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Hierarchical nano‐micro carbon spheres porous carbon composites are successfully synthesized derived from Euryale ferox shells by the in‐situ decoration of the porous carbon with carbon spheres from carboxymethyl cellulose under the activation of KOH. Effects of fabrication and activation manner on surface area of porous carbons were investigated. The influence of activation temperature, impregnation ratio and modifier were analyzed. The specific surface area, pore volume and average pore diameter of porous carbon was characterized by N2 adsorption isotherms. Porous carbon produced at 800 °C with an impregnation ratio of 3, 2 hours of carbonization time, 20 hours immersion time has been found 2506 m2 g−1, 1.515 cm3 g−1 and 2.4 nm of the optimum specific surface area, pore volume and average pore diameter, respectively. The result of Fourier‐infrared spectroscopy analysis of the prepared porous carbon confirmed that it has abundant functional groups on the surface. The scanning electron micrographs of the prepared porous carbon indicated that a well‐developed pore structure was formed during the experiment. [ABSTRACT FROM AUTHOR]

The incorporation of carbon materials can effectively enhance the performance of thermoelectric materials. By optimizing the thermoelectric properties of the carbon scaffold, it is possible to further improve the thermoelectric performance of the prepared carbon-based composites. To elevate the thermoelectric performance of the carbon scaffold, this work introduces a novel mesoscopic design strategy, utilizing natural flake graphite to create a three-dimensional ordered porous framework. Highly controllable anisotropic conductivity and thermal conductivity of the porous graphite skeleton were achieved, by combining sizable sodium chlorine templates (37.5–250 μm) with a natural flake graphite matrix (50–150 μm). A porous graphite with high electrical conductivity and low thermal conductivity along the vertical axis was obtained by carefully regulating the parameters. The sample demonstrated exceptional thermoelectric conversion performance, achieving a thermoelectric power factor of 12.2 μW m−1 K−2 and a figure of merit value of 28.3 × 10−4. Furthermore, the thermoelectric property of the samples could be greatly improved by adding a small amount of ferric chloride, with a thermoelectric power factor reaching 41.9 × 10−4 and a thermoelectric figure of merit reaching 81.4 μW m−1 K−2. This work provides an effective scheme for the mesoscopic regulation of porous graphite carbon structures and offers a new strategy for enhancing the performance of thermoelectric generators. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, tetradecanol–palmitic acid/expanded perlite composites containing carbon fiber (TD-PA/EP-CF CPCMs) were prepared by a vacuum impregnation method. Binary eutectic mixtures of PA and TD were utilized as thermal energy storage material in the composites, where EP behaved as supporting material. X-ray diffraction demonstrated that crystal structures of PA, TD, EP, and CF remained unchanged, confirming no chemical interactions among raw materials besides physical combinations. The microstructures indicated that TD-PA was sufficiently absorbed into EP porous structure, forming no leakage even in molten state. Differential scanning calorimetry estimated the melting temperature of TD-PA/EP-CF CPCM to 33.6 °C, with high phase change latent heat (PCLH) of 138.3 kJ kg−1. Also, the freezing temperature was estimated at 29.7 °C, with PCLH of 137.5 kJ kg−1. The thermal cycling measurements showed that PCM composite had adequate stability even after 200 melting/freezing cycles. Moreover, the thermal conductivity enhanced from 0.48 to 1.081 W m−1 K−1 in the presence of CF. Overall, the proposed CPCMs look promising materials for future applications due to their appropriate phase change temperature, elevated PCLH, and better thermal stability. [ABSTRACT FROM AUTHOR]

Carbon felt composites were prepared by chemical vapor deposition (CVD) method using Ni(NO3)2as a catalyst and methane as a pyrocarbon precursor. The pyrocarbon which has been deposited on fiber surface increased gradually with increase in deposition temperature. Besides, the surface of the deposited pyrocarbon was seen to contain many micropores. The phenol-adsorption capability evaluation of the composites showed that the adsorption equilibrium was achieved in 90 min, and the maximum adsorption quantity reached was 13.37 mg/g. The Langmuir isotherm model was preferred in fitting the adsorption data compared with the Freundilch isotherm model. The theoretical maximum adsorption was calculated to be 17.45 mg/g. At pH = 5, the adsorption quantity was a minimum of 10.66 mg/g. Moreover, the phenol-adsorption quantity increased with increasing deposition temperature. The adsorption quantity on carbon felt composites without pyrolytic carbon deposition was minimum, being 9.11 mg/g, while that of carbon fiber produced at 950°C reached the maximum of 13.37 mg/g. [ABSTRACT FROM PUBLISHER]

Carbon/carbon composites were prepared by thermal gradient chemical vapor infiltration with kerosene as precursor. The microstructure and electrical resistivity were examined by polarized light microscopy and low-resistance instrument, respectively. The effects of processing parameters on microstructure as well as the influences of sample density, processing parameters, and needle punch on electrical resistivity of carbon/carbon composites were analyzed. The results show that besides rough laminar, smooth laminar and isotropic pyrocarbon occur at temperatures of 1000°C and 1200°C, respectively. The graphitization degree of composites increases from 16.28% to 63.95% as the heat treatment temperature increases from 2100°C to 2500°C. The electrical resistivity of carbon/carbon composites decreases with increasing heat treatment temperature and sample density but increases as the texture of pyrocarbon varies from rough laminar to smooth laminar. The main mechanism for influencing the electrical resistivity of carbon/carbon composites can be changing carrier concentration, altering grain scattering, or both actions. [ABSTRACT FROM PUBLISHER]

Abstract: Carbon/carbon (C/C) composites were prepared by thermal gradient chemical vapor infiltration with a fast densification rate. The fracture morphology and mechanical properties were examined by scanning electron microscopy and mechanical testing, respectively. The effects of preform type and heat treatment temperature (HTT) on the mechanical properties of C/C composites were analyzed. The results show that the average flexural strength drops from 47.8MPa to 38.6MPa as the HTT increases from 2100°C to 2500°C. C/C composites with felt as preform show brittle fracture and samples with needle-punched felt as reinforcement present obvious pseudoplastic property. The interlaminar shear strength of needle-punched felt reinforced composites is higher than that of sample with felt as preform by 44.26% owing to the needle-punched fiber in the thickness direction. The strength of interfacial bonding plays a key role to mechanical properties and failure behavior of C/C composites. [Copyright &y& Elsevier]

Abstract: Large-size carbon/carbon composites (Φ 450× Φ 230×15mm3) have been produced by chemical vapor infiltration with kerosene as precursor. The microstructure of pyrocarbon was examined by polarized light microscopy and scanning electron microscopy. The infiltration kinetics was analyzed to investigate the infiltration rate limitation by parameters such as temperature. The results show that rough laminar carbon constitutes the majority of the matrix at a medium temperature (about 1100°C), while smooth laminar and isotropic structures occur at temperatures lower than 1000°C and higher than about 1200°C, respectively. The apparent activation energy of kerosene decomposition in the temperature range 900–1200°C is about 125.6kJ/mol. [Copyright &y& Elsevier]

• Carbon micro- and nanofibers were prepared by using gyration. • The distribution of fiber diameter showed a normal law with 400-600 nm. • GO changes the orderly arrangement of fibers into a network structure. • The conductivity of carbon nanofibers is greatly improved by adding GO. • When GO was added, the electrode showed excellent electrochemical performance. In this paper, graphene oxide (GO) were added into polyacrylonitrile to prepare carbon nanofiber by using gyration and subsequent carbonization process as to improve their electrochemical properties. The microstructure and electrochemical properties of prepared carbon nanofiber samples were investigated by using scanning electron microscopy and electrochemical workstation, respectively. The effects of the addition amount of graphene oxide and carbonation temperature on the microstructure and electrochemical properties of composite carbon nanofibers were studied. [ABSTRACT FROM AUTHOR]

Phase changes of Si powder in the MgO–C refractory were investigated in a reducing atmosphere system at 1500 °C. The phase compositions, morphology and microstructures of the products were determined using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and energy dispersive spectroscopy (EDS). β-SiC nanowires were synthesized in the pores of MgO–C bricks without the assistance of catalysis. The synthesized nanowires were typically a few hundred nanometers to several micrometers in length. The formation process was governed by VS mechanism. The formed β-SiC nanowires may help to reinforce the mechanical properties and enhance the antioxidation properties of MgO–C bricks. [ABSTRACT FROM AUTHOR]