Carbon Letters 2021 KCI Impact Factor : 0.52

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pISSN : 1976-4251 / eISSN : 2233-4998
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2020, Vol.30, No.6

  • 1.

    Electric heating performance of carbon thin films prepared from SU-8 photoresist by deep UV exposure and carbonization

    Lee Byoung-Min , Nam Hui-Gyun , Choi, Hyeong Yeol and 3 other persons | 2020, 30(6) | pp.595~601 | number of Cited : 0
    We report the structural characterization and electric heating performance of carbon thin flms (CTFs), which were prepared from negative-type SU-8 photoresist by deep UV exposure and following carbonization. The prepared CTFs were found to have pseudo-graphitic carbon structures containing partially graphite domains in the amorphous carbon matrix. The CTFs showed a very smooth surface morphology with a roughness of 0.42 nm. The 107 nm-thick CTFs exhibited an excellent electric heating performance by attaining a high maximal temperature of 207 °C and a rapid heating rate of 13.2 °C/s at an applied voltage of 30 V. Therefore, the CTFs prepared in this study can be applied as electrode materials for high-performance electric heaters.
  • 2.

    Influence of mixed methods on the surface area and gas products of activated carbon

    Hwang, Sang Youp , Lee Gi Bbum , Kim Ho and 1 other persons | 2020, 30(6) | pp.603~611 | number of Cited : 0
    Upgraded activated carbons (ACs) are typically synthesized by mixed methods, such as solid–solid mixing and wet impregna�tion of low-grade ACs with KOH. This study compares the properties of upgraded ACs prepared by diferent methods using elemental analysis, X-ray photoelectron spectroscopy, N2 adsorption isotherms, and X-ray difraction. In ACs produced by the solid–solid mixing, the ratio of potassium activator is proportional to the surface area and amount of gas produced. However, in wet impregnated ACs, the potassium ratio exhibits a zero or negative correlation. It is demonstrated that potassium ions in solution are not transferred to K2O and do not contribute to the surface area and pore size, generating less amount and diferent composition of gases. As such, impregnated ACs exhibit similar surface areas and large pores, regardless of the potassium ratio. The physical properties, such as specifc surface areas and pore size distribution, of ACs using wet impregna�tion were similar to the ACs generated by the water physical activation. It indicated that the KOH does not efciently act as a chemical activator in the wet impregnation method. Therefore, a certain amount and suitable mixing method of chemical activator play an important role in the property upgrade of ACs.
  • 3.

    Continuous synthesis of high-crystalline carbon nanotubes by controlling the configuration of the injection part in the floating catalyst chemical vapor deposition process

    PARK JIHONG , Park Junbeom , Lee Sung-Hyun and 1 other persons | 2020, 30(6) | pp.613~619 | number of Cited : 0
    Continuous synthesis of high-crystalline carbon nanotubes (CNTs) is achieved by reconfguring the injection part in the reactor that is used in the foating catalyst chemical vapor deposition (FC-CVD) process. The degree of gas mixing is divided into three cases by adjusting the confguration of the injection part: Case 1: most-delayed gas mixing (reference experiment), Case 2: earlier gas mixing than Case 1, Case 3: earliest gas mixing. The optimal synthesis condition is obtained using design of experiment (DOE) in the design of Case 1, and then is applied to the other cases to compare the synthesis results. In all cases, the experiments are performed by varying the timing of gas mixing while keeping the synthesis conditions constant. Production rate (Case 1: 0.63 mg/min, Case 2: 0.68 mg/min, Case 3: 1.29 mg/min) and carbon content (Case 1: 39.6 wt%, Case 2: 57.1 wt%, Case 3: 71.6 wt%) increase as the gas-mixing level increases. The amount of by-products decreases step�wise as the gas-mixing level increases. The IG/ID ratio increases by a factor of 7 from 10.3 (Case 1) to 71.7 (Case 3) as the gas-mixing level increases; a high ratio indicates high-crystalline CNTs. The radial breathing mode (RBM) peak of Raman spectrograph is the narrowest and sharpest in Case 3; this result suggests that the diameter of the synthesized CNTs is the most uniform in Case 3. This study demonstrates the importance of confguration of the injection part of the reactor for CNT synthesis using FC-CVD.
  • 4.

    Effect of soybean oil as a carbon source on the electrochemical property of LiNi1/3Co1/3Mn1/3O2 cathode material for lithium ion battery

    Nguyen Van Hiep , Ngo Minh Duc , Kim Young Ho | 2020, 30(6) | pp.621~626 | number of Cited : 0
    In this study, soybean oil, which is used in a large variety of processed foods, is used as a carbon source. Soybean oil is successfully coated onto the surface of LiNi1/3Co1/3Mn1/3O2 (NCM) by a simple method. The physical and electrochemical properties of NCM/C hybrid materials are determined. As a result, a 5 nm thickness carbon coating layer is formed on the surface of the NCM, resulting in improved capability and cyclic performance in the battery. The NCM/C battery shows an initial discharge capacity of 159 mAh g−1 and 95% capacity retention after 100 cycles (a discharge capacity of 120 mAh g−1 and 94% retention are observed after 100 cycles for the NCM cathode).
  • 5.

    Facile preparation of oxygen-rich activated carbon from petroleum coke for enhancing methylene blue adsorption

    Wu Wei , Zhang Xiaxiang , Yang Jianxiao and 2 other persons | 2020, 30(6) | pp.627~636 | number of Cited : 1
    The oxygen-rich activated carbon (AC) was facilely developed using petroleum coke as a raw material by KOH activa�tion under the rapid heating rate. The porosity and surface chemistry of ACs prepared under diferent heating rates were characterized and their adsorption properties for methylene blue (MB) were investigated. The results showed that the AC5 prepared under the heating rate of 5 °C min−1 had the highest surface area compared with the AC10, AC15 or AC20, while the AC20 prepared under the heating rate of 20 °C min−1 consisted of the highest oxygen content and most –OH functional group compares with the other ACs. These indicated that rapid heating rate was against the formation of more developed porosity, however, it was benefcial to producing more oxygen functional groups. As to MB adsorption, AC15 exhibited the maximum adsorption capacity for MB of 884 mg g−1 due to high surface area of 2803 m2 g−1 and high oxygen content of 23.27%. Moreover, despite the fact that AC20 had much lower surface area than the AC5, the AC20 showed higher MB adsorption capacity than the AC5. This was because the AC20 has the highest content of –OH, which was a positive impetus for MB adsorption. Therefore, rapid heating rate was an efective and simple approach to preparing the oxygen-rich ACs for improving the adsorption capacity of MB.
  • 6.

    Carbonization of oriented poly(vinyl alcohol) fibers impregnated with potassium bisulfate

    Petkieva Diana , Ozerin Alexander , Kurkin Tikhon and 3 other persons | 2020, 30(6) | pp.637~650 | number of Cited : 0
    The structural transformationss of oriented poly(vinyl alcohol) (PVA) fbers impregnated with potassium bisulfate (PBS) were studied in detail on the way from PVA precursor fbers till carbonized at a temperature of 1000 °C fbers. It has been shown that the impregnation of PVA fbers with a sulfur-containing compound (PBS) is an efcient technique to decrease the thermoplasticity of PVA fbers during heat treatment at high temperatures in air and argon and contributes to a high yield of coke residue after heat treatment up to 1000 °C. TMA, TGA, DSC, mass spectrometry, FTIR, Raman spectros�copy, SEM, WAXS and SAXS were used to study the structural transformations of oriented PVA fbers impregnated with PBS at the stages of their preliminary thermal stabilization (215 °C), thermal stabilization (215–400 °C) and carbonization (400–1000 °C). A reaction scheme has been proposed that fully describes carbonization chemistry in the entire studied temperature range. The processing temperature of 215 °C was found to be optimal for preliminary thermal stabilization of PVA fbers impregnated with PBS. The heat treatment in an inert medium can be recommended as the optimal for thermal stabilization of fbers impregnated with PBS. The characteristics of the carbonized PVA fbers, such as strength, modulus and electrical conductivity, were close to the characteristics of commercial cellulose-based carbon fbers yarns.
  • 7.

    Preparation of light-transmissive conductive film by free arc dispersed carbon nanotubes and thermos compression bonding

    Li Shaolong , Wang Kai , Feng Meng and 6 other persons | 2020, 30(6) | pp.651~656 | number of Cited : 1
    To investigate the efect of gas dispersing carbon nanotubes (CNTs) and hot pressing method on the transparency and the conductivity of thin flms, the free arc was used to disperse the CNTs in a high dispersion rate, and the dispersed CNTs were rapidly pressed into the surface of the PET flm by hot pressing to obtain electrical conductivity. The relationship between the light transmission and sheet resistance of the flm was studied by changing the deposition time and the presence or absence of electrostatic adsorption. It was found that the CNTs modifed flm still retains good electrical conductivity (sheet resist�ance up to 6×104 Ω, light transmittance 69%) through the cleaning of surfactants and ultrasonic waves, which proves that hot pressing is a simple physical method to achieve efective combination of CNTs and flms.
  • 8.

    Coal slime waste: a promising precursor to develop highly porous activated carbon for supercapacitors

    Li Jiajia , Hu Jiajun , Wang Kai and 1 other persons | 2020, 30(6) | pp.657~665 | number of Cited : 0
    Efective processing and use of coal slime is of great signifcance to protect the environment and save resources. Diferent coal slimes (untreated with 43 wt% ash content, crushed and fotation treated with 10 wt% ash content, and pre-carbonized) were activated with KOH to prepare porous activated carbon. The results show the activated carbon prepared from coal slime with 10 wt% ash had high specifc surface area (3037 m2 /g) and pore volume (1.66 cm3 /g), which was ascribed to the suitable contents of minerals as template and oxygen-containing functional groups. Electrochemical measurements exhibited the best specifc capacitance of 220 F/g at 0.1 A/g and the cycle stability of over 100% capacitance retention after 1000 cycles at 5 A/g in 6 M KOH solution. Due to the high specifc surface area, superior electrochemical performance, and facile and low cost, developing highly porous activated carbon for supercapacitors is one alternative way for efective use of coal slime waste.
  • 9.

    Solvothermal synthesis of Fe3S4@graphene composite electrode materials for energy storage

    Karuppasamy Muthumalai , Muthu Dinesh , Haldorai Yuvaraj and 1 other persons | 2020, 30(6) | pp.667~673 | number of Cited : 0
    Necessity of novel energy storage devices extensively increased due to consumption of high power in various devices. To address the issues, in this report, we are addressing with a composite Iron Sulfde/reduced Graphene Oxide (Fe3S4/rGO) synthesized using the standard solvothermal method. X-ray difraction and Field Emission Scanning Electron Microscope analysis results confrmed that Face-Centered cubic crystal structure of Fe3S4 and rGO’s surface is decorated with a mean diameter of <50 nm Fe3S4 respectively. Transmission Electron Microscopy images show further evidence that dispersed Fe3S4 on the rGO surface. Fe3S4/rGO exhibits specifc capacitance of 560 F/g than its individual counterparts (Fe3S4=200 F/g and rGO=145 F/g) at 1 A/g of current density and maximum cyclic stability of 91% capacitance retention after 2000 cycles that may be the infuence of synergy between the composite materials.
  • 10.

    Volatile organic compounds (VOCs) removal using ACFs with electroless plating CuO as catalysts

    Kim Min-Ji , Kim Kyung Hoon , Kim Yesol and 2 other persons | 2020, 30(6) | pp.675~682 | number of Cited : 1
    Activated carbon fbers (ACFs) were treated by electroless plating of CuO to improve their removal performance for volatile organic compounds (VOCs). The properties of these samples(CuO@ACFs) were evaluated by X-ray photoelectron spectros�copy (XPS), BET and N2O chemisorption to determine the area and dispersion of metallic CuO. The removal efciency for benzene was investigated by gas chromatography (GC). The breakthrough time of CuO@ACFs increased by approximately 120% compared to that of untreated ACFs at benzene of 100 ppm. CuO@ACFs removed 100% of the benzene in 20 h, indi�cating this material can be used as a removal technology for VOCs.
  • 11.

    Heavy metal ions (lead, cobalt, and nickel) biosorption from aqueous solution onto activated carbon prepared from Citrus limetta leaves

    Aboli Elham , Jafari Dariush , Esmaeili Hossein | 2020, 30(6) | pp.683~698 | number of Cited : 0
    In this research, Pb (II), Co (II), and Ni (II) toxic heavy metal ions adsorption from synthetic aqueous system have been studied using the activated carbon prepared from Citrus limetta leaves. Therefore, the relationship between the adsorption parameters (solution pH, dosage of adsorbent, temperature, initial concentration of the ions, and adsorption time) and the removal percentage of the prepared adsorbent have been investigated. Additionally, the adsorbent was analyzed through BET, SEM, EDX, FTIR, and XRD analyses. According to the results, the maximal adsorption efciencies for heavy metal ions were achieved in pH=6, the adsorbent dosage of 1 g/L, temperature=25 °C, the ion initial concentration of 5 mg/L, and contact time of 60 min, which were 99.53%, 98.63%, and 97.54% for Pb, Co, and Ni ions, respectively. Based on Kinetic studies, the performance of pseudo-second-order kinetic model was better than pseudo-frst-order model for the description of time-dependent behavior of the process. Additionally, the equilibrium data were ftted by Langmuir and Freundlich iso�therms, while the former performed better than the latter. The maximum adsorption capacity values for Pb, Co, and Ni ions were achieved equal to 69.82, 60.60, 58.139 mg/g, respectively. Considering the thermodynamic data, the studied processes were exothermic and spontaneous.
  • 12.

    In-situ carbon-coated tin oxide (ISCC-SnO2) for micro-supercapacitor applications

    Kumar Rahul , Nekouei Rasoul Khayyam , Sahajwalla Veena | 2020, 30(6) | pp.699~707 | number of Cited : 0
    In-situ carbon-coated tin oxide (ISCC-SnO2) was fabricated by colloidal processing and sucrose was used as a soluble carbon source. ISCC-SnO2 was characterized by X-ray difraction (XRD), Raman spectroscopy, and nitrogen adsorption–desorption by BET methods, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) properties of ISCC-SnO2 were investigated in 1 M Na2SO4 solution. The specifc capacitance of ISCC-SnO2 was achieved 42.7 mFcm−2 at a scan rate of 25 mVs−1 and showed excellent charge–discharge behavior.
  • 13.

    Simple and green fabrication of a biomass-derived N and O self-doped hierarchical porous carbon via a self-activation route for supercapacitor application

    Yang Binbin , Zhang Deyi , He Jingjing and 7 other persons | 2020, 30(6) | pp.709~719 | number of Cited : 2
    To meet the increased performance and cost requirements of commercial supercapacitor, a N and O self-doped hierarchical porous carbon is fabricated via a green and simple self-activation route utilizing leaves of wild hollyhock as raw materials. Comparing to commercial activated carbon, the reported material exhibits some marked merits, such as simple and green fabrication process, low cost, and superior capacitance performance. The specifc surface area of the obtained N and O co�doped hierarchical porous carbon arrives 954 m2 g−1, and the content of the self-doped nitrogen and oxygen reaches 2.64 at.% and 7.38 at.%, respectively. The specifc capacitance of the obtained material reaches 226 F g−1 while the specifc capacitance of the symmetric supercapacitor arrives 47.3 F g−1. Meanwhile, more than 90.3% of initial specifc capacitance is kept under a current density of 20 A g−1, and no arresting degradation is observed for capacitance after 5000 times cycle, perfectly demonstrating the excellent cycle and rate capability of the obtained material. The obtained N and O co-doped hierarchical porous carbon are expected to be an ideal substitution for commercial activated carbon.
  • 14.

    Improving thermal shock and ablation resistance of high thermal conductivity carbon/carbon composites by introducing carbon nanotubes

    Liu Xue-Song , Fu Qian-Gang , Wang Han-Hui and 3 other persons | 2020, 30(6) | pp.721~733 | number of Cited : 0
    In order to improve the thermal shock and ablation resistance of high thermal conductivity carbon/carbon composites, carbon nanotubes (CNTs) were introduced by electrophoretic deposition. After modifcation, the fexural strength of the composites increases by 53.0% due to the greatly strengthened interfaces. During thermal shock between 1100 °C and room temperature for 30 times, the strength continues to increase, attributed to the weakened interfaces in favor of fber and CNT pull-out. By introducing CNTs at interfaces, thermal conductivity of the composites along the fber axial direction decreases and that along the fber radial direction increases. As the thermal shock process prolongs, since the carbon structure integrity of CNT and matrix in the modifed composites is improved, the conductivity increases whatever the orientation is, until the thermal stress causes too many defects. As for the anti-ablation performance, the mass ablation rates of the CNT-modifed composites with fbers parallel to and vertical to the fame decrease by 69.6% and 43.9% respectively, and the diference in the mass ablation rate related with fber orientations becomes much less. Such performance improvement could be ascribed to the reduced oxidative damage and the enhanced interfaces.