C | An Open Access Journal from MDPI

14 pages, 8360 KB

Open AccessReview

Structural Models of Non-Graphitising Carbon: A Brief History

by Peter J. F. Harris

C 2025, 11(4), 78; https://doi.org/10.3390/c11040078 - 14 Oct 2025

Non-graphitising carbons are an important class of solid carbon materials which cannot be transformed into graphite by heat treatment, even at 3000 °C. Also known as hard carbons, they are of growing importance as anode materials for lithium-ion or sodium-ion batteries. When activated [...] Read more.

Non-graphitising carbons are an important class of solid carbon materials which cannot be transformed into graphite by heat treatment, even at 3000 °C. Also known as hard carbons, they are of growing importance as anode materials for lithium-ion or sodium-ion batteries. When activated they are widely used in the purification of air and water supplies. However, despite decades of research, the detailed atomic structures of these materials has still not been fully established. Many structural models have been put forward, beginning with the classic work of Rosalind Franklin, but none have gained universal acceptance. This review gives a historical survey of models for the structure of non-graphitising carbons and summarizes the latest thinking on the subject, which is based on the idea that the structure contains non-hexagonal rings, as in the fullerenes and fullerene-related structures. Studies using aberration-corrected transmission electron microscopy have provided important support for this idea. Full article

(This article belongs to the Special Issue 10th Anniversary of C — Journal of Carbon Research)

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15 pages, 3266 KB

Open AccessArticle

Nano-Functionalized Magnetic Carbon Composite for Purification of Man-Made Polluted Waters

by Tetyana I. Melnychenko, Vadim M. Kadoshnikov, Oksana M. Arkhipenko, Tetiana I. Nosenko, Iryna V. Mashkina, Lyudmila A. Odukalets, Sergey V. Mikhalovsky and Yuriy L. Zabulonov

C 2025, 11(4), 77; https://doi.org/10.3390/c11040077 - 13 Oct 2025

Abstract

Among the main man-made water pollutants that pose a danger to the environment are oil products, heavy metals, and radionuclides, as well as micro- and nanoplastics. To purify such waters, it is necessary to use advanced methods, with sorption being one of them. [...] Read more.

Among the main man-made water pollutants that pose a danger to the environment are oil products, heavy metals, and radionuclides, as well as micro- and nanoplastics. To purify such waters, it is necessary to use advanced methods, with sorption being one of them. The aim of this work is to develop a nano-functionalized composite, comprising magnetically responsive, thermally expanded graphite (TEG) and the natural clay bentonite, and to assess its ability to purify man-made contaminated waters. Throughout the course of the research, the methods of scanning electron microscopy, optical microscopy, dynamic light scattering, radiometry, and atomic absorption spectrophotometry were used. The use of the TEG–bentonite composite for the purification of the model water, simulating radioactively contaminated nuclear power plant (NPP) effluent, reduced the content of organic substances by 10–15 times, and the degree of extraction of cesium, strontium, cobalt, and manganese was between 81.4% and 98.8%. The use of the TEG–bentonite composite for the purification of real radioactively contaminated water obtained from the object “Shelter” (“Ukryttya” in Ukrainian), in the Chernobyl Exclusion Zone, Ukraine, with high activity, containing organic substances, including micro- and nanoplastics, reduced the radioactivity by three orders of magnitude. The use of cesium-selective sorbents for additional purification of the filtrate allowed for further decontamination of radioactively contaminated water with an efficiency of 99.99%. Full article

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

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33 pages, 5484 KB

Open AccessArticle

Comparative Study of Graphite Exfoliation Techniques Using Nafion as a Surfactant

by Anna O. Krasnova, Nadezhda V. Glebova, Andrey A. Nechitailov, Angelina G. Kastsova, Anna O. Pelageikina, Demid A. Kirilenko, Alexander V. Shvidchenko, Mikhail S. Shestakov, Aleksandra V. Koroleva and Ekaterina K. Khrapova

C 2025, 11(4), 76; https://doi.org/10.3390/c11040076 - 9 Oct 2025

Abstract

This work presents a comparative study of graphene exfoliation technologies from various graphite precursors—spectral graphite and thermally expanded graphite (Graflex)—using ultrasonic treatment and electrochemical methods in the presence of the ionic surfactant Nafion. The influence of exfoliation parameters, the nature of the starting [...] Read more.

This work presents a comparative study of graphene exfoliation technologies from various graphite precursors—spectral graphite and thermally expanded graphite (Graflex)—using ultrasonic treatment and electrochemical methods in the presence of the ionic surfactant Nafion. The influence of exfoliation parameters, the nature of the starting material, and the presence of surfactant additives on the morphology, dispersibility, stability, and structural characteristics of the resulting graphene-containing dispersions was investigated. Particular attention is paid to a two-step technology combining pulsed electrochemical exfoliation with subsequent mild ultrasonic treatment. Comprehensive characterization of the samples was carried out using UV–Vis spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), electron microscopy, electron diffraction (ED), dynamic light scattering (DLS), and X-ray photoelectron spectroscopy (XPS). It was found that the use of Nafion significantly enhances exfoliation efficiency and contributes to the stabilization of the dispersions. Graphene sheets obtained from Graflex exhibit significantly larger lateral dimensions (up to 1 μm or more) compared to those exfoliated from spectral graphite (100–300 nm). The approach combining the use of Graflex and pulsed electrochemical exfoliation in the presence of Nafion with subsequent low-power ultrasonic treatment enables the production of few-layer graphene (1–3 layers) with high stability. Full article

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

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18 pages, 3642 KB

Open AccessArticle

Enhanced Removal of Photosensitive Antibiotics in Water Using CO₂: A Beneficial Exploration of CO₂ Resource Utilization

by Miaomiao Ye, Jingqiu Wu, Qiuyuan Weng, Tengchao Bi and Xiaowei Liu

C 2025, 11(4), 75; https://doi.org/10.3390/c11040075 - 9 Oct 2025

Abstract

The utilization of carbon dioxide (CO₂) offers an effective approach for alleviating the carbon-reduction pressures associated with fossil energy consumption. However, studies on the use of CO₂ as an auxiliary agent in water treatment to enhance the removal of emerging [...] Read more.

The utilization of carbon dioxide (CO₂) offers an effective approach for alleviating the carbon-reduction pressures associated with fossil energy consumption. However, studies on the use of CO₂ as an auxiliary agent in water treatment to enhance the removal of emerging contaminants are limited. In this study, the photodegradation of ciprofloxacin (CIP) was investigated using ultraviolet (UV) irradiation combined with CO₂ dosing (UV/CO₂). The results demonstrated that the UV/CO₂ system effectively degraded CIP, with CO₂ concentration and solution pH exerting a critical influence. Inorganic anions and metal cations had negligible effects on CIP degradation efficiency, whereas natural organic matter (NOM) had a pronounced inhibitory effect. Mechanistic analysis revealed that superoxide radicals (

\cdot O_{2}^{-}

) and carbonate radicals (

{CO}_{3}^{• -}

) were the primary oxidizing species, whereas the excited triplet state of CIP (³CIP*) and singlet oxygen played crucial roles in initiating radical generation. LC–MS analysis and density functional theory calculations indicated that the main degradation routes involved defluorination, decarboxylation, and epoxidation of the piperazine ring. Toxicity assessment indicated that the transformation products generated by UV/CO₂ were less toxic than the parent compound. Furthermore, the UV/CO₂ process demonstrated high energy efficiency, with a low electrical energy per order (EEO) value of 0.4193 kWh·m⁻³·order⁻¹. These findings suggest that the UV/CO₂ system is a promising alternative for the treatment of photosensitive organic pollutants and provides a beneficial pathway for CO₂ utilization. Full article

(This article belongs to the Section CO₂ Utilization and Conversion)

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15 pages, 5399 KB

Open AccessArticle

Spatially Controlled Plasma Jet Synthesis of Carbyne Encapsulated in Carbon Nanotubes

by Oleg A. Streletskiy, Ilya A. Zavidovskiy, Vladimir A. Baidak, Anatoly S. Pashchina, Abdusame A. Khaidarov and Vladimir L. Bychkov

C 2025, 11(4), 74; https://doi.org/10.3390/c11040074 - 9 Oct 2025

Abstract

Carbyne, a linear chain of carbon atoms, possesses extraordinary properties but has remained elusive due to its extreme instability. While encapsulation within carbon nanotubes stabilizes carbyne, a lack of synthetic control over its location has prevented practical use. Here, we introduce a spatially [...] Read more.

Carbyne, a linear chain of carbon atoms, possesses extraordinary properties but has remained elusive due to its extreme instability. While encapsulation within carbon nanotubes stabilizes carbyne, a lack of synthetic control over its location has prevented practical use. Here, we introduce a spatially localized plasma jet technique that enables the guided spatially selective self-assembly of carbyne encapsulated within multiwalled carbon nanotube (carbyne@MWCNT) hybrids on graphite surfaces. This method uses intense, localized plasma energy to simultaneously grow nanotubes and synthesize carbyne within them, where the nanotube structure and carbyne encapsulation are governed by the localized heat flux distribution. Beyond confirming carbyne formation via its characteristic Raman mode, we discover its second-order vibrational spectrum, confirming anharmonic interactions between the chain and its nanotube container. This spatial control can be used to architect functional carbyne@MWCNT arrays, whose potential applications are discussed in detail. Full article

(This article belongs to the Special Issue Micro/Nanofabrication of Carbon-Based Devices and Their Applications)

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11 pages, 1486 KB

Open AccessArticle

Study of the Iodine Fixation over High Surface Area Graphite (HSAG-100) Under Mild Conditions

by Angel Maroto-Valiente, Carla A. Blanco-Camus, Ana I. Mártir Bueno, Elena M. Mesa-Bribián and Jesús Alvarez-Rodríguez

C 2025, 11(4), 73; https://doi.org/10.3390/c11040073 - 30 Sep 2025

Abstract

The controlled incorporation of halogens into carbon materials remains a challenge, particularly under mild and scalable conditions. In this work, we investigate the fixation of iodine on high-surface-area graphite (HSAG-100) using green solvents and moderate temperatures. Commercial HSAG was treated with iodine in [...] Read more.

The controlled incorporation of halogens into carbon materials remains a challenge, particularly under mild and scalable conditions. In this work, we investigate the fixation of iodine on high-surface-area graphite (HSAG-100) using green solvents and moderate temperatures. Commercial HSAG was treated with iodine in aqueous and in organic media, with and without promoters, and characterized by XPS, LEIS, N₂ physisorption, TGA/TPD, and XRD. The results reveal that iodine contents up to ~0.6 at% can be achieved, with incorporation strongly influenced by solvent and reaction time. XPS and LEIS confirmed the presence of C–I bonds, while BET analysis showed only moderate decreases in surface area and unchanged mesopore size distribution. Thermogravimetric and TPD analyses demonstrated the high thermal stability of C–I species, and XRD patterns ruled out intercalation between graphene layers. Collectively, these findings demonstrate that iodine can be covalently anchored to HSAG under mild conditions, preserving the graphitic structure and generating stable edge functionalities, thus opening a route for the design of halogen-doped carbons for catalytic and electrochemical applications. Full article

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

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20 pages, 21513 KB

Open AccessArticle

Tribological Properties and Wear Mechanisms of Carbide-Bonded Graphene Coating on Silicon Substrate

by Xiaomeng Zhu, Xiaojun Liu, Lihua Li, Kun Liu and Jian Zhou

C 2025, 11(3), 72; https://doi.org/10.3390/c11030072 - 15 Sep 2025

Abstract

Carbide-bonded graphene (CBG) coating, with its unique 3D cross-linked network structure, shows significant potential for protecting silicon substrates. However, a comprehensive understanding of its macroscale tribological properties remains lacking. This study investigated the macroscale friction and wear behaviors of CBG-coated silicon wafers using [...] Read more.

Carbide-bonded graphene (CBG) coating, with its unique 3D cross-linked network structure, shows significant potential for protecting silicon substrates. However, a comprehensive understanding of its macroscale tribological properties remains lacking. This study investigated the macroscale friction and wear behaviors of CBG-coated silicon wafers using reciprocating sliding tests against steel balls under various loads and sliding cycles. The CBG coating exhibited excellent friction-reduction and anti-wear performance, reducing the steady friction coefficient from 0.80 to 0.17 and wear rate by an order of magnitude compared to those of bare silicon. Higher loads slightly decreased both friction coefficients and wear rates, primarily due to the formation of denser tribofilms and transfer layers. Re-running experiments revealed three distinct wear stages—adhesive, abrasive, and accelerated substrate wear—driven by the evolution of tribofilms, transfer layers, and unabraded flat areas. Furthermore, comparative experiments confirmed that these “unabraded flat areas” on the wear track play a critical role in sustaining low friction and prolonging coating life. The findings identify CBG as a robust solid lubricant for high-contact-pressure applications and emphasize the influence of tribo-layer dynamics and wear debris behavior on coating performance. Full article

(This article belongs to the Topic Application of Graphene-Based Materials, 2nd Edition)

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12 pages, 5425 KB

Open AccessArticle

Effect of Carbon Fixation Time on the Properties of Gangue–Fly Ash Composite Filling Materials: Carbon Fixation Amount and Rheological Properties

by Haiquan Liu, Qiang Guo, Yong Chen, Yifan Zhang, Binbin Huo and Meng Li

C 2025, 11(3), 71; https://doi.org/10.3390/c11030071 - 8 Sep 2025

Abstract

Coal-based solid wastes are used for carbon fixation, which can achieve the dual purpose of resource utilization of coal-based solid wastes and CO₂ storage, but carbon fixation has a negative impact on the rheological properties of filling slurry. This paper explores the [...] Read more.

Coal-based solid wastes are used for carbon fixation, which can achieve the dual purpose of resource utilization of coal-based solid wastes and CO₂ storage, but carbon fixation has a negative impact on the rheological properties of filling slurry. This paper explores the effect of carbon fixation time on the carbon fixation performance and rheological properties of coal gangue (CG)–fly ash (FA) composite filling materials (CFS) through rheometer, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and other testing methods. The results show that, with an increase in the carbon fixation time, the carbon fixation amount of the CFS shows a trend of increasing first and then stabilizing. Considering the carbon fixation amount and rheological properties of the CFS together, the optimal carbon fixation time is 2 h. At this time, the carbon fixation amount of the CFS is 1.18%, and the yield stress and plastic viscosity are 155.93 Pa and 0.17 Pa·s, respectively. However, with a further increase in the carbon fixation time, the carbon fixation amount basically tends to be stable, mainly because the calcium ions in the CFS are gradually consumed by the reaction as the carbon fixation time increases. The research results are of great significance for improving the utilization of coal-based solid waste and CO₂ storage. Full article

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15 pages, 3020 KB

Open AccessArticle

Enhanced Electrocatalytic Activity for ORR Based on Synergistic Effect of Hierarchical Porosity and Co-N_x Sites in ZIF-Derived Heteroatom-Doped Carbon Materials

by Yan Yang, A-Min Tan, Qiu-Xuan Ren and Gai Zhang

C 2025, 11(3), 70; https://doi.org/10.3390/c11030070 - 8 Sep 2025

Abstract

The hierarchical porosity and active sites of porous carbon materials have significant impacts on the oxygen reduction reaction (ORR) process. The heteroatom-doped porous carbon materials (Z67-900, Z8-900, Z11-900, Z12-900) were synthesized by pyrolysis of ZIFs to reveal the synergistic effect of hierarchical porosity [...] Read more.

The hierarchical porosity and active sites of porous carbon materials have significant impacts on the oxygen reduction reaction (ORR) process. The heteroatom-doped porous carbon materials (Z67-900, Z8-900, Z11-900, Z12-900) were synthesized by pyrolysis of ZIFs to reveal the synergistic effect of hierarchical porosity and Co-N_x sites. The structures of prepared materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, and nitrogen adsorption. The results of electrocatalytic performance show that Z67-900 has the best performance among the four materials prepared. The onset potential (E₀) of Z67-900 is close to commercial Pt/C (20%), and the half-wave potential (E_1/2) of Z67-900 is 80 mV positive than that of Pt/C in an O₂-saturated 0.1 M KOH solution (1600 rpm) with sweep rate of 5 mV·s⁻¹. Moreover, Z67-900 has better methanol resistance. The hierarchical pore structure of Z67-900 facilitates mass transfer, while the Co-N_x sites provide active catalytic centers. This study provides a solid foundation for the rational design of highly efficient ZIF-derived heteroatom-doped catalysts. Full article

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

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18 pages, 1709 KB

Open AccessArticle

Formation of Improved Metallurgical Properties and Carbon Structure of Coke by Optimizing the Composition of Petrographically Heterogeneous Interbasin Coal Batches

by Denis Miroshnichenko, Kateryna Shmeltser, Maryna Kormer, Leonid Bannikov, Serhii Nedbailo, Mykhailo Miroshnychenko, Natalya Mukina and Mariia Shved

C 2025, 11(3), 69; https://doi.org/10.3390/c11030069 - 4 Sep 2025

Abstract

Given the multi-basin raw material base for coking that has been formed at most industry enterprises, there is an urgent need to optimize the component composition and improve the basic technological methods of coal raw material preparation, taking into account the petrographic characteristics [...] Read more.

Given the multi-basin raw material base for coking that has been formed at most industry enterprises, there is an urgent need to optimize the component composition and improve the basic technological methods of coal raw material preparation, taking into account the petrographic characteristics of coal batches. A comprehensive study of the components included in a coke chemical enterprise’s coking raw material base was carried out. The work used standardized methods for studying coal and coal batches’ technological and plastic–viscous properties. The qualitative characteristics of coke were determined using physical–mechanical and thermochemical methods of studying standardized indicators: crushability (M₂₅), abrasion (M₁₀), reactivity (CRI), post-reaction strength (CSR), and specific electrical resistance (ρ). The results were analyzed using the licensed Microsoft Excel computer program. Based on the results of proximate, plastometric, and petrographic analyses of the studied coal samples and data from experimental industrial coking, proposals were made to optimize the component composition, properties of the coal batch, and technology for its preparation for coking. The established inverse dependence of Gibbs free energy (ΔG_f,total) on the reaction capacity of coke CRI and its direct reliance on its post-reaction strength CSR confirmed the feasibility of using ΔG_f,total as a thermodynamic predictive parameter for optimizing and compiling coal batches that produce less reactive, stronger coke. This made it possible to improve the quality indicators of metallurgical coke. Thus, according to the M₂₅ crushability index, the mechanical strength increased by 0.6%, and the M₁₀ abrasion decreased by 0.4%. Significant improvements in thermochemical properties and an increase in the orderliness of the carbon structure were recorded: the CRI reactivity decreased by 3.1%, the CSR post-reaction strength increased by 8.3%, and the specific resistance decreased by 8.4%. Full article

(This article belongs to the Topic Advances in Carbon-Based Materials)

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13 pages, 3960 KB

Open AccessArticle

NaOH-Modified Activated Carbon Materials for Hydrogen Sulfide Removal

by Meriem Abid, Manuel Martínez-Escandell and Joaquín Silvestre-Albero

C 2025, 11(3), 68; https://doi.org/10.3390/c11030068 - 3 Sep 2025

Abstract

A high-surface-area activated carbon material (RG) is used as a platform to create highly concentrated NaOH composites. These materials are tested for the removal of H₂S under industrially relevant conditions (800 ppm H₂S in CO₂-, H₂ [...] Read more.

A high-surface-area activated carbon material (RG) is used as a platform to create highly concentrated NaOH composites. These materials are tested for the removal of H₂S under industrially relevant conditions (800 ppm H₂S in CO₂-, H₂O- and O₂-containing streams). The experimental results show that the breakthrough performance highly depends on the amount of NaOH incorporated and the experimental conditions used (e.g., relative humidity). The most promising material (RG-NaOH-30) reaches a saturation uptake of up to 800 mgH₂S/g at 25 °C and atmospheric pressure. This value is among the most promising results reported in the literature for H₂S removal, and it is well above traditional commercial samples. Breakthrough column tests confirm the promoting role of humidity in the reaction mechanism. Analysis of the adsorbents after H₂S confirms the formation of well-defined sulfur (S_n) microcrystals as the main reaction product. Full article

(This article belongs to the Special Issue Carbons for Health and Environmental Protection (2nd Edition))

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15 pages, 4854 KB

Open AccessArticle

Atomic-Scale Mechanisms of Catalytic Recombination and Ablation in Knitted Graphene Under Hyperthermal Atomic Oxygen Exposure

by Yating Pan, Yunpeng Zhu, Donghui Zhang and Ning Wei

C 2025, 11(3), 67; https://doi.org/10.3390/c11030067 - 2 Sep 2025

Abstract

Effective ablative thermal protection systems are essential for ensuring the structural integrity of hypersonic vehicles subjected to extreme aerothermal loads. However, the microscopic reaction mechanisms at the gas–solid interface, particularly under non-equilibrium high-enthalpy conditions, remain poorly understood. This study employs reactive molecular dynamics [...] Read more.

Effective ablative thermal protection systems are essential for ensuring the structural integrity of hypersonic vehicles subjected to extreme aerothermal loads. However, the microscopic reaction mechanisms at the gas–solid interface, particularly under non-equilibrium high-enthalpy conditions, remain poorly understood. This study employs reactive molecular dynamics (RMD) simulations with the ReaxFF-C/H/O force field to investigate the atomic-scale ablation behavior of a graphene-based knitted graphene structure impacted by atomic oxygen (AO). By systematically varying the AO incident kinetic energy (from 0.1 to 8.0 eV) and incidence angle (from 15° to 90°), we reveal the competing interplay between catalytic recombination and ablation processes. The results show that the catalytic recombination coefficient of oxygen molecules reaches a maximum at 5.0 eV, where surface-mediated O₂ formation is most favorable. At higher energies, the reaction pathway shifts toward enhanced CO and CO₂ production due to increased carbon atom ejection and surface degradation. Furthermore, as the AO incidence angle increases, the recombination efficiency decreases linearly, while C-C bond breakage intensifies due to stronger vertical energy components. These findings offer new insights into the anisotropic surface response of knitted graphene structures under hyperthermal oxygen exposure and provide valuable guidance for the design and optimization of next-generation thermal protection materials for hypersonic flight. Full article

(This article belongs to the Special Issue 10th Anniversary of C — Journal of Carbon Research)

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3 pages, 200 KB

Open AccessEditorial

Editorial for Special Issue “Carbon-Based Materials Applied in Water and Wastewater Treatment”

by Athanasia K. Tolkou

C 2025, 11(3), 66; https://doi.org/10.3390/c11030066 - 2 Sep 2025

Abstract

In the past decade, carbon nanostructures have emerged as one of the most rapidly advancing areas of research [...] Full article

(This article belongs to the Special Issue Carbon-Based Materials Applied in Water and Wastewater Treatment)

14 pages, 2007 KB

Open AccessArticle

Graphene Oxide Promoted Light Activation of Peroxymonosulfate for Highly Efficient Triphenyl Phosphate Degradation

by Yilong Li, Yi Xie, Xuqian Wang and Yabo Wang

C 2025, 11(3), 65; https://doi.org/10.3390/c11030065 - 21 Aug 2025

Abstract

The treatment of organic phosphate ester (OPE) pollutants in water is a challenging but highly necessary task. In this study, an advanced oxidation process through light activation of peroxymonosulfate (PMS) involving graphene oxide (GO) as a promoter was developed to degrade OPE in [...] Read more.

The treatment of organic phosphate ester (OPE) pollutants in water is a challenging but highly necessary task. In this study, an advanced oxidation process through light activation of peroxymonosulfate (PMS) involving graphene oxide (GO) as a promoter was developed to degrade OPE in water, taking triphenyl phosphate (TPhP) as an example. The developed “Light+PMS+GO” system demonstrated good convenience, high TPhP degradation efficiency, tolerance in a near-neutral pH, satisfactory re-usability, and a low toxicity risk of degradation products. Under the investigated reaction conditions, viz., the full spectrum of a 300 W Xe lamp, PMS of 200 mg L⁻¹, GO of 4 mg L⁻¹, and TPhP of 10 μmol L⁻¹, the “Light+PMS+GO” system achieved nearly 100% TPhP degradation efficiency during a 15 min reaction duration with a 5.81-fold enhancement in the reaction rate constant, compared with the control group without GO. Through quenching experiments and electron paramagnetic resonance studies, singlet oxygen was identified as the main reactive species for TPhP degradation. Further studies implied that GO could accumulate both oxidants and pollutants on the surface, providing additional reaction sites for PMS activation and accelerating electron transfer, which all contributed to the enhancement of TPhP degradation. Finally, the TPhP degradation pathway was proposed and a preliminary toxicity evaluation of degradation intermediates was conducted. The convenience, high removal efficiency, and good re-usability indicates that the developed “Light+PMS+GO” reaction system has great potential for future applications. Full article

(This article belongs to the Special Issue 10th Anniversary of C — Journal of Carbon Research)

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15 pages, 5132 KB

Open AccessArticle

Characterisation of a Biodegradable Electrode Substrate Based on Psyllium Husk–Carbon Nanoparticle Composites

by Cliodhna McCann, Victoria Gilpin, Regan McMath, Chris I. R. Gill, Karl McCreadie, James Uhomoibhi, Pagona Papakonstantinou and James Davis

C 2025, 11(3), 64; https://doi.org/10.3390/c11030064 - 17 Aug 2025

Abstract

Unrefined psyllium husk derived from Plantago ovata constitutes a complex mixture of water-soluble and insoluble polymeric chains that form an interpenetrating network capable of entrapping carbon nanoparticles. While the resulting composite was found to swell in aqueous electrolyte, it exhibited hydrogel-like properties where [...] Read more.

Unrefined psyllium husk derived from Plantago ovata constitutes a complex mixture of water-soluble and insoluble polymeric chains that form an interpenetrating network capable of entrapping carbon nanoparticles. While the resulting composite was found to swell in aqueous electrolyte, it exhibited hydrogel-like properties where the electrochemical activity was retained and found to be stable upon repetitive voltammetric cycling. Planar film systems were characterized by electron microscopy, Raman spectroscopy, tensile testing, gravimetric analysis, contact angle and cyclic voltammetry. A key advantage of the composite lies in its ability to be cast in 3D geometric forms such as pyramidal microneedle arrays (700 μm high × 200 μm base × 500 μm pitch) that could serve as viable electrode sensors. In contrast to conventional composite electrode materials that rely on non-aqueous solvents, the psyllium mixture is processed entirely from an aqueous solution. This, along with its plant-based origins and simple processing requirements, provides a versatile matrix for the design of biodegradable electrode structures that can be manufactured from more sustainable sources. Full article

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

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15 pages, 1152 KB

Open AccessArticle

Formation and Melting of Hydrate with Binary CO₂/C₂H₆ Mixtures in Silica Sand: Comparison Between Dissociation Data and Phase Equilibrium of Pure CO₂ and C₂H₆ Hydrates

by Alberto Maria Gambelli, Federico Rossi and Giovanni Gigliotti

C 2025, 11(3), 63; https://doi.org/10.3390/c11030063 - 17 Aug 2025

Abstract

The present study deals with hydrate formation with binary gaseous mixtures consisting of carbon dioxide mixed with ethane at varying concentrations. Since the production of hydrates is recognised as a stochastic process and also due to the marked influence that experimental apparatuses often [...] Read more.

The present study deals with hydrate formation with binary gaseous mixtures consisting of carbon dioxide mixed with ethane at varying concentrations. Since the production of hydrates is recognised as a stochastic process and also due to the marked influence that experimental apparatuses often have on the results, the continuous updating of the literature with new experimental data is needed. Hydrates were produced and dissociated in excess water and in unstirred conditions. The dissociation values were collected and tabulated. Each test was plotted and compared with the phase boundary equilibrium conditions of pure ethane and pure carbon dioxide hydrates. The results confirmed the lowering of pressures required for hydrate formation with the increase in ethane concentration in the gas mixture. In detail, the dissociation condition for CO₂/C₂H₆ hydrates was tested within the following thermodynamic ranges: 0.1–13 °C and 11.26–36.75 bar for the 25/75 vol% mixture, 0.1–13 °C and 9.74–35.07 bar for the 50/50 vol% mixture and 7.0–12.9 °C and 17.36–30.05 bar for the 75/25 vol% mixture. When 75 vol% ethane was used, the dissociation of hydrates occurred at conditions corresponding to the phase equilibrium of pure ethane hydrates, denoting that the system reached the most favourable thermodynamic conditions possible despite the presence of 25 vol% CO₂. Full article

(This article belongs to the Special Issue 10th Anniversary of C — Journal of Carbon Research)

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34 pages, 10992 KB

Open AccessArticle

Graphene-like Carbon Materials from King Grass Biomass via Catalytic Pyrolysis Using K₃[Fe(CN)₆] as a Dual Catalyst and Activator

by Alba N. Ardila Arias, Erasmo Arriola-Villaseñor, Madelyn Ortiz-Quiceno, Lucas Blandón-Naranjo and José Alfredo Hernández-Maldonado

C 2025, 11(3), 62; https://doi.org/10.3390/c11030062 - 14 Aug 2025

Abstract

The potential of king grass biomass as a precursor for carbon-based materials was evaluated through comprehensive physicochemical characterization. The biomass showed high fixed carbon content, reactive oxygenated groups, and favorable atomic ratios, supporting its suitability for conversion into porous carbon structures. This study [...] Read more.

The potential of king grass biomass as a precursor for carbon-based materials was evaluated through comprehensive physicochemical characterization. The biomass showed high fixed carbon content, reactive oxygenated groups, and favorable atomic ratios, supporting its suitability for conversion into porous carbon structures. This study focused on the synthesis of graphene-like materials via high-temperature pyrolysis (~1000 °C), employing FeCl₃ and potassium ferricyanide (K₃[Fe(CN)₆]) as catalytic agents. Although FeCl₃ is widely studied, it showed limited capacity to promote graphitic ordering. In contrast, K₃[Fe(CN)₆] exhibited a synergistic effect, combining iron-based catalytic species (Fe, Fe₃C) and potassium-derived activating compounds (K₂CO₃), which significantly enhanced graphitization and porosity. Characterization by Raman spectroscopy, XRD, and SEM confirmed that materials synthesized with K₃[Fe(CN)₆] presented improved crystallinity, lower defect densities (I_D/I_G = 0.37–1.11), and distinct 2D bands (I_2D/I_G = 0.32–0.80), indicating the formation of few-layer graphene domains. The most promising structure was obtained from cellulose treated with alkaline peroxide and deoxygenated prior to pyrolysis with K₃[Fe(CN)₆], showing properties comparable to commercial graphene. BET analysis revealed surface areas up to 714.50 m²/g. While non-catalyzed samples yielded higher mass, the catalytic approach with K₃[Fe(CN)₆] demonstrates a sustainable and efficient pathway for producing graphene-like carbon materials from lignocellulosic biomass. Full article

(This article belongs to the Special Issue Carbon Innovations in Renewable Energy Systems and Environmental Sustainability)

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24 pages, 10422 KB

Open AccessArticle

Optimizing Distribution of Light Irradiation in Column Reactor Array and Glass Chamber for Microalgae Carbon Sequestration Facilities

by Xiangjin Liang, Jun Lu, Yapeng Chen, Guangbiao Zhou, Zeyan Tao, Zhenyu Hu, Ying Liu, Wanlin Liu, Yang Xu and Jun Cheng

C 2025, 11(3), 61; https://doi.org/10.3390/c11030061 - 12 Aug 2025

Abstract

The column photobioreactor has become the predominant approach for carbon sequestration by microalgae in power plant settings, owing to its capacity for high-density cultivation and efficient light energy utilization. Due to the dense arrangement of the columnar photobioreactor and its height, insufficient light [...] Read more.

The column photobioreactor has become the predominant approach for carbon sequestration by microalgae in power plant settings, owing to its capacity for high-density cultivation and efficient light energy utilization. Due to the dense arrangement of the columnar photobioreactor and its height, insufficient light became one of the main factors limiting the carbon sequestration rate of microalgae growth. In this paper, a light resource optimization method of reflective baffle and top diffusing glass was proposed. When the angle of reflective baffle on the north and east walls was 35°, and the angle of reflective baffle on the west and south floors was 0°, the overall light radiation intensity of the reactor array became the largest, reaching up to 916.81 W/m², which was 14.39% higher than that before the optimization. The replacement of the top glass with diffusing material converted the direct radiation of solar radiation into scattered radiation. When the transmittance was 95% and the haze was 95%, the overall average light radiation intensity of the algal solution reached 830.93 W/m², which was an increase of 3.7%. Four new exhaust air distribution methods were proposed, in which the three-entrance staggered-arrangement type glasshouse had the lowest algal liquid temperature. Full article

(This article belongs to the Special Issue 10th Anniversary of C — Journal of Carbon Research)

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15 pages, 4099 KB

Open AccessArticle

Pulsed Laser Annealing of Deposited Amorphous Carbon Films

by Arianna D. Rivera, Eitan Hershkovitz, Panagiotis Panoutsopoulos, Manny X. de Jesus Lopez, Bradley Simpson, Honggyu Kim, Rajaram Narayanan, Jesse Johnson and Kevin S. Jones

C 2025, 11(3), 60; https://doi.org/10.3390/c11030060 - 8 Aug 2025

Abstract

Pulsed laser annealing (PLA) was performed on a 0.3 μm thick hydrogenated amorphous carbon (a-C:H) film deposited on silicon substrate by plasma-enhanced chemical vapor deposition (PECVD). The 532 nm, 32 ns PLA ranged in fluence from 0.2 to 0.94 J cm⁻². [...] Read more.

Pulsed laser annealing (PLA) was performed on a 0.3 μm thick hydrogenated amorphous carbon (a-C:H) film deposited on silicon substrate by plasma-enhanced chemical vapor deposition (PECVD). The 532 nm, 32 ns PLA ranged in fluence from 0.2 to 0.94 J cm⁻². There were no visible signs of film delamination over the entire fluence range for a single pulse. As the fluence increased, graphitization of the amorphous film bulk was observed. However, at the near surface of the film, there was a concomitant increase in sp³ content. The sp³ bonding observed is the result of the formation of a thin diamond-like layer on the surface of the carbon film. Along with increasing laser fluence, the film swelled by 75% up to 0.6 J cm⁻². In addition, carbon fiber formation was observed at 0.6 J cm⁻², increasing in size and depth up through 0.94 J cm⁻². The origin of this transformation may be associated with a rapid outgassing of hydrogen from the amorphous carbon during the PLA step. Additionally, there was a dramatic increase in the visible light absorption of these thin films with increasing laser fluence, despite the films being less than a micron thick. These results suggest that PLA of a-C:H film is a useful method for modifying the surface structure for optical or electrochemical applications without film ablation. Full article

(This article belongs to the Special Issue Carbon Functionalization: From Synthesis to Applications)

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