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18 pages, 11483 KB

Open AccessArticle

ZnCl₂-Activated Nanoporous Carbon Materials from Phyllanthus emblica Seed for High-Performance Supercapacitors

by Lok Kumar Shrestha, Sarita Manandhar, Sabina Shahi, Rabindra Nath Acharyya, Aabha Puri, Chhabi Lal Gnawali, Rinita Rajbhandari and Katsuhiko Ariga

C 2025, 11(4), 95; https://doi.org/10.3390/c11040095 - 17 Dec 2025

Viewed by 146

Abstract

This study reports the synthesis of an activated nanoporous carbon material from Phyllanthus emblica (Amala)—a biomass material which is an eco-friendly, economical, and sustainable precursor used to prepare activated carbon using zinc chloride (ZnCl₂) activation at various temperatures (500–700 °C) under [...] Read more.

This study reports the synthesis of an activated nanoporous carbon material from Phyllanthus emblica (Amala)—a biomass material which is an eco-friendly, economical, and sustainable precursor used to prepare activated carbon using zinc chloride (ZnCl₂) activation at various temperatures (500–700 °C) under a nitrogen gas atmosphere. A sample that was carbonized at 700 °C (AmC_Z700) attained a high specific surface area of 1436 m² g⁻¹ and a total pore volume of 0.962 cm³ g⁻¹, and, when used in an electrode, showed excellent supercapacitance performance, attaining a high specific capacitance of 263 F g⁻¹ at a current density of 1 A g⁻¹, followed by 55% capacitance retention at 50 A g⁻¹. Additionally, the assembled symmetric supercapacitor cell, when operated at 1.2 V, delivered an energy density of 8.9 Wh kg⁻¹ at a power density of 300 W kg⁻¹ and exhibited an excellent cycle life of 95% after 10,000 successive charge/discharge cycles, demonstrating the substantial potential of Phyllanthus emblica seed-derived carbon materials for the creation of high-performance supercapacitors. Full article

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

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15 pages, 3226 KB

Open AccessArticle

Enhanced Antibacterial Properties of Citric Acid-Crosslinked PVA/Starch Films Functionalized with Silver-Loaded Sorghum Straw Biochar

by Yue Wang, Jiayao Gao, Cuiluan Ma and Yucai He

C 2025, 11(4), 94; https://doi.org/10.3390/c11040094 - 16 Dec 2025

Viewed by 210

Abstract

In this work, a novel polyvinyl alcohol/starch (PVA/St)-based composite film was fabricated by integrating citric acid (CA) and silver-loaded biochar (C-Ag) nanofillers to enhance antibacterial functionality. Sorghum straw-derived biochar was loaded with silver nanoparticles (AgNPs) through a green synthesis route using Peucedanum praeruptorum [...] Read more.

In this work, a novel polyvinyl alcohol/starch (PVA/St)-based composite film was fabricated by integrating citric acid (CA) and silver-loaded biochar (C-Ag) nanofillers to enhance antibacterial functionality. Sorghum straw-derived biochar was loaded with silver nanoparticles (AgNPs) through a green synthesis route using Peucedanum praeruptorum Dunn extract. The successful crosslinking by CA and the uniform incorporation of AgNPs were confirmed by FTIR, XRD, and SEM. Notably, the optimized composite film containing 1.5 g/L C-Ag exhibited strong broad-spectrum antibacterial activity, with inhibition zones of 28 mm against E. coli, 29 mm against S. aureus, and 26 mm against P. aeruginosa, respectively. The high efficacy is attributed to the synergistic effect between the sustained release of Ag⁺ and the CA-induced acidic microenvironment. This work provides a green and high-performance antibacterial material to address the potential microbe contamination. Full article

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

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15 pages, 1042 KB

Open AccessArticle

GHG Emissions and Carbon Sequestration in Coastal Bambusa edulis Shelterbelts with Biochar and Organic Fertilizer

by Ying-Pin Huang, Chung-I Chen, Chih-Pei Shen, Jia-Yi Shen, Wei-Chih Chen, Yue-Hua Liou, Shih-Chi Lee, Chuan-Chi Chien, Xu-Chen Yang, Wen-Hung Huang and Ching-Wen Wang

C 2025, 11(4), 93; https://doi.org/10.3390/c11040093 - 15 Dec 2025

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Abstract

This study evaluated the seasonal greenhouse gas (GHG) emissions and carbon assimilation of Bambusa edulis under four soil amendment treatments—control (C), biochar (B), fertilizer using vermicompost (F), and biochar plus fertilizer (B + F)—in a coastal shelterbelt system in south-western Taiwan. Over a [...] Read more.

This study evaluated the seasonal greenhouse gas (GHG) emissions and carbon assimilation of Bambusa edulis under four soil amendment treatments—control (C), biochar (B), fertilizer using vermicompost (F), and biochar plus fertilizer (B + F)—in a coastal shelterbelt system in south-western Taiwan. Over a 12-month period, CO₂ and N₂O fluxes and photosynthetic carbon uptake were measured. The control (C) treatment served as the baseline, exhibiting the lowest greenhouse gas (GHG) emissions and carbon assimilation. Its summer N₂O emissions were 39.54 ± 20.79 g CO₂ e m⁻², and its spring carbon assimilation was 13.2 ± 0.84 kg CO₂ clump⁻¹. In comparison, the amendment treatments significantly enhanced both emissions and carbon uptake. The fertilizer-only (F) treatment resulted in the highest levels, with peak summer N₂O emissions increasing by 306.5% (to 160.73 ± 96.22 g CO₂ e m⁻²) and spring carbon assimilation increasing by 40.2% (to 18.5 ± 0.62 kg CO₂ clump⁻¹). An increase in these values was also observed in the combined biochar and fertilizer (B + F) treatment, although the magnitude was less than that of the F treatment alone. In the B + F treatment, summer N₂O emissions increased by 130.3% (to 91.1 ± 62.51 g CO₂ e m⁻²), while spring carbon assimilation increased by 17.4% (to 15.5 ± 0.36 kg CO₂ clump⁻¹). Soil CO₂ flux was significantly correlated with atmosphere temperature (r = 0.63, p < 0.01) and rainfall (r = 0.45, p < 0.05), while N₂O flux had a strong positive correlation with rainfall (r = 0.71, p < 0.001). The findings highlight a trade-off between nutrient-driven productivity and GHG intensity and demonstrate that optimized organic and biochar applications can enhance photosynthetic carbon gain while mitigating emissions. The results support bamboo’s role in climate mitigation and carbon offset strategies within nature-based solution frameworks. Full article

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

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49 pages, 5733 KB

Open AccessReview

A Review of Recent Advances in Biomass-Derived Porous Carbon Materials for CO₂ Capture

by Guihe Li, Jun He and Jia Yao

C 2025, 11(4), 92; https://doi.org/10.3390/c11040092 - 11 Dec 2025

Viewed by 633

Abstract

With the intensifying global climate crisis and the urgent demand for carbon neutrality, carbon dioxide (CO₂) capture technologies have received growing attention as effective strategies for mitigating greenhouse gas emissions. Carbon-based porous materials are widely regarded as promising CO₂ adsorbents [...] Read more.

With the intensifying global climate crisis and the urgent demand for carbon neutrality, carbon dioxide (CO₂) capture technologies have received growing attention as effective strategies for mitigating greenhouse gas emissions. Carbon-based porous materials are widely regarded as promising CO₂ adsorbents due to their tunable porosity, high surface area, and excellent chemical and thermal stability. Among them, biomass-derived porous carbon materials have received growing attention as sustainable, low-cost alternatives to fossil-based adsorbents. This review provides a comprehensive overview of recent advances in biomass-derived porous carbon materials for CO₂ capture, emphasizing the fundamental adsorption mechanisms, including physisorption, chemisorption, and their synergistic effects. Key synthesis pathways, such as pyrolysis and hydrothermal carbonization, are discussed in relation to the development of biomass-derived porous carbon materials. Furthermore, performance-enhancing strategies, such as activation treatments, heteroatom doping, and templating methods, are critically evaluated for their ability to tailor surface properties and improve CO₂ uptake capacity. Recent progress in typical biomass-derived porous carbon materials, including active carbon, hierarchical porous carbon, and other innovative carbon materials, is also highlighted. In addition to summarizing recent advances in porous carbon synthesis, this review introduces a unified techno-economic framework that integrates cost, sustainability, and performance-driven benefits. Overall, this review aims to provide systematic insights into the performance of biomass-derived porous carbon materials and to guide the rational design of efficient, sustainable adsorbents for real-world carbon capture applications. Full article

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

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11 pages, 1162 KB

Open AccessCommunication

Combined Effect of Sonication and Electron Beam Irradiation on the Photocatalytic Organic Dye Decomposition Efficiency of Graphitic Carbon Nitride

by Aika Harako, Shuhei Shimoda, Keita Suzuki, Atsushi Fukuoka and Tomoya Takada

C 2025, 11(4), 91; https://doi.org/10.3390/c11040091 - 5 Dec 2025

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Abstract

The photocatalytic efficiency of graphitic carbon nitride (g-C₃N₄) for the decomposition of aqueous rhodamine B (RhB) was investigated. To examine the combined effects of sonication and electron beam (EB) irradiation on the photocatalytic efficiency, g-C₃N₄ was [...] Read more.

The photocatalytic efficiency of graphitic carbon nitride (g-C₃N₄) for the decomposition of aqueous rhodamine B (RhB) was investigated. To examine the combined effects of sonication and electron beam (EB) irradiation on the photocatalytic efficiency, g-C₃N₄ was sonicated in 1,3-butanediol and subsequently irradiated with EB. The photocatalytic efficiency was improved by the low-dose EB irradiation due to the generation of structural defects that acted as active reaction sites. Sonication before EB irradiation induced mild exfoliation and further improved photocatalytic efficiency. Prolonged sonication enhanced this improvement, primarily by increasing the specific surface area of g-C₃N₄. The positive effect of sonication was more remarkable for g-C₃N₄ irradiated with low-dose EB than for g-C₃N₄ irradiated with higher-dose EB. The photocatalytic RhB decomposition rate measured for g-C₃N₄ sonicated for 480 min and irradiated at 200 kGy was approximately 6.8 times higher than that measured for the untreated g-C₃N₄. The difference between the sonication effects can be ascribed to the electrostatic interactions and the resultant agglomeration of the g-C₃N₄ particles after EB irradiation. High-dose EB irradiation caused electrification followed by coarsening of the particles, whereas low-dose EB irradiation did not produce these results and led to positive effects due to the EB-induced g-C₃N₄ structural alteration. Full article

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

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23 pages, 4789 KB

Open AccessArticle

Impact of Activated Carbon Modification on the Ion Removal Efficiency in Flow Capacitive Deionization

by Wen-Huan Qiao, Ya-Ni Liu, Ya Li, Yu Xie, Hai-Yi Yang and Jun-Wei Hou

C 2025, 11(4), 90; https://doi.org/10.3390/c11040090 - 2 Dec 2025

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Abstract

Flow capacitive deionization (FCDI) technology holds significant promise for cost-effective and energy-efficient desalination; however, its practical application is hindered by limited electrode stability and desalination performance. In this study, we propose a novel composite strategy that combines chemical surface modification with surfactant-assisted dispersion [...] Read more.

Flow capacitive deionization (FCDI) technology holds significant promise for cost-effective and energy-efficient desalination; however, its practical application is hindered by limited electrode stability and desalination performance. In this study, we propose a novel composite strategy that combines chemical surface modification with surfactant-assisted dispersion to enhance electrode performance in FCDI systems. We observed that the dispersion stability and capacitance of the flow electrodes were significantly improved after oxidation (AC-O) or amination (AC-N) of activated carbon (AC). To further investigate the underlying ion adsorption mechanisms, we performed Density Functional Theory (DFT) simulations. The simulations revealed that oxidative modification (AC-O) enhances chloride ion adsorption through stronger electrostatic and van der Waals interactions, while amination (AC-N) is more effective for sodium ion adsorption. Subsequently, surfactants (sodium dodecyl sulfate, SDS; cetyltrimethylammonium bromide, CTAB) were used to prepare stable and high-performance flow electrodes. Electrochemical characterization and desalination tests in a 1000 mg·L⁻¹ saline solution demonstrated that the AC-O/SDS composite exhibited excellent dispersion stability (>7 d) and significantly enhanced conductivity and specific capacitance, increasing by factors of 2.48 and 2.50, respectively, compared to unmodified AC. This optimized electrode achieved a desalination efficiency of 74.37% and a desalination rate of 6.2542 mg·L⁻¹·min⁻¹, outperforming the unmodified electrode by a factor of 5.72. Our findings provide a robust, sustainable approach for fabricating advanced flow electrodes and offer valuable insights into electrode structure optimization, opening new possibilities for the application of FCDI technology in water treatment and material sciences. Full article

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

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10 pages, 1635 KB

Open AccessArticle

How to Detect Low-Energy Isomers of Fullerenes Using Clar Covers

by Henryk A. Witek and Rafał Podeszwa

C 2025, 11(4), 89; https://doi.org/10.3390/c11040089 - 29 Nov 2025

Viewed by 270

Abstract

We demonstrate that the energetic stability of carbon (5,6)-fullerene isomers can, to a large extent, be inferred from two topological invariants: the Kekulé count K and the Clar count C. Although neither invariant alone exhibits a strong correlation with the total electronic [...] Read more.

We demonstrate that the energetic stability of carbon (5,6)-fullerene isomers can, to a large extent, be inferred from two topological invariants: the Kekulé count K and the Clar count C. Although neither invariant alone exhibits a strong correlation with the total electronic energy at equilibrium geometry, the application of a min–max principle (maximizing C while minimizing K) proves effective in identifying the lowest-energy subset of

C_{n}

isomers for

n =

50–100. This finding substantially reduces the complexity of determining the most stable isomer among larger fullerenes. Full article

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

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20 pages, 5111 KB

Open AccessArticle

Hydrates Formed with Binary CH₄/C₂H₆ Mixtures: Effects of Adding 25–75 vol% Ethane on the Quantity of Hydrates Formed, Growth Mechanism and Structure Preservation

by Alberto Maria Gambelli, Daniela Pezzolla, Federico Rossi and Giovanni Gigliotti

C 2025, 11(4), 88; https://doi.org/10.3390/c11040088 - 20 Nov 2025

Viewed by 697

Abstract

This study explores the production of hydrates with binary (CH₄/C₂H₆) gaseous mixtures, varying the concentration of each species from 25 to 75 vol%. The thermodynamics of this process are explored in detail, and the achieved results are [...] Read more.

This study explores the production of hydrates with binary (CH₄/C₂H₆) gaseous mixtures, varying the concentration of each species from 25 to 75 vol%. The thermodynamics of this process are explored in detail, and the achieved results are explained in terms of cage occupancy and compared with the phase boundary equilibrium conditions of pure methane and pure ethane hydrates. The addition of ethane is found to not contribute significantly to the quantity of gas captured in hydrates. Conversely, it delays the massive growth of hydrates, shifting the process towards conditions supporting the formation of pure methane hydrates. The presence of C₂H₆ molecules within the hydrate lattices improved their overall stability and avoided the dissociation of water cages even under temperature increases (from the conditions measured at the end of formation) up to 14.40 °C. This latter property makes ethane a viable support species for the solid storage of energy gases in the form of hydrates. Full article

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

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31 pages, 4703 KB

Open AccessArticle

Metal-Doped Carbon Dots as Heterogeneous Fenton Catalysts for the Decolourisation of Dyes—Activity Relationships and Mechanistic Insights

by Weiyun Chen, Ivan Cole, Andrew S. Ball and Hong Yin

C 2025, 11(4), 87; https://doi.org/10.3390/c11040087 - 20 Nov 2025

Viewed by 539

Abstract

The removal of synthetic dyes from industrial effluents remains challenging due to their chemical stability and poor biodegradability. Here we engineer metal-doped carbon dots (CDs) as heterogeneous Fenton-like catalysts and elucidate how dopant identity governs structure–activity relationships and reactive oxygen species (ROS) pathways. [...] Read more.

The removal of synthetic dyes from industrial effluents remains challenging due to their chemical stability and poor biodegradability. Here we engineer metal-doped carbon dots (CDs) as heterogeneous Fenton-like catalysts and elucidate how dopant identity governs structure–activity relationships and reactive oxygen species (ROS) pathways. Fe-, Cu-, Zn- and Mg-doped CDs were prepared via a one-pot hydrothermal route and comprehensively characterised by TEM, FTIR, XPS and zeta-potential analysis. The resulting nanoparticles displayed narrow size distributions (10.2–15.2 nm) and dopant-dependent surface chemistries and charges. Catalytic tests with methylene blue (MB) and rhodamine B (RB) show that Fe-doped CDs deliver the highest activity toward MB degradation (k = 0.0218 min⁻¹), attributable to efficient Fe²⁺/Fe³⁺ redox cycling coupled with hydroxyl-rich surfaces that promote H₂O₂ activation. Zn-doped CDs achieve complete RB decolourisation under Fenton-like conditions, which we ascribe to their higher surface charge and abundant oxygenated sites that enhance pollutant adsorption and ROS generation. Cu- and Mg-doped CDs exhibit intermediate and dopant-specific performances consistent with their respective redox and adsorption characteristics. Collectively, these results establish clear correlations between dopant chemistry, surface functionality, and ROS formation routes, providing mechanistic guidance for the rational design of carbon-based Fenton catalysts for sustainable water remediation. Full article

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

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19 pages, 10104 KB

Open AccessArticle

One-Stage Microwave-Assisted Carbonization and Phosphoric Acid Activation of Peanut Shell and Spruce Cone Biomass for Crystal Violet Adsorption

by Przemysław Pączkowski, Viktoriia Kyshkarova, Sergii Guzii, Inna Melnyk and Barbara Gawdzik

C 2025, 11(4), 86; https://doi.org/10.3390/c11040086 - 20 Nov 2025

Cited by 1 | Viewed by 542

Abstract

This study focuses on a single-step microwave-assisted carbonization and activation method for biomasses derived from peanut shells and spruce cones. Using phosphoric acid as the activating agent, this process leads to carbon materials with a micro-mesoporous structure, favoring dye adsorption. Elemental and surface [...] Read more.

This study focuses on a single-step microwave-assisted carbonization and activation method for biomasses derived from peanut shells and spruce cones. Using phosphoric acid as the activating agent, this process leads to carbon materials with a micro-mesoporous structure, favoring dye adsorption. Elemental and surface analyses confirmed that the physicochemical properties of the obtained carbons are strongly dependent on the biomass’ source. The carbon materials obtained in this way, differing in porous structure and the presence of functional groups on their surfaces, were used for static adsorption of hazardous dye crystal violet from water. The adsorption behavior of both materials fits well with the Langmuir and Freundlich isotherms, indicating a combination of monolayer and heterogeneous surface adsorption, driven primarily by physical interactions. Of these two materials, carbon derived from spruce cones was characterized by better porosity, higher surface functionality, and higher adsorption capacity, demonstrating its potential as a cost-effective and sustainable material for wastewater treatment applications. Full article

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

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20 pages, 3230 KB

Open AccessArticle

Synergistic Effects in Hybrid Buckypapers of Graphene Nanoplatelets and Carbon Nanotubes: Processing and Performance

by Thais da Silva, Thiély da Silva, Rieyssa Corrêa, Rui Ribeiro, Guilherme Morgado, Larissa Montagna, Braian Uribe, Maraisa Goncalves, Michelle Costa, Fabio Passador, Maria Conceição Paiva and Edson Botelho

C 2025, 11(4), 85; https://doi.org/10.3390/c11040085 - 19 Nov 2025

Viewed by 505

Abstract

Hybrid buckypapers (BPs) composed of graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) hold great potential for applications in flexible electronics, electromagnetic shielding, and energy storage. In this study, hybrid BPs were fabricated and characterized to evaluate their structural, thermal, and electrical properties. Hybrid [...] Read more.

Hybrid buckypapers (BPs) composed of graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) hold great potential for applications in flexible electronics, electromagnetic shielding, and energy storage. In this study, hybrid BPs were fabricated and characterized to evaluate their structural, thermal, and electrical properties. Hybrid BPs with varying GNP/CNT mass ratios (0/100, 25/75, 50/50, 75/25, 85/15, 90/10, and 95/5 wt%) were prepared via vacuum-assisted filtration of well-dispersed aqueous suspensions stabilized by surfactants. The resulting hybrid GNP/CNT BPs were dried and subjected to post-treatment processes to enhance structural integrity and electrical performance. Characterization techniques included scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Raman spectroscopy, thermogravimetric analysis (TGA), nitrogen adsorption/desorption isotherms, and impedance spectroscopy (IS). The hybrid GNP/CNT BPs exhibited electrical conductivities comparable to conventional CNT-based BPs. At GNP concentrations of 25 to 50 wt%, electrical conductivity values approached those of CNT-based BPs, while at GNP concentrations between 75 and 90 wt%, a slight increase in conductivity was observed (171%). These results highlight a synergistic effect at lower CNT concentrations, where the combination of CNTs and GNPs enhances conductivity. The findings suggest that optimal conductivity is achieved through a balanced incorporation of both materials, offering promising prospects for advanced BP applications. Full article

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

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18 pages, 15025 KB

Open AccessArticle

Preparation and CO₂ Adsorption Performance of Nitrogen-Doped Carbon Derived from Phenolic Resin

by Liang Xu, Jie Peng, Zhaoyang Niu, Wenbin Li and Donghui Zhang

C 2025, 11(4), 84; https://doi.org/10.3390/c11040084 - 18 Nov 2025

Viewed by 667

Abstract

Carbon dioxide emissions, particularly from large point sources such as fossil-fuel power plants, represent a primary driver of global warming. Although various carbon-based adsorbents have been developed for carbon capture applications, most existing materials exhibit limited CO₂ adsorption capacity at flue gas-relevant [...] Read more.

Carbon dioxide emissions, particularly from large point sources such as fossil-fuel power plants, represent a primary driver of global warming. Although various carbon-based adsorbents have been developed for carbon capture applications, most existing materials exhibit limited CO₂ adsorption capacity at flue gas-relevant partial pressures and are susceptible to interference from impurity components. In this study, a series of nitrogen-doped carbons was prepared from commercial phenolic resin and melamine via a two-step carbonization–activation process. The effects of precursor-to-dopant ratio and thermal conditions on CO₂ adsorption were systematically investigated. The results indicated that CO₂ uptake was influenced by specific surface area, nitrogen content, micropore volume, and total pore volume, with a maximum adsorption capacity of 2.455 mmol·g⁻¹ and selectivity over 28 at 25 °C and 1 bar. The series also exhibited excellent cycling stability (<1% loss after 5 cycles) and fast kinetics (>90% uptake within 3 min), suggesting its potential applicability in flue gas CO₂ capture. Full article

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

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28 pages, 4534 KB

Open AccessArticle

Mechanistic Evaluation of Pb(II) Adsorption on Magnetic Activated Carbon/Fe₃O₄ Composites: Influence of Hydrothermal and Ultrasonic Synthesis Routes

by Gaukhar Smagulova, Aigerim Imash, Akniyet Baltabay, Aruzhan Keneshbekova, Alisher Abdisattar, Ramazan Kazhdanbekov, Aidos Lesbayev and Zulkhair Mansurov

C 2025, 11(4), 83; https://doi.org/10.3390/c11040083 - 4 Nov 2025

Viewed by 1284

Abstract

This study presents a comparative analysis of two synthesis approaches for fabricating magnetic sorbents based on activated carbon (AC) incorporated with magnetite (Fe₃O₄) nanoparticles: hydrothermal synthesis and ultrasonic treatment. The results demonstrate that ultrasonic-assisted synthesis yields a magnetically responsive [...] Read more.

This study presents a comparative analysis of two synthesis approaches for fabricating magnetic sorbents based on activated carbon (AC) incorporated with magnetite (Fe₃O₄) nanoparticles: hydrothermal synthesis and ultrasonic treatment. The results demonstrate that ultrasonic-assisted synthesis yields a magnetically responsive composite, us-AC/Fe₃O₄, exhibiting a Pb²⁺ removal efficiency of 92.84%, which is comparable to that of pristine activated carbon (99.0%). A key advantage of the synthesized composite lies in its facile recovery via magnetic separation following adsorption, rendering it a promising candidate for the remediation of heavy metal-contaminated water. Kinetic modeling suggests a dual adsorption mechanism: initial stages are governed by physisorption, while chemisorption dominates in the later phases. Adsorption isotherm modeling demonstrated that the Langmuir model provided the best description of Pb²⁺ adsorption on AC and us-AC/Fe₃O₄, with the highest sorption capacities observed for pristine activated carbon, followed by the ultrasonically modified composite, and comparatively lower values for the hydrothermally treated material. These findings underscore the potential of ultrasonic processing as an effective route for developing magnetically separable sorbents with high performance in aqueous heavy metal removal. Full article

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

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12 pages, 2259 KB

Open AccessArticle

Bituminous Coal-Derived Carbon Anode: Molten Salt-Assisted Synthesis and Enhanced Performance in Sodium-Ion Battery

by Yuxuan Du, Jian Wang, Peihua Li, Yalong Wang, Yibo Zhao and Shuwei Chen

C 2025, 11(4), 82; https://doi.org/10.3390/c11040082 - 27 Oct 2025

Viewed by 940

Abstract

The high-efficiency and clean utilization of coal resources is a key strategy for new energy development, and converting coal into carbon materials offers a promising route to valorize bituminous coal. However, fabricating high-performance bituminous coal-derived carbon for sodium ion (Na⁺) insertion/extraction [...] Read more.

The high-efficiency and clean utilization of coal resources is a key strategy for new energy development, and converting coal into carbon materials offers a promising route to valorize bituminous coal. However, fabricating high-performance bituminous coal-derived carbon for sodium ion (Na⁺) insertion/extraction remains a major challenge, as it is difficult to regulate the carbon’s microstructural properties to match Na⁺ storage demands. Herein, we propose a molten salt-assisted carbonization strategy to prepare bituminous coal-derived hard carbon (HC) for use as a sodium-ion battery (SIB) anode material, and we focus on regulating the structure of carbon. The results show that as-prepared HC exhibits significantly enhanced electrochemical performance for Na⁺ storage when the molar ratio of NaCl to KCl is 1:1. The optimized material achieves a reversible capacity of 366.7 mAh g⁻¹ at the current density of 100 mA g⁻¹ after 60 cycles and retains 99% of its initial capacity after 500 cycles at a current density of 1 A g⁻¹. The main finding is that the lattice spacing can be regulated by tuning the composition of the molten salt, and anode performance is enhanced remarkably by changes in the HC structure. This work provides a feasible strategy for designing and preparing a bituminous coal-derived carbon anode material for use in the energy storage field. Full article

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

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13 pages, 1919 KB

Open AccessCommunication

An Innovative Solution Method for the Evaluation of CO₂ Disposal in the Seafloor Environment

by Boyun Guo, Muhammad Towhidul Islam and Vincent Nana Boah Amponsah

C 2025, 11(4), 81; https://doi.org/10.3390/c11040081 - 27 Oct 2025

Viewed by 864

Abstract

Injecting carbon dioxide (CO₂) into underground geo-structures, such as depleted oil and gas reservoirs, reduces man-made CO₂ emissions into the atmosphere or removes what is already there. Studies have identified the risks of CO₂ leaks from these underground geo-structures [...] Read more.

Injecting carbon dioxide (CO₂) into underground geo-structures, such as depleted oil and gas reservoirs, reduces man-made CO₂ emissions into the atmosphere or removes what is already there. Studies have identified the risks of CO₂ leaks from these underground geo-structures through wellbores back into the atmosphere due to the high mobility of CO₂ in gaseous and supercritical states. This work aims at proposing a novel method of CO₂ storage using the Joule–Thomson cooling effect to effectively produce CO₂ hydrates on seafloors, with an objective to avoid the leakage risks of storage in depleted oil and gas reservoirs. Through the combination of thermodynamic data, analysis of hydrate stability, and engineering design with established working parameters, this study proposes an innovative concept and an enabling process for CO₂ placement onto seafloors for safe storage. The results of case analysis of typical seawater conditions reveal that the appropriate seafloor depth ranges for different applications (>1900 m for liquid CO₂ and 700–1900 m for CO₂ hydrate). An engineering design procedure for real applications is outlined. Full article

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

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12 pages, 1658 KB

Open AccessArticle

Supercapacitor Using Polypyrrole and Carbon Nanotube Composite as Electrodes

by Arturo Tepale-Cortés, Hilda Moreno-Saavedra, Marquidia J. Pacheco, Joel O. Pacheco, Celso Hernández-Tenorio and Ricardo Valdivia

C 2025, 11(4), 80; https://doi.org/10.3390/c11040080 - 24 Oct 2025

Viewed by 1040

Abstract

Electrodes and electrolytes are critical components for the performance of supercapacitors. In this study, supercapacitors with different interfaces were assembled using polypyrrole (PPy) or a polypyrrole–carbon nanotube (PPy-CNT) composite as active materials, and dimethyl sulfoxide (DMSO) and sodium chloride (NaCl) were used as [...] Read more.

Electrodes and electrolytes are critical components for the performance of supercapacitors. In this study, supercapacitors with different interfaces were assembled using polypyrrole (PPy) or a polypyrrole–carbon nanotube (PPy-CNT) composite as active materials, and dimethyl sulfoxide (DMSO) and sodium chloride (NaCl) were used as electrolytes. Electrochemical measurements were obtained by cyclic voltammetry (CV) at a scan rate of 20 mV/s and galvanostatic charge–discharge (GCD) measurements at a scan rate of 50 µA/s. The results suggest that the supercapacitor with a PPy-CNT composite and NaCl electrolyte has promising electrochemical characteristics. Full article

(This article belongs to the Special Issue Carbon and Related Composites for Sensors and Energy Storage: Synthesis, Properties, and Application (2nd Edition))

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21 pages, 677 KB

Open AccessReview

Carbon Black Nanoparticles in Non-Instrumental Immunoassays Development for Diagnostic Applications

by Maria Nikitina, Stepan Devyatov and Mikhail Rayev

C 2025, 11(4), 79; https://doi.org/10.3390/c11040079 - 14 Oct 2025

Viewed by 1103

Abstract

Due to their unique physicochemical properties, carbon black nanoparticles represent a promising alternative for solving analytical problems. However, diagnostic reagents based on carbon black nanoparticles have not yet found widespread practical application. This review examines the development and application of carbon black nanoparticle [...] Read more.

Due to their unique physicochemical properties, carbon black nanoparticles represent a promising alternative for solving analytical problems. However, diagnostic reagents based on carbon black nanoparticles have not yet found widespread practical application. This review examines the development and application of carbon black nanoparticle conjugates with recognition molecules as diagnostic reagents in test systems that enable non-instrumental interpretation of results. The review critically evaluates the methods for synthesis and characterization of carbon black-based diagnostic reagents. Furthermore, the review summarizes and discusses existing studies comparing the effectiveness of carbon black nanoparticle-based bioconjugates with traditional colorimetric labels. The scientific articles included in the review were carefully analyzed for the presence of an assessment of the reproducibility of methods for obtaining diagnostic reagents based on carbon black nanoparticles and their long-term storage. The main challenges and future prospects of using carbon black nanoparticles in immunoassays are discussed. Full article

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

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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

Viewed by 1045

Abstract

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

Viewed by 1195

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

Viewed by 1133

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

Viewed by 927

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

Viewed by 1055

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

Viewed by 1114

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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C, Volume 11, Issue 4 (December 2025) – 23 articles

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