C | December 2021 - Browse Articles

14 pages, 5986 KiB

Open AccessArticle

Activated Carbon Impregnated with Elementary Iodine: Applications against Virus- and Bacteria-Related Issues

by Yuri Natori, Yoshiaki Kinase, Norihiro Ikemoto, Fabio Spaziani, Tsutomu Kojima, Hitomi Kakuta, Junko Fujita, Kazuyuki Someya, Katsuyoshi Tatenuma, Toshiyo Yabuta, Hiroki Takakuwa and Koichi Otsuki

C 2021, 7(4), 86; https://doi.org/10.3390/c7040086 - 15 Dec 2021

Cited by 6 | Viewed by 4463

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Carbon Nanohybrids for Biomedical Applications)

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7 pages, 2572 KiB

Open AccessCommunication

Solvent and Substituent Effect on Selectivity of Triphenylether-Based Ionophores: A Voltammetric Study

by Susheel K. Mittal, Shivali Gupta and Manmohan Chhibber

C 2021, 7(4), 85; https://doi.org/10.3390/c7040085 - 13 Dec 2021

Viewed by 1918

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 [...] Read more.

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. Full article

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10 pages, 3777 KiB

Open AccessArticle

Carbon Nanotubes Use for the Semiconductors ZnSe and ZnS Material Surface Modification via the Laser-Oriented Deposition Technique

by Natalia Kamanina, Andrey Toikka, Bulat Valeev and Dmitry Kvashnin

C 2021, 7(4), 84; https://doi.org/10.3390/c7040084 - 7 Dec 2021

Cited by 4 | Viewed by 2920

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 [...] Read more.

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. Full article

(This article belongs to the Collection Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties)

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26 pages, 2122 KiB

Open AccessReview

Removal of Hydrophobic Contaminants from the Soil by Adsorption onto Carbon Materials and Microbial Degradation

by Shippi Dewangan, Amarpreet K. Bhatia, Ajaya Kumar Singh and Sónia A. C. Carabineiro

C 2021, 7(4), 83; https://doi.org/10.3390/c7040083 - 3 Dec 2021

Cited by 8 | Viewed by 4585

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 [...] Read more.

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. Full article

(This article belongs to the Collection Feature Papers in the Science and Engineering of Carbons)

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14 pages, 5516 KiB

Open AccessArticle

Viability of Activated Carbon Derived from Polystyrene Sulphonate Beads as Electrical Double Layer Capacitors

by Gbenro Babajide Folaranmi, Anthony Ekennia, Nkiruka Chidiebere Ani and Richard Chukwuemeka Ehiri

C 2021, 7(4), 82; https://doi.org/10.3390/c7040082 - 26 Nov 2021

Cited by 1 | Viewed by 2876

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 [...] Read more.

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. Full article

(This article belongs to the Collection Nanoporous Carbon Materials for Advanced Technological Applications)

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16 pages, 6251 KiB

Open AccessArticle

Comparison of Electrical Contacting Techniques to Carbon Fiber Reinforced Plastics for Self-Strain-Sensing Applications

by Patrick Scholle, Sören Rüther and Michael Sinapius

C 2021, 7(4), 81; https://doi.org/10.3390/c7040081 - 25 Nov 2021

Cited by 1 | Viewed by 4288

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Carbon Fiber Composites – Composite Driven Multifunctionality and Applications)

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11 pages, 1944 KiB

Open AccessArticle

Prediction of the Near-Infrared Absorption Spectrum of Single-Walled Carbon Nanotubes Using a Bayesian Regularized Back Propagation Neural Network Model

by Takao Onishi, Yuji Matsukawa, Yuto Yamazaki and Daisuke Miyashiro

C 2021, 7(4), 80; https://doi.org/10.3390/c7040080 - 25 Nov 2021

Cited by 1 | Viewed by 3113

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 [...] Read more.

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. Full article

(This article belongs to the Collection Novel Applications of Carbon Nanotube-Based Materials)

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13 pages, 5661 KiB

Open AccessArticle

Premade Nanoparticle Films for the Synthesis of Vertically Aligned Carbon Nanotubes

by Abdul Hoque, Ahamed Ullah, Beth S. Guiton and Noe T. Alvarez

C 2021, 7(4), 79; https://doi.org/10.3390/c7040079 - 19 Nov 2021

Cited by 2 | Viewed by 3858

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 [...] Read more.

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. Full article

(This article belongs to the Collection Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties)

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13 pages, 29458 KiB

Open AccessArticle

Influence of Carbon Nanotube Attributes on Carbon Nanotube/Cu Composite Electrical Performances

by Rajyashree Sundaram, Atsuko Sekiguchi, Guohai Chen, Don Futaba, Takeo Yamada, Ken Kokubo and Kenji Hata

C 2021, 7(4), 78; https://doi.org/10.3390/c7040078 - 15 Nov 2021

Cited by 3 | Viewed by 3516

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 [...] Read more.

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. Full article

(This article belongs to the Collection Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties)

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19 pages, 4111 KiB

Open AccessArticle

Enhanced Breaking of Lignin and Mesopore Formation in Zinc Chloride Assisted Hydrothermal Carbonization of Waste Biomasses

by Hendrik Multhaupt, Patrick Bottke and Michael Wark

C 2021, 7(4), 77; https://doi.org/10.3390/c7040077 - 11 Nov 2021

Cited by 2 | Viewed by 3188

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 [...] Read more.

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. Full article

(This article belongs to the Collection Carbon-Derived Materials from Bioresources for Advanced Applications)

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18 pages, 2014 KiB

Open AccessReview

Graphene Synthesis and Its Recent Advances in Applications—A Review

by Anuluxan Santhiran, Poobalasuntharam Iyngaran, Poobalasingam Abiman and Navaratnarajah Kuganathan

C 2021, 7(4), 76; https://doi.org/10.3390/c7040076 - 10 Nov 2021

Cited by 21 | Viewed by 12600

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, [...] Read more.

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. Full article

(This article belongs to the Collection Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties)

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13 pages, 1265 KiB

Open AccessArticle

Crystallization Kinetics of Poly(lactic acid)–Graphene Nanoscroll Nanocomposites: Role of Tubular, Planar, and Scrolled Carbon Nanoparticles

by Oluwakemi Ajala, Caroline Werther, Rauf Mahmudzade, Peyman Nikaeen and Dilip Depan

C 2021, 7(4), 75; https://doi.org/10.3390/c7040075 - 31 Oct 2021

Cited by 2 | Viewed by 2703

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 [...] Read more.

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. Full article

(This article belongs to the Collection Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties)

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16 pages, 2094 KiB

Open AccessReview

A Mini Review of Recent Findings in Cellulose-, Polymer- and Graphene-Based Membranes for Fluoride Removal from Drinking Water

by Athanasia K. Tolkou, Elie Meez, George Z. Kyzas, Vincenzo Torretta, Maria Cristina Collivignarelli, Francesca Maria Caccamo, Eleni A. Deliyanni and Ioannis A. Katsoyiannis

C 2021, 7(4), 74; https://doi.org/10.3390/c7040074 - 26 Oct 2021

Cited by 7 | Viewed by 3360

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 [...] Read more.

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. Full article

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21 pages, 51157 KiB

Open AccessReview

Carbon Nanoarchitectonics for Energy and Related Applications

by Rekha Goswami Shrestha, Lok Kumar Shrestha and Katsuhiko Ariga

C 2021, 7(4), 73; https://doi.org/10.3390/c7040073 - 19 Oct 2021

Cited by 13 | Viewed by 3601

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 [...] Read more.

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. Full article

(This article belongs to the Collection Feature Papers in the Science and Engineering of Carbons)

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16 pages, 7817 KiB

Open AccessArticle

Effects of Reducing Agent on the Activity of PtRu/Carbon Black Anode Catalyst of Direct Methanol Fuel Cell

by Yu-Wen Chen and Han-Gen Chen

C 2021, 7(4), 72; https://doi.org/10.3390/c7040072 - 19 Oct 2021

Cited by 1 | Viewed by 2618

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 [...] Read more.

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). Full article

(This article belongs to the Special Issue Carbon Materials for Physical and Chemical Hydrogen Storage)

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15 pages, 3081 KiB

Open AccessArticle

Applicability of Atmospheric Pressure Plasma Jet (APPJ) Discharge for the Reduction in Graphene Oxide Films and Synthesis of Carbon Nanomaterials

by Sri Hari Bharath Vinoth Kumar, Josefa Ibaceta-Jaña, Natalia Maticuic, Krystian Kowiorski, Matthias Zelt, Ulrich Gernert, Ludwika Lipińska, Bernd Szyszka, Rutger Schlatmann, Uwe Hartmann and Ruslan Muydinov

C 2021, 7(4), 71; https://doi.org/10.3390/c7040071 - 14 Oct 2021

Cited by 2 | Viewed by 4771

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 [...] Read more.

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. Full article

(This article belongs to the Collection Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties)

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38 pages, 11507 KiB

Open AccessReview

Fabrication and Supercapacitor Applications of Multiwall Carbon Nanotube Thin Films

by Kyle Jiang and Rosario A. Gerhardt

C 2021, 7(4), 70; https://doi.org/10.3390/c7040070 - 30 Sep 2021

Cited by 10 | Viewed by 4932

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 [...] Read more.

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. Full article

(This article belongs to the Collection Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties)

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18 pages, 3531 KiB

Open AccessArticle

Nanoporous Carbon Magnetic Hybrid Derived from Waterlock Polymers and Its Application for Hexavalent Chromium Removal from Aqueous Solution

by Georgios Asimakopoulos, Angeliki Karakassides, Maria Baikousi, Christina Gioti, Dimitrios Moschovas, Apostolos Avgeropoulos, Athanasios B. Bourlinos, Alexios P. Douvalis, Constantinos E. Salmas and Michael A. Karakassides

C 2021, 7(4), 69; https://doi.org/10.3390/c7040069 - 30 Sep 2021

Cited by 3 | Viewed by 3122

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 [...] Read more.

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 (S_gBET = 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. Full article

(This article belongs to the Collection Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties)

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15 pages, 5153 KiB

Open AccessArticle

CH Activation by a Heavy Metal Cation: Production of H₂ from the Reaction of Acetylene with C₄H₄-Os(+) in Gas phase

by Zikri Altun, Erdi Ata Bleda and Carl Trindle

C 2021, 7(4), 68; https://doi.org/10.3390/c7040068 - 30 Sep 2021

Cited by 1 | Viewed by 2654

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 [...] Read more.

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 C_2nH_2n-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. Full article

(This article belongs to the Special Issue Carbon Materials for Physical and Chemical Hydrogen Storage)

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12 pages, 5960 KiB

Open AccessArticle

Atomic Layer Deposition of Nanolayered Carbon Films

by Zhigang Xiao, Kim Kisslinger and Rebhadevi Monikandan

C 2021, 7(4), 67; https://doi.org/10.3390/c7040067 - 27 Sep 2021

Cited by 2 | Viewed by 4397

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), [...] Read more.

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. Full article

(This article belongs to the Collection Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties)

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C, Volume 7, Issue 4 (December 2021) – 20 articles

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