Subjects -> CHEMISTRY (Total: 928 journals)
    - ANALYTICAL CHEMISTRY (59 journals)
    - CHEMISTRY (661 journals)
    - CRYSTALLOGRAPHY (23 journals)
    - ELECTROCHEMISTRY (28 journals)
    - INORGANIC CHEMISTRY (45 journals)
    - ORGANIC CHEMISTRY (47 journals)
    - PHYSICAL CHEMISTRY (65 journals)

CHEMISTRY (661 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
Accounts of Materials Research     Hybrid Journal  
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 30)
ACS Applied Polymer Materials     Hybrid Journal   (Followers: 8)
ACS Catalysis     Hybrid Journal   (Followers: 52)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 23)
ACS Combinatorial Science     Hybrid Journal   (Followers: 21)
ACS Environmental Au     Open Access   (Followers: 9)
ACS Macro Letters     Hybrid Journal   (Followers: 25)
ACS Materials Letters     Open Access   (Followers: 2)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 42)
ACS Nano     Hybrid Journal   (Followers: 182)
ACS Photonics     Hybrid Journal   (Followers: 14)
ACS Symposium Series     Full-text available via subscription   (Followers: 3)
ACS Synthetic Biology     Hybrid Journal   (Followers: 30)
Acta Chemica Malaysia     Open Access  
Acta Chimica Slovaca     Open Access   (Followers: 2)
Acta Chimica Slovenica     Open Access   (Followers: 2)
Acta Chromatographica     Full-text available via subscription   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 8)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 7)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 10)
Adsorption Science & Technology     Open Access   (Followers: 7)
Advanced Electronic Materials     Hybrid Journal   (Followers: 7)
Advanced Functional Materials     Hybrid Journal   (Followers: 71)
Advanced Journal of Chemistry, Section A     Open Access   (Followers: 3)
Advanced Journal of Chemistry, Section B     Open Access   (Followers: 1)
Advanced Science Focus     Free   (Followers: 6)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 2)
Advanced Therapeutics     Hybrid Journal   (Followers: 1)
Advances in Chemical Engineering and Science     Open Access   (Followers: 109)
Advances in Chemical Science     Open Access   (Followers: 51)
Advances in Chemistry     Open Access   (Followers: 34)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 15)
Advances in Environmental Chemistry     Open Access   (Followers: 11)
Advances in Enzyme Research     Open Access   (Followers: 10)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 33)
Advances in Nanoparticles     Open Access   (Followers: 17)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Polymer Science     Hybrid Journal   (Followers: 51)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 18)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Sample Preparation     Open Access   (Followers: 5)
Advances in Science and Technology     Full-text available via subscription   (Followers: 16)
Aerosol Science and Engineering     Hybrid Journal  
African Journal of Chemical Education     Open Access   (Followers: 5)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 6)
Aggregate     Open Access   (Followers: 2)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alchemy : Journal of Chemistry     Open Access   (Followers: 4)
Alchemy : Jurnal Penelitian Kimia     Open Access  
Alotrop     Open Access  
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 43)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 19)
American Journal of Chemistry     Open Access   (Followers: 37)
American Journal of Plant Physiology     Open Access   (Followers: 9)
Analyst     Hybrid Journal   (Followers: 35)
Analytical Science Advances     Open Access   (Followers: 1)
Angewandte Chemie     Hybrid Journal   (Followers: 151)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 228)
Annales Universitatis Mariae Curie-Sklodowska, sectio AA – Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 6)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 4)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 5)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 13)
Antiviral Chemistry and Chemotherapy     Open Access   (Followers: 1)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 24)
Applied Surface Science     Hybrid Journal   (Followers: 31)
Arabian Journal of Chemistry     Open Access   (Followers: 4)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Applied Chemistry Research     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 2)
Asian Journal of Chemical Sciences     Open Access  
Asian Journal of Chemistry and Pharmaceutical Sciences     Open Access  
Asian Journal of Physical and Chemical Sciences     Open Access   (Followers: 2)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 7)
Biochemical Pharmacology     Hybrid Journal   (Followers: 11)
Biochemistry     Hybrid Journal   (Followers: 200)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 5)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 2)
Biomacromolecules     Hybrid Journal   (Followers: 23)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 3)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 90)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 66)
Bioorganic Chemistry     Hybrid Journal   (Followers: 9)
Biopolymers     Hybrid Journal   (Followers: 15)
Biosensors     Open Access   (Followers: 3)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 3)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of Institute of Chemistry and Chemical Technology, Mongolian Academy of Sciences     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 5)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 1)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 12)
Canadian Mineralogist     Full-text available via subscription   (Followers: 5)
Carbohydrate Polymer Technologies and Applications     Open Access  
Carbohydrate Polymers     Hybrid Journal   (Followers: 9)
Carbohydrate Research     Hybrid Journal   (Followers: 24)
Carbon     Hybrid Journal   (Followers: 65)
Carbon Capture Science & Technology     Open Access  
Carbon Trends     Open Access   (Followers: 3)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 9)
Catalysis Science and Technology     Hybrid Journal   (Followers: 9)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Catalysts     Open Access   (Followers: 11)
Cell Reports Physical Science     Open Access  
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
Chem     Hybrid Journal  
Chem Catalysis     Hybrid Journal  
ChemBioEng Reviews     Full-text available via subscription   (Followers: 3)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 22)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Hybrid Journal   (Followers: 81)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 26)
Chemical Physics Impact     Full-text available via subscription  
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 4)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 22)
Chemical Reviews     Hybrid Journal   (Followers: 168)
Chemical Science     Open Access   (Followers: 39)
Chemical Science International Journal     Open Access  
Chemical Technology     Open Access   (Followers: 75)
Chemical Thermodynamics and Thermal Analysis     Open Access   (Followers: 2)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 4)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 54)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 22)
ChemInform     Hybrid Journal   (Followers: 5)
Chemistry     Open Access  
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Industry     Full-text available via subscription   (Followers: 6)
Chemistry - A European Journal     Hybrid Journal   (Followers: 121)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 19)
Chemistry Africa : A Journal of the Tunisian Chemical Society     Hybrid Journal  
Chemistry and Materials Research     Open Access   (Followers: 18)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 6)
Chemistry Education Review     Open Access   (Followers: 1)
Chemistry in Education     Open Access   (Followers: 3)
Chemistry Letters     Full-text available via subscription   (Followers: 44)
Chemistry of Heterocyclic Compounds     Hybrid Journal   (Followers: 4)
Chemistry of Materials     Hybrid Journal   (Followers: 161)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 10)
Chemistry World     Hybrid Journal   (Followers: 20)
Chemistry-Didactics-Ecology-Metrology     Open Access  
ChemistryOpen     Open Access   (Followers: 1)
ChemistrySelect     Hybrid Journal  
Chemistry–Methods     Open Access   (Followers: 1)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
ChemNanoMat     Hybrid Journal   (Followers: 1)
Chemoecology     Hybrid Journal   (Followers: 2)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 13)
Chemosensors     Open Access   (Followers: 1)
ChemPhotoChem     Hybrid Journal  
ChemPhysChem     Hybrid Journal   (Followers: 12)
ChemPhysMater     Full-text available via subscription  
ChemPlusChem     Hybrid Journal   (Followers: 2)
Chempublish Journal     Open Access  
ChemSystemsChem     Hybrid Journal   (Followers: 1)
ChemTexts     Hybrid Journal   (Followers: 1)
CHIMIA International Journal for Chemistry     Open Access   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 9)
Chromatographia     Hybrid Journal   (Followers: 22)
Chromatography     Open Access   (Followers: 2)
Chromatography Research International     Open Access   (Followers: 4)
Ciencia     Open Access  
Clay Minerals     Hybrid Journal   (Followers: 8)
Cogent Chemistry     Open Access   (Followers: 3)
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 6)
Colloids and Interfaces     Open Access  
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 2)
Combustion Science and Technology     Hybrid Journal   (Followers: 26)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 1)
Communications Chemistry     Open Access   (Followers: 2)
Communications Materials     Open Access  
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comptes Rendus : Chimie     Open Access  
Comptes Rendus : Physique     Open Access   (Followers: 2)

        1 2 3 4 | Last

Similar Journals
Journal Cover
C - Journal of Carbon Research
Number of Followers: 5  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2311-5629
Published by MDPI Homepage  [84 journals]
  • C, Vol. 8, Pages 20: Chemical Reduction of GO: Comparing Hydroiodic Acid
           and Sodium Borohydride Chemical Approaches by X-ray Photoelectron

    • Authors: Wei Liu, Giorgio Speranza
      First page: 20
      Abstract: The efficiency of two wet chemical processes based on hydroiodic acid (HI) and sodium borohydride (NaBH4) used to reduce graphene oxide (GO) have been studied. At this aim, the oxygen abundance of reduced graphene oxide (rGO) was studied as a function of the reductant concentration. A number of rGO samples were produced and their chemical compositions were studied using X-ray photoelectron spectroscopy. The analyses show that the reduction of the oxygen concentration proceeds non-linearly. At the beginning, when pristine GO is utilized a higher extent of reduction is obtained. The oxygen concentration decreases from ~32% to 10.5% by increasing the HI concentration to 0.24 M. A steeper reduction was observed for NaBH4, where the oxygen concentration lowers to ~13.6% using just 50 mg of NaBH4. Next, reduction reactions performed with increasing amounts of reductants in aqueous suspensions show a progressive saturation effect, indicating a limit in the final oxygen concentration. We obtained a residual oxygen concentration of 5.3% using 7.58 M of HI and 8.6% with 1200 mg of NaBH4. The chemical analysis highlights that the reduction of the oxygen concentration in rGO samples is mainly derived from the cleavage of C-OH bonds and the next reconstruction of C-C bonds.
      Citation: C
      PubDate: 2022-03-22
      DOI: 10.3390/c8020020
      Issue No: Vol. 8, No. 2 (2022)
  • C, Vol. 8, Pages 21: Engineering of Nanostructured Carbon Catalyst
           Supports for the Continuous Reduction of Bromate in Drinking Water

    • Authors: João M. Cunha Bessa da Costa, José R. Monteiro Barbosa, João Restivo, Carla A. Orge, Anabela Nogueira, Sérgio Castro-Silva, Manuel F. Ribeiro Pereira, Olívia S. Gonçalves Pinto Soares
      First page: 21
      Abstract: Recent works in the development of nanostructured catalysts for bromate reduction in drinking water under hydrogen have highlighted the importance of the properties of the metallic phase support in their overall performance. Since most works in catalyst development are carried out in powder form, there is an overlooked gap in the correlation between catalyst support properties and performance in typical continuous applications such as fixed bed reactors. In this work, it is shown that the mechanical modification of commercially available carbon nanotubes, one of the most promising supports, can significantly enhance the activity of the catalytic system when tested in a stirred tank reactor, but upon transition to a fixed bed reactor, the formation of preferential pathways for the liquid flow and high pressure drops were observed. This effect could be minimized by the addition of an inert filler to increase the bed porosity; however, the improvement in catalytic performance when compared with the as-received support material was not retained. The operation of the continuous catalytic system was then optimized using a 1 wt.% Pd catalyst supported on the as-received carbon nanotubes. Effluent and hydrogen flow rates as well as catalyst loadings were systematically optimized to find an efficient set of parameters for the operation of the system, regarding its catalytic performance, capacity to treat large effluent flows, and minimization of catalyst and hydrogen requirements. Experiments carried out in the presence of distilled water as a reaction medium demonstrate that bromate can be efficiently removed from the liquid phase, whereas when using a real water matrix, a tendency for the deactivation of the catalyst over time was more apparent throughout 200 flow passages over the catalytic bed, which was mostly attributed to the competitive adsorption of inorganic matter on the catalyst active centers, or the formation of mineral deposits blocking access to the catalyst.
      Citation: C
      PubDate: 2022-03-22
      DOI: 10.3390/c8020021
      Issue No: Vol. 8, No. 2 (2022)
  • C, Vol. 8, Pages 22: A Review of Embodied Carbon in Landscape
           Architecture. Practice and Policy

    • Authors: Nikologianni, Plowman, Brown
      First page: 22
      Abstract: This paper aims to discuss the importance of the climate crisis and embodied carbon in the landscape architecture sector. The study was carried out in a multiprofessional team with the collaboration of the Landscape Institute (LI) Chartered Body of Landscape Architecture, UK, and experts in the field. Using the expertise and knowledge of professionals as well as existing landscape examples and pioneering tools on carbon, this review paper focuses on the importance of low/net-zero carbon landscapes for our cities and regions and the ways in which these can contribute to the broader health and wellbeing of our communities. Examining the current situation on carbon methodologies and the latest knowledge on carbon calculations through a landscape lens, the paper explores why embodied carbon is important for open spaces/landscapes and the necessary policies to support a more efficient implementation of these concepts. The intensity of recent environmental challenges demands action. This review highlights the need for holistic approaches that integrate embodied carbon calculations on large-scale landscape design. Using the innovative example of the Pathfinder App, a carbon calculation tool, as well as other similar software, this paper argues that more steps are needed towards the calculation and adaptation of CO2 emissions resulting from design, construction and materials in landscape schemes. The low availability of carbon calculation tools, specially developed for landscape schemes, is a major concern for the profession as it creates several issues with the sustainable development of the landscape projects as well as fragmented policies that exclude spatial and open spaces. Even though carbon calculation and embodied carbon are being calculated in buildings or materials, it is a relatively new area when it comes to land, the landscape and open and green space, and therefore, this study will present and discuss some of the pioneering carbon calculation tools focusing on landscape projects.
      Citation: C
      PubDate: 2022-03-26
      DOI: 10.3390/c8020022
      Issue No: Vol. 8, No. 2 (2022)
  • C, Vol. 8, Pages 23: On the Problem of “Super” Storage of
           Hydrogen in Graphite Nanofibers

    • Authors: Yury S. Nechaev, Evgeny A. Denisov, Alisa O. Cheretaeva, Nadezhda A. Shurygina, Ekaterina K. Kostikova, Andreas Öchsner, Sergei Yu. Davydov
      First page: 23
      Abstract: This article is devoted to some fundamental aspects of “super” storage in graphite nanofibers (GNF) of “reversible” (~20–30 wt.%) and “irreversible” hydrogen (~7–10 wt.%). Extraordinary results for hydrogen “super” storage were previously published by the group of Rodriguez and Baker at the turn of the century, which been unable to be reproduced or explained in terms of physics by other researchers. For the first time, using an efficient method of processing and analysis of hydrogen thermal desorption spectra, the characteristics of the main desorption peak of “irreversible” hydrogen in GNF were determined: the temperature of the highest desorption rate (Tmax = 914–923 K), the activation energy of the desorption process (Q ≈ 40 kJ mol−1), the pre-exponential rate constant factor (K0 ≈ 2 × 10−1 s−1), and the amount of hydrogen released (~8 wt.%). The physics of hydrogen “super” sorption includes hydrogen diffusion, accompanied by the “reversible” capture of the diffusant by certain sorption “centers”; the hydrogen spillover effect, which provides local atomization of gaseous H2 during GNF hydrogenation; and the Kurdjumov phenomenon on thermoelastic phase equilibrium. It is shown that the above-mentioned extraordinary data on the hydrogen “super” storage in GNFs are neither a mistake nor a mystification, as most researchers believe.
      Citation: C
      PubDate: 2022-03-29
      DOI: 10.3390/c8020023
      Issue No: Vol. 8, No. 2 (2022)
  • C, Vol. 8, Pages 24: Laser-Assisted Growth of Carbon-Based Materials by
           Chemical Vapor Deposition

    • Authors: Abiodun Odusanya, Imteaz Rahaman, Pallab Kumar Sarkar, Abdelrahman Zkria, Kartik Ghosh, Ariful Haque
      First page: 24
      Abstract: Carbon-based materials (CBMs) such as graphene, carbon nanotubes (CNT), highly ordered pyrolytic graphite (HOPG), and pyrolytic carbon (PyC) have received a great deal of attention in recent years due to their unique electronic, optical, thermal, and mechanical properties. CBMs have been grown using a variety of processes, including mechanical exfoliation, pulsed laser deposition (PLD), and chemical vapor deposition (CVD). Mechanical exfoliation creates materials that are irregularly formed and tiny in size. On the other hand, the practicality of the PLD approach for large-area high-quality CMB deposition is quite difficult. Thus, CVD is considered as the most effective method for growing CBMs. In this paper, a novel pulsed laser-assisted chemical vapor deposition (LCVD) technique was explored to determine ways to reduce the energy requirements to produce high quality CBMs. Different growth parameters, such as gas flow rate, temperature, laser energy, and deposition time were considered and studied thoroughly to analyze the growth pattern. CBMs are grown on Si and Cu substrates, where we find better quality CBM films on Cu as it aids the surface solubility of carbon. Raman spectroscopy confirms the presence of high-quality PyC which is grown at a temperature of 750 °C, CH4 gas flow rate of 20 sccm, a laser frequency of 10 Hz, and an energy density of 0.116 J/cm2 per pulse. It is found that the local pulsed-laser bombardment helps in breaking the carbon-hydrogen bonds of CH4 at a much lower substrate temperature than its thermal decomposition temperature. There is no significant change in the 2D peak intensity in the Raman spectrum with the further increase in temperature which is the indicator of the number of the graphene layer. The intertwined graphene flakes of the PyC are observed due to the surface roughness, which is responsible for the quenching in the Raman 2D signal. These results will provide the platform to fabricate a large area single layer of graphene, including the other 2D materials, on different substrates using the LCVD technique.
      Citation: C
      PubDate: 2022-04-26
      DOI: 10.3390/c8020024
      Issue No: Vol. 8, No. 2 (2022)
  • C, Vol. 8, Pages 25: Pore Structure and Gas Diffusion Features of Ionic
           Liquid-Derived Carbon Membranes

    • Authors: Ourania Tzialla, Anastasios Labropoulos, Georgios Pilatos, Georgios Romanos, Konstantinos G. Beltsios
      First page: 25
      Abstract: In the present study, the concept of Ionic Liquid (IL)-mediated formation of carbon was applied to derive composite membranes bearing a nanoporous carbon phase within their separation layer. Thermolytic carbonization of the supported ionic liquid membranes, prepared by infiltration of the IL 1-methyl-3-butylimidazolium tricyanomethanide into the porous network of Vycor® porous glass tubes, was applied to derive the precursor Carbon/Vycor® composites. All precursors underwent a second cycle of IL infiltration/pyrolysis with the target to finetune the pore structural characteristics of the carbonaceous matter nesting inside the separation layer. The pore structural assets and evolution of the gas permeation properties and separation efficiency of the as-derived composite membranes were investigated with reference to the duration of the second infiltration step. The transport mechanisms of the permeating gases were elucidated and correlated to the structural characteristics of the supported carbon phase and the analysis of LN2 adsorption isotherms. Regarding the gas separation efficiency of the fabricated Carbon/Vycor® composite membranes, He/CO2 ideal selectivity values as high as 4.31 at 1 bar and 25 °C and 4.64 at 0.3 bar and 90 °C were achieved. In addition, the CO2/N2 ideal selectivity becomes slightly improved for longer second-impregnation times.
      Citation: C
      PubDate: 2022-04-29
      DOI: 10.3390/c8020025
      Issue No: Vol. 8, No. 2 (2022)
  • C, Vol. 8, Pages 26: Recent Advances on Capacitive Proximity Sensors: From
           Design and Materials to Creative Applications

    • Authors: Reza Moheimani, Paniz Hosseini, Saeed Mohammadi, Hamid Dalir
      First page: 26
      Abstract: Capacitive proximity sensors (CPSs) have recently been a focus of increased attention because of their widespread applications, simplicity of design, low cost, and low power consumption. This mini review article provides a comprehensive overview of various applications of CPSs, as well as current advancements in CPS construction approaches. We begin by outlining the major technologies utilized in proximity sensing, highlighting their characteristics and applications, and discussing their advantages and disadvantages, with a heavy emphasis on capacitive sensors. Evaluating various nanocomposites for proximity sensing and corresponding detecting approaches ranging from physical to chemical detection are emphasized. The matrix and active ingredients used in such sensors, as well as the measured ranges, will also be discussed. A good understanding of CPSs is not only essential for resolving issues, but is also one of the primary forces propelling CPS technology ahead. We aim to examine the impediments and possible solutions to the development of CPSs. Furthermore, we illustrate how nanocomposite fusion may be used to improve the detection range and accuracy of a CPS while also broadening the application scenarios. Finally, the impact of conductance on sensor performance and other variables that impact the sensitivity distribution of CPSs are presented.
      Citation: C
      PubDate: 2022-05-05
      DOI: 10.3390/c8020026
      Issue No: Vol. 8, No. 2 (2022)
  • C, Vol. 8, Pages 27: Chemical Production of Graphene Oxide with High
           Surface Energy for Supercapacitor Applications

    • Authors: Mehdi Karbak, Ouassim Boujibar, Sanaa Lahmar, Cecile Autret-Lambert, Tarik Chafik, Fouad Ghamouss
      First page: 27
      Abstract: The chemical exfoliation of graphite to produce graphene and its oxide is undoubtedly an economical method for scalable production. Carbon researchers have dedicated significant resources to developing new exfoliation methods leads to graphene oxides with high quality. However, only a few studies have been dedicated to the effect of the starting graphite material on the resulting GO. Herein, we have prepared two different GOs through chemical exfoliation of graphite materials having different textural and structural characteristics. All samples have been subjected to structural investigations and comprehensive characterizations using Raman, X-ray diffraction, scanning electron microscopy, TGA, N2 physisorption, and FTIR spectroscopy. Our results provide direct evidence of how the crystallite size of the raw graphite affects the oxidation degree, surface functionality, and sheet size of the resulting GO. Building on these significant understandings, the optimized GO achieves a highly specific capacitance of 191 F.g−1 at the specific current of 0.25 A.g−1 in an aqueous electrolyte. This superior electrochemical performance was attributed to several factors, among which the specific surface area was accessible to the electrolyte ions and oxygenated functional groups on the surface, which can significantly modify the electronic structure of graphene and further enhance the surface energy.
      Citation: C
      PubDate: 2022-05-07
      DOI: 10.3390/c8020027
      Issue No: Vol. 8, No. 2 (2022)
  • C, Vol. 8, Pages 28: The Evaluation of Quality of the Co-Firing Process of
           Glycerine Fraction with Coal in the High Power Boiler

    • Authors: Rafal Kozdrach, Andrzej Stepien
      First page: 28
      Abstract: The article presents the test results of the co-firing process of a glycerine fraction derived from the production of liquid biofuels (fatty acid methyl esters) with coal. The test was performed in industrial conditions using a steam boiler with a capacity of approx. 2 MW in one of the building materials manufacturing facilities. The process of co-firing a mixture of a 3% glycerine fraction and eco-pea coal was evaluated. The reference fuel was eco-pea coal. The combustion process, composition and temperature of exhaust gases were analyzed. Incorrect combustion of glycerine fraction may result in the emission of toxic, mutagenic, and carcinogenic substances, including polycyclic aromatic hydrocarbons. During the test of the combustion process of a mixture of glycerine fraction and eco-pea coal, a decrease in the content of O2, CO, and NOx was observed as well as an increase in the content of H2, CO2, and SO2 in the fumes and growth of temperature of exhaust gases in relation to the results of combustion to eco-pea coal. Reduced content of carbon monoxide in exhaust gases produced in the combustion could be caused by the high temperature of the grate or by an excessive amount of oxygen in the grate. The higher content of oxygen in glycerine changes the value of excess air coefficient and the combustion process is more effective. The bigger content of sulfur dioxide in burnt fuels containing the glycerine fraction could be caused by the presence of reactive ingredients contained in the glycerine fraction. The reduced content of nitrogen oxides in exhaust gases originating from the combustion of a fuel mixture containing a fraction of glycerine could be caused by lower content of nitrogen in the glycerine fraction submitted to co-firing with coal and also higher combustion temperature and amount of air in the combustion chamber. The increased content of carbon dioxide in exhaust gases originating from the combustion of fuel mixture containing glycerine fraction could be caused by the influence of glycerine on the combustion process. The increase of hydrogen in the glycerine fraction causes the flame temperature to grow and makes the combustion process more efficient.
      Citation: C
      PubDate: 2022-05-12
      DOI: 10.3390/c8020028
      Issue No: Vol. 8, No. 2 (2022)
  • C, Vol. 8, Pages 29: Recent Progress in Synthesis and Application of
           Activated Carbon for CO2 Capture

    • Authors: Chong Yang Chuah, Afiq Mohd Laziz
      First page: 29
      Abstract: Greenhouse gas emissions to the atmosphere have been a long-standing issue that has existed since the Industrial Revolution. To date, carbon dioxide capture through the carbon capture, utilization, and storage approach has been one of the feasible options to combat the strong release of carbon dioxide into the atmosphere. This review focuses in general on the utilization of activated carbon as a tool when performing the carbon-capture process. Activated carbon possesses a lower isosteric heat of adsorption and a stronger tolerance to humidity as compared to zeolites and metal–organic frameworks, despite the overall gas-separation performance of activated carbon being comparatively lower. In addition, investigations of the activation methods of activated carbon are summarized in this review, together with an illustration of CO2 adsorption performance, in the context of process simulations and pilot-plant studies. This is followed by providing future research directions in terms of the applicability of activated carbon in real CO2-adsorption processes.
      Citation: C
      PubDate: 2022-05-14
      DOI: 10.3390/c8020029
      Issue No: Vol. 8, No. 2 (2022)
  • C, Vol. 8, Pages 4: The X-ray, Raman and TEM Signatures of
           Cellulose-Derived Carbons Explained

    • Authors: Petros Kasaira Mubari, Théotime Beguerie, Marc Monthioux, Elsa Weiss-Hortala, Ange Nzihou, Pascal Puech
      First page: 4
      Abstract: Structural properties of carbonized cellulose were explored to conjugate the outcomes from various characterization techniques, namely X-ray diffraction (XRD), Raman spectroscopy, and high-resolution transmission electron microscopy. All these techniques have evidenced the formation of graphene stacks with a size distribution. Cellulose carbonized at 1000 and 1800 °C at a heating rate of 2 °C/min showed meaningful differences in Raman spectroscopy, whereas in XRD, the differences were not well pronounced, which implies that the crystallite sizes calculated by each technique have different significations. In the XRD patterns, the origin of a specific feature at a low scattering angle commonly reported in the literature but poorly explained so far, was identified. The different approaches used in this study were congruous in explaining the observations that were made on the cellulose-derived carbon samples. The remnants of the basic structural unit (BSU) are developed during primary carbonization. Small graphene-based crystallites inherited from the BSUs, which formerly developed during primary carbonization, were found to coexist with larger ones. Even if the three techniques give information on the average size of graphenic domains, they do not see the same characteristics of the domains; hence, they are not identical, nor contradictory but complementary. The arguments developed in the work to explain which characteristics are deduced from the signal obtained by each of the three characterization techniques relate to physics phenomena; hence, they are quite general and, therefore, are valid for all kind of graphenic materials.
      Citation: C
      PubDate: 2022-01-03
      DOI: 10.3390/c8010004
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 5: Experimental Volumetric Hydrogen Uptake Determination
           at 77 K of Commercially Available Metal-Organic Framework Materials

    • Authors: Jose A. Villajos
      First page: 5
      Abstract: Storage is still limiting the implementation of hydrogen as an energy carrier to integrate the intermittent operation of renewable energy sources. Among different solutions to the currently used compressed or liquified hydrogen systems, physical adsorption at cryogenic temperature in porous materials is an attractive alternative due to its fast and reversible operation and the resulting reduction in storage pressure. The feasibility of cryoadsorption for hydrogen storage depends mainly on the performance of the used materials for the specific application, where metal-organic frameworks or MOFs are remarkable candidates. In this work, gravimetric and volumetric hydrogen uptakes at 77 K and up to 100 bar of commercially available MOFs were measured since these materials are made from relatively cheap and accessible building blocks. These materials also show relatively high porous properties and are currently near to large-scale production. The measuring device was calibrated at different room temperatures to calculate an average correction factor and standard deviation so that the correction deviation is included in the measurement error for better comparability with different measurements. The influence of measurement conditions was also studied, concluding that the available adsorbing area of material and the occupied volume of the sample are the most critical factors for a reproducible measurement, apart from the samples’ preparation before measurement. Finally, the actual volumetric storage density of the used powders was calculated by directly measuring their volume in the analysis cell, comparing that value with the maximum volumetric uptake considering the measured density of crystals. From this selection of commercial MOFs, the materials HKUST-1, PCN-250(Fe), MOF-177, and MOF-5 show true potential to fulfill a volumetric requirement of 40 g·L−1 on a material basis for hydrogen storage systems without further packing of the powders.
      Citation: C
      PubDate: 2022-01-05
      DOI: 10.3390/c8010005
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 6: Revealing Hydrogen States in Carbon Structures by
           Analyzing the Thermal Desorption Spectra

    • Authors: Yury S. Nechaev, Evgeny A. Denisov, Nadezhda A. Shurygina, Alisa O. Cheretaeva, Ekaterina K. Kostikova, Sergei Yu. Davydov, Andreas Öchsner
      First page: 6
      Abstract: An effective methodology for the detailed analysis of thermal desorption spectra (TDS) of hydrogen in carbon structures at micro- and nanoscale was further developed and applied for a number of TDS data of one heating rate, in particular, for graphite materials irradiated with atomic hydrogen. The technique is based on a preliminary description of hydrogen desorption spectra by symmetric Gaussians with their special processing in the approximation of the first- and the second-order reactions. As a result, the activation energies and the pre-exponential factors of the rate constants of the hydrogen desorption processes are determined, analyzed and interpreted. Some final verification of the results was completed using methods of numerical simulation of thermal desorption peaks (non-Gaussians) corresponding to the first- and the second-order reactions. The main research finding of this work is a further refinement and/or disclosure of poorly studied characteristics and physics of various states of hydrogen in microscale graphite structures after irradiation with atomic hydrogen, and comparison with the related results for nanoscale carbon structures. This is important for understanding the behavior and relationship of hydrogen in a number of cases of high energy carbon-based materials and nanomaterials.
      Citation: C
      PubDate: 2022-01-11
      DOI: 10.3390/c8010006
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 7: Hydrogenation and Dehydrogenation of Liquid Organic
           Hydrogen Carriers: A New Opportunity for Carbon-Based Catalysts

    • Authors: Salvador Ordóñez, Eva Díaz, Laura Faba
      First page: 7
      Abstract: The development of a hydrogen-based economy is the perfect nexus between the need of discontinuing the use of fossil fuels (trying to mitigate climate change), the development of a system based on renewable energy (with the use of hydrogen allowing us to buffer the discontinuities produced in this generation) and the achievement of a local-based robust energy supply system [...]
      Citation: C
      PubDate: 2022-01-13
      DOI: 10.3390/c8010007
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 8: The Influence of Hydrogen Passivation on Conductive
           Properties of Graphene Nanomesh—Prospect Material for Carbon
           Nanotubes Growing

    • Authors: Vladislav V. Shunaev, Olga E. Glukhova
      First page: 8
      Abstract: Graphene nanomesh (GNM) is one of the most intensively studied materials today. Chemical activity of atoms near GNM’s nanoholes provides favorable adsorption of different atoms and molecules, besides that, GNM is a prospect material for growing carbon nanotubes (CNTs) on its surface. This study calculates the dependence of CNT’s growing parameters on the geometrical form of a nanohole. It was determined by the original methodic that the CNT’s growing from circle nanoholes was the most energetically favorable. Another attractive property of GNM is a tunable gap in its band structure that depends on GNM’s topology. It is found by quantum chemical methods that the passivation of dangling bonds near the hole of hydrogen atoms decreases the conductance of the structure by 2–3.5 times. Controlling the GNM’s conductance may be an important tool for its application in nanoelectronics.
      Citation: C
      PubDate: 2022-01-14
      DOI: 10.3390/c8010008
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 9: From Waste Plastics to Carbon Nanotube Audio Cables

    • Authors: Varun Shenoy Gangoli, Tim Yick, Fang Bian, Alvin Orbaek White
      First page: 9
      Abstract: Carbon nanotubes (CNTs) have long been at the forefront of materials research, with applications ranging from composites for increased tensile strength in construction and sports equipment to transistor switches and solar cell electrodes in energy applications. There remains untapped potential still when it comes to energy and data transmission, with our group having previously demonstrated a working ethernet cable composed of CNT fibers. Material composition, electrical resistance, and electrical capacitance all play a strong role in the making of high-quality microphone and headphone cables, and the work herein describes the formation of a proof-of-concept CNT audio cable. Testing was done compared to commercial cables, with frequency response measurements performed for further objective testing. The results show performance is on par with commercial cables, and the CNTs being grown from waste plastics as a carbon source further adds to the value proposition, while also being environmentally friendly.
      Citation: C
      PubDate: 2022-01-25
      DOI: 10.3390/c8010009
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 10: Asymmetrical Cross-Sectional Buckling in Arc-Prepared
           Multiwall Carbon Nanotubes Revealed by Iodine Filling

    • Authors: Abraao Cefas Torres-Dias, Anthony Impellizzeri, Emmanuel Picheau, Laure Noé, Alain Pénicaud, Christopher Ewels, Marc Monthioux
      First page: 10
      Abstract: We report the intercalation of iodine chains in highly crystalline arc-discharge multiwalled carbon nanotubes (MWCNTs), not in the central cavity but instead between the concentric graphene shells. High-resolution transmission electron microscopy demonstrated that the intercalation was asymmetric with respect to the longitudinal axis of the nanotubes. This filling is explained through the existence of asymmetric intershell channels which formed as the tubes shrank upon cooling after growth. Shrinkage occurred because the geometrically constrained equilibrium intershell spacing was higher at growth than room temperature, due to the highly anisotropic coefficient of thermal expansion of graphite (or graphene stacks). Computational modelling supported the formation of such cavities and explained why they all formed on the same side of the tubes. The graphene shells were forced to bend outward, thereby opening aligned intergraphene nanocavities, and subsequently allowing the intercalation with iodine once the tube ends were opened by oxidative treatment. These observations are specific to catalyst-free processes because catalytic processes use too low temperatures, but they are generally applicable in geometrically closed carbon structures grown at high temperatures and so should be present in all arc-grown MWCNTs. They are likely to explain multiple observations in the literature of asymmetric interlayer spacings in multiple-shell graphenic carbon structures.
      Citation: C
      PubDate: 2022-01-27
      DOI: 10.3390/c8010010
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 11: Acknowledgment to Reviewers of C in 2021

    • Authors: C Editorial Office C Editorial Office
      First page: 11
      Abstract: Rigorous peer-reviews are the basis of high-quality academic publishing [...]
      Citation: C
      PubDate: 2022-01-28
      DOI: 10.3390/c8010011
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 12: Reduced Graphene Oxide—Polycarbonate Electrodes
           on Different Supports for Symmetric Supercapacitors

    • Authors: Okhay, Bastos, Andreeva, Tuukkanen, Tkach
      First page: 12
      Abstract: Electrode materials for electrochemical capacitors or supercapacitors (SCs) are widely studied, as they are needed for the development of energy storage devices in electrical vehicles and flexible electronics. In the current work, a self-supported paper of reduced graphene oxide (rGO) with polycarbonate (PC) (as rGO-PC composite) was prepared by simple vacuum filtration and low-temperature annealing. rGO-PC as a freestanding single electrode was studied in a three-electrode system and presented a capacitive energy storage mechanism. To fabricate SCs based on rGO-PC, flexible polyethylene terephthalate (PET) with layers of both Cu tape (Cu tape) and carbon tape (C tape) (PET/Cu/C), as well as PET covered by graphene ink (PET/GrI), were used as supports. Fabricated flexible symmetric SCs have shown similar behavior with a higher areal capacitance value than that on PET/Cu/C substrate.
      Citation: C
      PubDate: 2022-02-02
      DOI: 10.3390/c8010012
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 13: Compositing Fullerene-Derived Porous Carbon Fibers
           with Reduced Graphene Oxide for Enhanced ORR Catalytic Performance

    • Authors: Zhimin He, Ziqian Guo, Kun Guo, Takeshi Akasaka, Xing Lu
      First page: 13
      Abstract: Compositing all-carbon materials with distinct dimensions and structures has demonstrated the great potential to bring synergistic promotion to individual components for the electrocatalytic activity of oxygen reduction reaction (ORR). Fullerene-derived porous carbon fibers (FPCFs) offer unique one-dimensional (1D) nanostructures with abundant defects and a large specific surface area while graphene features two-dimensional (2D) nanostructures with fast electron transfer. Both carbon materials are promising alternatives to Pt-based electrocatalysts for ORR. Herein, a novel hierarchical composite (FPCFs@rGO) composed of FPCFs and reduced graphene oxide (rGO) is constructed by sonication-assisted mixing and high-temperature pyrolysis. When tested as an electrocatalyst for ORR, the 1D/2D FPCFs@rGO composite presents significantly enhanced performance compared to each individual component, indicating an eminent synergistic effect between FPCFs and rGO. The improved ORR performance of FPCFs@rGO is attributed to the unique hierarchical structure with abundant structural defects, a large specific surface area, and high porosity.
      Citation: C
      PubDate: 2022-02-11
      DOI: 10.3390/c8010013
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 14: Structural and Electrochemical Characteristics of
           Platinum Nanoparticles Supported on Various Carbon Carriers

    • Authors: Margarita Kozlova, Sergey Butrim, Maksim Solovyev, Artem Pushkarev, Irina Pushkareva, Valery Kalinichenko, Svetlana Akelkina, Sergey Grigoriev
      First page: 14
      Abstract: Graphene-like materials have attracted significant attention as alternative catalyst carriers due to the broad possibilities of changing their shape, composition, and properties. In this study we investigated the structural and electrochemical characteristics of platinum electrocatalysts supported on reduced graphene oxide (rGO), including those modified with amine functionalities, nitrogen heteroatoms (rGO-Am), and oxygen enriched (rGO-O). Synthesis of Pt nanoparticles (20 wt.%) on the graphene-like nanomaterials surface was carried out using a modified polyol procedure. The Pt20/rGO-Am showed a lower Pt nanoparticles size together with high Pt utilization and EASA values compared to rGO-supported catalysts and the Pt/C reference sample due to the uniform distribution of nucleation centers on the surface of graphene nanoparticles, and the greater ability of these centers to electrically bond with platinum.
      Citation: C
      PubDate: 2022-02-14
      DOI: 10.3390/c8010014
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 15: Carbon Composites—Graphene-Oxide-Catalyzed
           Sugar Graphitization

    • Authors: Madhu Singh, Randy L. Vander Wal
      First page: 15
      Abstract: Utilization of biopolymers to form graphitic carbons is challenged by their high oxygen content and resulting curved and defective carbon lamellae upon high-temperature heat-treatment. Two composites, one with graphene-oxide (GO) and the other with reduced graphene-oxide (rGO) as fillers, respectively, in a matrix of sugar, each for the same added 2.5 wt.%, exhibited different degrees of graphitization compared to pure sugar on its own. Reactive oxygen groups on GO contribute to reactive templating and crystallite formation. Under high-temperature heat-treatment, sugar, a well-known non-graphitizing precursor, is converted to graphitic carbon in the presence of GO. Possessing fewer oxygen groups, rGO forms two phases in the sugar matrix—a non-graphitic phase and a graphitic phase. The latter is attributed to the remaining oxygen on the rGO.
      Citation: C
      PubDate: 2022-02-14
      DOI: 10.3390/c8010015
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 16: Temperature Dependence of Hydrogen Adsorption on
           Pd-Modified Carbon Blacks and Their Enthalpy-Entropy Changes

    • Authors: Takehiro Kaneko, Takeshi Toyama, Yoshiyuki Kojima, Nobuyuki Nishimiya
      First page: 16
      Abstract: Metal-carbon composites have recently gained attention as potential hydrogen storage materials. In the present investigation, carbon blacks (CBs) with 0.6 mass %, 4.9 mass %, and 9.3 mass % of Pd were prepared to investigate the cooperative effect together with Pd and CB for hydrogen storage. The hydrogen adsorption isotherms were measured at 77 K, 98 K, 123 K, 148 K, 173 K, 223 K, and 273 K under mild pressures below 1 MPa. The lower temperature gave the higher hydrogen content. Almost all the hydrogen contents of Pd-modified CBs exceeded the sum of the adsorption contents of CB and the occluded amounts of the assumed hydride, PdH0.6. The highest hydrogen content was recorded for Pd 0.6 mass %-modified CB at 77 K. At temperatures above 77 K, CBs with the higher Pd contents adsorbed more hydrogen than Pd 0.6 mass %-modified CB, and they indicated an increase in the absolute values of adsorption enthalpy with the progress of adsorption. Pd was thought to be at first blocking deep potential sites, with accessibility to hydrogen acceptable sites gradually increasing as adsorption progressed.
      Citation: C
      PubDate: 2022-02-22
      DOI: 10.3390/c8010016
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 17: Functionalization of Graphene by π–π
           Stacking with C60/C70/Sc3N@C80 Fullerene Derivatives for Supercapacitor
           Electrode Materials

    • Authors: Piotr Piotrowski, Agata Fedorczyk, Jacek Grebowski, Agnieszka Krogul-Sobczak
      First page: 17
      Abstract: Non-covalent modification of graphene is one of the strategies used for enhancing its energy storage properties. Herein, we report the design and synthesis of a series of fullerene derivatives that are capable of assembly on graphene sheets by π–π stacking interactions. Newly synthesized graphene-fullerene hybrid nanomaterials were characterized using spectroscopic and microscopic techniques. In order to determine the specific capacitance of obtained electrode materials galvanostatic charge-discharge measurements were performed. The obtained results allowed the determination of which fullerene core and type of substituent introduced on its surface can increase the capacitance of resulting electrode. Benefiting from introduced fullerene derivative molecules, graphene with naphthalene functionalized C70 fullerene showed specific capacitance enhanced by as much as 15% compared to the starting material.
      Citation: C
      PubDate: 2022-03-11
      DOI: 10.3390/c8010017
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 18: Synthetic, Photosynthetic, and Chemical Strategies to
           Enhance Carbon Dioxide Fixation

    • Authors: Supriyo Ray, Jason Abraham, Nyiah Jordan, Mical Lindsay, Neha Chauhan
      First page: 18
      Abstract: The present human population is more than three times what it was in 1950. With that, there is an increasing demand for the consumption of fossil fuels for various anthropogenic activities. This consumption is the major source of carbon dioxide emission causing greenhouse effects leading to global warming. The dependency on fossil fuels around the globe is such that it would be hard to move away from it any time soon. Hence, we must work on strategies to improve carbon dioxide fixation as we are making advancements in clean energy technology. This review explores the natural carbon dioxide fixation pathways in plants and various microorganisms and discusses their limitations and alternative strategies. It explains what necessitates the exploration of synthetic pathways and discusses strategies and matrices to consider while evaluating various pathways. This review also discusses the recent breakthroughs in the field of nanosciences that could accelerate chemical methods of carbon dioxide fixation.
      Citation: C
      PubDate: 2022-03-15
      DOI: 10.3390/c8010018
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 19: Low-Sulphur Vacuum Gasoil of Western Siberia Oil: The
           Impact of Its Structural and Chemical Features on the Properties of the
           Produced Needle Coke

    • Authors: Mikhail Y. Dolomatov, Daniyar Z. Burangulov, Milana M. Dolomatova, Danil F. Osipenko, Viktor P. Zaporin, Alina A. Tukhbatullina, Arslan F. Akhmetov, Denis S. Sabirov
      First page: 19
      Abstract: The specific branches of industry utilize needle coke, a carbon form with a highly anisotropic structure. Searching for novel raw materials for its production is now rigorously studied. In the present work, we use low-sulfur gasoil for this purpose, namely its high-boiling fractions. We study their chemical and physicochemical parameters with the set of physicochemical and spectral methods. The data of FT-IR and UV-Vis spectroscopies with a phenomenological method (that allows assessing average electronic structure parameters) indicate that the gas oil of the West Siberian origin contains polycyclic aromatic hydrocarbons (PAHs) with 3–5 condensed benzene rings. The maximum amount of PAHs with molecular masses of 400–600 a.u. is contained in the fractions with boiling points higher than 450 °C. According to the data of polarized-light optical microscopy, the higher boiling point of the gasoil fraction the higher anisotropy of the produced coke. This occurs as a result of an increase in the amount of PAHs capable of condensation with the formation of a mesophase. Thus, low-sulfur gas oils from thermally processed West Siberian oil are promising raw materials for the production of needle coke in delayed coking processes.
      Citation: C
      PubDate: 2022-03-17
      DOI: 10.3390/c8010019
      Issue No: Vol. 8, No. 1 (2022)
  • C, Vol. 8, Pages 1: Increased Electrical Conductivity of Carbon Nanotube
           Fibers by Thermal and Voltage Annealing

    • Authors: Varun Shenoy Gangoli, Chris J. Barnett, James D. McGettrick, Alvin Orbaek White, Andrew R. Barron
      First page: 1
      Abstract: We report the effect of annealing, both electrical and by applied voltage, on the electrical conductivity of fibers spun from carbon nanotubes (CNTs). Commercial CNT fibers were used as part of a larger goal to better understand the factors that go into making a better electrical conductor from CNT fibers. A study of thermal annealing in a vacuum up to 800 °C was performed on smaller fiber sections along with a separate analysis of voltage annealing up to 7 VDC; both exhibited a sweet spot in the process as determined by a combination of a two-point probe measurement with a nanoprobe, resonant Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Scaled-up tests were then performed in order to translate these results into bulk samples inside a tube furnace, with similar results that indicate the potential for an optimized method of achieving a better conductor sample made from CNT fibers. The results also help to determine the surface effects that need to be overcome in order to achieve this.
      Citation: C
      PubDate: 2021-12-23
      DOI: 10.3390/c8010001
      Issue No: Vol. 8, No. 1 (2021)
  • C, Vol. 8, Pages 2: High Surface Area Nanoporous Activated Carbons
           Materials from Areca catechu Nut with Excellent Iodine and Methylene Blue

    • Authors: Sahira Joshi, Rekha Goswami Shrestha, Raja Ram Pradhananga, Katsuhiko Ariga, Lok Kumar Shrestha
      First page: 2
      Abstract: Nanoporous carbon materials from biomass exhibit a high surface area due to well-defined pore structures. Therefore, they have been extensively used in separation and purification technologies as efficient adsorbents. Here, we report the iodine and methylene blue adsorption properties of the hierarchically porous carbon materials prepared from Areca catechu nut. The preparation method involves the phosphoric acid (H3PO4) activation of the Areca catechu nut powder. The effects of carbonization conditions (mixing ratio with H3PO4, carbonization time, and carbonization temperature) on the textural properties and surface functional groups were studied. The optimum textural properties were obtained at a mixing ratio of 1:1, carbonized for 3 h at 400 °C, and the sample achieved a high specific surface area of 2132.1 m2 g−1 and a large pore volume of 3.426 cm3 g−1, respectively. The prepared materials have amorphous carbon structures and contain oxygenated surface functional groups. Due to the well-defined micro-and mesopore structures with the high surface area and large pore volume, the optimal sample showed excellent iodine and methylene blue adsorption. The iodine number and methylene blue values were ca. 888 mg g−1 and 369 mg g−1, respectively. The batch adsorption studies of methylene dye were affected by pH, adsorbent dose, contact time, and initial concentration. The optimum parameters for the methylene blue adsorption were in alkaline pH, adsorbent dose of 2.8 g L−1, and contact time of 180 min. Equilibrium data could be best represented by the Langmuir isotherm model with a monolayer adsorption capacity of 333.3 mg g−1. Thus, our results demonstrate that the Areca catechu nut has considerable potential as the novel precursor material for the scalable production of high surface area hierarchically porous carbon materials that are essential in removing organic dyes from water.
      Citation: C
      PubDate: 2021-12-27
      DOI: 10.3390/c8010002
      Issue No: Vol. 8, No. 1 (2021)
  • C, Vol. 8, Pages 3: Carbon Nanomaterials for Theranostic Use

    • Authors: Izabela Kościk, Daniel Jankowski, Anna Jagusiak
      First page: 3
      Abstract: Based on statistics from the National Cancer Institute in the US, the rate of new cases of cancer is 442.4 per 100,000 men and women per year, and more than one-third do not survive the disease. Cancer diagnosis and treatment are the most important challenges in modern medicine. The majority of cancer cases are diagnosed at an early stage. However, the possibility of simultaneous diagnosis and application of therapy (theranostics) will allow for acceleration and effectiveness of treatment. Conventional chemotherapy is not effective in reducing the chemoresistance and progression of various types of cancer. In addition, it causes side effects, which are mainly a result of incorrect drug distribution. Hence, new therapies are being explored as well as new drug delivery strategies. In this regard, nanotechnology has shown promise in the targeted delivery of therapeutics to cancer cells. This review looks at the latest advances in drug delivery-based diagnosis and therapy. Drug delivery nanosystems made of various types of carbon (graphene, fullerenes, and carbon nanotubes) are discussed. Their chemical properties, advantages, and disadvantages are explored, and these systems are compared with each other.
      Citation: C
      PubDate: 2021-12-31
      DOI: 10.3390/c8010003
      Issue No: Vol. 8, No. 1 (2021)
  • C, Vol. 7, Pages 67: Atomic Layer Deposition of Nanolayered Carbon Films

    • Authors: Zhigang Xiao, Kim Kisslinger, Rebhadevi Monikandan
      First page: 67
      Abstract: In this paper, carbon thin films were grown using the plasma-enhanced atomic layer deposition (PE-ALD). Methane (CH4) was used as the carbon precursor to grow the carbon thin film. The grown film was analyzed by the high-resolution transmission electron micrograph (TEM), X-ray photoelectron spectroscopy (XPS) analysis, and Raman spectrum analysis. The analyses show that the PE-ALD-grown carbon film has an amorphous structure. It was found that the existence of defective sites (nanoscale holes or cracks) on the substrate of copper foil could facilitate the formation of nanolayered carbon films. The mechanism for the formation of nanolayered carbon film in the nanoscale holes was discussed. This finding could be used for the controlled growth of nanolayered carbon films or other two-dimensional nanomaterials while combining with modern nanopatterning techniques.
      Citation: C
      PubDate: 2021-09-27
      DOI: 10.3390/c7040067
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 68: CH Activation by a Heavy Metal Cation: Production of
           H2 from the Reaction of Acetylene with C4H4-Os(+) in Gas phase

    • Authors: Zikri Altun, Erdi Ata Bleda, Carl Trindle
      First page: 68
      Abstract: While first-row transition metal cations, notably Fe(+), catalyze the gas-phase conversion of acetylene to benzene, a distinct path is chosen in systems with Os, Ir, and Rh cations. Rather than losing the metal cation M(+) from the benzene–M(+) complex, as is observed for the Fe(+) system, the heavy metal ions activate CH bonds. The landmark system C4H4-Os(+) reacts with acetylene to produce C6H4-Os(+) and dihydrogen. Following our work on isomers of the form C2nH2n-Fe(+), we show by DFT modeling that the CH bonds of the metalla-7-cycle structure, C6H6-Os(+), are activated and define the gas-phase reaction path by which H2 is produced. The landmark structures on the network of reaction paths can be used as a basis for the discussion of reactions in which a single Os atom on an inert surface can assist reactions of hydrocarbons.
      Citation: C
      PubDate: 2021-09-30
      DOI: 10.3390/c7040068
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 69: Nanoporous Carbon Magnetic Hybrid Derived From
           Waterlock Polymers and Its Application for Hexavalent Chromium Removal
           from Aqueous Solution

    • Authors: Georgios Asimakopoulos, Angeliki Karakassides, Maria Baikousi, Christina Gioti, Dimitrios Moschovas, Apostolos Avgeropoulos, Athanasios B. Bourlinos, Alexios P. Douvalis, Constantinos E. Salmas, Michael A. Karakassides
      First page: 69
      Abstract: Sodium polyacrylate is the superabsorbent waterlock polymer used in disposable diapers, which are the third largest single consumer item in landfills. As diapers are difficult to recycle, their use produces an incredible amount of environmental waste. In the present article, we present a reliable and facile approach to transform sodium polyacrylate, the main constitute in the used diapers, in a carbon-based magnetic sorbent material, capable for use in environmental applications. A nanoporous carbon magnetic hybrid material was prepared by reacting NaPA with iron acetate species under chemical activation conditions. Analysis of the characterization results revealed, the creation of a nanoporous structure, with high specific surface area value (SgBET = 611 m2/g), along with the formation of nanosized zero valent iron nanoparticles and iron carbide (Fe3C), inside the carbon pore system. 57Fe Mössbauer spectroscopy verified also the existence of these two main iron-bearing phases, as well as additional minor magnetic phases, such as Fe3O4 and γ-Fe2O3. Vibrating sample magnetometry (VSM) measurements of the obtained hybrid confirmed its ferromagnetic/ferrimagnetic behavior. The hybrid material demonstrated a rapid sorption of Cr(VI) ions (adsorption capacity: 90 mg/g, 24 h pH = 3). The results showed highly pH-dependent sorption efficiency of the hybrids, whereas a pseudo-second-order kinetic model described their kinetics.
      Citation: C
      PubDate: 2021-09-30
      DOI: 10.3390/c7040069
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 70: Fabrication and Supercapacitor Applications of
           Multiwall Carbon Nanotube Thin Films

    • Authors: Kyle Jiang, Rosario A. Gerhardt
      First page: 70
      Abstract: Multiwalled carbon nanotubes (MWCNTs) are a one-dimensional nanomaterial with several desirable material properties, including high mechanical tensile modulus and strength, high electrical conductivity, and good thermal conductivity. A wide variety of techniques have been optimized to synthesize MWCNTs and to fabricate thin films of MWCNTs. These synthesis and fabrication methods vary based on precursor materials, process parameters, and physical and chemical principals, and have a strong influence on the properties of the nanotubes and films. Thus, the fabrication methods determine the performance of devices that can exploit the advantageous material properties of MWCNTs. Techniques for the fabrication of carbon nanotubes and carbon nanotube thin films are reviewed, followed by a discussion of the use of MWCNTs as an electrode material for electrochemical double-layer supercapacitors (EDLCs). EDLCs feature high power density, excellent reversibility and lifetime, and improved energy density over electrolytic capacitors. Beyond surveying fabrication techniques previously explored for MWCNT electrodes, an alternative approach based on inkjet printing capable of depositing a small amount of active material is discussed. Such an approach allows for a high degree of control over electrode properties and can potentially reduce cost and active material waste, which are essential components to the gradual conversion to green energy.
      Citation: C
      PubDate: 2021-09-30
      DOI: 10.3390/c7040070
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 71: Applicability of Atmospheric Pressure Plasma Jet
           (APPJ) Discharge for the Reduction in Graphene Oxide Films and Synthesis
           of Carbon Nanomaterials

    • Authors: Sri Hari Bharath Vinoth Kumar, Josefa Ibaceta-Jaña, Natalia Maticuic, Krystian Kowiorski, Matthias Zelt, Ulrich Gernert, Ludwika Lipińska, Bernd Szyszka, Rutger Schlatmann, Uwe Hartmann, Ruslan Muydinov
      First page: 71
      Abstract: Atmospheric pressure plasma jets (APPJ) are widely used in industry for surface cleaning and chemical modification. In the recent past, they have gained more scientific attention especially in the processing of carbon nanomaterials. In this work, a novel power generation technique was applied to realize the stable discharge in N2 (10 vol.% H2) forming gas in ambient conditions. This APPJ was used to reduce solution-processed graphene oxide (GO) thin films and the result was compared with an established and optimized reduction process in a low–pressure capacitively coupled (CCP) radiofrequency (RF) hydrogen (H2) plasma. The reduced GO (rGO) films were investigated by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Effective deoxygenation of GO was observed after a quick 2 s treatment by AAPJ. Further deoxygenation at longer exposure times was found to proceed with the expense of GO–structure integrity. By adding acetylene gas into the same APPJ, carbon nanomaterials on various substrates were synthesized. The carbon materials were characterized by Raman spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analyses. Fullerene-like particles and graphitic carbon with short carbon nanotubes were detected on Si and Ag surfaces, respectively. We demonstrate that the APPJ tool has obvious potential for the versatile processing of carbon nanomaterials.
      Citation: C
      PubDate: 2021-10-14
      DOI: 10.3390/c7040071
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 72: Effects of Reducing Agent on the Activity of
           PtRu/Carbon Black Anode Catalyst of Direct Methanol Fuel Cell

    • Authors: Yu-Wen Chen, Han-Gen Chen
      First page: 72
      Abstract: A series of PtRu/carbon black catalysts were prepared by means of deposition-precipitation and reduced by various reducing agents. NaBH4, HCHO and NaH2PO2, respectively, were used as the reduction agents. Some of the samples were reduced by various amounts of NaH2PO2 to investigate the effects of P/Pt ratios on the characteristics and activity of the catalyst. These catalysts were characterized by X-ray diffraction and transmission electron microscopy. The components of these catalysts were detected by X-ray fluorescence, X-ray photoelectron microscopy, and extended X-ray absorption of fine structures (EXAFS). The methanol oxidation ability of the catalysts was tested by cyclic voltammetry measurement. The results show that NaH2PO2 could effectively reduce the particle size of PtRu metal. It can suppress the growth of metal particles. In addition, the P/Pt ratio is crucial. The catalyst reduced by NaH2PO2 with a P/Pt ratio of 1.2 had the highest activity among all catalysts. It had the higher Pt and Ru metal contents and smaller metal particle size than the other catalysts. Its activity was 253.12 A/g, which is higher that than the commercial catalyst (Johnson Matthey H10100, 251.32 A/g).
      Citation: C
      PubDate: 2021-10-19
      DOI: 10.3390/c7040072
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 73: Carbon Nanoarchitectonics for Energy and Related

    • Authors: Rekha Goswami Shrestha, Lok Kumar Shrestha, Katsuhiko Ariga
      First page: 73
      Abstract: Nanoarchitectonics has been recently proposed as a post-nanotechnology concept. It is the methodology to produce functional materials from nanoscale units. Carbon-based materials are actively used in nanoarchitectonics approaches. This review explains several recent examples of energy and related applications of carbon materials from the viewpoint of the nanoarchitectonics concept. Explanations and discussions are described according to the classification of carbon sources for nanostructured materials: (i) carbon nanoarchitectonics from molecules and supramolecular assemblies; (ii) carbon nanoarchitectonics from fullerenes; (iii) carbon nanoarchitectonics from biomass; and (iv) carbon nanoarchitectonics with composites and hybrids. Functional carbon materials can be nanoarchitected through various processes, including well-skilled organic synthesis with designed molecular sources; self-assembly of fullerenes under various conditions; practical, low-cost synthesis from biomass; and hybrid/composite formation with various carbon sources. These examples strikingly demonstrate the enormous potential of nanoarchitectonics approaches to produce functional carbon materials from various components such as small molecules, fullerene, other nanocarbons, and naturally abundant biomasses. While this review article only shows limited application aspects in energy-related usages such as supercapacitors, applications for more advanced cells and batteries, environmental monitoring and remediation, bio-medical usages, and advanced devices are also expected.
      Citation: C
      PubDate: 2021-10-19
      DOI: 10.3390/c7040073
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 74: A Mini Review of Recent Findings in Cellulose-,
           Polymer- and Graphene-Based Membranes for Fluoride Removal from Drinking

    • Authors: Athanasia K. Tolkou, Elie Meez, George Z. Kyzas, Vincenzo Torretta, Maria Cristina Collivignarelli, Francesca Maria Caccamo, Eleni A. Deliyanni, Ioannis A. Katsoyiannis
      First page: 74
      Abstract: Effective fluoride removal from water is a persistent global concern both for drinking water and wastewater treatment. According to World Health Organization (WHO), standards for the maximum contaminant level in drinking water cannot be higher than 1.5 mg F− L−1 since affects the skeletal and nervous systems of humans. Various technologies have been developed to decrease fluoride concentration from waters, such as adsorption, coagulation, precipitation and membrane separation. Membrane technology has been found to be a very effective technology, significantly reducing fluoride to desired standards levels; however, it has received less attention than other technologies because it is a costly process. This review aims to discuss the recent studies using modified membranes for fluoride removal. Emphasis is given on cellulose-, polymer- and graphene-based membranes and is further discussing the modification of membranes with several metals that have been developed in the last years. It was observed that the main focus of the total publications has been on the use of polymer-based membranes. Most of the membranes applied for defluoridation exhibit greater efficiency at pH values close to that of drinking water (i.e., 6–8), and maximum treatment capacity was obtained with the use of a cellulose modified membrane Fe-Al-Mn@chitosan with a permeate flux of 2000 L m−2 h−1, following the carbon-based amyloid fibril nano-ZrO2 composites (CAF-Zr) 1750 L m−2. A technical-economic comparison study of NF and RO is also referred, concluding that NF membrane is slightly less expensive.
      Citation: C
      PubDate: 2021-10-26
      DOI: 10.3390/c7040074
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 75: Crystallization Kinetics of Poly(lactic
           acid)–Graphene Nanoscroll Nanocomposites: Role of Tubular, Planar, and
           Scrolled Carbon Nanoparticles

    • Authors: Oluwakemi Ajala, Caroline Werther, Rauf Mahmudzade, Peyman Nikaeen, Dilip Depan
      First page: 75
      Abstract: Graphene nanoscrolls (GNS) are 1D carbon-based nanoparticles. In this study, they were investigated as a heterogeneous nucleating agent in the poly(lactic acid) (PLA) matrix. The isothermal and non-isothermal melting behavior and crystallization kinetics of PLA-GNS nanocomposites were investigated using a differential scanning calorimeter (DSC). Low GNS content not only accelerated the crystallization rate, but also the degree of crystallinity of PLA. The Avrami model was used to fit raw experimental data, and to evaluate the crystallization kinetics for both isothermal and non-isothermal runs through the nucleation and growth rate. Additionally, the effect of the dimensionality and structure of the nanoparticle on the crystallization behavior and kinetics of PLA is discussed. GNS, having a similar fundamental unit as CNT and GNP, were observed to possess superior mechanical properties when analyzed by the nanoindentation technique. The scrolled architecture of GNS facilitated a better interface and increased energy absorption with PLA compared to CNTs and GNPs, resulting in superior mechanical properties.
      Citation: C
      PubDate: 2021-10-31
      DOI: 10.3390/c7040075
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 76: Graphene Synthesis and Its Recent Advances in
           Applications—A Review

    • Authors: Anuluxan Santhiran, Poobalasuntharam Iyngaran, Poobalasingam Abiman, Navaratnarajah Kuganathan
      First page: 76
      Abstract: Owing to the remarkable chemical and physical properties, graphene has been widely investigated by researchers over the last 15 years. This review summarizes major synthetic methods such as mechanical exfoliation, liquid phase exfoliation, unzipping of carbon nanotube, oxidation-reduction, arc discharge, chemical vapor deposition, and epitaxial growth of graphene in silicon carbide. Recent advances in the application of graphene in graphene-based lithium ion batteries, supercapacitors, electrochemical sensors, transparent electrodes and environmental based remedies are discussed.
      Citation: C
      PubDate: 2021-11-10
      DOI: 10.3390/c7040076
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 77: Enhanced Breaking of Lignin and Mesopore Formation in
           Zinc Chloride Assisted Hydrothermal Carbonization of Waste Biomasses

    • Authors: Hendrik Multhaupt, Patrick Bottke, Michael Wark
      First page: 77
      Abstract: Hydrochars from hydrothermal carbonization of different biowaste materials (dried dandelion, sawdust, coconut shell powder) formed in the presence of aqueous salt solutions were compared to those obtained by the common method in pure water. Hydrochars with increased carbon contents, pore volume and surface areas were specifically obtained from coconut shell powder in the presence of zinc chloride. Compositional and structural changes within the hydrochar products caused by the process conditions and/or the additive were characterized by solid state 13C NMR spectroscopy, proving that cellulose and, in particular, lignin units in the biomass are more easily attacked in the presence of the salt. Under saline conditions, a distinct particle break-up led to the creation of mesoporosity, as observable from hysteresis loops in nitrogen adsorption isotherms, which were indicative of the presence of pores with diameters of about 3 to 10 nm. The obtained hydrochars were still rich in functional groups which, together with the mesoporosity, indicates the compounds have a high potential for pollutant removal. This was documented by adsorption capacities for the methylene blue and methyl orange dyes, which exceeded the values obtained for other hydrochar-based adsorbers. A subsequent physical activation of the mesoporous hydrochars in steam at different temperatures and times resulted in a further drastic increase in the surface areas, of up to about 750 m2/g; however, this increase is mainly due to micropore formation coupled with a loss of surface functionality. Consequently, the adsorption capacity for the quite large dyes does not provide any further benefit, but the uptake of smaller gas molecules is favored.
      Citation: C
      PubDate: 2021-11-11
      DOI: 10.3390/c7040077
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 78: Influence of Carbon Nanotube Attributes on Carbon
           Nanotube/Cu Composite Electrical Performances

    • Authors: Rajyashree Sundaram, Atsuko Sekiguchi, Guohai Chen, Don Futaba, Takeo Yamada, Ken Kokubo, Kenji Hata
      First page: 78
      Abstract: Carbon nanotube (CNT)/copper composites offer promise as lightweight temperature-stable electrical conductors for future electrical and electronic devices substituting copper. However, clarifying how constituent nanotube structures influence CNT/Cu electrical performances has remained a major research challenge. Here, we investigate the correlation between the CNT/Cu electrical performances and nanotube structure by preparing and characterizing composites containing nanotubes of different structural attributes. We prepared three types of composites—single-wall (SW)-CNT/Cu wires, SW-CNT/Cu pillars, and multi-wall (MW)-CNT/Cu wires. The composites were fabricated from the corresponding CNT templates by two-step Cu electrodeposition, which retains template nanotube attributes through the fabrication process. The nanotube characteristics (diameter, G/D, alignment, etc.) in each template as well as the internal structure and electrical performances of the corresponding composites were characterized. SW-CNT/Cu wires and pillars outperformed MW-CNT/Cu wires, showing ≈ 3× higher room-temperature four-probe conductivities (as high as 30–40% Cu-conductivity). SW-CNT/Cu also showed up to 4× lower temperature coefficients of resistances i.e., more temperature-stable conductivities than MW-CNT/Cu. Our results suggest that few-walled small-diameter nanotubes can contribute to superior temperature-stable CNT/Cu conductivities. Better CNT crystallinity (high G/D), fewer nanotube ends/junctions, and nanotube alignment may be additionally beneficial. We believe that these results contribute to strategies for improving CNT/Cu performances to enable the real-world application of these materials as Cu substitutes.
      Citation: C
      PubDate: 2021-11-15
      DOI: 10.3390/c7040078
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 79: Premade Nanoparticle Films for the Synthesis of
           Vertically Aligned Carbon Nanotubes

    • Authors: Abdul Hoque, Ahamed Ullah, Beth S. Guiton, Noe T. Alvarez
      First page: 79
      Abstract: Carbon nanotubes (CNTs) offer unique properties that have the potential to address multiple issues in industry and material sciences. Although many synthesis methods have been developed, it remains difficult to control CNT characteristics. Here, with the goal of achieving such control, we report a bottom-up process for CNT synthesis in which monolayers of premade aluminum oxide (Al2O3) and iron oxide (Fe3O4) nanoparticles were anchored on a flat silicon oxide (SiO2) substrate. The nanoparticle dispersion and monolayer assembly of the oleic-acid-stabilized Al2O3 nanoparticles were achieved using 11-phosphonoundecanoic acid as a bifunctional linker, with the phosphonate group binding to the SiO2 substrate and the terminal carboxylate group binding to the nanoparticles. Subsequently, an Fe3O4 monolayer was formed over the Al2O3 layer using the same approach. The assembled Al2O3 and Fe3O4 nanoparticle monolayers acted as a catalyst support and catalyst, respectively, for the growth of vertically aligned CNTs. The CNTs were successfully synthesized using a conventional atmospheric pressure-chemical vapor deposition method with acetylene as the carbon precursor. Thus, these nanoparticle films provide a facile and inexpensive approach for producing homogenous CNTs.
      Citation: C
      PubDate: 2021-11-19
      DOI: 10.3390/c7040079
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 80: Prediction of the Near-Infrared Absorption Spectrum
           of Single-Walled Carbon Nanotubes Using a Bayesian Regularized Back
           Propagation Neural Network Model

    • Authors: Takao Onishi, Yuji Matsukawa, Yuto Yamazaki, Daisuke Miyashiro
      First page: 80
      Abstract: DNA-wrapped single-walled carbon nanotubes (DNA-SWCNTs) in stable dispersion are expected to be used as biosensors in the future, because they have the property of absorption of light in the near infrared (NIR) region, which is safe for the human body. However, this practical application requires the understanding of the DNA-SWCNTs’ detailed response characteristics. The purpose of this study is to predict, in detail, the response characteristics of the absorption spectra that result when the antioxidant catechin is added to oxidized DNA-SWCNTs, from a small amount of experimental data. Therefore, in the present study, we predicted the characteristics of the absorption spectra of DNA-SWCNTs using the Bayesian regularization backpropagation neural network (BRBPNN) model. The BRBPNN model was trained with the catechin concentration and initial absorption peaks as inputs and the absorption spectra after catechin addition as outputs. The accuracy of the predicted absorption peaks and wavelengths after the addition of catechin, as predicted by the BRBPNN model, was within 1% of the error of the experimental data. By inputting the catechin concentrations under hundreds of conditions into this BRBPNN model, we were able to obtain detailed prediction curves for the absorption peaks. This method has the potential to help to reduce the experimental costs and improve the efficiency of investigating the properties of high-cost materials such as SWCNTs.
      Citation: C
      PubDate: 2021-11-25
      DOI: 10.3390/c7040080
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 81: Comparison of Electrical Contacting Techniques to
           Carbon Fiber Reinforced Plastics for Self-Strain-Sensing Applications

    • Authors: Patrick Scholle, Sören Rüther, Michael Sinapius
      First page: 81
      Abstract: The electrical conductivity of carbon fibers can be used to enable the design of intrinsically smart carbon fiber reinforced plastics (CFRPs). Resistance and impedance measurements of the structural material itself can then be used to measure physical stimuli such as strain or damage without requiring a dedicated sensor to be installed. Measuring the resistance with high precision requires good electrical contact between the measurement equipment and the conductive carbon fibers. In the literature, many different combinations of surface contacting material and surface preparation procedures are used, but only seldomly compared to one another. This article aims to compare frequently used electrical contact methods by analyzing their contact resistance to a pultruded CFRP rod. Furthermore, this study explores the change of contact resistance with increasing mechanical strain. The results show that contact resistance is highly dependent on both the material used for contacting the fibers as well as the surface preparation technique. From the combinations analyzed in this article, the electrodeposition in combination with a surface treatment using concentrated sulphuric acid shows the most promising results.
      Citation: C
      PubDate: 2021-11-25
      DOI: 10.3390/c7040081
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 82: Viability of Activated Carbon Derived from
           Polystyrene Sulphonate Beads as Electrical Double Layer Capacitors

    • Authors: Gbenro Babajide Folaranmi, Anthony Ekennia, Nkiruka Chidiebere Ani, Richard Chukwuemeka Ehiri
      First page: 82
      Abstract: In this paper, a commercial polymeric resin precursor (polystyrene sulphonate beads) was used as a source of carbon spheres. The resin was pyrolyzed at different temperatures (700, 800, and 900 °C) and the resulting carbons were analyzed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). From the result of EIS, carbon spheres obtained at 700 °C (CS−700) have the least ohmnic resistance and highest capacitance. In furtherance, the resin was chemically activated with iron (III) chloride FeCl3·6H2O at different concentration (0.1 M, 0.3 M, and 0.5 M) and pyrolyzed at 700 °C to obtain activated carbon sphere namely (ACS 700−0.1, ACS 700−0.3, and ACS 700−0.5) in which the last digit of the samples denotes the concentration of FeCl3. Scanning electron microscope (SEM) showed that the carbon is of spherical shape; X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and X-ray photon electron spectroscopy (XPS) revealed successful introduction of Fe on the surface of the carbon. Out of all the activated carbon spheres, ACS 700−0.1 exhibited highest double layer capacitance of 9 µF cm−2 and lowest charge transfer resistance of 3.33 KΩ·cm2. This method shows that carbon spheres obtained from a polymeric source can be easily improved by simple resin modification and the carbon could be a potential candidate for an electrical double layer capacitor
      Citation: C
      PubDate: 2021-11-26
      DOI: 10.3390/c7040082
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 83: Removal of Hydrophobic Contaminants from the Soil by
           Adsorption onto Carbon Materials and Microbial Degradation

    • Authors: Shippi Dewangan, Amarpreet K. Bhatia, Ajaya Kumar Singh, Sónia A. C. Carabineiro
      First page: 83
      Abstract: The pollution of soil is a worldwide concern as it has harmful consequences on the environment and human health. With the continuous expansion of industry and agriculture, the content of hydrophobic organic pollutants in the soil has been increasing, which has caused serious pollution to the soil. The removal of hydrophobic organic contaminants from soil, aiming to recover environmental safety, is an urgent matter to guarantee sufficient food and water for populations. Adsorption has proven to be an effective and economically practicable method for removing organic contaminants. This paper summarizes the use of low-cost adsorbents, such as biochar and activated carbon, for removing hydrophobic organic contaminants from soil. Biochar is usually appropriate for the adsorption of organic contaminants via the adsorption mechanisms of electrostatic interaction, precipitation, and ion exchange. Biochar also has numerous benefits, such as being obtained from several kinds of raw materials, having low costs, recyclability, and potential for environmental treatment. This paper illustrates biochar’s adsorption mechanism for organic contaminants and discusses the microbial degradation of hydrophobic organic contaminants.
      Citation: C
      PubDate: 2021-12-03
      DOI: 10.3390/c7040083
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 84: Carbon Nanotubes Use for the Semiconductors ZnSe and
           ZnS Material Surface Modification via the Laser-Oriented Deposition

    • Authors: Natalia Kamanina, Andrey Toikka, Bulat Valeev, Dmitry Kvashnin
      First page: 84
      Abstract: It is known that a material’s volume and the surface structuring by the nanoparticles causes a significant change in the material’s basic properties. In this aspect, the structuration of the surface of semiconductors is of interest, because their wide potential application in optoelectronics can extend the products’ transparency, hardness, wettability, and other important parameters. This paper presents possible methods for the surface modification of zinc selenide and zinc sulfide when carbon nanotubes are deposited on the surface by the application of the laser-oriented technique. It also shows changes of the spectral, mechanical, and wetting characteristics of the considered materials. Using the molecular dynamic simulations, the possible process of the carbon nanotubes penetration into the considered surfaces is presented. The simulation results are partially supported by the obtained experimental data.
      Citation: C
      PubDate: 2021-12-07
      DOI: 10.3390/c7040084
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 85: Solvent and Substituent Effect on Selectivity of
           Triphenylether-Based Ionophores: A Voltammetric Study

    • Authors: Susheel K. Mittal, Shivali Gupta, Manmohan Chhibber
      First page: 85
      Abstract: The past two decades have seen considerable attention given to chemical sensing due to its quick, reproducible, and accurate results. These are extensively used for the detection of cations and anions in different environmental matrices. Organic-molecule-based sensors have proved to be a great promising tool in determining target species. This communication demonstrates the use of triphenylether derivatives (L1–L4) as receptors for the sensing of cations and anions, using voltammetry as a sensing tool. The effect of the oxidative/reductive nature of the ionophores and, hence, their selectivity behavior was studied in MeCN and MeOH solvents. Three receptors (L2–L4) responded selectively towards cyanide ions following the intramolecular charge-transfer mechanism, while sensing in the case of L1 was not studied because it lacked a proper cavity size.
      Citation: C
      PubDate: 2021-12-13
      DOI: 10.3390/c7040085
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 86: Activated Carbon Impregnated with Elementary Iodine:
           Applications against Virus- and Bacteria-Related Issues

    • Authors: Yuri Natori, Yoshiaki Kinase, Norihiro Ikemoto, Fabio Spaziani, Tsutomu Kojima, Hitomi Kakuta, Junko Fujita, Kazuyuki Someya, Katsuyoshi Tatenuma, Toshiyo Yabuta, Hiroki Takakuwa, Koichi Otsuki
      First page: 86
      Abstract: An iodine-doped activated carbon (named IodAC) was developed by adsorbing molecular iodine (I2) on commercially available activated carbon (AC). Iodine was selected with the purpose to add its well-known antibacterial and antiviral properties to the AC and in order to produce an innovative material for environmental pathogens control and for healthcare-related applications. The impregnation method achieved the goal of strongly adsorbing iodine on the AC surface, since both volatility and water solubility resulted to be negligible, and therefore it did not affect the stability of the material. An antibacterial test (on Escherichia coli) and an antiviral test (on an avian influenza strain) were conducted, showing the effectiveness of IodAC against the pathogens. In addition, IodAC was also compared to slaked lime (a material widely used for disinfection of outdoor spaces and livestock farming areas). The data proved the performance of IodAC against virus and bacteria and also evidenced a more stable and long-lasting disinfecting power of IodAC compared to slaked lime, the later reacting with carbon dioxide and suffering a gradually decrease of its disinfectant power; such drawback does not affect IodAC. Overall, the presented results show that IodAC can be used for a wide range of applications, including as a granular disinfectant for public spaces, for water disinfection, zoonotic diseases countermeasures (e.g., as an animal feed additive for avian influenza control), post-harvest food storage, and sanitization. Its characteristics also indicate its potential to be used for medical treatments, such as for blood, intestinal (for HIV, sepsis, irritable syndrome, ulcerative colitis therapy), and medical supplies (antibacterial bandages, gauze, cotton, etc.) sterilization.
      Citation: C
      PubDate: 2021-12-15
      DOI: 10.3390/c7040086
      Issue No: Vol. 7, No. 4 (2021)
  • C, Vol. 7, Pages 50: Carbons Formed in Methane Thermal and Thermocatalytic
           Decomposition Processes: Properties and Applications

    • Authors: Emmi Välimäki, Lasse Yli-Varo, Henrik Romar, Ulla Lassi
      First page: 50
      Abstract: The hydrogen economy will play a key role in future energy systems. Several thermal and catalytic methods for hydrogen production have been presented. In this review, methane thermocatalytic and thermal decomposition into hydrogen gas and solid carbon are considered. These processes, known as the thermal decomposition of methane (TDM) and thermocatalytic decomposition (TCD) of methane, respectively, appear to have the greatest potential for hydrogen production. In particular, the focus is on the different types and properties of carbons formed during the decomposition processes. The applications for carbons are also investigated.
      Citation: C
      PubDate: 2021-06-25
      DOI: 10.3390/c7030050
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 51: Comments on the XPS Analysis of Carbon Materials

    • Authors: David J. Morgan
      First page: 51
      Abstract: The surface chemistry of carbon materials is predominantly explored using x-ray photoelectron spectroscopy (XPS). However, many published papers have critical failures in the published analysis, stemming from an ill-informed approach to analyzing the spectroscopic data. Herein, a discussion on lineshapes and changes in the spectral envelope of predominantly graphitic materials are explored, together with the use of the D-parameter, to ascertain graphitic content, using this information to highlight a simple and logical approach to strengthen confidence in the functionalization derived from the carbon core-level spectra.
      Citation: C
      PubDate: 2021-07-06
      DOI: 10.3390/c7030051
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 52: Fused Filament Fabrication Three-Dimensional Printing
           Multi-Functional of Polylactic Acid/Carbon Black Nanocomposites

    • Authors: Nectarios Vidakis, Markos Petousis, Emmanuel Velidakis, Nikolaos Mountakis, Peder Erik Fischer-Griffiths, Sotirios Grammatikos, Lazaros Tzounis
      First page: 52
      Abstract: Conductive Polymer Composites (CPCs) have recently gained an extensive scientific interest as feedstock materials in Fused Filament Fabrication (FFF) Three-dimensional (3D) printing. Polylactic Acid (PLA), widely used in FFF 3D printing, as well as its Carbon Black (CB) nanocomposites at different weight percentage (wt.%) filler loadings (0.5, 1.0, 2.5 and 5.0 wt.%), were prepared via a melt mixing filament extrusion process in this study and utilized to manufacture FFF 3D printed specimens. The nanocomposites were examined for their electrical conductivity. The highest loaded 3D printed CPC (5.0 wt.%) was tested as an electrothermal Joule heating device. Static tensile, flexural, Charpy’s impact and Vickers microhardness mechanical properties were investigated for the neat and PLA/CB 3D printed nanocomposites. Dynamic Mechanical Analysis (DMA) revealed a stiffening mechanism for the PLA/CB nanocomposites. Scanning Electron Microscopy (SEM) elucidated the samples’ internal and external microstructural characteristics. The PLA/CB 5.0 wt.% nanocomposite demonstrated also antibacterial properties, when examined with a screening process, against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). It can be envisaged that the 3D printed PLA/CB CPCs exhibited a multi-functional performance, and could open new avenues towards low-cost personalized biomedical objects with complex geometry, amongst others, i.e., surgery tools, splints, wearables, etc.
      Citation: C
      PubDate: 2021-07-17
      DOI: 10.3390/c7030052
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 53: Reduction of Device Operating Temperatures with
           Graphene-Filled Thermal Interface Materials

    • Authors: Jacob S. Lewis
      First page: 53
      Abstract: The majority of research into few layer graphene (FLG) thermal interface materials (TIM) concerns the direct quantification of innate composite properties with much less direct analysis of these materials in realistic applications. In this study, equilibrium temperatures of engineered device substitutes fixed to passive heat sink solutions with varying FLG concentration TIMs are experimentally measured at varying heat dissipation rates. A custom, precisely-controlled heat source’s temperature is continually measured to determine equilibrium temperature at a particular heat dissipation. It is found that altering the used FLG TIM concentrations from 0 vol.% to as little as 7.3 vol.% resulted in a decrease of combined TIM and passively-cooled heat sink thermal resistance from 4.23∘C/W to 2.93∘C/W, amounting to a reduction in operating temperature of ≈108∘C down to ≈85∘C at a heat dissipation rate of 20 W. The results confirm FLG TIMs’ promising use in the application of device heat dissipation in a novel, controllable experimental technique.
      Citation: C
      PubDate: 2021-07-21
      DOI: 10.3390/c7030053
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 54: Facile Synthesis and Characterization of a
           Bromine-Substituted (Chloromethyl)Pyridine Precursor Towards the

    • Authors: Troy T. Handlovic, Tyler Moreira, Anoshia Khan, Haroon Saeed, Yousuf Khan, Mohammed R. Elshaer, Justin A. Bogart
      First page: 54
      Abstract: Multidentate ligands involving tethered pyridyl groups coordinated to transition metal ions have been frequently used to mimic the 3-histidine (3H), 2-histidine-1-carboxylate (2H1C) brace motifs or other combinations of histidine and carboxylate endogenous ligating residues found in bioinorganic metalloenzymes. It is of interest to immobilize these ligand chelates onto heterogeneous supports. This, however, requires the use of bromine-substituted (chloromethyl)pyridines, whose current synthetic routes involve the use of extremely pyrophoric chemicals, such as n-butyllithium that require cryogenic reaction conditions, and toxic chemicals, such as thionyl chloride, that are challenging to handle and require extensive hazard controls. Herein, we report alternative methodologies towards the syntheses of 2-bromo-6-hydroxymethylpyridine and 2-bromo-6-chloromethylpyridine from inexpensive commercially available 2,6-dibromopyridine using isopropylmagnesium chloride lithium chloride complex (Turbo Grignard) and cyanuric chloride which are easier to handle and require milder reaction conditions than the conventional reagents. Gas chromatography-mass spectrometry (GC-MS) methods were developed and simple 1H- and 13C- nuclear magnetic resonance (NMR) and Fourier-transform infrared (FT-IR) spectroscopies were also used to monitor the conversion of both reaction steps and showed that products could be obtained and isolated through simple workups without the presence of unreacted starting material or undesired overchlorinated 2-chloro-6-chloromethylpyridine side product.
      Citation: C
      PubDate: 2021-07-23
      DOI: 10.3390/c7030054
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 55: Biomass-Derived Carbons as Versatile Materials for
           Energy-Related Applications: Capacitive Properties vs. Oxygen Reduction
           Reaction Catalysis

    • Authors: Stefan Breitenbach, Nemanja Gavrilov, Igor Pašti, Christoph Unterweger, Jiri Duchoslav, David Stifter, Achim Walter Hassel, Christian Fürst
      First page: 55
      Abstract: Biomass-derived carbons are very attractive materials due to the possibility of tuning their properties for different energy-related applications. Various pore sizes, conductivities and the inherent presence of heteroatoms make them attractive for different electrochemical reactions, including the implementation of electrochemical capacitors or fuel cell electrodes. This contribution demonstrates how different biomass-derived carbons prepared from the same precursor of viscose fibers can reach appreciable capacitances (up to 200 F g−1) or a high selectivity for the oxygen reduction reaction (ORR). We find that a highly specific surface area and a large mesopore volume dominate the capacitive response in both aqueous and non-aqueous electrolytic solutions. While the oxygen reduction reaction activity is not dominated by the same factors at low ORR overpotentials, these take the dominant role over surface chemistry at high ORR overpotentials. Due to the high selectivity of the O2 reduction to peroxide and the appreciable specific capacitances, it is suggested that activated carbon fibers derived from viscose fibers are an attractive and versatile material for electrochemical energy conversion applications.
      Citation: C
      PubDate: 2021-07-24
      DOI: 10.3390/c7030055
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 56: Preparation and Carbonization of Glucose and
           Pyromellitic Dianhydride Crosslinked Polymers

    • Authors: Fabrizio Caldera, Antonella Moramarco, Federico Cesano, Anastasia Anceschi, Alessandro Damin, Marco Zanetti
      First page: 56
      Abstract: In this work, four types of nanosponges were prepared from pyromellitic dianhydride (PMDA) and D-glucose (GLU) with different molar ratios (1.5:1, 2:1, 2.5:1 and 3:1). The obtained PMDA/GLU nanosponges were then pyrolyzed at 800 °C for 30 min under N2 gas flow. The prepared polymeric nanosponges were investigated by FTIR spectroscopy, elemental and thermogravimetric analyses to unravel the role played by the different molar ratio of the precursors in the formation of the polymer. The pyrolyzed nanosponges were investigated by means of porosity measurements, X-ray diffraction analysis, Raman spectroscopy and high-resolution transmission electron microscopy. Notably, no significant correlation of the amounts of used precursors with the porous texture and structure was evidenced. The results corroborate that PMDA and GLU can be easily combined to prepare nanosponges and that the carbon materials produced by their pyrolysis can be associated with glassy carbons with a microporous texture and relatively high surface area. Such hard carbons can be easily obtained and shrewdly used to segregate relatively small molecules and organic contaminants; in this study methylene blue adsorption was investigated.
      Citation: C
      PubDate: 2021-07-26
      DOI: 10.3390/c7030056
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 57: Ab Initio Study of Porous Graphene–CNT Silicon
           Composite for Li-Ion and Na-Ion Batteries

    • Authors: Dmitry A. Kolosov, Olga E. Glukhova
      First page: 57
      Abstract: In this work, we investigated composite materials based on graphene and carbon nanotubes with a silicon cluster from the standpoint of using them as Li-ion battery (LIB) and Na-ion battery (NIB) anodes. For our study, we used the density functional theory method, taking into account the van der Waals interaction. The cavities of the composite were filled with lithium and sodium, and the energy characteristics of the structure were calculated through SIESTA molecular dynamics. The calculations showed the negative energy of adsorption for lithium and sodium and the negative value of the heat of formation of the composites. The introduction of a silicon cluster led to an increase in the specific capacity by 22.2% for the sodium and 37% for the lithium in comparison with the pure composite. The calculation of the transmission function showed a decrease in the resistance of the composite when a silicon cluster was added to the composite. We predict that the application of the considered composite will increase the efficiency of existing lithium-ion and sodium-ion batteries.
      Citation: C
      PubDate: 2021-07-29
      DOI: 10.3390/c7030057
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 58: Review of Cryogenic Carbon Capture Innovations and
           Their Potential Applications

    • Authors: Carolina Font-Palma, David Cann, Chinonyelum Udemu
      First page: 58
      Abstract: Our ever-increasing interest in economic growth is leading the way to the decline of natural resources, the detriment of air quality, and is fostering climate change. One potential solution to reduce carbon dioxide emissions from industrial emitters is the exploitation of carbon capture and storage (CCS). Among the various CO2 separation technologies, cryogenic carbon capture (CCC) could emerge by offering high CO2 recovery rates and purity levels. This review covers the different CCC methods that are being developed, their benefits, and the current challenges deterring their commercialisation. It also offers an appraisal for selected feasible small- and large-scale CCC applications, including blue hydrogen production and direct air capture. This work considers their technological readiness for CCC deployment and acknowledges competing technologies and ends by providing some insights into future directions related to the R&D for CCC systems.
      Citation: C
      PubDate: 2021-07-29
      DOI: 10.3390/c7030058
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 59: The Growth Behavior of Amorphous Hydrogenated Carbon
           a-C:H Layers on Industrial Polycarbonates—A Weak Interlayer and a
           Distinct Dehydrogenation Zone

    • Authors: Torben Schlebrowski, Melanie Fritz, Lucas Beucher, Yongxin Wang, Stefan Wehner, Christian B. Fischer
      First page: 59
      Abstract: Polycarbonate (PC) is a material that is used in many areas: automotive, aerospace engineering and data storage industries. Its hardness is of particular importance, but some applications are affected by its low wettability or scratch susceptibility. This can be changed either by blending with other polymers, or by surface modifications, such as the application of an amorphous hydrogenated carbon layer (a-C:H). In this study, individual a-C:H layers of different thicknesses (10–2000 nm) were deposited on PC by RF PECVD. Both the layer morphology with AFM and SEM and the bonding states of the carbon on the surface with synchrotron-assisted XPS and NEXAFS were studied. The aim was to investigate the coatability of PC and the stability of the a-C:H. Special attention was paid to the interlayer region from 0 to 100 nm, since this is responsible for the layer to base material bonding, and to the zone of dehydrogenation (from about 1000 nm), since this changes the surface composition considerably. For PC, the interlayer was relatively small with a thickness of only 20 nm. Additionally, a correlation was found between the evolving grain structure and the development of the C‒H peak according to NEXAFS C K-edge measurements.
      Citation: C
      PubDate: 2021-07-29
      DOI: 10.3390/c7030059
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 60: Monitoring of Curing and Cyclic Thermoresistive
           Response Using Monofilament Carbon Nanotube Yarn Silicone Composites

    • Authors: Tannaz Tayyarian, Omar Rodríguez-Uicab, Jandro L. Abot
      First page: 60
      Abstract: The curing process and thermoresistive response of a single carbon nanotube yarn (CNTY) embedded in a room temperature vulcanizing (RTV) silicone forming a CNTY monofilament composite were investigated toward potential applications in integrated curing monitoring and temperature sensing. Two RTV silicones of different crosslinking mechanisms, SR1 and SR2 (tin- and platinum-cured, respectively), were used to investigate their curing kinetics using the electrical response of the CNTY. It is shown that the relative electrical resistance change of CNTY/SR1 and CNTY/SR2 monofilament composites increased by 3.8% and 3.3%, respectively, after completion of the curing process. The thermoresistive characterization of the CNTY monofilament composites was conducted during heating–cooling ramps ranging from room temperature (RT~25 °C) to 100 °C. The thermoresistive response was nearly linear with a negative temperature coefficient of resistance (TCR) at heating and cooling sections for both CNTY/SR1 and CNTY/SR2 monofilament composites. The average TCR value was −8.36 × 10−4 °C−1 for CNTY/SR1 and −7.26 × 10−4 °C−1 for CNTY/SR2. Both monofilament composites showed a negligible negative residual relative electrical resistance change with average values of ~−0.11% for CNTY/SR1 and ~−0.16% for CNTY/SR2 after each cycle. The hysteresis amounted to ~21.85% in CNTY/SR1 and ~29.80% in CNTY/SR2 after each cycle. In addition, the effect of heating rate on the thermoresistive sensitivity of CNTY monofilament composites was investigated and it was shown that it reduces as the heating rate increases.
      Citation: C
      PubDate: 2021-08-04
      DOI: 10.3390/c7030060
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 61: Applicability and Limitations of Simplified Elastic
           Shell Theories for Vibration Modelling of Double-Walled Carbon Nanotubes

    • Authors: Matteo Strozzi, Oleg V. Gendelman, Isaac E. Elishakoff, Francesco Pellicano
      First page: 61
      Abstract: The applicability and limitations of simplified models of thin elastic circular cylindrical shells for linear vibrations of double-walled carbon nanotubes (DWCNTs) are considered. The simplified models, which are based on the assumptions of membrane and moment approximate thin-shell theories, are compared with the extended Sanders–Koiter shell theory. Actual discrete DWCNTs are modelled by means of couples of concentric equivalent continuous thin, circular cylindrical shells. Van der Waals interaction forces between the layers are taken into account by adopting He’s model. Simply supported and free–free boundary conditions are applied. The Rayleigh–Ritz method is considered to obtain approximate natural frequencies and mode shapes. Different aspect and thickness ratios, and numbers of waves along longitudinal and circumferential directions, are analysed. In the cases of axisymmetric and beam-like modes, it is proven that membrane shell theory, differently from moment shell theory, provides results with excellent agreement with the extended Sanders–Koiter shell theory. On the other hand, in the case of shell-like modes, it is found that both membrane and moment shell theories provide results reporting acceptable agreement with the extended Sanders–Koiter shell theory only for very limited ranges of geometries and wavenumbers. Conversely, for shell-like modes it is found that a newly developed, simplified shell model, based on the combination of membrane and semi-moment theories, provides results in satisfactory agreement with the extended Sanders–Koiter shell theory in all ranges.
      Citation: C
      PubDate: 2021-08-09
      DOI: 10.3390/c7030061
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 62: Asymmetric Fiber Supercapacitors Based on a
           FeC2O4/FeOOH-CNT Hybrid Material

    • Authors: Paa Kwasi Adusei, Kevin Johnson, Sathya N. Kanakaraj, Guangqi Zhang, Yanbo Fang, Yu-Yun Hsieh, Mahnoosh Khosravifar, Seyram Gbordzoe, Matthew Nichols, Vesselin Shanov
      First page: 62
      Abstract: The development of new flexible and lightweight electronics has increased the demand for compatible energy storage devices to power them. Carbon nanotube (CNT) fibers have long been known for their ability to be assembled into yarns, offering their integration into electronic devices. They are hindered, however, by their low intrinsic energy storage properties. Herein, we report a novel composite yarn, synthesized through solvothermal processes, that attained energy densities in the range between 0.17 µWh/cm2 and 3.06 µWh/cm2, and power densities between 0.26 mW/cm2 and 0.97 mW/cm2, when assembled in a supercapacitor with a PVDF-EMIMBF4 electrolyte. The created unique composition of iron oxalate + iron hydroxide + CNT as an anode worked well in synergy with the much-studied PANI + CNT cathode, resulting in a highly stable yarn energy storage device that maintained 96.76% of its energy density after 4000 cycles. This device showed no observable change in performance under stress/bend tests which makes it a viable candidate for powering wearable electronics.
      Citation: C
      PubDate: 2021-08-14
      DOI: 10.3390/c7030062
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 63: 2013–2014 Survey of Chars Using Raman

    • Authors: John McDonald-Wharry
      First page: 63
      Abstract: In late 2013, an open call for charcoal and biochar samples was distributed in an effort to compare a wide range of char samples by Raman spectroscopy. The samples contributed to this survey included: laboratory produced biochars, recent biochars produced in field conditions, and ancient char samples previously analysed by carbon dating. By using selected Raman measurements, the char samples could be ranked in terms of the degree of thermochemical alteration or extent of carbon nanostructural development. The Raman results for recently produced biomass chars were generally consistent with the conversion of amorphous carbon formed at lower temperatures into condensed, polyaromatic, and graphene-like carbon formed at higher temperatures. A number of parameters calculated from the Raman spectra could be used to estimate the effective heat treatment temperatures in the recently produced biochars. Other samples such as anthracite coal, tire pyrolysis carbon, and ancient chars departed from the trends observed in the recently produced biomass chars using this approach. In total, 45 samples were analysed by Raman spectroscopy for this survey. Ancient and buried char samples displayed higher intensities for features in the Raman spectra associated with amorphous carbon.
      Citation: C
      PubDate: 2021-08-19
      DOI: 10.3390/c7030063
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 64: Thermal and Principal Ablation Properties of
           Carbon-Fibre-Reinforced Polymers with Out-of-Plane Fibre Orientation

    • Authors: Sebastian Eibl, Thomas J. Schuster
      First page: 64
      Abstract: This work characterises thermal properties of a typical epoxy-based carbon-fibre-reinforced polymer used in aircraft construction, but with an out-of-plane fibre orientation, and assesses its potential as a structural ablative material. Samples of the commercially available Hexply® 8552/IM7 are prepared with out-of-plane angles up to 90°, with a focus on 0° to 15°, enhancing thermal conductivity through the thickness of the panel. Ablation processes are simulated by a hot-air blower at 580 °C, and examined in detail by ultrasonic testing and microfocused computed X-ray tomography afterwards. Matrix degradation is characterised by infrared spectroscopy and mass loss. To assess structural properties, tensile, compression, and bending tests are performed. The results show a loss in mechanical performance with an increasing fibre angle, which may be negligible for angles lower than ~5° in the initial state. Composite material with an out-of-plane fibre orientation is deeply penetrated concerning matrix degradation by thermal loading, but it is held together by the fibres fixed in the intact matrix underneath. This type of material shows a high potential for structural components in single-use, high-temperature, ablative applications with a focus on saving weight.
      Citation: C
      PubDate: 2021-08-21
      DOI: 10.3390/c7030064
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 65: Graphene-Enhanced Battery Components in Rechargeable
           Lithium-Ion and Lithium Metal Batteries

    • Authors: Hao-Hsun Chang, Tseng-Hsiang Ho, Yu-Sheng Su
      First page: 65
      Abstract: Stepping into the 21st century, “graphene fever” swept the world due to the discovery of graphene, made of single-layer carbon atoms with a hexagonal lattice. This wonder material displays impressive material properties, such as its electrical conductivity, thermal conductivity, and mechanical strength, and it also possesses unique optical and magnetic properties. Many researchers see graphene as a game changer for boosting the performance of various applications. Emerging consumer electronics and electric vehicle technologies require advanced battery systems to enhance their portability and driving range, respectively. Therefore, graphene seems to be a great candidate material for application in high-energy-density/high-power-density batteries. The “graphene battery”, combining two Nobel Prize-winning concepts, is also frequently mentioned in the news and articles all over the world. This review paper introduces how graphene can be adopted in Li-ion/Li metal battery components, the designs of graphene-enhanced battery materials, and the role of graphene in different battery applications.
      Citation: C
      PubDate: 2021-09-16
      DOI: 10.3390/c7030065
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 66: Conformational Analysis of [60]PCBM from DFT
           Simulations of Electronic Energies, Bond Strain and the 13C NMR Spectrum:
           Input Geometry Determination and Ester Bond Rotation Dynamics

    • Authors: Tong Liu, T. John S. Dennis
      First page: 66
      Abstract: With the aim of determining the best input geometry for DFT calculations of [60]PCBM, the geometry of 24 chemically possible [60]PCBM conformers were optimised and their electronic energies and average bond strains were determined. A DFT analysis of the relevant dihedral angles provided insights into the dynamical behaviour of the ester group through sterically restricted bond rotations. In addition, the 13C NMR spectra of the six better performing conformers were simulated and compared with an experiment. There is a close correlation between average bond strain, total electronic energy and mean absolute error of the simulated 13C NMR spectra of the ester carbons. The best overall candidate conformer for the input geometry had the C61-C4, C4-C3 and C3-C2 single bonds of the alkyl chain in syn, anti and anti arrangements, respectively, and had the C2-C1 and C1-O single bonds of the ester in syn and anti arrangements, respectively. This contrasts strikingly with most representations of PCBM in the literature, which depict all relevant bonds in anti arrangements.
      Citation: C
      PubDate: 2021-09-21
      DOI: 10.3390/c7030066
      Issue No: Vol. 7, No. 3 (2021)
  • C, Vol. 7, Pages 30: Ultra-Thin Carbon Films: The Rise of sp3-C-Based 2D

    • Authors: Fabrice Piazza, Marc Monthioux
      First page: 30
      Abstract: We warmly thank all the colleagues who have enthusiastically participated in the project of this Special Issue on “2D Ultra-Thin Carbon Films”, considering a globally unfavorable context characterized by (i) a myriad of publication options; (ii) strong pressure, by the highly competitive research (and researcher) funding and evaluation system, to publish in high impact factor journals, specifically for topics of worldwide interest; and (iii) all sorts of restrictions imposed by the sanitary crisis [...]
      Citation: C
      PubDate: 2021-03-25
      DOI: 10.3390/c7020030
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 31: sp2 Carbon Stable Radicals

    • Authors: Elena F. Sheka
      First page: 31
      Abstract: sp2 Nanocarbons such as fullerenes, carbon nanotubes, and graphene molecules are not only open-shell species, but spatially extended, due to which their chemistry is quite specific. Cogently revealed dependence of the final products composition on size and shape of the carbons in use as well as on the chemical prehistory is accumulated in a particular property—the stabilization of the species’ radical efficiency, thus providing the matter of stable radicals. If the feature is highly restricted and rarely available in ordinary chemistry, in the case of sp2 nanocarbons it is just an ordinary event providing, say, tons-in-mass stable radicals when either producing such widely used technological products as carbon black or dealing with deposits of natural sp2 carbons such as anthracite, shungite carbon, and other. Suggested in the paper is the consideration of stable radicals of sp2 nanocarbons from the standpoint of spin-delocalized topochemistry. Characterized in terms of the total and atomically partitioned number of effectively unpaired electrons as well as of the distribution of the latter over carbon atoms and described by selectively determined barriers of different reactions exhibiting topological essence of intermolecular interaction, sp2 nanocarbons reveal a peculiar topokinetics that lays the foundation of the stability of their radical properties.
      Citation: C
      PubDate: 2021-03-26
      DOI: 10.3390/c7020031
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 32: Preparation of Pt/CNT Thin-Film Electrodes by
           Electrochemical Potential Pulse Deposition for Methanol Oxidation

    • Authors: Jose Quintero-Ruiz, Ramiro Ruiz-Rosas, Javier Quílez-Bermejo, David Salinas-Torres, Diego Cazorla-Amorós, Emilia Morallón
      First page: 32
      Abstract: High-quality performance of catalysts is increasingly required to meet industry exigencies. However, chemical synthesis is often insufficient to maximize the potential properties of the catalysts. On the other hand, electrochemical synthesis has arisen as a promising alternative to overcome these limitations and provide precise control in the preparation of catalysts. In this sense, this work involved the well-controlled electrochemical synthesis of a catalyst based on platinum nanoparticle deposition on carbon nanotubes using only electrochemical treatments. Thin films of functionalized carbon nanotubes were cast onto the surface of a glassy carbon electrode using potential pulsed electrodeposition, resulting in a better distribution of the carbon nanotubes on the electrode when comparing with traditional methods. Then, platinum nanoparticles were electrodeposited on the carbon nanotube-modified electrode. To check the performance of the catalyst and the relevance of the electrochemical synthesis treatments, the samples were analyzed as electrocatalysts towards methanol electrooxidation, showing an important improvement in the catalytic activity in comparison with electrodes that were prepared by traditional methodologies.
      Citation: C
      PubDate: 2021-03-26
      DOI: 10.3390/c7020032
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 33: Investigation of the Effects of Multi-Wall and
           Single-Wall Carbon Nanotubes Concentration on the Properties of ABS

    • Authors: Brenda Janett Alonso Gutierrez, Sithiprumnea Dul, Alessandro Pegoretti, Jaime Alvarez-Quintana, Luca Fambri
      First page: 33
      Abstract: The effects of two types of carbon nanotubes, namely multiwall (MWCNT) and single-wall (SWCNT) carbon nanotube, on the thermal and mechanical properties of acrylonitrile-butadiene-styrene (ABS) nanocomposites, have been investigated. ABS filled-CNT nanocomposites with various filler loadings of 5–10 wt% were properly produced by a solvent-free process in blend compounding at 190 °C. Compression moulded plates and extruded filaments were obtained at 190 °C and 230 °C, respectively. Melt flow index (MFI), shore hardness, Vicat temperature, differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) were performed to characterize and compared the different CNT nanocomposites. ABS/SWCNT composite filaments showed higher tensile properties (i.e., stiffness and strength), than ABS/MWCNT. The electrical resistivity of ABS/SWCNT and ABS/MWCNT filaments decreased to 0.19 Ω.cm and 0.65 Ω.cm for nanocomposites with 10 wt% of nanofillers; a power law was presented to describe the electrical resistivity of composites as a function of the CNTs content. A final comparative parameter regarding melt flow, stiffness and conductivity was also evaluated for understanding the combined effects of the nanofillers. SWCNT nanocomposites exhibited better overall cumulative results than MWCNT nanocomposites.
      Citation: C
      PubDate: 2021-03-27
      DOI: 10.3390/c7020033
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 34: A Threshold Line for Safe Geologic CO2 Storage Based
           on Field Measurement of Soil CO2 Flux

    • Authors: Takashi Kuriyama, Phung Quoc Huy, Salmawati Salmawati, Kyuro Sasaki
      First page: 34
      Abstract: Carbon capture and storage (CCS) is an established and verified technology that can implement zero emissions on a large enough scale to limit temperature rise to below 2 °C, as stipulated in the Paris Agreement. However, leakage from CCS sites must be monitored to ensure containment performance. Surface monitoring of carbon dioxide (CO2) concentrations at onshore CCS sites is one method to locate and quantify CCS site leakage. Employing soil accumulation chambers, we have established baseline data for the natural flux of CO2 as a threshold alert to detect CO2 leakage flux to ensure the safety of onshore CCS sites. Within this context, we conducted on-site CO2 measurements at three different locations (A, B, and C) on the INAS test field at the Ito campus, Kyushu University (Japan). Furthermore, we developed a specific measurement system based on the closed-chamber method to continuously measure CO2 flux from soil and to investigate the correlation between CO2 flux from the soil surface and various parameters, including environmental factors and soil sample characteristics. In addition, gas permeability and the effect of different locations on soil CO2 flux are discussed in this study. Finally, we present an equation for estimating the soil CO2 flux used in the INAS field site that includes environmental factors and soil characteristics. This equation assists in defining the threshold line for an alert condition related to CO2 leakage at onshore CCS sites.
      Citation: C
      PubDate: 2021-03-27
      DOI: 10.3390/c7020034
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 35: A Review on van der Waals Boron Nitride Quantum Dots

    • Authors: Amit Acharya, Sambhawana Sharma, Xiuling Liu, Dongyan Zhang, Yoke Khin Yap
      First page: 35
      Abstract: Boron nitride quantum dots (BNQDs) have gained increasing attention for their versatile fluorescent, optoelectronic, chemical, and biochemical properties. During the past few years, significant progress has been demonstrated, started from theoretical modeling to actual application. Many interesting properties and applications have been reported, such as excitation-dependent emission (and, in some cases, non-excitation dependent), chemical functionalization, bioimaging, phototherapy, photocatalysis, chemical, and biological sensing. An overview of this early-stage research development of BNQDs is presented in this article. We have prepared un-bias assessments on various synthesis methods, property analysis, and applications of BNQDs here, and provided our perspective on the development of these emerging nanomaterials for years to come.
      Citation: C
      PubDate: 2021-03-27
      DOI: 10.3390/c7020035
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 36: Morphological Characterization and Lumped Element
           Model of Graphene and Biochar Thick Films

    • Authors: Muhammad Yasir, Pietro Zaccagnini, Gianluca Palmara, Francesca Frascella, Niccolò Paccotti, Patrizia Savi
      First page: 36
      Abstract: Carbon based materials exhibit interesting mechanical, thermal and electrical properties which make them excellent contenders for use as fillers in composites as film. Graphene has been vastly used among the carbon-based materials. More recently eco-friendly carbon-based materials like biochar have emerged. The deployment of carbon-based materials in films needs to be studied since films are more versatile and permit the exploitation of electrical properties of such materials over circuits and systems. Typical circuits and systems exploiting electrical properties of novel materials perform a number of applications including sensing, detection, tunable devices and energy harvesting. In this paper, films composed of 9:1 graphene or biochar are deployed on a microstrip line. The morphological properties of graphene and biochar and their respective films are studied with Raman spectra and Field Emission Scanning Electron Microscope (FESEM). The electrical properties (four-point probe measurements and scattering parameter measurements) of the films. Low frequency measurements are used as starting point for circuit models estimating the lumped impedance of the films. From the morphological characterization it is shown that biochar films appear as granulates carbonaceous materials whereas graphene films contains several flakes forming a network. From the low frequency measurements and microwave characterization it is seen that graphene films are more conductive as compared to biochar films. In many applications, it is useful to know the surface impedance of the film since it varies on interaction with any external stimulus (variation of pressure, humidity, gas, etc.).
      Citation: C
      PubDate: 2021-03-27
      DOI: 10.3390/c7020036
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 37: Impact of Graphene or Reduced Graphene Oxide on
           Performance of Thermoelectric Composites

    • Authors: Olena Okhay, Alexander Tkach
      First page: 37
      Abstract: In recent years, worldwide research has been focused on clean and sustainable energy sources that can respond to the exponentially rising energy demands of humankind. The harvesting of unused heat in relation to automotive exhaustion, industrial processes, and home heating is one possible way of enabling the transformation from a fossil fuel-based society to a low-carbon socioeconomic epoch. Thermoelectric (TE) generators can convert heat to electrical energy thanks to high-performance TE materials that work via Seebeck effects when electricity appears between the cold part and the hot part of these materials. High figure of merit (ZT) TE material is characterized by high electrical conductivity and Seebeck coefficient, together with low thermal conductivity. This article aims to summarize ZT values reported for chalcogenides, skutterudites, and metal oxides with graphene (G) or reduced graphene oxide (rGO), and intends to understand the relationship between the addition of G-rGO to composites and ZT variation. In a majority of the publications, ZT value increases with the addition of G/rGO, although the relative growth of ZT varies for different material families, as well as inside the same group of materials, with it often being related not to a G/rGO amount but with the quality of the composite.
      Citation: C
      PubDate: 2021-04-21
      DOI: 10.3390/c7020037
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 38: Polyamide 12/Multiwalled Carbon Nanotube and Carbon
           Black Nanocomposites Manufactured by 3D Printing Fused Filament
           Fabrication: A Comparison of the Electrical, Thermoelectric, and
           Mechanical Properties

    • Authors: Nectarios Vidakis, Markos Petousis, Lazaros Tzounis, Emmanuel Velidakis, Nikolaos Mountakis, Sotirios A. Grammatikos
      First page: 38
      Abstract: In this study, nanocomposites with polyamide 12 (PA12) as the polymer matrix and multiwalled carbon nanotubes (MWCNTs) and carbon black (CB) at different loadings (2.5, 5.0, and 10.0 wt.%) as fillers, were produced in 3D printing filament form by melt mixing extrusion process. The filament was then used to build specimens with the fused filament fabrication (FFF) three-dimensional (3D) printing process. The aim was to produce by FFF 3D printing, electrically conductive and thermoelectric functional specimens with enhanced mechanical properties. All nanocomposites’ samples were electrically conductive at filler loadings above the electrical percolation threshold. The highest thermoelectric performance was obtained for the PA12/CNT nanocomposite at 10.0 wt.%. The static tensile and flexural mechanical properties, as well as the Charpy’s impact and Vickers microhardness, were determined. The highest improvement in mechanical properties was observed for the PA12/CNT nanocomposites at 5.0 wt.% filler loading. The fracture mechanisms were identified by fractographic analyses of scanning electron microscopy (SEM) images acquired from fractured surfaces of tensile tested specimens. The nanocomposites produced could find a variety of applications such as; 3D-printed organic thermoelectric materials for plausible large-scale thermal energy harvesting applications, resistors for flexible circuitry, and piezoresistive sensors for strain sensing.
      Citation: C
      PubDate: 2021-04-23
      DOI: 10.3390/c7020038
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 39: Activated Carbon from Biomass Sustainable Sources

    • Authors: Yong X. Gan
      First page: 39
      Abstract: Biomass wastes are abundant around us. They are renewable and inexpensive. Product manufacturing from renewable resources has caught increasing interest recently. Activated carbon preparation from biomass resources, including various trees, leaves, plant roots, fruit peels, and grasses, is a good example. In this paper, an overview of activated carbon production from biomass resources will be given. The first part will be on the processing technologies. The second part will focus on the carbon activation methods. The third part will introduce the biomass resources. The fourth part will be on surface modification of activated carbon through the addition of various components. Finally, the development of product applications will be discussed with an emphasis on adsorption, filtration, water purification, energy conversions, and energy storage.
      Citation: C
      PubDate: 2021-04-27
      DOI: 10.3390/c7020039
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 40: Poly(Vinylamine) Derived N-Doped C-Dots with
           Antimicrobial and Antibiofilm Activities

    • Authors: Semiha Duygu Sutekin, Mehtap Sahiner, Selin Sagbas Suner, Sahin Demirci, Olgun Güven, Nurettin Sahiner
      First page: 40
      Abstract: Nitrogen-doped carbon dots (N-doped C-dots) was synthesized by using poly(vinyl amine) (PVAm) as a nitrogen source and citric acid (CA) as a carbon source via the hydrothermal method. Various weight ratios of CA and PVAm (CA:PVAm) were used to synthesize N-doped C-dots. The N-doped C-dots revealed emission at 440 nm with excitation at 360 nm and were found to increase the fluorescence intensity with an increase in the amount of PVAm. The blood compatibility studies revealed no significant hemolysis for N-doped C-dots that were prepared at different ratios of CA:PVAm for up to 500 μg/mL concentration with the hemolysis ratio of 1.96% and the minimum blood clotting index of 88.9%. N-doped C-dots were found to be more effective against Gram-positive bacteria than Gram-negative bacteria, with the highest potency on Bacillus subtilis (B. subtilis). The increase in the weight ratio of PVAm in feed during C-dots preparation from 1 to 3 leads to a decrease of the minimum bactericidal concentration (MBC) value from 6.25 to 0.75 mg/mL for B. subtilis. Antibiofilm ability of N-doped C-dots prepared by 1:3 ratio of CA:PVAm was found to reduce %biofilm inhibition and eradication- by more than half, at 0.78 mg/mL for E. coli and B. subtilis generated biofilms and almost destroyed at 25 mg/mL concentrations.
      Citation: C
      PubDate: 2021-04-27
      DOI: 10.3390/c7020040
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 41: Thermogravimetric Analysis (TGA) of Graphene
           Materials: Effect of Particle Size of Graphene, Graphene Oxide and
           Graphite on Thermal Parameters

    • Authors: Farzaneh Farivar, Pei Lay Yap, Ramesh Udayashankar Karunagaran, Dusan Losic
      First page: 41
      Abstract: Thermogravimetric analysis (TGA) has been recognized as a simple and reliable analytical tool for characterization of industrially manufactured graphene powders. Thermal properties of graphene are dependent on many parameters such as particle size, number of layers, defects and presence of oxygen groups to improve the reliability of this method for quality control of graphene materials, therefore it is important to explore the influence of these parameters. This paper presents a comprehensive TGA study to determine the influence of different particle size of the three key materials including graphene, graphene oxide and graphite on their thermal parameters such as carbon decomposition range and its temperature of maximum mass change rate (Tmax). Results showed that Tmax values derived from the TGA-DTG carbon combustion peaks of these materials increasing from GO (558–616 °C), to graphene (659–713 °C) and followed by graphite (841–949 °C) The Tmax values derived from their respective DTG carbon combustion peaks increased as their particle size increased (28.6–120.2 µm for GO, 7.6–73.4 for graphene and 24.2–148.8 µm for graphite). The linear relationship between the Tmax values and the particle size of graphene and their key impurities (graphite and GO) confirmed in this study endows the use of TGA technique with more confidence to evaluate bulk graphene-related materials (GRMs) at low-cost, rapid, reliable and simple diagnostic tool for improved quality control of industrially manufactured GRMs including detection of “fake” graphene.
      Citation: C
      PubDate: 2021-04-27
      DOI: 10.3390/c7020041
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 42: Towards Controlled Degradation of Poly(Lactic) Acid
           in Technical Applications

    • Authors: Teixeira, Eblagon, Miranda, R. Pereira, Figueiredo
      First page: 42
      Abstract: Environmental issues urge for the substitution of petrochemical-based raw materials with more environmentally friendly sources. The biggest advantages of PLA over non-biodegradable plastics are that it can be produced from natural sources (e.g., corn or sugarcane), and at the end of its lifetime it can be returned to the soil by being composted with microorganisms. PLA can easily substitute petroleum-based plastics in a wide range of applications in many commodity products, such as disposable tableware, packaging, films, and agricultural twines, partially contributing to limiting plastic waste accumulation. Unfortunately, the complete replacement of fossil fuel-based plastics such as polyethylene (PE) or poly(ethylene terephthalate) (PET) by PLA is hindered by its higher cost, and, more importantly, slower degradation as compared to other degradable polymers. Thus, to make PLA more commercially attractive, ways to accelerate its degradation are actively sought. Many good reviews deal with PLA production, applications, and degradation but only in the medical or pharmaceutical field. In this respect, the present review will focus on controlled PLA degradation and biodegradation in technical applications. The work will include the main degradation mechanisms of PLA, such as its biodegradation in water, soil, and compost, in addition to thermal- and photo-degradation. The topic is of particular interest to academia and industry, mainly because the wider application of PLA is mostly dependent on discovering effective ways of accelerating its biodegradation rate at the end of its service life without compromising its properties.
      Citation: C
      PubDate: 2021-04-30
      DOI: 10.3390/c7020042
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 43: Nanocomposite of Ellagic Acid with Multi-Walled
           Carbon Nanotubes for the Simultaneous Voltammetric Detection of Six

    • Authors: Najmeh Sabbaghi, Meissam Noroozifar, Kagan Kerman
      First page: 43
      Abstract: In this proof-of-concept study, a highly sensitive electrochemical sensor using a graphite paste electrode modified with ellagic acid and multi-walled carbon nanotubes (MGPE/MWCNTs-EA) was developed for the simultaneous determination of six biomolecules: ascorbic acid (AA), dopamine (DA), uric acid (UA), tryptophan (Trp), xanthine (XA), and caffeine (CA). Differential pulse voltammetry (DPV) was performed at a potential range from 0.1–1.2 V vs. Ag/AgCl in phosphate electrolyte (pH 2.0). The modified GPE enabled the simultaneous determination of biomolecules under investigation in human urine and blood serum samples with detection limits ranging from 11–91 nM with recoveries of 94.0–106.0%. The electrochemical performance of the modified GPE for the analytes was stable and reproducible and checked with standard high performance liquid chromatography technique. The data suggested that the modified GPE provided a promising platform for routine quantitative determination of the biomolecules under investigation in quality control studies of real samples collected from food and pharmaceutical products.
      Citation: C
      PubDate: 2021-05-03
      DOI: 10.3390/c7020043
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 44: Variable Temperature Synthesis of Tunable
           Flame-Generated Carbon Nanoparticles

    • Authors: Francesca Picca, Angela Di Pietro, Mario Commodo, Patrizia Minutolo, Andrea D’Anna
      First page: 44
      Abstract: In this study, flame-formed carbon nanoparticles of different nanostructures have been produced by changing the flame temperature. Raman spectroscopy has been used for the characterization of the carbon nanoparticles, while the particle size has been obtained by online measurements made by electrical mobility analysis. The results show that, in agreement with recent literature data, a large variety of carbon nanoparticles, with a different degree of graphitization, can be produced by changing the flame temperature. This methodology allows for the synthesis of very small carbon nanoparticles with a size of about 3-4 nm and with different graphitic orders. Under the perspective of the material synthesis process, the variable-temperature flame-synthesis of carbon nanoparticles appears as an attractive procedure for a cost-effective and easily scalable production of highly tunable carbon nanoparticles.
      Citation: C
      PubDate: 2021-05-06
      DOI: 10.3390/c7020044
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 45: Molybdenum Disulfide Quantum Dots: Properties,
           Synthesis, and Applications

    • Authors: Jeff Kabel, Sambhawana Sharma, Amit Acharya, Dongyan Zhang, Yoke Khin Yap
      First page: 45
      Abstract: Molybdenum disulfide quantum dots (MoS2 QDs) are a unique class of zero-dimensional (0D) van der Waals nanostructures. MoS2 QDs have attracted significant attention due to their unique optical, electronic, chemical, and biological properties due to the presence of edge states of these van der Waals QDs for various chemical functionalization. Their novel properties have enabled applications in many fields, including advanced electronics, electrocatalysis, and biomedicine. In this review, the various synthesis techniques, the novel properties, and the wide applications of MoS2 quantum dots are discussed in detail.
      Citation: C
      PubDate: 2021-05-08
      DOI: 10.3390/c7020045
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 46: The Performance of Fibrous CDC Electrodes in Aqueous
           and Non-Aqueous Electrolytes

    • Authors: Siret Malmberg, Mati Arulepp, Krista Laanemets, Maike Käärik, Ann Laheäär, Elvira Tarasova, Viktoria Vassiljeva, Illia Krasnou, Andres Krumme
      First page: 46
      Abstract: The aim of this study was to investigate the electrochemical behaviour of aqueous electrolytes on thin-layer (20 µm) nanoporous carbide-derived carbon (CDC) composite fibrous directly electrospun electrodes without further carbonisation. There have been previously investigated fibrous electrodes, which are produced by applying different post-treatment processes, however this makes the production of fibrous electrodes more expensive, complex and time consuming. Furthermore, in the present study high specific capacitance was achieved with directly electrospun nanoporous CDC-based fibrous electrodes in different neutral aqueous electrolytes. The benefit of fibrous electrodes is the advanced mechanical properties compared to the existing commercial electrode technologies based on pressure-rolled or slurry-cast powder mix electrodes. Such improved mechanical properties are preferred in more demanding applications, such as in the space industry. Electrospinning technology also allows for larger electrode production capacities without increased production costs. In addition to the influence of aqueous electrolyte chemical composition, the salt concentration effects and cycle stability with respect to organic electrolytes are investigated. Cyclic voltammetry (CV) measurements on electrospun electrodes showed the highest capacitance for asymmetrical cells with an aqueous 1 M NaNO3-H2O electrolyte. High CV capacitance was correlated with constant current charge–discharge (CC) data, for which a specific capacitance of 191 F g−1 for the positively charged electrode and 311 F g−1 for the negatively charged electrode was achieved. The investigation of electrolyte salt concentration on fibrous electrodes revealed the typical capacitance dependence on ionic conductivity with a peak capacitance at medium concentration levels. The cycle-life measurements of selected two-electrode test cells with aqueous and non-aqueous electrolytes revealed good stability of the electrospun electrodes.
      Citation: C
      PubDate: 2021-05-14
      DOI: 10.3390/c7020046
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 47: Porphyrin MOF-Derived Porous Carbons: Preparation and

    • Authors: Flávio Figueira, Filipe A. Almeida Paz
      First page: 47
      Abstract: Metal–organic frameworks (MOFs) are crystalline materials with permanent porosity, composed of metal nodes and organic linkers whose well-ordered arrangement enables them to act as ideal templates to produce materials with a uniform distribution of heteroatom and metal elements. The hybrid nature of MOFs, well-defined pore structure, large surface area and tunable chemical composition of their precursors, led to the preparation of various MOF-derived porous carbons with controlled structures and compositions bearing some of the unique structural properties of the parent networks. In this regard, an important class of MOFs constructed with porphyrin ligands were described, playing significant roles in the metal distribution within the porous carbon material. The most striking early achievements using porphyrin-based MOF porous carbons are here summarized, including preparation methods and their transformation into materials for electrochemical reactions.
      Citation: C
      PubDate: 2021-05-15
      DOI: 10.3390/c7020047
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 48: Raman Spectroscopy Investigation of Graphene Oxide
           Reduction by Laser Scribing

    • Authors: Vittorio Scardaci, Giuseppe Compagnini
      First page: 48
      Abstract: Laser scribing has been proposed as a fast and easy tool to reduce graphene oxide (GO) for a wide range of applications. Here, we investigate laser reduction of GO under a range of processing and material parameters, such as laser scan speed, number of laser passes, and material coverage. We use Raman spectroscopy for the characterization of the obtained materials. We demonstrate that laser scan speed is the most influential parameter, as a slower scan speed yields poor GO reduction. The number of laser passes is influential where the material coverage is higher, producing a significant improvement of GO reduction on a second pass. Material coverage is the least influential parameter, as it affects GO reduction only under restricted conditions.
      Citation: C
      PubDate: 2021-06-17
      DOI: 10.3390/c7020048
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 49: Fluorescent Nanodiamonds Synthesized in One-Step by
           Pulsed Laser Ablation of Graphite in Liquid-Nitrogen

    • Authors: Massimo Cazzanelli, Luca Basso, Claudio Cestari, Nicola Bazzanella, Enrico Moser, Michele Orlandi, Alessandro Piccoli, Antonio Miotello
      First page: 49
      Abstract: In this work, we present a relevant upgrade to the technique of pulsed laser ablation of fluorescent nanodiamonds (NDs), relying on an automatized graphite-target movement maintaining a constant level of liquid nitrogen over its surface during hours of deposition. Around 60 mg of NDs nanopowder was synthesized and optomagnetically characterized to assess its optical quality. Chemical purification of the ablated nanopowders, which removes the graphitic byproducts, permits to obtain pure fluorescent NDs with an efficiency of 7 ± 1% with respect to the total nanopowder mass. This value compares positively with the efficiency of other commercial NDs synthesis techniques such as detonation, cavitation, and high pressure–high temperature.
      Citation: C
      PubDate: 2021-06-21
      DOI: 10.3390/c7020049
      Issue No: Vol. 7, No. 2 (2021)
  • C, Vol. 7, Pages 16: Energy Absorption in Carbon Fiber Composites with
           Holes under Quasi-Static Loading

    • Authors: Omar Alhyari, Golam Newaz
      First page: 16
      Abstract: Composite tubular structures have shown promise as energy absorbers in the automobile industry. This paper investigates the energy absorption characteristics of carbon fiber reinforced plastic (CFRP) tubes with pre-existing holes. Holes may represent an extreme case of impact damage that perforates the tube, e.g., stones from road surface impacting the tubes. Tubes with holes represent more conservative performance characteristics, since impact damage of the same size will have residual material, which may carry some load. Tubes with holes can provide the lower limit of CFRP tube performance under axial crushing relative to impact damaged tubes with perforation diameter close to the hole diameter. In this study, tubes with lay-up of [05/902/04] with one and two holes in defined locations and different diameters are experimentally studied under quasi-static loading. It was found that specific energy absorption (SEA) reduces by 50% with one or two holes of 15 mm size, 100 mm from top of the tube. The SEA reduction is about 60% lower than the regular tube when the diameter of the hole is 20 mm located at 100 mm from top. The most severe reduction occurs if the location of single or double holes are 75 mm from the top. In this case, a SEA reduction of 75% can be expected. Results indicate that holes can significantly alter the energy absorption capability of the tubes. It is also clear that in axial crushing of composite tubes, the location of the hole (100 to 75 mm) appears to create more pronounced effect than the size of the hole itself (15 vs. 20 mm) for the cases investigated. The failure modes for tubes with holes seem to preserve similar damage modes with delamination, frond creation, and brittle fracture, which is typically observed in regular composite tubes under axial crushing load. This is due to primarily front end crushing, which dominates the failure modes, while hole induced damage occurs later.
      Citation: C
      PubDate: 2021-02-01
      DOI: 10.3390/c7010016
      Issue No: Vol. 7, No. 1 (2021)
  • C, Vol. 7, Pages 17: Fully Hydrogenated and Fluorinated
           Bigraphenes–Diamanes: Theoretical and Experimental Studies

    • Authors: Leonid A. Chernozatonskii, Victor A. Demin, Dmitry G. Kvashnin
      First page: 17
      Abstract: Diamanes are 2D diamond-like films that are nanometers in thickness. Diamanes can exist as bilayer or multilayer graphene with various modes of stacking and interlayer covalent sp3 bonds. The term “diamane” is used broadly for a variety of diamond-like materials at the nanoscale, from individual diamond clusters to nanocrystal films. A short overview of recent progress in the investigation of diamanes, starting from the first theoretical predictions to practical realization, is presented. The results of both theoretical and experimental studies on diamanes with various atomic structures and types of functionalization are considered. It is shown that diamanes are stronger than graphene and graphane and have wide bandgaps ranging from 3.1 to 4.5 eV depending on the structure. Diamane-like structures have been obtained using different experimental techniques, and their structures have been determined by Raman spectroscopy. The potential applications of these carbon nanostructures are briefly reviewed.
      Citation: C
      PubDate: 2021-02-02
      DOI: 10.3390/c7010017
      Issue No: Vol. 7, No. 1 (2021)
  • C, Vol. 7, Pages 18: Carbon Nanotubes Transform Soft Gellan Gum Hydrogels
           into Hybrid Organic–Inorganic Coatings with Excellent Cell Growth

    • Authors: Anatolii Abalymov, Louis Van der Meeren, Dmitry Volodkin, Bogdan Parakhonskiy, Andre G. Skirtach
      First page: 18
      Abstract: Carbone nanotubes (CNTs) possess distinct properties, for example, hardness, which is very complementary to biologically relevant soft polymeric and protein materials. Combining CNTs with bio-interfaces leads to obtaining new materials with advanced properties. In this work, we have designed novel organic-inorganic hybrid coatings by combining CNTs with gellan gum (GG) hydrogels. The surface topography of the samples is investigated using scanning electron microscopy and atomic force microscopy. Mechanical properties of synthesized hybrid materials are both assessed at the macro-scale and mapped at the nanoscale. A clear correlation between the CNT concentration and the hardness of the coatings is revealed. Cell culture studies show that effective cell growth is achieved at the CNT concentration of 15 mg/mL. The presented materials can open new perspectives for hybrid bio-interfaces and can serve as a platform for advanced cell culture.
      Citation: C
      PubDate: 2021-02-04
      DOI: 10.3390/c7010018
      Issue No: Vol. 7, No. 1 (2021)
  • C, Vol. 7, Pages 19: Carbon-Based Nanomaterials for Delivery of
           Biologicals and Therapeutics: A Cutting-Edge Technology

    • Authors: Alok Mahor, Prem Prakash Singh, Peeyush Bharadwaj, Neeraj Sharma, Surabhi Yadav, Jessica M. Rosenholm, Kuldeep K. Bansal
      First page: 19
      Abstract: After hydrogen and oxygen, carbon is the third most abundant component present in the cosmos with excellent characteristic features of binding to itself and nearly all elements. Since ancient times, carbon-based materials such as graphite, charcoal, and carbon black have been utilized for writing and drawing materials. As these materials possess excellent chemical, mechanical, electrical, and thermal features, they have been readily engineered into carbon-based nanomaterials (CNMs) such as carbon nanotubes, graphene oxide, graphene quantum dots, nanodiamonds, fullerenes, carbon nano-onions, and so forth. These materials are now widely explored in biomedical applications. Thus, the emergence of CNMs has opened up a gateway for the detection, delivery, and treatment of a multitude of diseases. They are being actively researched for applications within tissue engineering, as vaccine vectors, and for the delivery of therapeutics to the immune system. This review focuses on the recent advances in various types of CNMs, their fabrication techniques, and their application in the delivery of therapeutics both in vitro and in vivo. The review also focuses on the toxicity concern of the CNMs and the possible remedies to tackle the toxicity issues. Concluding remarks emphasize all the CNMs discussed in the review over their possible biomedical applications, while the future perspectives section discusses the approaches to bring CNMs into the mainstream of clinical trials and their therapeutic applications.
      Citation: C
      PubDate: 2021-02-05
      DOI: 10.3390/c7010019
      Issue No: Vol. 7, No. 1 (2021)
  • C, Vol. 7, Pages 20: Preparation and Applications of Fluorinated Graphenes

    • Authors: Yasser Ahmad, Nicolas Batisse, Xianjue Chen, Marc Dubois
      First page: 20
      Abstract: The present review focuses on the numerous routes for the preparation of fluorinated graphene (FG) according to the starting materials. Two strategies are considered: (i) addition of fluorine atoms on graphenes of various nature and quality and (ii) exfoliation of graphite fluoride. Chemical bonding in fluorinated graphene, related properties and a selection of applications for lubrication, energy storage, and gas sensing will then be discussed.
      Citation: C
      PubDate: 2021-02-07
      DOI: 10.3390/c7010020
      Issue No: Vol. 7, No. 1 (2021)
  • C, Vol. 7, Pages 21: A Comparative Study of Aromatization Catalysts: The
           Advantage of Hybrid Oxy/Carbides and Platinum-Catalysts Based on Carbon

    • Authors: Luisa M. Pastrana-Martínez, Sergio Morales-Torres, Francisco J. Maldonado-Hódar
      First page: 21
      Abstract: This manuscript is focused on the relationship between sol-gel synthesis processes and the development of new active phases with fitted morphology, porosity and surface chemistry. The influence of the above parameters on the catalytic performance of the prepared materials for the aromatization of n-hexane to benzene is also evaluated. Different series of catalysts were prepared, either using noble metals (i.e., Pt) or metal oxides (i.e., Mo, W), as active phases. In both cases, the catalytic performance and stability of classical aromatization catalysts was significantly improved. Interesting one-pot carboreduction process of the metal oxide during carbonization is suggested as a real alternative for the preparation of high-performance aromatization catalysts, leading to the formation of less acidic and non-stoichiometric oxides and carbides.
      Citation: C
      PubDate: 2021-02-12
      DOI: 10.3390/c7010021
      Issue No: Vol. 7, No. 1 (2021)
  • C, Vol. 7, Pages 22: Anisotropic Magnetism in Gradient Porous Carbon
           Composite Aerogels

    • Authors: Bahner, Hug, Polarz
      First page: 22
      Abstract: Porosity is of high importance for functional materials, as it allows for high surface areas and the accessibility of materials. While the fundamental interplay between different pore sizes and functionalities is quite well understood, few studies on gradually changing properties in a material exist. To date, only a few examples of such materials have been synthesized successfully. Herein, we present a facile method for synthesizing macroscopic carbon aerogels with locally changing pore sizes and functionalities. We used ultracentrifugation to fractionate differently functionalized and sized polystyrene nanoparticles. The assembly into gradient templates was conducted in a resorcinol–formaldehyde (RF) sol, which acted as a liquid phase and carbon precursor. We show that the modification of nanoparticles and a sol–gel precursor is a powerful tool for introducing dopants (sulfur and phosphorous) and metal nanoparticles (e.g., Ni) into gradient porous carbons formed during the carbonization of the RF sol. Understanding the underlying interactions between particles and precursors will lead to a plethora of possibilities in the material design of complex functionally graded materials. We showed this by exchanging parts of the template with magnetite–polystyrene composites as templating nanoparticles. This led to the incorporation of magnetite nanoparticles in the formed gradient porous carbon aerogels. Finally, gradually increasing concentrations of magnetite were obtained, ultimately leading to macroscopic carbon aerogels with locally changing magnetic properties, while the graded porosity was maintained.
      Citation: C
      PubDate: 2021-02-13
      DOI: 10.3390/c7010022
      Issue No: Vol. 7, No. 1 (2021)
  • C, Vol. 7, Pages 23: Removal of Lead by Oxidized Graphite

    • Authors: Namasivayam Selvanantharajah, Poobalasuntharam Iyngaran, Poobalasingam Abiman, Navaratnarajah Kuganathan
      First page: 23
      Abstract: Lead ion adsorption on the surfaces of pristine and oxidized graphite is studied quantitatively using X-ray photoelectron spectroscopy (XPS) and standard electrochemical measurements. The XPS analysis confirmed the oxidation of graphite, yielding a final composite consisting of 15.97% of oxygen and 84.03% of carbon in comparison with the pristine graphite powder consisting of 6.13% oxygen and 93.87% carbon. The adsorption of lead (II) ion was confirmed by the peaks observed at 138 eV and 143.8 eV, associated with the emissions from Pb4f 7/2 and Pb4f 5/2, respectively. The effective concentration of Pb2+ ion and the optimum dosage of oxidized graphite were calculated to be 400 μM and 200 mg, respectively. Adsorption capacity of bare graphite was 41.18%, whereas that of oxidized graphite was 73.3%. The present results show that graphite oxide is a candidate material for the adsorption of Pb2+ ion from water.
      Citation: C
      PubDate: 2021-02-20
      DOI: 10.3390/c7010023
      Issue No: Vol. 7, No. 1 (2021)
  • C, Vol. 7, Pages 24: C—Journal of Carbon Research: 300th
           Publications Milestone

    • Authors: Craig E. Banks, Jandro L. Abot
      First page: 24
      Abstract: The C—Journal of Carbon Research (ISSN 2311-5629) is quite pleased to announce the publication of its 300th article [...]
      Citation: C
      PubDate: 2021-02-20
      DOI: 10.3390/c7010024
      Issue No: Vol. 7, No. 1 (2021)
  • C, Vol. 7, Pages 25: Selection of Mixed Amines in the CO2 Capture Process

    • Authors: Pao-Chi Chen, Hsun-Huang Cho, Jyun-Hong Jhuang, Cheng-Hao Ku
      First page: 25
      Abstract: In order to select the best mixed amines in the CO2 capture process, the absorption of CO2 in mixed amines was explored at the required concentrations by using monoethanolamine (MEA) as a basic solvent, mixed with diisopropanolamine (DIPA), triethanolamine (TEA), 2-amino-2-methyl-1-propanol (AMP), and piperazine (PZ). Here, a bubble column was used as the scrubber, and a continuous operation was adopted. The Taguchi method was used for the experimental design. The conditional factors included the type of mixed amine (A), the ratio of the mixed amines (B), the liquid feed flow (C), the gas-flow rate (D), and the concentration of mixed amines (E). There were four levels, respectively, and a total of 16 experiments. The absorption efficiency (EF), absorption rate (RA), overall mass transfer coefficient (KGa), and scrubbing factor (<i>ϕ</i>) were used as indicators and were determined in a steady-state by the mass balance and two-film models. According to the Taguchi analysis, the importance of the parameters and the optimum conditions were obtained. In terms of the absorption efficiency (EF), the absorption rate (absorption factor) (RA/<i>ϕ</i>), and the overall mass transfer coefficient (KGa), the order of importance is D > E > A > B > C, D > E > C > B > A, and D > E > C > A > B, respectively, and the optimum conditions are A1B4C4D3E3, A1B3C4D4E2, A4B2C3D4E4, and A1B1C1D4E1. The optimum condition validation results showed that the optimal values of EF, RA, and KGa are 100%, 30.69 × 10−4 mol/s·L, 1.540 l/s, and 0.269, respectively. With regard to the selection of mixed amine, it was found that the mixed amine (MEA + AMP) performed the best in the CO2 capture process.
      Citation: C
      PubDate: 2021-02-24
      DOI: 10.3390/c7010025
      Issue No: Vol. 7, No. 1 (2021)
  • C, Vol. 7, Pages 26: A New Composite Material on the Base of Carbon
           Nanotubes and Boron Clusters B12 as the Base for High-Performance
           Supercapacitor Electrodes

    • Authors: Dmitry A. Kolosov, Olga E. Glukhova
      First page: 26
      Abstract: We explore the quantum capacitance, stability, and electronic properties of single-walled carbon nanotubes decorated with B12 icosahedral boron clusters by first-principle calculation methods implemented in the SIESTA code. After the optimization of the built supercells, the B12 clusters formed bonds with the walls of the carbon nanotubes and demonstrated metallic properties in all cases. The network of carbon nanotubes with its large area and branched surface is able to increase the capacity of the electric double-layer capacity, but the low quantum capacity of each nanotube in this network limits its application in supercapacitors. We found that the addition of boron clusters to both the outer and inner walls increased the quantum capacitance of carbon nanotubes. The calculation of the transmission function near the Fermi energy showed an increase in the conductivity of supercells. It was also found that an increase in the concentration of boron clusters in the structure led to a decrease in the heat of formation that positively affects the stability of supercells. The calculation of the specific charge density showed that with an increase in the boron concentration, the considered material demonstrated the properties of an asymmetric electrode.
      Citation: C
      PubDate: 2021-02-25
      DOI: 10.3390/c7010026
      Issue No: Vol. 7, No. 1 (2021)
  • C, Vol. 7, Pages 27: The Role of Surface Chemistry and Polyethylenimine
           Grafting in the Removal of Cr (VI) by Activated Carbons from Cashew Nut

    • Authors: Victoria A. Smith, Juster F. A. Rivera, Ruby Bello, Elena Rodríguez-Aguado, Mohammed R. Elshaer, Rebecca L. Wodzinski, Svetlana Bashkova
      First page: 27
      Abstract: Activated carbons prepared from cashew nut shells and modified by grafting polyethylenimine onto the surface were tested for removal of Cr (VI). The removal efficiency of carbons without and with polyethylenimine decreased with an increase in pH, with maximum efficiency found at pH 2. The average maximum adsorption capacities of carbons were calculated to be 340 ± 20 mg/g and 320 ± 20 mg/g for unmodified and modified carbons, respectively. Surface characterization of carbons revealed that C–O functionalities are actively involved in both polyethylenimine grafting and Cr (VI) removal. Moreover, lactone groups and amides, formed by polyethylenimine grafting, seemingly undergo acid hydrolysis with formation of phenol and carboxylic groups. Considering that Cr (III) is the only form of chromium found on the surface of both carbons, the reduction mechanism is deduced as the predominant one. Here Cr (VI), majorly present as HCrO4¯, is attracted to the positively charged carbon surface, reduced to Cr (III) by phenol groups, and adsorbed inside the pores. The mechanism of Cr (VI) removal appears to be similar for unmodified and modified carbons, where the smaller adsorption capacity of the latter one can be related to steric hindrance and pore inaccessibility.
      Citation: C
      PubDate: 2021-02-27
      DOI: 10.3390/c7010027
      Issue No: Vol. 7, No. 1 (2021)
  • C, Vol. 7, Pages 28: Impact of Nitrogen, Boron and Phosphorus Impurities
           on the Electronic Structure of Diamond Probed by X-ray Spectroscopies

    • Authors: Sneha Choudhury, Ronny Golnak, Christian Schulz, Klaus Lieutenant, Nicolas Tranchant, Jean-Charles Arnault, Marie-Amandine Pinault-Thaury, François Jomard, Peter Knittel, Tristan Petit
      First page: 28
      Abstract: Doping diamond with boron, nitrogen or phosphorus enables a fine tuning of its electronic properties, which is particularly relevant for applications involving electron emission. However, the chemical nature of the doping sites and its correlation with electron emission properties remain to be clarified. In this work, we applied soft X-ray spectroscopy techniques to probe occupied and unoccupied electronic states in undoped, boron-, phosphorus- and nitrogen-containing single crystal diamonds. X-ray absorption, X-ray emission and X-ray photoemission spectroscopies, performed at the carbon K-edge, provide a full picture of new electronic states created by impurities in diamond. The different probing depths of fluorescence- and electron-based detection techniques enable a comparison between surface and bulk contributions.
      Citation: C
      PubDate: 2021-03-09
      DOI: 10.3390/c7010028
      Issue No: Vol. 7, No. 1 (2021)
  • C, Vol. 7, Pages 29: Carbide-Derived Carbons: WAXS and Raman Spectra for
           Detailed Structural Analysis

    • Authors: Riinu Härmas, Rasmus Palm, Heisi Kurig, Laura Puusepp, Torben Pfaff, Tavo Romann, Jaan Aruväli, Indrek Tallo, Thomas Thomberg, Alar Jänes, Enn Lust
      First page: 29
      Abstract: Quick characterization methods to determine the structure of carbon materials are sought after for a wide array of technical applications. In this study we present the combined analysis of the structure of carbide-derived carbons (CDCs) with Raman spectroscopy and wide-angle X-ray scattering (WAXS) methods. We present the optimal deconvolution method to be used for the detailed analysis of Raman spectroscopy data of CDCs and comparison to corresponding WAXS results is made. For a broad set of CDCs both WAXS and Raman spectroscopy data showed that the average graphene layer extent increases with synthesis temperature of CDC, while the coherent domain lengths obtained from Raman spectroscopy higher by an average of 4.4 nm. In addition, the presence of correlations between the parameters (D-band width and the parameter A∑D/A∑G) from Raman spectroscopy and the synthesis temperature are established. Based on the WAXS and Raman spectra data analysis the strong influence of the precursor carbide structure on the graphitization pathway is shown.
      Citation: C
      PubDate: 2021-03-20
      DOI: 10.3390/c7010029
      Issue No: Vol. 7, No. 1 (2021)
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