbon membrane exhibited superior conductivity (123.8 S cm−1) and electromagnetic shielding effectiveness value of 16 dB (X band) with thickness of 28 μm. This work provided feasible strategy in fabricating carbon-based membrane for advanced electronic devices. [ABSTRACT FROM AUTHOR]

To improve the mechanical properties of carbon/carbon (C/C) composites, in-situ synthetized single-crystalline hafnium carbide nanowires (HfCnws) were introduced into the carbon fiber preforms by electrophoresis-thermal evaporation method. The Multi-walled carbon nanotubes (MWCNTs) were utilized as the carbon source and templates for forming HfCnws. The microstructure, chemical composition and mechanical properties of the HfCnws modified carbon/carbon (HfCnws-C/C) composites were characterized. Results reveal that HfC is produced preferentially in the inner nodular parts and end parts of MWCNTs. The raising heat-treatment temperature would influence the diffusion rate of Hf atoms and then the number of nucleation sites, which further changed the aspect ratio and morphology of HfCnws. The HfCnws have refined the grain size of pyrolytic carbon (PyC), and significantly improve the flexural strength of C/C composites by 79.3%. [ABSTRACT FROM AUTHOR]

Carbon dots could significantly change the property of a normal material and have received wide attention in the recent decade. In this research, glucose as a carbon source, carbon dots decorated medical stone (CD-MS) was successfully synthesized for efficient adsorptive removal of organic pollutants. Pyrolytic temperature and glucose concentration for the adsorbent preparation were proved to have a significant impact on the adsorptive performance. The optimal pyrolytic temperature and glucose concentration were found to be 300°C and 0.5 M, yielding the optimized adsorbent 0.5CDMS-300 superior to other carbon dots decorated MS. Surface morphology analysis demonstrated that the carbon dots were successfully immobilized on the surface of MS while the atomic ratio of C increased from 2.6% of the raw MS to 11.25% of the 0.5CD-MS-300. Three organic pollutants including p-nitrophenol, orange II and methylene blue with different charge properties were employed to explore the adsorptive performance of the 0.5CD-MS-300. The results indicated that the surface of 0.5CDMS-300 was negatively charged while carbon dots had significantly improved the adsorption capability of the raw MS. As such, the resulting adsorbent 0.5CD-MS-300 can be considered as a powerful adsorbent for the removal of some organic contaminants from wastewater. [ABSTRACT FROM AUTHOR]

This paper presents a model describing polymorphic phase transition in a shock wave based on experimental data on shock compression of a material. It is assumed that the phase transition in a non-porous material is of martensitic type and occurs in a stationary shock wave that arises in the immediate vicinity behind the first shock wave. Conditions for the occurrence of this shock wave are determined. The model has been tested for non-porous pyrolytic graphite. It has been shown that the model adequately describes the experimental results obtained in various studies for this type of graphite. [ABSTRACT FROM AUTHOR]

A cellular carbon support was first obtained by modifying the surface of a cellular carbon material with pyrolytic carbon. On this support, palladium catalysts with controlled particle size of deposited metal were synthesized for the first time. By the example of the reaction of gas-phase hydrogenation of acetylene, the possibility of using such catalysts in selective hydrogenation reactions was shown. [ABSTRACT FROM AUTHOR]

Hafnium carbide nanowires (HfCnws) were in-situ grown in carbon/carbon (C/C) composites, and subsquently the preforms were densified by isothermal chemical vapor infiltration to obtain HfCnws modified carbon/carbon (HfCnws-C/C) composites. Morphology and microstructure of HfCnws were examined, and the effect of HfCnws on the mechanical property and ablation resistance of C/C composites were also investigated. Results show that introducing HfCnws refined the grain size of pyrolytic carbon (PyC). The out-of-plane compression, interlaminar shear and flexual strength of HfCnws-C/C composites increased by 120.80%, 45.60% and 94.65%, respectively compared with pure C/C, and the HfCnws-C/C shows good ablation resistance under oxy-acetylene flame ablation. [ABSTRACT FROM AUTHOR]

The process of solid–electrolyte interphase (SEI) formation is systematically investigated along with its chemical composition on carbon electrodes in an ionic liquid‐based, Li‐containing electrolyte in a combined surface science and electrochemical model study using highly oriented pyrolytic graphite (HOPG) and binder‐free graphite powder electrodes (Mage) as model systems. The chemical decomposition process is explored by deposition of Li on a pre‐deposited multilayer film of 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMP][TFSI]) under ultrahigh vacuum conditions. Electrochemical SEI formation is induced by and monitored during potential cycling in [BMP][TFSI]+0.1 m LiTFSI. The chemical composition of the resulting layers is characterized by X‐ray photoelectron spectroscopy (XPS), both at the surface and in deeper layers, closer to the electrode|SEI interface, after partial removal of the film by Ar+ ion sputtering. Clear differences between chemical and electrochemical SEI formation, and also between SEI formation on HOPG and Mage electrodes, are observed and discussed. [ABSTRACT FROM AUTHOR]

A carbothermal reduction reaction (CRR) approach was developed in this research to tailor the surface phase structure of the SiO 2f /SiO 2 composites with high chemical reactivity to replace the original inert surface. Results show that SiC can form after CRR treatments. For AgCuTi-SiO 2f /SiO 2 wetting interfaces, TiC and residual pyrolytic carbon layer can be found inside the reaction layer, which was the key, promoting the wettability of the AgCuTi-SiO 2f /SiO 2 system. The contact angle of the AgCuTi-SiO 2f /SiO 2 system dropped from 127° to 43° after the CRR treatments. The reliability of the bonded AgCuTi-SiO 2f /SiO 2 interface was also characterized by putting 3 different systems into comparison, i.e., the original AgCuTi-SiO 2f /SiO 2 system, the AgCuTi-SiO 2f /SiO 2 system with CRR treatments (SiC formation) and the AgCuTi-SiO 2f /SiO 2 system coated with powdered carbon (no SiC formation). The shear strength of the SiO 2f /SiO 2 -AgCuTi-SiO 2f /SiO 2 system with CRR treatments was the highest, which was 3 times that of the other 2 brazing systems. [ABSTRACT FROM AUTHOR]

Cobalt interaction and its effects on carbon-based systems at the nanoscale have recently attracted much attention in different fields, such as catalysis of carbon nanotubes or graphene and graphite nano-patterning taking advantage of its ferromagnetic behavior. Experiments performed in our laboratories show how the re-oxidation process of two equivalent monolayers of CoO deposited on highly oriented pyrolytic graphite at 400 °C leads to the formation of nanochannels at lower temperature than using other methods. Here we present the in-situ characterization of the carbon gasification reaction that drives this process by means of near ambient pressure X-ray photoelectron spectroscopy performed at the ALBA synchrotron facility. The reason why this reaction takes place at such low temperature compared to other methods is due to the weakening of the carbon σ bonds by the initial CoO wetting layer formed at the early stages of growth on the graphite surface. Besides nanochannels, ex-situ atomic force microscopy measurements also show the appearance of two more kinds of nanostructures: nano-strips and nano-rings. The appearance of these nanostructures reveals the impressive modification of the surface after the re-oxidation process mediated by the cobalt oxide. Image 1 [ABSTRACT FROM AUTHOR]

Fundamental charge‐transfer dynamics for technologically relevant carbons, such as disordered "hard" carbons, can be studied by designing planar mimics. We fabricate thin films of "pyrolytic carbon" (pyC) by decomposition of benzene at 1000 °C and examine the physical and electrochemical properties of the native pyC film, as well as variants after heteroatom doping, plasma oxidation, and metal nanoparticle modification. The pyC films are optically reflective at the macroscale, relatively planar (1–3 nm RMS roughness by atomic force microscopy) and disordered (via Raman scattering). Thiophenyl‐doped pyC films (0.6–1.7 atom % sulfur) suitably mimic the disorder, chemical state (X‐ray photoelectron spectroscopy), and work function (Kelvin probe) of a workhorse carbon black, Vulcan XC‐72. Using ferri/ferrocyanide as a redox probe, we find that oxygen functionalities enhance the heterogeneous electron‐transfer rate constant up to 3×, while high levels of sulfur dopants decrease the rate 2×. We also explore thiophenyl‐directed adsorption of Au nanoparticles and show that hydrogen evolution at 0.1 mA cm−2 occurs ∼95 mV more positive at <1 % Au@pyC∼S than at pyC∼S. [ABSTRACT FROM AUTHOR]

The effect of ash fusion characteristic on the structure characteristics and gasification activity of residual carbon, and the migration of K during biomass (rice straw, B RS) gasification at 1100 °C were investigated. Results showed that the carbon and AAEMs were wrapped by molten ash, and the residual carbons in B RS gasification char were composed of pyrolytic carbon and partial-gasified carbon. The molten ash formed spherical particles adhering to the surface of gasification char, and the particle size gradually enlarged. With the progress of B RS gasification, the BET surface area and microporous surface area decreased monotonously, and the I D1 /I G values increased firstly and then decreased, and the total active sites were poorer at the gasification time of 15 and 20 minutes. The gasification activity of residual carbon had no linear relationship with gasification time, and followed the order of DB RS -25> DB RS -10> DB RS -20≈DB RS -15≈DB RS -5. Furthermore, the total content of K increased obviously, and the water-soluble K, ion-exchanged K, and acid-soluble K were changed to insoluble K with the increase of gasification time. • The ash fusion on the property of residual carbon and K migration are studied. • Molten ash forms increasingly large spherical particles, and the carbon and AAEMs are wrapped. • Surface area monotonically decreases, and I D1 /I G first increases and then decreases. • The gasification activity of residual carbon does not change linearly. • The total content of K increases, and other forms of K are changed to insoluble K. [ABSTRACT FROM AUTHOR]

Abstract Radially aligned porous carbon nanotube arrays have been verified to effectively utilize the excellent performance of carbon nanotubes. Present work focuses on growing such unique structure on pyrolytic carbon coated carbon fibers by chemical vapor deposition. Results showed that high-quality and straight carbon nanotubes grow in radial morphology with diameter of about 150 nm and length ranging from 20 to 30 μm. The catalyst (cementite crystal phase) is located at the middle part of carbon nanotubes and the inner cavity is gradually collapsed. Weibull strength distribution indicated that after the growth of carbon nanotubes, both strength and strength stability of pyrolytic carbon coated carbon fibers are improved. Our work provides a great candidate for potential applications in the field of composite. Graphical abstract Image 1 Highlights • Radially aligned porous carbon nanotube arrays are successfully grown on pyrolytic carbon coated carbon fibers. • Structure of as-deposited carbon nantube arrays is characterized in detail. • Both strength and strength stability of pyrolytic carbon coated carbon fibers are improved. [ABSTRACT FROM AUTHOR]

It has been a long-standing challenge in modern material design to create low-density, lightweight materials that are simultaneously robust against defects and can withstand extreme thermomechanical environments, as these properties are often mutually exclusive: The lower the density, the weaker and more fragile the material. Here, we develop a process to create nanoarchitected carbon that can attain specific strength (strength-to-density ratio) up to one to three orders of magnitude above that of existing micro- and nanoarchitected materials. We use two-photon lithography followed by pyrolysis in a vacuum at 900 °C to fabricate pyrolytic carbon in two topologies, octet- and iso-truss, with unit-cell dimensions of ∼2 μm, beam diameters between 261 nm and 679 nm, and densities of 0.24 to 1.0 g/cm³. Experiments and simulations demonstrate that for densities higher than 0.95 g/cm³ the nanolattices become insensitive to fabrication-induced defects, allowing them to attain nearly theoretical strength of the constituent material. The combination of high specific strength, low density, and extensive deformability before failure lends such nanoarchitected carbon to being a particularly promising candidate for applications under harsh thermomechanical environments. [ABSTRACT FROM AUTHOR]

Two carbon layers: micro-formed of pyrolytic carbon (CVD) and nano-constructed of multi-walled carbon nanotubes (MWCNTs) by electrophoretic deposition (EPD), both formed on a Ti support, were contacted with selected proteins. As target proteins, albumin from chicken egg white (Alb), bovine serum albumin (BSA) and human serum albumin (HSA), were tested. To unravel the carbon layer-albumin interaction 2D correlation Raman microspectroscopy was applied, checking also the importance of its origin, animal or human. 2D correlation confirms that albumin adheres to the surface of both studied carbon layers. Additionally, it allowed to resolve additional valuable characteristic, which is not directly visible in the Raman spectra. For C (CVD) carbon layer a change in albumin conformation was observed, but for nano-MWCNTs layer interactions with particular amino acid side chains with the surface was seen. Differences between albumins can drive on the synthetic material-albumin interactions. [ABSTRACT FROM AUTHOR]

Abstract: The chemical modification of an sp2 hybridized carbon surface in a controllable manner is very challenging but also crucial for many applications. An inverse electron demand Diels–Alder (IEDDA) reaction using microcontact printing technique is introduced to spatially control the modification of a highly ordered pyrolytic graphite (HOPG) surface under ambient conditions. The covalent modification was characterized by Raman spectroscopy, XPS, and SECM. Tetrazine derivatives can effectively react with an HOPG surface and with microcontact printing methods resulting in spatially patterned surfaces being produced with micrometer‐scale resolution. [ABSTRACT FROM AUTHOR]

The electrophoretic deposition (EPD) of ZnO nanoparticles onto highly oriented pyrolytic graphite (HOPG) chips from a nonaqueous suspension is reported. Deposits are fast fired at 1200 °C in vacuum, and lifted off the substrate using Kapton tape. The SEM micrographs revealed exfoliated graphene multilayer flakes on the back surface of the ZnO layers. The I-V characteristics of the ZnO/HOPG junctions demonstrate the atmospheric sensitivity of the junction energy barrier. This is the first report of using HOPG chips as substrates for the EPD of metal oxides. Forming metal oxide/graphene junctions has explicit technical difficulties, and the presented method is anticipated to find niche applications in fabricating wide area metal oxide/graphene multilayer junction devices such as radiation detectors and supercapacitors. [ABSTRACT FROM AUTHOR]

In this work, carbon papers and aerogels based on graphene layers and chitosan were prepared. They were obtained by mixing chitosan (CS) and a high surface area nanosized graphite (HSAG) in water in the presence of acetic acid. HSAG/CS water dispersions were stable for months. High resolution transmission electron microscopy revealed the presence of few graphene layers in water suspensions. Casting or lyophilization of such suspensions led to the preparation of carbon paper and aerogel, respectively. In X-ray spectra of both aerogels and carbon paper, peaks due to regular stacks of graphene layers were not detected: graphene with unaltered sp2 structure was obtained directly from graphite without the use of any chemical reaction. The composites were demonstrated to be electrically conductive thanks to the graphene. Chitosan thus makes it possible to obtain monolithic carbon aerogels and flexible and free-standing graphene papers directly from a nanosized graphite by avoiding oxidation to graphite oxide and successive reduction. Strong interaction between polycationic chitosan and the aromatic substrate appears to be at the origin of the stability of HSAG/CS adducts. Cation-p interaction is hypothesized, also on the basis of X-ray photoelectron spectroscopy findings. This work paves the way for the easy large-scale preparation of carbon papers through a method that has a low environmental impact and is based on a biosourced polymer, graphene, and water. [ABSTRACT FROM AUTHOR]

[Display omitted] • The industrial solid waste silicon powder is used as low-cost anode material. • Porous composites are constructed by a scalable, facile, and eco-friendly method. • C@void/Si-G anode exhibits excellent reversible capacity and cycling capability. • The synergistic effect of carbon and porous space produces excellent properties. Silicon is a potential anode material for Li battery due to its high theoretical specific capacity (4200 mAh g−1). However, Si is hampered for practical application in Li-battery due to its enormous volume alternation causing instability. Herein, we demonstrated a novel carbon-coated porous structure (C@void/Si-G) synthesized by uniformly wrapping Si into pitch pyrolytic carbon shells and then in-situ removing the sodium chloride template can overcome the bottleneck. It is worth noting that our process for C@void/Si-G also offers a simple route for cost down and mass production of anode material. The C@void/Si-G anodes exhibit an excellent capacity of 1082.7 mAh g−1 at 0.2 C after 200 cycles. Furthermore, it holds a high capacity retention of 81.9 % after 500 cycles at 0.5 C. We found that C@void/Si-G composite only rises about 41% volumetric expansion during 500 operation cycles. This can effectively avoid direct contact between silicon and electrolyte to form a stable solid electrolyte interphase (SEI) film. Especially, practical application of the C@void/Si-G anode is demonstrated in a full cell pairing with LiNi 0.3 Co 0.3 Mn 0.3 O 2 cathode. The full cell presents great cycle retention of 90.1 % at 0.2 C after 100 cycles and a high energy density (446 Wh kg−1). [ABSTRACT FROM AUTHOR]

Carbonization of N-containing aromatic polymers is a promising route to prepare N-doped carbon materials with low cost, easy regulation, and no external N source. However, there are relatively few studies applying these materials for persulfate activation, and the catalytic mechanisms of the existing reaction systems are divergent. In this paper, a series of N-doped carbon materials were prepared by carbonizing polyaniline (PANI), polypyrrole (PPy), and PANI-PPy copolymers. The copolymer-derived carbon materials exhibit superior peroxydisulfate (PDS) catalytic activity compared to some commercially available and reported carbon materials. Combing quenching experiments, EPR analysis, chemical probe analysis, and various electrochemical analysis methods identified the singlet oxygen (1O 2) and electron transfer as the main reaction pathways of all systems, but the contribution of each pathway was influenced by the types of precursors. The structure-activity relationship indicated that the carbonyl group (C O) was the main active site for the 1O 2 pathway, while the electron transfer ability of the reaction system and the potential of the complex formed by catalyst and PDS jointly determined the electron transfer pathway. This paper provides a new strategy for obtaining excellent N-doped carbon-based persulfate activators and deepens the insight into the mechanism of PDS activation by N-doped carbon materials. [Display omitted] • An excellent PDS activator derived from carbonized PANI-PPy copolymer was prepared. • 1O 2 and electron transfer pathways dominate the 2,4-DCP degradation. • The contribution of each pathway was influenced by the types of precursors. • C= O was the main active site affecting the contribution of the 1O 2 pathway. • The electrochemical properties determined the electron transfer pathway. [ABSTRACT FROM AUTHOR]

Black carbon plays an important role in climate change. Whereas, accurate measurement of black carbon (also known as elemental carbon (EC)) is still a challenging issue because portion of the pyrolytic carbon produced from the organic carbon (OC) can cause the overestimation of EC when measured by thermal-optical method. As one of the remote regions in the world, the Tibetan Plateau (TP) is characterized as high OC/EC ratio in its atmosphere. In this study, potential influence of relative high OC concentration to EC were investigated at three remote sites (Yaze, Everest and Nam Co) in the TP. The results showed that carbonaceous aerosols from different sources can affect the fraction of OC extracted by methanol. Concentration of OC extracted by methanol had a significantly positive correlation with the reduction of pyrolytic carbon and EC concentrations, indicating that part of OC extracted by methanol can decrease the production of pyrolytic carbon and then reduce the overestimation of EC. After considering this effect, it is shown in this study that actual EC concentration at Yaze, Everest and Nam Co were overestimated by approximately 40.0 ± 12.6%, 28.8 ± 9.1% and 24.8 ± 4.7%, respectively. Accordingly, combined with the overestimation of EC concentration by carbonates, actual ratios of solar energy absorbed by organic carbon to EC were 1.67, 2.33 and 2.78 times those of original ones at Yaze, Everest and Nam Co, respectively. Therefore, warming effect caused by EC on the TP should be lower than that previously estimated. This phenomenon needs to be considered for both in situ study and model simulation in the future. [Display omitted] • Overestimation of EC concentration by OC in aerosols of the TP were investigated. • Fraction of OC extracted by methanol was affected by the sources of aerosols. • EC concentration overestimated by OC of aerosols at Yaze was up to 40.0%. • Fraction of solar energy absorbed by OC relative to EC was underestimated. [ABSTRACT FROM AUTHOR]

• Glucose-derived carbon skeleton is reconstructed by in-situ zinc molten salt. • Graphene microcrystal is locally rearranged by reconfiguring the bridging carbon. • The conversion from bridging sp3-C to sp2-C decreases the work function of carbon. • The lower work function contributes to the first electron transport of ORR in OHP. • The locally ordered carbon exhibits more excellent ORR activity than Pt/C. The development of new regulation strategy for constructing functional carbon skeletons is a standing challenge for oxygen reduction reaction (ORR). Herein, the locally ordered graphene microcrystals with suitable N -sites derived from glucose are synthesized under the assistance of low melting point zinc molten salt. Utilizing the structural features of graphene microcrystals ("house of cards" model), the work function of carbon skeleton is reduced after inducing the conversion of bridging sp3-C to bridging sp2-C (ratio of sp2-C to sp3-C increases from 3.75 to 7.41). The lower work function of locally ordered microarchitectures decreases the long-range electron transfer barrier in outer-Helmholtz plane. And the synergy between pyridinic N and graphitic N is beneficial for enhancing short-range electron transfer process in inner-Helmholtz plane. After rearrangement of carbon skeletons, the half-wave potential can increase from 0.846 V to 0.874 V, and the HO 2 – by-product yield decreases from 31.5 % to 6.9 %. Furthermore, the discharge voltage of locally ordered microarchitecture (1.31 V) at 10 mA cm−2 can surpass the commercial Pt/C (1.25 V) in Zn-air battery devices. In brief, it provides a new direction of structure design for carbonaceous catalysts. [ABSTRACT FROM AUTHOR]

• We proposed an effective strategy of double carbon coating by one-pot synthesis for enhancing structural stability of SnS anode materials for sodium-ion batteries. • The hierarchical carbon network enhances electronic conductivity of the SnS/carbon hybrid materials, leading to enhanced rate performance. • The in-situ pyrolytic carbon coating alleviates the dissolution of intermediates and buffer the volume change of the SnS material, while the graphene wrapping further improves the structural stability. Two-dimensional (2D) layered metal sulfides have shown great potentials for sodium-ion anode materials owing to fast interlayer diffusion. As one of 2D layered metal sulfides, SnS has been widely studied because of its high theoretical specific capacity (1022 mAh/g vs 372 mAh/g for hard carbon) and large interlayer spacing (4.33 Å vs about 3.4 Å for hard carbon). However, SnS still face several problems, such as low electronic conductivity, large volume change, dissolution of intermediate products, and poor structural stability. To solve these problems, herein, tin sulfide (SnS)/carbon hybrid materials were prepared through simple solvothermal and subsequent sintering processes. By a one-pot synthesis, SnS nanospheres were in-situ coated with pyrolytic carbon and wrapped by conductive reduced graphene oxide sheets (SnS@C@rGO). This hierarchical carbon network enhances electronic conductivity of the SnS@C@rGO hybrid, leading to enhanced rate performance. Moreover, the in situ pyrolytic carbon coating can alleviate the dissolution of intermediates and buffer the volume change of the SnS material, while the graphene wrapping can further improve the structural stability, leading to enhanced cycling performance. When used as anode material, the double-coated SnS@C@rGO anode delivered the highest retention capacity of 383.5 mAh/g after 100 cycles at a current density of 1 A/g, when compared with SnS@C (114.4 mAh/g) and SnS@rGO (230.7 mAh/g). Even at a high current density of 5 A/g, the SnS@C@rGO anode still delivered a high retention capacity of 312.2 mAh/g after 500 cycles, when compared with SnS@C (119.3 mAh/g) and SnS@rGO (140.1 mAh/g). This work demonstrates an effective strategy of double carbon coating for enhancing structural stability and battery performance of SnS anode materials, which can also be used to modify other anode materials for sodium- and lithium-ion batteries. [ABSTRACT FROM AUTHOR]