Carbon Letters 2021 KCI Impact Factor : 0.52

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pISSN : 1976-4251 / eISSN : 2233-4998
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2021, Vol.31, No.1

  • 1.

    Graphene quantum dots synthesis and energy application: a review

    S. Akash Prabhu , K. Geetha. | 2021, 31(1) | pp.1~12 | number of Cited : 3
    Graphene Quantum Dots (GQDs), zero-dimensional nanoparticles which are derived from carbon-based sources owned the new pavement for the energy storage applications. With the varying synthesis routes, the in-built properties of GQDs are enhanced in different categories like quantum efficiency, nominal size range, and irradiation wavelength which could be applied for the several of energy and optoelectronics applications. GQDs are especially applicable in the specific energy storage devices such as super capacitors, solar cells, and lithium-ion batteries which were demonstrated in this work. This paper critically reviews about the synthesis techniques used for the GQDs involving energy storage applications with increased capacitance, energy conversion, retention capability, and stability.
  • 2.

    High removal of emerging contaminants from wastewater by activated carbons derived from the shell of cashew of Para

    Pascal S. Thue , Pascal S. Thue , Eder C. Lima | 2021, 31(1) | pp.13~28 | number of Cited : 1
    Activated carbon from the shell of the cashew of Para (SCP) was produced by chemical activation with ZnCl using the ratio of SCP: ZnCl2 1.0:1.5 at 700 °C. The prepared activated carbon (SCP700) was used for the removal of two emerging contaminants, 4-bromophenol (4-BrPhOH) and 4-chloroaniline (4-ClPhNH2) that are primarily employed in the industry. Different analytical techniques were used to characterize the activated carbon. From the N2 adsorption–desorption isotherms were obtained the specific surface area of 1520 m2 g−1 and total pore volume of 0.492 cm3 g−1. The functional groups were identified by the FTIR technique and quantified by modified Boehm titration. The results revealed the bearing of several functional groups on the SCP700 surface, which may utterly influence the removal of the emerging contaminants. The equilibrium experiments showed that the maximum uptaken capacities (Qmax) achieved at 45 °C were 488.2 (4-BrPhOH) and 552.5 mg g−1 (4-ClPhNH2). The thermodynamic parameters demonstrated that the processes of 4-BrPhOH and 4-ClPhNH2 adsorption are exothermic, spontaneous, energetically suitable, and the magnitude of ΔH° is compatible with physisorption. The mechanism of the adsorption of the emerging contaminants onto the carbon surface is dominated by microporous filling, hydrogen bonds, π-stacking interactions, and other Van der Waals interactions. The use of activated carbon for the treatment of industrial synthetic wastewater with several inorganic and organic molecules commonly found in industrial effluents showed a very high percentage of uptaking (up to 98.64%).
  • 3.

    Silane coupling agent assisting dopamine-functionalized biomass porous carbons for enhanced adsorption of organic acids: effects of acid–alkali activation on microstructure

    Qi Wang , Yaying Lv , Tao Zhu. | 2021, 31(1) | pp.29~37 | number of Cited : 0
    Biomass porous carbons derived from Laminaria japonica were prepared by KOH and H3PO4 activation methods, respectively. The results indicated that the chemical activation had an apparent effect on the molecular framework and space of materials. To enhance the selective adsorption for organic acids, biomass carbons were modified by dopamine combined with N-(2-aminoethyl)-3-aminopropyltrimethoxysilane. The SEM and BET results illustrated the effect of the chemical activation approach on the morphology and porous texture. The biomass porous carbon using KOH activation method had the highest surface area (up to 1558 m2/g). Compared with unmodified materials, the modified materials showed higher adsorption capacity for organic acids (27.90 μg/mL for chlorogenic acid and 25.47 μg/mL for caffeic acid). It was suggested that modification of porous carbons might be a viable pathway to increase the specific adsorption affinity and efficiency for organic acids in dried jujube samples.
  • 4.

    Carbon nanodots with tunable luminescence properties synthesized by electrical discharge in octane

    Alena Nevar , Natalie Tarasenka , Mikhail Nedelko and 1 other persons | 2021, 31(1) | pp.39~46 | number of Cited : 0
    We report on the one-step synthesis of luminescent carbon nanodots (C-dots) via an electrical discharge between two graphite electrodes submerged into organic solvent (octane). This is a simple approach for the fabrication of C-dots with tunable photoluminescence (PL) that differs from the other preparation methods, as no post-passivation step is required. The synthesized carbon nanoparticles are of spherical shape and their size is distributed in the range of 2–5 nm and exhibit luminescence sensitive to excitation wavelength.
  • 5.

    Study of the methane flow influence in the micro-tribology behavior of DLC coatings deposited by PECVD: a Raman analysis

    César Daniel Rivera-Tello , Francisco Javier Flores‑Ruiz , M. Flores and 3 other persons | 2021, 31(1) | pp.47~56 | number of Cited : 0
    This paper presents a Raman spectroscopy study of the influence of methane flow on the micro-tribological behavior of diamond-like carbon coatings deposited with an industrial plasma-enhanced chemical vapor deposition system. Results have shown a direct relationship between the methane flow and thickness of the coatings. The analysis of the Raman spectra and deposition parameters allowed establishing the influence of H content with the methane flow, the disorder level and estimation of the sp3 fraction on the carbon coatings. The micro-tribology tests showed a strong dependence of the wear resistance and hardness with Raman parameters. The coating deposited at 72-sccm methane flow presented a thickness of 1.7 µm and a sp3 fraction of 0.33. This sp3 fraction gave rise to a hardness of 24 GPa and an excellent wear resistance of 3.3 × 10–6 mm3 N−1 mm−1 for this DLC coating. Wear tests showed a swelling in the wear profiles on this coating, which was associated with the occurrence of a re-hybridization process.
  • 6.

    Electrochemical performance of porous carbons derived from needle coke with different textures for supercapacitor electrode materials

    Junxia Cheng , Zhenjie Lu , Xuefei Zhao and 1 other persons | 2021, 31(1) | pp.57~65 | number of Cited : 1
    The porous carbons with high specific surface area and excellent electrochemical properties were prepared using three types of green needle coke as raw materials. Electrochemical performances of the porous carbons derived from different microstructure green needle coke were investigated. The XRD and Raman spectra demonstrated that the content of the ordered carbon microcrystals were decreased and the content of amorphous and cross-linked structure were increased in the porous carbons with comparison to the raw materials. The results of N2 adsorption–desorption analysis verified that the content of ordered microcrystalline structure in the raw materials evidently influence the specific surface area and pore size distribution of the porous carbons. The porous carbon with 1665 m2 g−1 specific surface area and 2.89 nm average pore size has shown that the specific capacitance was 288 F g−1 at the current density 1 A g−1. Furthermore, the capacity retention was 94.93% and the Coulombic efficiency was 92.87% after 5000 charge/discharge cycles.
  • 7.

    Fabrication of porous carbon beads from polyacrylonitrile as electrode materials for electric double-layer capacitors

    Byoung‑Min Lee , Beom‑Seok Choi , Jang‑Yong Lee and 3 other persons | 2021, 31(1) | pp.67~74 | number of Cited : 2
    In this study, we developed a facile and template-free strategy for the preparation of activated porous carbon beads (APCBs) from polyacrylonitrile. The chemical activation with KOH was found to enhance the pore properties, such as specific surface area (SSA), pore volume, and pore area. The APCBs exhibited a large SSA of 1147.99 m2/g and a pore area of 131.73 m2/g. The APCB-based electrodes showed a good specific capacitance of 112 F/g at 1 A/g in a 6 M KOH electrolyte, and excellent capacitance retention of 100% at a current density of 5 A/g after 1000 cycles. Therefore, the APCBs prepared in this study can be applied as electrode materials for electric double-layer capacitors.
  • 8.

    Comparisons of activated carbons produced from sycamore balls, ripe black locust seed pods, and Nerium oleander fruits and also their H2 storage studies

    Osman Üner , Ünal Geçgel , Tarık Avcu | 2021, 31(1) | pp.75~92 | number of Cited : 0
    Starting materials are very significant to produce activated carbons because every starting material has a different chemical structure; hence they affect the surface functional groups and surface morphologies of obtained activated carbons. In this study, sycamore balls, ripe black locust seed pods, and Nerium oleander fruits have been used as starting materials by ZnCl2 chemical activations for the first time. Firstly, activated carbons were obtained from these starting materials with ZnCl2 chemical activation by changing production conditions (carbonization time, carbonization temperature, and impregnation ratio) also affecting the structural and textural properties of the resultant activated carbons. Then, the starting materials and resultant activated carbons were characterized by utilizing diverse analysis techniques, such as TGA, elemental analysis, proximate analysis, BET surface areas, pore volumes, pore size distributions, N2 adsorption–desorption isotherms, SEM, FTIR spectra, and H2 adsorption isotherms. The highest surface areas were determined to be 1492.89, 1564.84, and 1375.47 m2/g for the activated carbons obtained from sycamore balls, ripe black locust seed pods, and N. oleander fruits, respectively. The yields of these activated carbons with the highest surface areas were calculated to be around 40%. As the carbonization temperature increased with sufficient ZnCl2 amount, N2 adsorption–desorption isotherms began to turn into Type IV isotherms given by mesoporous adsorbents with its hysteresis loops. Also, their hysteresis loops resembled Type H4 loop generally associated with narrow slit-like pores. Moreover, hydrogen uptakes under 750 mmHg at 77 K were determined to be 1.31, 1.48, and 1.24 wt% for the activated carbons with the maximum surface areas produced from sycamore balls, ripe black locust seed pods, and N. oleander fruits, respectively. As a result, the highest surface areas of the activated carbons with different structural properties produced in this study were obtained with different production conditions.
  • 9.

    A lightweight and flexible CNT/Fe3O4 composite with high electromagnetic interference shielding performance

    Chao Zhuo , Yu Yingying , Lei Fang and 1 other persons | 2021, 31(1) | pp.93~97 | number of Cited : 0
    Lightweight and flexible electromagnetic interference (EMI) shielding materials are in great demand for wearable EMI device. In the present work, lightweight and flexible carbon nanotube (CNT)/ferroferric oxide (Fe3O4) composite film was made through a feasible chemical vapor deposition process for CNT film synthesis, followed by a hydrothermal reduction process for Fe3O4 coating. In the as-prepared composite, CNT film and Fe3O4 particles work as conductive skeleton and strong magnetic particle, respectively. The as-prepared composite film shows a novel EMI shielding effectiveness (SE) of 91 dB in the X-band, a small thickness of 0.09 mm and a low density of 0.86 g/cm3, which is superior to most of the carbon-based EMI materials.
  • 10.

    Graphene exfoliation with supercritical fluids

    Rodolfo Morales Ibarra , Motonobu Goto , Juan García-Serna and 1 other persons | 2021, 31(1) | pp.99~105 | number of Cited : 1
    Graphene is an unconventional material with a two-dimensional hexagonal crystalline array of elemental carbon atoms and outstanding properties; accordingly, a desirable objective in the line of research of graphene is the development of novel and more productive methods of synthesis, validating its properties and applications. In our exploratory research, we have effectively exfoliated graphene from graphite using supercritical fluids (water, ethanol and carbon dioxide). The exfoliated graphene was properly characterized; via scanning electron microscopy, the morphology of graphene was observed; Raman spectra confirmed the exfoliation of graphene depicting the characteristic shift towards smaller Raman number in the 2D band (2676 cm−1) compared to that of graphite (≈ 2700 cm−1); transmission electron microscopy analysis exhibited the crystalline structure of graphene attesting also the expected transparency of exfoliated layers. Graphene exfoliation from graphite by supercritical fluids promises to be a simple large-scale method for graphene production.
  • 11.

    Nanostructures of chemically modified multi-walled carbon nanotubes and poly(3-hexylthiophene) to improve photophysic/photovoltaic features

    Afsaneh Hadi , Mohammad Hossein Hekmatshoar , Farhang Abbasi and 1 other persons | 2021, 31(1) | pp.107~115 | number of Cited : 0
    Multi-walled carbon nanotube/poly(3-hexylthiophene) (CNT/P3HT) and CNT-graft-poly(3-dodecylthiophene) (PDDT)/P3HT nanohybrids were applied in active layers to study the effects of these nanostructures on the polymer solar cell (PSC) performance. The charge-carrier dynamics and photophysics were studied in the binary and ternary systems based on P3HT, pre-developed nanostructures and/or phenyl-C71-butyric acid methyl ester (PC71BM) through the electrochemical impedance spectroscopy and morphological analyses. The weaker bimolecular recombination in the photoactive layer, consisting of CNT-graft-PDDT/P3HT nanostructures, was confirmed by short-circuit current (Jsc) and open-circuit voltage (Voc) measurements as a function of light intensity. PSC composed of P3HT:PC71BM:CNT-graft-PDDT/P3HT PSC exhibited the highest PCE of 4.18% with significantly increased Jsc and Voc.
  • 12.

    Chickpea peel waste as sustainable precursor for synthesis of fluorescent carbon nanotubes for bioimaging application

    Vikram Singh , Shovon Chatterjee , Mahendra Palecha and 3 other persons | 2021, 31(1) | pp.117~123 | number of Cited : 0
    In this study, we report a controlled one-pot green synthesis of multiwalled carbon nanotubes (MWCNTs) via pyrolysis of sustainable agriculture waste (chickpea peel) at 400 °C in aqueous medium. These MWCNTs demonstrated 7.0 nm diameter, 0.28 nm graphitic spacing with carbonyl, hydroxyl, and carboxylic acid functionality. The D band (presence of sp3 defects) and G band (E2g mode of graphite) at 1350 cm−1 and 1580 cm−1 originated in Raman spectrum, respectively. The prepared MWCNTs showed blue fluorescence with 10% fluorescence quantum yield in aqueous medium. The MWCNTs showed triple exponential decay characteristics with an average fluorescence lifetime of 4.7 ns. The synthesized MWCNTs revealed a consistent fluorescence in the cytoplasm of 22RV1 human prostate carcinoma cell line without exerting any sign of cytotoxicity. The MWCNTs also exhibited remarkable cytocompatibility in human immortalized prostate epithelial RWPE1 cells.
  • 13.

    Effect of graphene addition on the mechanical characteristics of AA7075 aluminium nanocomposites

    R. Ranga Raj , J. Yoganandh , M. S. Senthil Saravanan and 2 other persons | 2021, 31(1) | pp.125~126 | number of Cited : 1
    Processing and characterization of graphene (Gr)-reinforced aluminium alloy 7075 (AA7075) microcomposites and nanocomposites are reported in this work. Composites are fabricated by mechanical alloying process at wet conditions. The bulk composites are prepared by uniaxial die pressing to get higher densification and sintered in an inert atmosphere. Density of the nanocomposites is higher than the microcomposites due to the reduction of grain size by increased milling time. X-ray diffraction (XRD) analysis confirms graphene interaction with the AA7075 matrix lattice spaces. The effective distribution of graphene with aluminium alloy is further confirmed by the Transmission Electron Microscopy (TEM) analysis. The hardness of the composites proportionally increases with the graphene addition owing to grain refinement. Wear morphology is characterized using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Microcomposites reveal abrasive and ploughing wear mechanism of material removal from the surface. Nanocomposites show adhesive wear with delamination and particle pull-out from the material surface.
  • 14.

    High-performance electric double-layer capacitor fabricated with nanostructured carbon black-paint pigment as an electrode

    V. Samynaathan , Sangeetha R. Iyer , K. Shree Kesavan and 2 other persons | 2021, 31(1) | pp.137~146 | number of Cited : 0
    Engineering the microstructure of the carbonaceous materials is a promising strategy to enhance the capacitive performance of supercapacitors. In this work, nanostructured Black Pearl (1500 BP) carbon which is a conductive carbon being commercially used in printing rolls, conductive packaging, conductive paints, etc. is analyzed for its feasibility as an electrode material for Electric Double-Layer Capacitors (EDLCs). To achieve that commercial Black Pearl (BP), carbon is treated with mild acid H3PO4 to remove the impurities and enhance the active sites by regulating the growth of agglomerates and creating micropores in the nano-pigments. Generally, the coalescence of nanoparticles owing to their intrinsic surface energy has tendency to create voids of different sizes that act like meso/micropores facilitating the diffusion of ions. The electrochemical performance of BP carbon before and after chemical activation is investigated in aqueous (H2SO4, KOH and KCl) and a non-aqueous electrolyte (1 M TEMABF4 in acetonitrile) environment employing different electrochemical techniques such as Cyclic Voltammetry (CV), Galvanostatic charge/discharge (GCD) and Electrochemical Impendence Spectroscopy (EIS). The chemically activated BP carbon delivers the highest specific capacitance of ∼156 F g−1 in an aqueous electrolyte, 6 M KOH. The highest specific power, ~ 15.3 kW kg−1 and specific energy, 14.6 Wh kg−1 are obtained with a symmetric capacitor employing non-aqueous electrolyte because of its high working potential, 2.5 V.
  • 15.

    Obituary: B. S. Rhee (June 25, 1932–December 4, 2020)

    Ryu S. K. | 2021, 31(1) | pp.147~147 | number of Cited : 0
    We are saddened to report the death of B. S. Rhee. He passed away suddenly on December, 4, 2020, while sleeping at the age of 88. He was the first and foremost researcher in the field of carbon materials in Korea. He graduated in 1958 with a M. S. at Yonsei University, Seoul, working as an instructor, and in 1963 became an assistant professor at Chungnam National University, Daejeon. In 1967, he took educational leave to study abroad at the Institute for Chemical Technology at the Universitat Karlsruhe, in Germany. He earned his Ph. D. in 1970 under the supervision of Prof. Erich Fitzer, internationally renowned in the field of carbon materials. The title of his dissertation was “Pyrokohlenstoff-Spiral-und Whiskerwachstum und Eigenschafte”. After returning to Korea, he continuously collaborated with Professor Fitzer with the support of the Korea-German international projects. He was the only one and only carbon researcher in Korea before I joined his research project in 1982. In the early 1980’s, carbon fibers and new carbon materials gained global attention, and large Korean industries became interested in his research results. Eventually, in 1983, the SK group and KIMM (Korea Institute of Machinery & Materials) cooperatively signed a large contract with Professor Rhee titled ‘Industrialization of Carbon Fiber Development Technique’. This was the first step in developing carbon fibers in Korea. Shortly afterwards, he twice received a UNDP research grant for the ‘Development of Carbon fiber from Pitch and Carbon Fiber Reinforced Composites’ (1986–1987, 1990–1991). During this time, many well-known experts in the field of carbon materials, such as Prof. Fitzer (Germany), Dr. Ehrburger (France), Prof. Edie (USA), Prof. Mocha (Japan) and others, were invited to his laboratory to assist in his research. He and many experts contributed greatly to advance carbon research in Korea. Prof. Rhee was extremely diligent. During his stay in Karlsruhe, each day he was the first researcher to turn on and the last to turn off the laboratory light. Once Prof. Fitzer told me “Mr. Rhee is really a mystery”. His diligent character was inborn. At Chungnam University, he always arrived at the laboratory first and left the laboratory after 11 p.m. Sometimes he went to the laboratory on Sunday—until the late 1970’s, when economic conditions were not good in Korea. University professors use the university commuter bus to go to school and return home. Prof. Rhee should have bought a car to return home from laboratory after 11 p.m. After I joined his research team, I also had to share this uncomfortable daily life. I had to go to the laboratory very early morning, eat pizza at lunch and dinner with him, and return home after 11 p.m. Prof. Rhee’s favorite food was pizza. Sometimes I suggested that he eat another food, but his feet always took him to the pizza house. Once, I asked him why he returned home after 11 p.m. He answered that he didn’t like listening to Mrs. Rhee’s nagging about why he worked such long hours. If he returned home late, Mrs. Rhee would be sleeping. During these days, I also had to see my children sleeping. For me, it was very hard to endure his unique lifestyle and frugal mind. On the other hand, I learned to appreciate his research philosophy that research is not hard work if you are passionate about it. He published many excellent papers and trained many students. The present chairman of the Korean Carbon Society, D. H. Jeong, and next chairman, Y. S. Lee, are both former Ph. D. students of Professor Rhee. After he retired from the university in 1996, he continued to go to the university and conduct research in my laboratory. He continued his research even after I retired university in 2011 until he passed away this December. His precious contributions in carbon materials research will remain eternally in Korea. Now Professor Rhee has gone to heaven, and I worry that he may bother God with his hard work.