C | September 2023 - Browse Articles

20 pages, 3649 KiB

Open AccessArticle

Impacts of Mn Content and Mass Loading on the Performance of Flexible Asymmetric Solid-State Supercapacitors Using Mixed-Phase MnO₂/N-Containing Graphene Composites as Cathode Materials

by Hsin-Ya Chiu and Chun-Pei Cho

C 2023, 9(3), 88; https://doi.org/10.3390/c9030088 - 10 Sep 2023

Cited by 1 | Viewed by 2055

Abstract

MnO₂/nitrogen-containing graphene (x-NGM) composites with varying contents of Mn were used as the electrode materials for flexible asymmetric solid-state supercapacitors. The MnO₂ was a two-phase mixture of γ- and α-MnO₂. The combination of nitrogen-containing graphene and MnO₂ [...] Read more.

MnO₂/nitrogen-containing graphene (x-NGM) composites with varying contents of Mn were used as the electrode materials for flexible asymmetric solid-state supercapacitors. The MnO₂ was a two-phase mixture of γ- and α-MnO₂. The combination of nitrogen-containing graphene and MnO₂ improved reversible Faraday reactions and charge transfer. However, excessive MnO₂ reduced conductivity, hindering ion diffusion and charge transfer. Overloading the electrode with active materials also negatively affected conductivity. Both the mass loading and MnO₂ content were crucial to electrochemical performance. x-NGM composites served as cathode materials, while graphene acted as the anode material. Operating by two charge storage mechanisms enabled a synergistic effect, resulting in better charge storage purposes. Among the supercapacitors, the 3-NGM1//G1 exhibited the highest conductivity, efficient charge transfer, and superior capacitive characteristics. It showed a superior specific capacitance of 579 F·g⁻¹, leading to high energy density and power density. Flexible solid-state supercapacitors using x-NGM composites demonstrated good cycle stability, with a high capacitance retention rate of 86.7% after 2000 bending cycles. Full article

(This article belongs to the Special Issue Carbon and Related Composites for Sensors and Energy Storage: Synthesis, Properties, and Application)

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22 pages, 6143 KiB

Open AccessArticle

Membranes of Multiwall Carbon Nanotubes in Chitosan–Starch with Mechanical and Compositional Properties Useful in Li-Ion Batteries

by Yoxkin Estévez-Martínez, Enrique Quiroga-González, Erick Cuevas-Yañez, Sergio Durón-Torres, Daniel Alaníz-Lumbreras, Elizabeth Chavira-Martínez, Rubén Posada-Gómez, Jeremias Bravo-Tapia and Víctor Castaño-Meneses

C 2023, 9(3), 87; https://doi.org/10.3390/c9030087 - 8 Sep 2023

Cited by 2 | Viewed by 1996

Abstract

This work reports on membranes of a combination of chitosan–starch with lithium-modified multiwall carbon nanotubes. One of the most important contributions of this article is the functionalization of the surface of multiwall carbon nanotubes by means of an accessible technique that allows for [...] Read more.

This work reports on membranes of a combination of chitosan–starch with lithium-modified multiwall carbon nanotubes. One of the most important contributions of this article is the functionalization of the surface of multiwall carbon nanotubes by means of an accessible technique that allows for high grafting yields of lithium and their incorporation into a polymeric matrix. The natural compounds chitosan and starch were used as a support to embed the nanotubes, forming membranes with good mechanical stability. A thorough characterization via Raman, infrared and X-ray photoelectron spectroscopies, transmission and scanning electron microscopies and dynamic mechanical analysis is presented here, as well as electrochemical characterization. The composition, structure and mechanical stability of the membranes make them viable candidates to be used as anodes sustainable Li-ion batteries. Full article

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

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17 pages, 4953 KiB

Open AccessArticle

A Grand Canonical Monte Carlo Simulation for the Evaluation of Pore Size Distribution of Nuclear-Grade Graphite from Kr Adsorption Isotherms

by Giuliano M. Laudone and Katie L. Jones

C 2023, 9(3), 86; https://doi.org/10.3390/c9030086 - 4 Sep 2023

Cited by 1 | Viewed by 2532

Abstract

Characterizing materials with low surface areas or with very small sample sizes requires innovative approaches beyond traditional N

_{2}

and Ar adsorption measurements. The measurement of Kr adsorption isotherms is often employed to serve this purpose, yet its potential remains limited by the [...] Read more.

Characterizing materials with low surface areas or with very small sample sizes requires innovative approaches beyond traditional N

_{2}

and Ar adsorption measurements. The measurement of Kr adsorption isotherms is often employed to serve this purpose, yet its potential remains limited by the lack of models for the interpretation of the experimental results in terms of pore size distribution. In this work, simulated adsorption isotherms of Kr onto graphite in slit-shaped pores are generated with a Grand Canonical Monte Carlo method. The pore size distributions of nuclear-grade graphite samples and activated carbon are modelled by fitting simulated isotherms to the experimental data. The resulting distributions are favourably compared with those generated by commercially available modelling packages, based on the use of N₂ adsorption isotherms using GCMC and BJH methods. The new GCMC-Kr kernel developed in this study offers an alternative method for the evaluation of the distribution of pore sizes in nuclear graphite and other low surface area materials, which can be employed when N₂ and Ar adsorption measurements cannot be carried out. Full article

(This article belongs to the Special Issue Adsorption on Carbon-Based Materials)

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15 pages, 6137 KiB

Open AccessArticle

Photocatalytic Materials Based on g-C₃N₄ Obtained by the One-Pot Calcination Method

by Radik R. Shamilov, Zufar M. Muzipov, Dmitriy O. Sagdeev, Kirill V. Kholin, Alina F. Saifina, Aidar T. Gubaidullin and Yuriy G. Galyametdinov

C 2023, 9(3), 85; https://doi.org/10.3390/c9030085 - 2 Sep 2023

Cited by 4 | Viewed by 2351

Abstract

Photocatalysts based on graphitic carbon nitride (g-C₃N₄) attracted considerable attention due to their efficiency in hydrogen production and decomposition of organic pollutants in aqueous solutions. In this work, a new approach to synthesis of g-C₃N₄-based [...] Read more.

Photocatalysts based on graphitic carbon nitride (g-C₃N₄) attracted considerable attention due to their efficiency in hydrogen production and decomposition of organic pollutants in aqueous solutions. In this work, a new approach to synthesis of g-C₃N₄-based heterostructures with improved photocatalytic properties was proposed. The properties of two different CdZnS/g-C₃N₄ and ZnIn₂S₄/g-C₃N₄ heterostructures synthesized and studied in the same conditions were compared. Pure g-C₃N₄ photocatalysts as well as CdZnS/g-C₃N₄ and ZnIn₂S₄/g-C₃N₄ heterostructures were synthesized using a one-pot method by calcining the mixture of the initial components. Photocatalytic properties of the synthesized substances were evaluated in a model reaction of rhodamine B decomposition induced by visible light. It was shown that ultrasonic treatment in the presence of a nonionic surfactant enhances the photocatalytic activity of g-C₃N₄ structures as a result of a higher photocatalyst dispersity. The electronic structures of the CdZnS/g-C₃N₄ and ZnIn₂S₄/g-C₃N₄ heterostructures were analyzed in detail. The photocatalytic activity of heterostructures was found to be 2–3-fold higher as compared with an unmodified g-C₃N₄ due to formation of a type II heterojunction and Z-scheme structures. Decomposition of rhodamine B occurred mostly via formation of active oxygen radicals by irradiation. Full article

(This article belongs to the Special Issue Advanced Carbon Nanomaterials and Hybrids)

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15 pages, 1026 KiB

Open AccessArticle

Large-Separation Behavior of the Casimir–Polder Force from Real Graphene Sheet Deposited on a Dielectric Substrate

by Galina L. Klimchitskaya and Vladimir M. Mostepanenko

C 2023, 9(3), 84; https://doi.org/10.3390/c9030084 - 31 Aug 2023

Viewed by 1438

Abstract

The Casimir–Polder force between atoms or nanoparticles and graphene-coated dielectric substrates is investigated in the region of large separations. Graphene coating with any value of the energy gap and chemical potential is described in the framework of the Dirac model using the formalism [...] Read more.

The Casimir–Polder force between atoms or nanoparticles and graphene-coated dielectric substrates is investigated in the region of large separations. Graphene coating with any value of the energy gap and chemical potential is described in the framework of the Dirac model using the formalism of the polarization tensor. It is shown that the Casimir–Polder force from a graphene-coated substrate reaches the limit of large separations at approximately 5.6

μ

m distance between an atom or a nanoparticle and graphene coating independently of the values of the energy gap and chemical potential. According to our results, however, the classical limit, where the Casimir–Polder force no longer depends on the Planck constant and the speed of light, may be attained at much larger separations depending on the values of the energy gap and chemical potential. In addition, we have found a simple analytic expression for the Casimir–Polder force from a graphene-coated substrate at large separations and determined the region of its applicability. It is demonstrated that the asymptotic results for the large-separation Casimir–Polder force from a graphene-coated substrate are in better agreement with the results of numerical computations for the graphene sheets with larger chemical potential and smaller energy gap. Possible applications of the obtained results in nanotechnology and bioelectronics are discussed. Full article

(This article belongs to the Special Issue Advances in Modelling of Size Effects in Graphene and Carbon Nanotubes)

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19 pages, 7417 KiB

Open AccessArticle

Carbonized Melamine Cyanurate as a Palladium Catalyst Support for the Dehydrogenation of N-heterocyclic Compounds in LOHC Technology

by Anton P. Koskin, Yurii V. Larichev, Sergey A. Stepanenko, Yury V. Dubinin, Artem B. Ayupov, Andrey A. Saraev, Evgeny A. Suprun and Petr M. Yeletsky

C 2023, 9(3), 83; https://doi.org/10.3390/c9030083 - 30 Aug 2023

Cited by 3 | Viewed by 2007

Abstract

In this work, the use of graphite-like carbon nitride (g-C₃N₄) with improved texture characteristics for the synthesis of supported palladium catalysts of dehydrogenation of nitrogen-containing heterocycles was studied. This process is key to the creation of liquid organic carrier [...] Read more.

In this work, the use of graphite-like carbon nitride (g-C₃N₄) with improved texture characteristics for the synthesis of supported palladium catalysts of dehydrogenation of nitrogen-containing heterocycles was studied. This process is key to the creation of liquid organic carrier technology (LOHC) using N-heterocycles as reversibly hydrogenated/dehydrogenated substrates. For the preparation of graphite-like carbon nitride supports with advanced textural characteristics, well-established technology of the melamine cyanurate complex carbonization and standard techniques of adsorption precipitation together with wet impregnation were used for the synthesis of Pd-containing systems. The activity of the synthesized catalysts was studied in decahydroquinoline dehydrogenation. The high weight content of extractable hydrogen (7.2 wt%) and the high extraction rate, respectively, make it possible to consider these substances as the most promising N-heterocyclic compounds for this technology. It was shown that an increase in the specific surface area of g-C₃N₄ allows for achieving a slightly lower but comparable fineness of palladium particles for the 1 wt% Pd/MCA-500 sample, compared to the standard 1 wt% Pd/C. In this case, the catalytic activity of 1 wt% Pd/MCA-500 in the dehydrogenation of both substrates exceeded the analogous parameter for catalysts supported by nitrogen-free supports. This regularity is presumably associated with the electron-donor effect of surface nitrogen, which favorably affects the dehydrogenation rate as well as the stability of catalytic systems. Full article

(This article belongs to the Special Issue Advanced Carbon Nanomaterials and Hybrids)

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14 pages, 2262 KiB

Open AccessArticle

Resistive Gas Sensors Based on Porous Sp-Containing Films Obtained by Dehydrohalogenation of PVDC and PVDC-PVC Copolymer

by Oleg A. Streletskiy, Ilya A. Zavidovskiy, Islam F. Nuriahmetov, Olesya Y. Nishchak, Alexander V. Pavlikov and Natalya F. Savchenko

C 2023, 9(3), 82; https://doi.org/10.3390/c9030082 - 28 Aug 2023

Cited by 9 | Viewed by 2130

Abstract

Resistive sensing responses of the thin films obtained by dehydrohalogenation of polyvinylidene chloride (PVDC) and polyvinylidene chloride–polyvinyl chloride (PVDC-PVC) copolymer were investigated. The structure of the samples was studied by transmission electron microscopy, Fourier-transform infrared spectroscopy and Raman spectroscopy. The analyses demonstrate the [...] Read more.

Resistive sensing responses of the thin films obtained by dehydrohalogenation of polyvinylidene chloride (PVDC) and polyvinylidene chloride–polyvinyl chloride (PVDC-PVC) copolymer were investigated. The structure of the samples was studied by transmission electron microscopy, Fourier-transform infrared spectroscopy and Raman spectroscopy. The analyses demonstrate the formation of a porous structure based on polyyne–polyene chains. The formation of a foam-like oxidized sp-rich structure was observed for the samples obtained via the chemical treatment of the PVDC. However, a loose film with a developed structure and a lower fraction of sp-hybridized carbon was observed for KOH-treated PVDC-PVC. The resistive sensing responses of both of the dehydrohalogenated structures were measured for various concentrations of acetone, acetic acid, ammonia hydroxide, methanol, ethanol, benzene and water. The interplay between the efficiency of the dehydrohalogenation of the films, their structure and sensing selectivity is discussed. Full article

(This article belongs to the Section Carbon Materials and Carbon Allotropes)

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15 pages, 5946 KiB

Open AccessArticle

Diffusion Behavior of Iodine in the Micro/Nano-Porous Graphite for Nuclear Reactor at High Temperature

by Ming-Bo Qi, Peng-Fei Lian, Peng-Da Li, He-Yao Zhang, Jin-Xing Cheng, Qing-Bo Wang, Zhong-Feng Tang, T. J. Pan, Jin-Liang Song and Zhan-Jun Liu

C 2023, 9(3), 81; https://doi.org/10.3390/c9030081 - 26 Aug 2023

Cited by 2 | Viewed by 1727

Abstract

The diffusion behavior of iodine in micro/nano-porous graphite under high-temperature conditions was studied using analysis methods such as Rutherford backscattering Spectrometry, scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The results indicate that iodine diffusion leads to the Lattice Contractions in Microcrystals, a [...] Read more.

The diffusion behavior of iodine in micro/nano-porous graphite under high-temperature conditions was studied using analysis methods such as Rutherford backscattering Spectrometry, scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The results indicate that iodine diffusion leads to the Lattice Contractions in Microcrystals, a decrease in interlayer spacing, and a rise of defect density. And the reversal or repair of microstructure change was observed: the microcrystal size of the graphite increases, the interlayer spacing appears to return to the initial state, and the defect density decreases, upon diffusion of iodine out of iodine-loaded graphite. The comparative study comparing the iodine diffusion performance of nanoporous graphite (G400 and G450) between microporous graphite (G500), showed that nanoporous graphite exhibits a better barrier to the iodine diffusion. The study on the diffusion behavior of iodine in micro/nano-porous graphite holds substantial academic and engineering value for the screening, design, and performance optimization of nuclear graphite. Full article

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

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12 pages, 1093 KiB

Open AccessArticle

Carbon Capture and Storage through Upcycling of Suberinic Acid Residues in Wood Composites Finishing

by Aleksandra Jeżo and Grzegorz Kowaluk

C 2023, 9(3), 80; https://doi.org/10.3390/c9030080 - 25 Aug 2023

Cited by 4 | Viewed by 1627

Abstract

Finishing coatings used in the wood-based composite industry play a key role in the final appearance of the finished product. However, the use of such coatings is not only for aesthetic purposes, but also to protect the product against surface damage and moisture [...] Read more.

Finishing coatings used in the wood-based composite industry play a key role in the final appearance of the finished product. However, the use of such coatings is not only for aesthetic purposes, but also to protect the product against surface damage and moisture or to minimize the emission of harmful substances. The latter is an extremely important factor in terms of safety for both the manufacturer and the user, which is why the emissivity test is one of the most important tests conducted in this case. Carbon-rich materials, such as those remaining from the extraction of birch bark, can fulfill the role of minimizing the emission of harmful substances. In this article, an attempt to create coatings in the form of a film by combining a biopolymer with suberinic acid residues (SARs) was made. Two types of biopolymers were used, polylactide (PLA) and polycaprolactone (PCL), in various polymer–SAR ratios. Suberinic acid as a residue is a raw material that can potentially contribute positively to the fixing of CO₂ from the atmosphere, which creates the possibility for further use. As part of this study, the obtained coatings were tested in terms of scratch resistance, relative hardness, cold liquids, total volatile organic compounds (TVOCs), formaldehyde emission, surface absorption, etc. Differences between the polymers used and the effect of the SAR additive on selected surface properties were demonstrated. The addition of carbon-rich SAR significantly improves gas barrier properties of the PLA- and PCL-based surface finishing materials. The relative hardness and scratch resistance also increased with rising SAR content. However, the increasing content of SAR filler acts as a limiter in the depth of penetration of the deposited surface finishing materials onto the wood surface. It is possible to state that this innovative approach regarding (1) the utilization of biopolymers as a matrix, instead of conventional, crude oil-based resins, and (2) the incorporation of post-processed carbon-rich waste lignocellulosic materials to produce the surface finishing and/or protective films has been confirmed. Full article

(This article belongs to the Collection Carbon in the Circular Economy)

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12 pages, 1240 KiB

Open AccessArticle

Divergence in Antiviral Activities of Carbon Dots versus Nano-Carbon/Organic Hybrids and Implications

by Cristian E. Rodriguez, Audrey F. Adcock, Buta Singh, Subhadra Yerra, Yongan Tang, Ya-Ping Sun and Liju Yang

C 2023, 9(3), 79; https://doi.org/10.3390/c9030079 - 20 Aug 2023

Cited by 1 | Viewed by 1956

Abstract

Carbon dots (CDots) are generally defined as small carbon nanoparticles (CNPs) with effective surface passivation, for which the classical synthesis is the functionalization of pre-existing CNPs with organic molecules. However, “dot” samples produced by “one-pot” thermal carbonization of organic precursors are also popular [...] Read more.

Carbon dots (CDots) are generally defined as small carbon nanoparticles (CNPs) with effective surface passivation, for which the classical synthesis is the functionalization of pre-existing CNPs with organic molecules. However, “dot” samples produced by “one-pot” thermal carbonization of organic precursors are also popular in the literature. These carbonization-produced samples may contain nano-carbon domains embedded in organic matters from the precursors that survived the thermal processing, which may be considered and denoted as “nano-carbon/organic hybrids”. Recent experimental evidence indicated that the two different kinds of dot samples are largely divergent in their photo-induced antibacterial functions. In this work, three representative carbonization-produced samples from the precursor of citric acid–oligomeric polyethylenimine mixture with processing conditions of 200 °C for 3 h (CS200), 330 °C for 6 h (CS330), and microwave heating (CS_MT) were compared with the classically synthesized CDots on their photo-induced antiviral activities. The results suggest major divergences in the activities between the different samples. Interestingly, CS_MT also exhibited significant differences between antibacterial and antiviral activities. The mechanistic origins of the divergences were explored, with the results of different antimicrobial activities among the hybrid samples rationalized in terms of the degree of carbonization in the sample production and the different sample structural and morphological characteristics. Full article

(This article belongs to the Special Issue Carbons for Health and Environmental Protection)

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11 pages, 3656 KiB

Open AccessArticle

Diamond as Insulation for Conductive Diamond—A Spotted Pattern Design for Miniaturized Disinfection Devices

by Manuel Zulla, Vera Vierheilig, Maximilian Koch, Andreas Burkovski, Matthias Karl and Stefan Rosiwal

C 2023, 9(3), 78; https://doi.org/10.3390/c9030078 - 18 Aug 2023

Viewed by 1750

Abstract

Boron-doped diamond (BDD) electrodes are well known for the in situ production of strong oxidants. These antimicrobial agents are produced directly from water without the need of storage or stabilization. An in situ production of reactive oxygen species (ROS) used as antimicrobial agents [...] Read more.

Boron-doped diamond (BDD) electrodes are well known for the in situ production of strong oxidants. These antimicrobial agents are produced directly from water without the need of storage or stabilization. An in situ production of reactive oxygen species (ROS) used as antimicrobial agents has also been used in recently developed medical applications. Although BDD electrodes also produce ROS during water electrolysis, only a few medical applications have appeared in the literature to date. This is probably due to the difficulties in the miniaturization of BDD electrodes, while maintaining a stable and efficient electrolytic process in order to obtain a clinical applicability. In this attempt, a cannula-based electrode design was achieved by insulating the anodic diamond layer from a cathodic cannula, using a second layer of non-conducting diamond. The undoped diamond (UDD) layer was successfully grown in a spotted pattern, resulting in a perfectly insulated yet still functional BDD layer, which can operate as a miniaturized flow reactor for medical applications. The spotted pattern was achieved by introducing a partial copper layer on top of the BDD layer, which was subsequently removed after growing the undoped diamond layer via etching. The initial analytical observations showed promising results for further chemical and microbial investigations. Full article

(This article belongs to the Special Issue Carbons for Health and Environmental Protection)

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17 pages, 11571 KiB

Open AccessArticle

Effect of Cu on Performance of Self-Dispersing Ni-Catalyst in Production of Carbon Nanofibers from Ethylene

by Sofya D. Afonnikova, Yury I. Bauman, Vladimir O. Stoyanovskii, Mikhail N. Volochaev, Ilya V. Mishakov and Aleksey A. Vedyagin

C 2023, 9(3), 77; https://doi.org/10.3390/c9030077 - 14 Aug 2023

Cited by 9 | Viewed by 2210

Abstract

The development of effective catalysts for the pyrolysis of light hydrocarbons with the production of carbon nanomaterials represents a relevant direction. In the present work, the influence of copper addition on performance of a self-dispersed Ni-catalyst and structural features of the obtained carbon [...] Read more.

The development of effective catalysts for the pyrolysis of light hydrocarbons with the production of carbon nanomaterials represents a relevant direction. In the present work, the influence of copper addition on performance of a self-dispersed Ni-catalyst and structural features of the obtained carbon nanofibers (CNFs) was studied. The precursors of Ni and Ni-Cu catalysts were prepared by activation of metal powders in a planetary mill. During contact with the C₂H₄/H₂ reaction mixture, a rapid disintegration of the catalysts with the formation of active particles catalyzing the growth of CNFs has occurred. The kinetics of CNF accumulation during ethylene decomposition on Ni- and Ni-Cu catalysts was studied. The effect of temperature on catalytic performance was explored and it was shown that introduction of copper promotes 1.5–2-fold increase in CNFs yield in the range of 525–600 °C; the maximum CNFs yield (100 g/g_cat and above, for 30-min reaction) is reached on Ni-Cu-catalyst at 575–600 °C. A comparative analysis of the morphology and structure of CNF was carried out using electron microscopy methods. The growth mechanism of carbon filaments in the shape of “railway crossties” on large nickel crystals (d > 250 nm) was proposed. It was found that the addition of copper leads to a decrease in the bulk density of the carbon product from 40–60 to 25–30 g/L (at T = 550–600 °C). According to the low-temperature nitrogen adsorption data, specific surface area (SSA) of CNF samples (at T < 600 °C) lies in the range of 110–140 m²/g, regardless of the catalyst composition; at T = 600 °C the introduction of copper contributed to an increase in the specific surface of CNF by 100 m²/g. Full article

(This article belongs to the Special Issue Advanced Carbon Nanomaterials and Hybrids)

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19 pages, 738 KiB

Open AccessArticle

Effective Quantum Graph Models of Some Nonequilateral Graphyne Materials

by César R. de Oliveira and Vinícius L. Rocha

C 2023, 9(3), 76; https://doi.org/10.3390/c9030076 - 8 Aug 2023

Viewed by 1442

Abstract

It is shown that it is possible to adapt the quantum graph model of graphene to some types of nonequilateral graphynes considered in the literature; we also discuss the corresponding nanotubes. The proposed models are, in fact, effective models and are obtained through [...] Read more.

It is shown that it is possible to adapt the quantum graph model of graphene to some types of nonequilateral graphynes considered in the literature; we also discuss the corresponding nanotubes. The proposed models are, in fact, effective models and are obtained through selected boundary conditions and an ad hoc prescription. We analytically recover some results from the literature, in particular, the presence of Dirac cones for

α

-,

β

- and

(6, 6, 12)

-graphynes; for

γ

-graphyne, our model presents a band gap (according to the literature), but only for a range of parameters, with a transition at a certain point with quadratic touch and then the presence of Dirac cones. Full article

(This article belongs to the Special Issue Advances in Modelling of Size Effects in Graphene and Carbon Nanotubes)

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14 pages, 2825 KiB

Open AccessArticle

Electrical Resistance Evolution of Graphite and Talc Geological Heterostructures under Progressive Metamorphism

by Augusto Gonçalves Nobre, Fabio Ramos Dias de Andrade, Andres Fabian Salazar-Naranjo, Josue Neroti Rigue, Ricardo Barreto da Silva, Silvio Roberto Farias Vlach and Romulo Augusto Ando

C 2023, 9(3), 75; https://doi.org/10.3390/c9030075 - 30 Jul 2023

Cited by 2 | Viewed by 1926

Abstract

The electrical properties of isolated graphene established precedents for studies of electrical superconducting materials at room temperature. After the discovery of stabilized graphene and graphite nanoplatelets in a geological context, the interest in characterizing the properties of these minerals arose. This work evaluates [...] Read more.

The electrical properties of isolated graphene established precedents for studies of electrical superconducting materials at room temperature. After the discovery of stabilized graphene and graphite nanoplatelets in a geological context, the interest in characterizing the properties of these minerals arose. This work evaluates the electrical resistance evolution of mineral graphite and talc heterostructures under progressive metamorphism simulated in the laboratory. The experiments were conducted on an end-loaded piston-cylinder apparatus. This equipment allows for the application of equal pressure in all sample directions (lithostatic pressure) and heating, simulating geological phenomena. The behavior of two sets of mineral samples were compared: graphite and talc in billets and powder. Samples in billets were submitted to treatments at 400 °C and 4 kbar; 400 °C and 6 kbar; and 700 °C and 9 kbar. The powder samples were subjected to 700 °C and 9 kbar, with two ways of disposing the mineral powders (mixed and in adjacent contact) beyond 900 °C and 9 kbar (in adjacent contact). The results show that the samples in billets had lower electrical resistance when compared to the powder samples. The lowest electrical resistance was observed in the sample treated at 400 °C and 6 kbar, conditions that are consistent with metamorphic mineral assemblage observed in the field. Powdered samples showed better cleavage efficiency during the experiment, resulting in thinner flakes and even graphene, as pointed out by Raman spectroscopy. However, these flakes were not communicating, which resulted in high electrical resistance, due to the need for an electrical current to pass through the talc, resulting in a Joule effect. The maximum electrical resistance obtained in the experiment was obtained in the sample submitted to 900 °C, in which talc decomposed into other mineral phases that were even more electrically insulating. This work demonstrates that electrical resistance prospecting can be an efficient tool to identify potential target rocks with preserved mineral nanometric heterostructures that can form an important raw material for the nanotechnology industry. Full article

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

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8 pages, 5356 KiB

Open AccessArticle

Graphene Oxide Membranes: Controlled Laser Reduction for Sensing Applications

by Aiden Rowley, Yijing Stehle, Luke Kilby and Caleb Bashant

C 2023, 9(3), 74; https://doi.org/10.3390/c9030074 - 30 Jul 2023

Cited by 1 | Viewed by 1753

Abstract

Reduced graphene oxide (rGO) has attracted attention as an active electrode material for flexible electrochemical devices due to its high electric conductivity and large surface area. Compared to other reduction processes, laser reduction is a precise, low-cost, and chemical-free process that is directly [...] Read more.

Reduced graphene oxide (rGO) has attracted attention as an active electrode material for flexible electrochemical devices due to its high electric conductivity and large surface area. Compared to other reduction processes, laser reduction is a precise, low-cost, and chemical-free process that is directly applied to graphene oxide (GO) membranes. This study aims to develop rGO through laser irradiation for application as electrodes in thin flexible electrochemical sensors. Laser irradiation parameters will be optimized to achieve reduction of a low oxygen to carbon (O/C) ratio and surface impedance. The influence of humidity on the impedance of rGO electrodes will be studied. The observed instability of the rGO electrode is related to incomplete reduction and oxygenated defects involved in reduction. Partially removed oxygenated functional groups not only influence the impedance of the electrode but make it sensitive to the humidity of the working environment. The result provides references for GO’s laser reduction optimization, demonstrates the potential of applying rGO as an electrode in sensing applications, but also reveals the limitation of applying the laser reduced rGO electrode in a non-constant humidity environment. Full article

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

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17 pages, 9700 KiB

Open AccessArticle

Graphene Oxide: A Comparison of Reduction Methods

by Natália Garrote de Barros, Abel Cardoso Gonzaga Neto, Kleber Bitencourt Vaccioli, Hugo Rafael Vallejo Angulo, Leonardo Gondim de Andrade e Silva, Samuel Marcio Toffoli and Ticiane Sanches Valera

C 2023, 9(3), 73; https://doi.org/10.3390/c9030073 - 27 Jul 2023

Cited by 9 | Viewed by 4207

Abstract

This paper presents a comparison of traditional thermal and chemical reduction methods with more recent ionizing radiation reduction via gamma rays and electron beams (e-beams). For GO, all synthesis protocols were adapted to increase production scale and are a contribution of this work. [...] Read more.

This paper presents a comparison of traditional thermal and chemical reduction methods with more recent ionizing radiation reduction via gamma rays and electron beams (e-beams). For GO, all synthesis protocols were adapted to increase production scale and are a contribution of this work. The typical Raman D-band of the GO was prominent (I_D/I_G ratio increased sixfold). When comparing the GO reduction techniques, dramatic differences in efficiency and GO particle characteristics were observed. Although thermal and chemical reduction are effective reduction methods, as shown through the use of FTIR spectroscopy and the C/O ratio from EDS chemical analysis, the thermal process renders great weight losses, whereas chemical processing may involve the use of hazardous chemical compounds. On the other hand, comparing the gamma rays and e-beam for 80 kGy, the Raman spectra and chemical analysis suggested that the e-beam caused a greater GO reduction: C/O ratio from EDS of 5.4 and 4.1, respectively. In addition to being fast and effective, ionizing radiation reduction processes allow easier control of the reduction degree by adjusting the radiation dose. When the dose increased from 40 to 80 kGy, the Raman spectra and EDS showed that the I_D/I_G and C/O ratios increased by 15 and 116%, respectively. Full article

(This article belongs to the Special Issue Advanced in Low Dimensional Carbon: Processing and Applications)

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21 pages, 759 KiB

Open AccessReview

Activated Carbon for Sepsis Prevention and Intervention: A Modern Way of Utilizing Old Therapies

by Elisaveta Snezhkova, Heinz Redl, Johannes Grillari and Marcin Osuchowski

C 2023, 9(3), 72; https://doi.org/10.3390/c9030072 - 25 Jul 2023

Cited by 1 | Viewed by 5632

Abstract

(1) Background: Uncontrolled inflammation often contributes to life-threatening sepsis sequela such as multi-organ dysfunction syndrome (MODS), and is accompanied by abnormal levels of pathological and damage-associated molecular patterns (PAMPs & DAMPs) in biological fluids. Activated carbon or charcoal (AC) of new generation with [...] Read more.

(1) Background: Uncontrolled inflammation often contributes to life-threatening sepsis sequela such as multi-organ dysfunction syndrome (MODS), and is accompanied by abnormal levels of pathological and damage-associated molecular patterns (PAMPs & DAMPs) in biological fluids. Activated carbon or charcoal (AC) of new generation with ameliorated biocompatibility has spurred renewed interest in the regulation of these toxins’ levels in inflammation states. (2) Methods: We searched PubMed, Google Scholar, ScienceDirect, Researchgate, and other sources for the relevant literature from 1550 B.C. till 2022 A.C. (3) Results: Laboratory and clinical investigations demonstrate that activated carbon or charcoal (AC) mitigates inflammation in different pathological states when applied orally, per rectum, or in a hemoperfusion system. AC protects the microbiome and bone marrow, acts as an anti-inflammatory and anti-oxidant remedy, and recovers the plasmatic albumin structure. The mechanism of AC action is related to a non-selective (broad-range) or/and selective adsorption of PAMPs & DAMPs from biological fluids. A high-adsorptive capacity towards noxious substances and application of AC as early as possible seems paramount in inflammation treatment for preventing sepsis and/or multi-organ failure. (4) Conclusion: AC could be considered an adjunctive treatment for preventing sepsis and/or multi-organ failure. Full article

(This article belongs to the Special Issue Carbons for Health and Environmental Protection)

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21 pages, 2874 KiB

Open AccessArticle

Adsorption of Cobalt and Strontium Ions on Plant-Derived Activated Carbons: The Suggested Mechanisms

by Irina Ceban (Ginsari), Tudor Lupascu, Sergey Mikhalovsky and Raisa Nastas

C 2023, 9(3), 71; https://doi.org/10.3390/c9030071 - 21 Jul 2023

Cited by 3 | Viewed by 2318

Abstract

In this study, activated carbons derived from walnut shells (CA-N) and apple wood (CA-M) were used as adsorbents to remove cobalt(II) and strontium(II) ions from aqueous solutions. The novel materials were obtained using nitric acid (CA-Mox) and nitric acid/urea mixture (CA-Mox-u, CA-Nox-u) as [...] Read more.

In this study, activated carbons derived from walnut shells (CA-N) and apple wood (CA-M) were used as adsorbents to remove cobalt(II) and strontium(II) ions from aqueous solutions. The novel materials were obtained using nitric acid (CA-Mox) and nitric acid/urea mixture (CA-Mox-u, CA-Nox-u) as oxidizing agents. The physical–chemical characteristics of activated carbons were determined from nitrogen sorption isotherms, SEM-EDX, FTIR, pH metric titrations, the Boehm titration method and elemental analysis. The results of batch experiments indicate that maximum adsorption can be achieved in broad pH ranges: 4–8 for Co(II) and 4–10 for Sr(II). The maximum adsorption capacities of Co(II) and Sr(II) on oxidized activated carbons at pH = 4 are: CA-Mox, 0.085 and 0.076 mmol/g; CA-Mox-u, 0.056 and 0.041 mmol/g; and CA-Nox-u, 0.041 and 0.034 mmol/g, respectively. The mathematical models (pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models, and Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin–Pyzhev isotherm models) were used to explain the adsorption kinetics, to study the adsorption mechanism and predict maximum adsorption capacity of the adsorbents. The adsorption mechanisms of toxic metal ions on activated carbons were proposed. Full article

(This article belongs to the Special Issue Carbons for Health and Environmental Protection)

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33 pages, 4123 KiB

Open AccessReview

Recent Advancements in Applications of Graphene to Attain Next-Level Solar Cells

by Sonal Santosh Bagade, Shashidhar Patel, M. M. Malik and Piyush K. Patel

C 2023, 9(3), 70; https://doi.org/10.3390/c9030070 - 19 Jul 2023

Cited by 10 | Viewed by 4859

Abstract

This paper presents an intensive review covering all the versatile applications of graphene and its derivatives in solar photovoltaic technology. To understand the internal working mechanism for the attainment of highly efficient graphene-based solar cells, graphene’s parameters of control, namely its number of [...] Read more.

This paper presents an intensive review covering all the versatile applications of graphene and its derivatives in solar photovoltaic technology. To understand the internal working mechanism for the attainment of highly efficient graphene-based solar cells, graphene’s parameters of control, namely its number of layers and doping concentration are thoroughly discussed. The popular graphene synthesis techniques are studied. A detailed review of various possible applications of utilizing graphene’s attractive properties in solar cell technology is conducted. This paper clearly mentions its applications as an efficient transparent conducting electrode, photoactive layer and Schottky junction formation. The paper also covers advancements in the 10 different types of solar cell technologies caused by the incorporation of graphene and its derivatives in solar cell architecture. Graphene-based solar cells are observed to outperform those solar cells with the same configuration but lacking the presence of graphene in them. Various roles that graphene efficiently performs in the individual type of solar cell technology are also explored. Moreover, bi-layer (and sometimes, tri-layer) graphene is shown to have the potential to fairly uplift the solar cell performance appreciably as well as impart maximum stability to solar cells as compared to multi-layered graphene. The current challenges concerning graphene-based solar cells along with the various strategies adopted to resolve the issues are also mentioned. Hence, graphene and its derivatives are demonstrated to provide a viable path towards light-weight, flexible, cost-friendly, eco-friendly, stable and highly efficient solar cell technology. Full article

(This article belongs to the Special Issue Advances in Bilayer Graphene)

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14 pages, 2077 KiB

Open AccessArticle

The Complex Case of Carbon-Measuring Tools in Landscape Architecture

by Anastasia Nikologianni and Alex Albans

C 2023, 9(3), 69; https://doi.org/10.3390/c9030069 - 12 Jul 2023

Cited by 1 | Viewed by 2528

Abstract

As the world takes a more strategic approach to the climate crisis, carbon in its various forms has become a key factor in ascertaining the sustainability of the landscape. Landscape has been recognised as a resource and mechanism for addressing the role of [...] Read more.

As the world takes a more strategic approach to the climate crisis, carbon in its various forms has become a key factor in ascertaining the sustainability of the landscape. Landscape has been recognised as a resource and mechanism for addressing the role of carbon in the environment, with literature focused on the landscape’s carbon capacity as interconnected systems of land, soil, water and organic life. It has, however, largely neglected the crucial role of the cultural, social and historical aspects of the landscape, particularly at the level of design. This paper acknowledges and explores the complexity of landscape as a natural-cultural system with the consequent difficulties this poses in legislating, calculating and measuring carbon for global, national and local targets for low/zero carbon and carbon offsetting. The discussion takes place in the arena of landscape architecture at regional/city/local scales and the life-cycle of a project including its integration into its wider social, cultural and environmental setting. This paper develops the discourse in three major areas: first, by examining how the complexity of landscape is obscured in the context of carbon-measuring tools used in landscape architecture; secondly exploring one such tool in practice to demonstrate how site-specific design decisions can impact carbon levels; and third by proposing how an integrated understanding of landscape can be built into projects to embrace complexity and operationalise low carbon visions. Full article

(This article belongs to the Section Carbon Cycle, Capture and Storage)

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16 pages, 6377 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effect of Carbon Nanoparticles on the Porous Texture of ι-Carrageenan-Based N-Doped Nanostructured Porous Carbons and Implications for Gas Phase Applications

by Samantha K. Samaniego Andrade, Alfréd Menyhárd, Szilvia Klébert, Miklós Mohai, Balázs Nagy and Krisztina László

C 2023, 9(3), 68; https://doi.org/10.3390/c9030068 - 12 Jul 2023

Cited by 2 | Viewed by 2051

Abstract

S and N double-doped high surface area biomass-derived carbons were obtained from marine biomass-derived ι-carrageenan. Adding carbon nanoparticles (CNPs), namely graphene oxide (GO) or carbon nanotubes (CNTs), in the early stage of the synthesis leads to a modified porous texture and surface chemistry. [...] Read more.

S and N double-doped high surface area biomass-derived carbons were obtained from marine biomass-derived ι-carrageenan. Adding carbon nanoparticles (CNPs), namely graphene oxide (GO) or carbon nanotubes (CNTs), in the early stage of the synthesis leads to a modified porous texture and surface chemistry. The porous textures were characterized by N₂ (−196.15 °C) and CO₂ (0 °C) isotherms. The best GO- and CNT-added carbons had an apparent surface area of 1780 m²/g and 1170 m²/g, respectively, compared to 1070 m²/g for the CNP-free matrix. Analysis of the Raman spectra revealed that CNT was more efficient in introducing new defects than GO. Based on XPS, the carbon samples contain 2–4.5 at% nitrogen and 1.1 at% sulfur. The Dubinin–Radushkevich (DR) and Henry models were used to assess the strength of the interactions between various gases and the surface. The N₂/H₂ and CO₂/CH₄ selectivities were estimated with ideal adsorbed solution theory (IAST). While the CNPs, particularly GO, had a remarkable influence on the porous texture and affected the surface chemistry, their influence on the separation selectivity of these gases was more modest. Full article

(This article belongs to the Special Issue Carbons for Health and Environmental Protection)

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30 pages, 2689 KiB

Open AccessReview

Biochar for Soil Carbon Sequestration: Current Knowledge, Mechanisms, and Future Perspectives

by Simeng Li and Desarae Tasnady

C 2023, 9(3), 67; https://doi.org/10.3390/c9030067 - 7 Jul 2023

Cited by 39 | Viewed by 14954

Abstract

Biochar, a sustainable solid material derived from biomass pyrolysis enriched in carbon, has emerged as a promising solution for soil carbon sequestration. This comprehensive review analyzes the current knowledge on biochar’s application in this context. It begins by examining biochar properties and production [...] Read more.

Biochar, a sustainable solid material derived from biomass pyrolysis enriched in carbon, has emerged as a promising solution for soil carbon sequestration. This comprehensive review analyzes the current knowledge on biochar’s application in this context. It begins by examining biochar properties and production methods, highlighting its recalcitrant nature as a potential stable carbon sink. The influence of various feedstocks and pyrolysis conditions on various physicochemical properties of biochar and its soil carbon sequestration potential is explored. Mechanisms through which biochar enhances soil carbon sequestration are discussed, including its role as a physical barrier against carbon loss and its ability to promote stable soil aggregates and influence soil microorganisms. Challenges and limitations, such as variations in biochar properties and optimal application rates, are addressed, along with strategies for maximizing biochar effectiveness through amendments. The review concludes by emphasizing the importance of long-term field studies, standardized protocols, and economic assessments to support the widespread adoption of biochar for soil carbon sequestration and its potential in climate change mitigation. Full article

(This article belongs to the Special Issue Carbons for Health and Environmental Protection)

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12 pages, 932 KiB

Open AccessArticle

Factors Affecting the Formation the Carbon Structure of Coke and the Method of Stabilizing Its Physical and Mechanical Properties

by Denis Miroshnichenko, Kateryna Shmeltser and Maryna Kormer

C 2023, 9(3), 66; https://doi.org/10.3390/c9030066 - 5 Jul 2023

Cited by 7 | Viewed by 2123

Abstract

The raw materials (coals different stages of metamorphism) and technological factors (period and temperature) of the coke-making that determine the carbon structure of blast furnace coke, and its physical and mechanical properties are analyzed. The change granulometric composition of the coke as a [...] Read more.

The raw materials (coals different stages of metamorphism) and technological factors (period and temperature) of the coke-making that determine the carbon structure of blast furnace coke, and its physical and mechanical properties are analyzed. The change granulometric composition of the coke as a function of the coal batch properties is described in detail. The installation determines the possibility of influencing the carbon structure of coke, its granulometric composition in its production in order to increase the yields of the most valuable fractions, and improving its quality characteristics to achieve high-performance blast furnaces. Analysis of the results indicates that, with no changes in the coking conditions, the granulometric composition depends significantly on the ash content and packing density of the coal batch. Research has shown that the petrographic composition of the coal batch also affects the structure and size of the coke. The closest relationship is established between the magnitude of the fusinized components ΣFC and the output of the coke fractions 80–60 mm, 40–25 mm, and <25 mm. The method of mechanical treatment and stabilizing of blast furnace coke is proposed, which includes the improvement of the initial indexes of its quality M₂₅, M₁₀, and class >80 mm in continuous or periodically working open or closed industrial cylindrical oblique stabilizer drum. Full article

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23 pages, 3344 KiB

Open AccessArticle

Evaluation and Optimization of Tour Method for Synthesis of Graphite Oxide with High Specific Surface Area

by Hanna Bukovska, Fernando García-Perez, Natalia Brea Núñez, Laura J. Bonales, Andrés Velasco, M. Ángeles Clavero, Javier Martínez, Alberto J. Quejido, Isabel Rucandio and M. Belén Gómez-Mancebo

C 2023, 9(3), 65; https://doi.org/10.3390/c9030065 - 5 Jul 2023

Cited by 3 | Viewed by 3194

Abstract

Many of the graphene-based structures exhibit an adsorption capacity due to their high specific surface area (SSA) and micropore volume. This capacity makes them competent materials for applications in energy and environmental sectors where efficiency is highly dependent on these properties for applications, [...] Read more.

Many of the graphene-based structures exhibit an adsorption capacity due to their high specific surface area (SSA) and micropore volume. This capacity makes them competent materials for applications in energy and environmental sectors where efficiency is highly dependent on these properties for applications, such as water decontamination, solar cells or energy storage. The aim of this work is to study graphene-related materials (GRM) for applications where a high SSA is a requirement, considering the ideal SSA of graphene ≅ 2600 m²g⁻¹. For the synthesis of most of the GRMs, some oxidation method such as the Tour method is used to oxidize graphite to graphite oxide (GrO) as an initial step. Our work studies the optimization of this initial step to evaluate the best conditions to obtain GrO with the maximum possible SSA. The different parameters influencing the process have been evaluated and optimized by applying an experimental design (ED). The resulting materials have been characterized by Brunauer–Emmett–Teller (BET), elemental analysis (EA), X-ray diffraction (XRD) and Raman and scanning electron microscopy (SEM). The evaluation of the results shows a maximum SSA of GrO of 67.04 m²g⁻¹ for a temperature of 60 °C, a time of 12 h, a H₂O₂ volume of 50 mL and 4 g of KMnO₄. Full article

(This article belongs to the Special Issue Adsorption on Carbon-Based Materials)

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17 pages, 1005 KiB

Open AccessArticle

Casimir–Polder Force on Atoms or Nanoparticles from Gapped and Doped Graphene: Asymptotic Behavior at Large Separations

by Galina L. Klimchitskaya and Vladimir M. Mostepanenko

C 2023, 9(3), 64; https://doi.org/10.3390/c9030064 - 4 Jul 2023

Cited by 1 | Viewed by 1446

Abstract

The Casimir–Polder force acting on atoms and nanoparticles spaced at large separations from real graphene sheets possessing some energy gaps and chemical potentials is investigated in the framework of the Lifshitz theory. The reflection coefficients expressed via the polarization tensor of graphene, found [...] Read more.

The Casimir–Polder force acting on atoms and nanoparticles spaced at large separations from real graphene sheets possessing some energy gaps and chemical potentials is investigated in the framework of the Lifshitz theory. The reflection coefficients expressed via the polarization tensor of graphene, found based on the first principles of thermal quantum field theory, are used. It is shown that for graphene the separation distances, starting from which the zero-frequency term of the Lifshitz formula contributes more than 99% of the total Casimir–Polder force, are less than the standard thermal length. According to our results, however, the classical limit for graphene, where the force becomes independent of the Planck constant, may be reached at much larger separations than the limit of the large separations determined by the zero-frequency term of the Lifshitz formula, depending on the values of the energy gap and chemical potential. The analytic asymptotic expressions for the zero-frequency term of the Lifshitz formula at large separations are derived. These asymptotic expressions agree up to 1% with the results of numerical computations starting from some separation distances that increase with increasing energy gaps and decrease with increasing chemical potentials. The possible applications of the obtained results are discussed. Full article

(This article belongs to the Special Issue Advances in Modelling of Size Effects in Graphene and Carbon Nanotubes)

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11 pages, 2110 KiB

Open AccessArticle

RF Sensor with Graphene Film for HRP Concentration Detection

by Fabio Peinetti, Muhammad Yasir and Patrizia Savi

C 2023, 9(3), 63; https://doi.org/10.3390/c9030063 - 23 Jun 2023

Cited by 1 | Viewed by 1706

Abstract

This paper presents a radio-frequency (RF) antenna as a sensor to detect Horseradish peroxidase (HRP). At the core of the proposed approach is a graphene film deposited on a stub connected to an RF antenna. The graphene film is doctor bladed on the [...] Read more.

This paper presents a radio-frequency (RF) antenna as a sensor to detect Horseradish peroxidase (HRP). At the core of the proposed approach is a graphene film deposited on a stub connected to an RF antenna. The graphene film is doctor bladed on the stub. The film is then properly chemically functionalized in order to detect the presence of Horseradish peroxidase (HRP). We validate the proof-of-concept operation of HRP concentration detection by measuring the frequency shift of the reflection coefficient of the antenna using very small concentration of HRP (

0.03

mM to

0.6

mM). Full article

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

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10 pages, 3170 KiB

Open AccessArticle

Single-Bilayer Graphene Test Structures for Kelvin Probe Microscopy

by Sergey P. Lebedev, Ilya A. Eliseyev, Mikhail S. Dunaevskiy, Ekaterina V. Gushchina and Alexander A. Lebedev

C 2023, 9(3), 62; https://doi.org/10.3390/c9030062 - 21 Jun 2023

Viewed by 1410

Abstract

A new technique for determining the point spread function, which is required for measuring the surface potential using Kelvin probe microscopy (KPM), is presented. The method involves using a silicon carbide substrate coated with single-layer and bilayer graphene as a test structure and [...] Read more.

A new technique for determining the point spread function, which is required for measuring the surface potential using Kelvin probe microscopy (KPM), is presented. The method involves using a silicon carbide substrate coated with single-layer and bilayer graphene as a test structure and obtaining KPM potential profiles in different directions on the surface. This makes it possible to determine the KPM point spread function, which can be used to perform deconvolution and accurately recover the surface potential. Full article

(This article belongs to the Special Issue Advances in Modelling of Size Effects in Graphene and Carbon Nanotubes)

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C, Volume 9, Issue 3 (September 2023) – 27 articles

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