C | Special Issue : 10th Anniversary of C — Journal of Carbon Research

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31 pages, 3293 KB

Open AccessArticle

Fe/N/C Catalyst Production by Collinear CO₂ Laser Pyrolysis: Toward a Specific Mass-Weighted Energy-Deposited (J.g⁻¹) Parameter Opening Discussion on FeN_x Site Formation

by Henri Perez, Claire Dazon, Pierre Lonchambon, Suzy Surblé, Emeline Charon, Mathieu Frégnaux, Arnaud Etcheberry, Charles Rivron and Olivier Sublemontier

C 2026, 12(2), 33; https://doi.org/10.3390/c12020033 - 15 Apr 2026

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Abstract

We report the synthesis of Fe/N/C ORR electrocatalysts by an original collinear CO₂ laser pyrolysis of liquid aerosol droplets in various configurations and compared them to a catalyst synthesized in the classical perpendicular one. While the precursors were always injected at the [...] Read more.

We report the synthesis of Fe/N/C ORR electrocatalysts by an original collinear CO₂ laser pyrolysis of liquid aerosol droplets in various configurations and compared them to a catalyst synthesized in the classical perpendicular one. While the precursors were always injected at the bottom side of the reactor, two collinear configurations of the laser entry into the reactor are considered: by the Top Side (T.S.) or by the Bottom Side (B.S.). The two corresponding catalysts sets show significant different ORR performances. An in-depth XPS analysis and fitting of the N1s spectra allowed for drawing the ORR performance as a function of FeN_x sites components. An original approach considering the energy delivered to a quantity of precursors in J.g⁻¹, linked to the flame temperature feature, evidenced very different conditions for perpendicular CO₂ laser pyrolysis and each of the two collinear configurations. This mass-weighted energy delivered in the classical perpendicular configuration is too low to allow for the formation of FeN_x sites and the resulting ORR performance is extremely poor, suggesting a marginal role of nitrogen species without interaction with iron atoms. In contrast, the delivered mass-weighted energies are sufficient in both collinear configurations to produce FeN_x sites. The ORR performance for catalysts produced in these both configurations is positively correlated with the amount of energy deposited on the precursors. The ORR performance in the T.S. laser configuration is positively correlated to the amount of FeN_x sites. The best performing catalysts obtained in the B.S. configuration show an opposite variation. These trends, and the ORR performance degradation of B.S. catalysts under prolonged chronoamperometry are discussed in light of the effect of temperature on the formation of the various kind of FeN_x sites. A tentative explanation is given, considering that N1s XPS fitting with a single FeN_x component may hinder the fact that Pyridinic sites components may contain a part of FeN_x sites, as suggested by theoretical calculation from the literature. The best catalysts obtained in this work by collinear configuration show similar performances to those obtained by double stage perpendicular pyrolysis previously reported with an ORR onset potential of ~860 mV. Full article

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

26 pages, 7005 KB

Open AccessArticle

Eco-Friendly Orange Peels/Aluminum/Graphene Oxide Composites for Reactive Red 120 and Methylene Violet Dye Removal from Textile Wastewater

by Sofia Fykari, George Z. Kyzas and Athanasia K. Tolkou

C 2026, 12(1), 23; https://doi.org/10.3390/c12010023 - 5 Mar 2026

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Abstract

In this work, sustainable aluminum-modified orange peels functionalized with graphene oxide (OP-Al-GO) were synthesized and evaluated for the removal of Methylene Violet (MV) and Reactive Red 120 (RR120) from aqueous solutions. Adsorption performance was systematically investigated in single-dye systems, binary dye mixtures, and [...] Read more.

In this work, sustainable aluminum-modified orange peels functionalized with graphene oxide (OP-Al-GO) were synthesized and evaluated for the removal of Methylene Violet (MV) and Reactive Red 120 (RR120) from aqueous solutions. Adsorption performance was systematically investigated in single-dye systems, binary dye mixtures, and real textile wastewater samples, and compared with that of orange peels (OP), orange peel–aluminum composite (OP-Al), and graphene oxide (GO). pH_pzc analysis clarified the surface charge of the adsorbent, while SEM and FTIR showed that the incorporation of aluminum and GO increased roughness and functional groups appearance, enhancing dye adsorption and confirming successful interactions. The OP-Al-GO composites exhibited improved removal efficiency for both dyes (64.8% for RR120 and 96.2% for MV) at pH 3.0. The presence of aluminum improved structural stability and surface charge regulation, while graphene oxide contributed to multiple adsorption mechanisms, including electrostatic attraction and π–π interactions. The adsorption kinetics were found to follow a pseudo-second-order (PSO) kinetic model for RR120 and an intraparticle-diffusion model (IPD) for MV, while isotherm analysis revealed a Langmuir behavior for MV and a Freundlich behavior for RR120. Langmuir maximum adsorption capacities were 298.7 and 10.8 mg/g for MV and RR120, respectively. High removal efficiency was maintained in binary dye mixtures, with OP-Al-GO achieving 96.9% removal of MV and 85.7% of RR120. Furthermore, the proposed adsorbent was tested on real wastewater samples, and the results highlight that the proposed adsorbents are promising, low-cost, and environmentally sustainable for textile wastewater treatment. Full article

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

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10 pages, 1352 KB

Open AccessArticle

Rectifying and Photoconductive Responses in Graphene–Double-Insulator–Graphene (GI²G) Structures

by Takashi Uchino, Yanjun Heng, Chao Tang, Akira Satou, Hirokazu Fukidome and Taiichi Otsuji

C 2026, 12(1), 18; https://doi.org/10.3390/c12010018 - 20 Feb 2026

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Abstract

Advanced solar energy-harvesting devices, such as optical rectennas, typically use metal–insulator–metal diodes because of the ultrafast response of these diodes at high frequencies. However, the diode performance is limited by weak current–voltage (I–V) asymmetry and optical losses in metallic [...] Read more.

Advanced solar energy-harvesting devices, such as optical rectennas, typically use metal–insulator–metal diodes because of the ultrafast response of these diodes at high frequencies. However, the diode performance is limited by weak current–voltage (I–V) asymmetry and optical losses in metallic electrodes. Graphene offers a promising alternative electrode material owing to its high carrier mobility, broadband optical transparency, and compatibility with nanoscale device architectures. Nevertheless, graphene-based optical rectennas face challenges associated with insufficient diode nonlinearity. In this study, we developed a vertically stacked graphene–double-insulator–graphene (GI²G) tunnel diode. Devices with various junction sizes were fabricated to investigate size-dependent rectifying behavior. A reduced graphene overlap area was defined by electron-beam lithography to introduce asymmetry and increase nonlinear conduction. An Al₂O₃/SiO₂ tunnel barrier composed of dielectrics with different band gaps and electron affinities improved the asymmetric I–V characteristics. Photoresponse measurements under AM1.5G illumination revealed a clear photocurrent, indicating rectification-related photoresponse. The photoresponse increased with decreasing junction area, which is consistent with enhanced rectification performance in smaller junctions. These results demonstrate that the GI²G tunnel diode provides a promising platform for next-generation energy harvesting and optical sensing applications. Full article

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

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12 pages, 1228 KB

Open AccessArticle

Background Issues in X-Ray Diffraction and Raman Spectroscopy of Carbon Materials

by Pascal Puech, Sébastien Moyano, Petros Mubari, Elsa Weiss-Hortala and Marc Monthioux

C 2026, 12(1), 2; https://doi.org/10.3390/c12010002 - 27 Dec 2025

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Abstract

Removing background signals is a common preprocessing step, but it is not without drawbacks. In X-ray diffraction data, background correction can artificially symmetrize diffraction peaks, which becomes a critical issue for lamellar materials such as graphenic carbon when the Laue indices lie in [...] Read more.

Removing background signals is a common preprocessing step, but it is not without drawbacks. In X-ray diffraction data, background correction can artificially symmetrize diffraction peaks, which becomes a critical issue for lamellar materials such as graphenic carbon when the Laue indices lie in the plane (e.g., the 10 and 11 peaks). We discuss several approaches to background correction and their implications for the resulting data. In Raman spectroscopy, defects activate the phonon density of states, leading to higher intensity below the D band than above the G band, with respect to the Raman shift. After discussing the linear and circular polarization on the Raman selection rules, we show how flattening the background—a widely used measure of disorder—alters the I_D/I_G ratio. Finally, principal component analysis (PCA) provides a useful preliminary exploration of data structure; however, because its components may include negative contributions, it cannot be directly applied to spectral decomposition. In contrast, non-negative component decomposition offers an optimal way to preserve the Raman background, even in the presence of luminescence. We confirm our analysis with ANOVA p-values. Full article

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

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19 pages, 6173 KB

Open AccessArticle

Strain-Engineered Thermal Transport at One- to Two-Dimensional Junctions in 3D Nanostructures

by Moath Al Hayek, Aayush Patel, Joshua Ellison and Jungkyu Park

C 2026, 12(1), 1; https://doi.org/10.3390/c12010001 - 19 Dec 2025

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Abstract

In the present study, molecular dynamics simulations with three interatomic potentials (Polymer Consistent Force Field, Adaptive Intermolecular Reactive Empirical Bond Order, and Tersoff) are employed to investigate strain-dependent interfacial thermal resistance across one-dimensional to two-dimensional junctions. Carbon nanotube–graphene junctions exhibit exceptionally low interfacial [...] Read more.

In the present study, molecular dynamics simulations with three interatomic potentials (Polymer Consistent Force Field, Adaptive Intermolecular Reactive Empirical Bond Order, and Tersoff) are employed to investigate strain-dependent interfacial thermal resistance across one-dimensional to two-dimensional junctions. Carbon nanotube–graphene junctions exhibit exceptionally low interfacial resistances (1.69–2.37 × 10⁻¹⁰ K·m²/W at 300 K)—two to three orders of magnitude lower than conventional metal–dielectric interfaces. Strain-dependent behavior is highly potential-dependent, with different potentials showing inverse, positive, or minimal strain sensitivity. Local phonon density of states analysis with Tersoff reveals that strain-induced spectral redistribution in graphene toward lower frequencies enhances phonon coupling with carbon nanotube modes. Temperature significantly affects resistance, with 37–59% increases at 10 K compared to 300 K due to long-wavelength phonon scattering. Boron nitride nanotube–hexagonal boron nitride nanosheet junctions exhibit 60% higher resistance (3.2 × 10⁻¹⁰ K·m²/W) with temperature-dependent strain behavior and spacing-insensitive performance. Interfacial resistance is independent of pillar height, confirming junction-dominated transport. The discovery of exceptionally low interfacial resistances and material-specific strain responses enables the engineering of thermally switchable devices and mechanically robust thermal pathways. These findings directly address critical challenges in next-generation flexible electronics where devices must simultaneously manage high heat fluxes while maintaining thermal performance under repeated mechanical deformation. 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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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

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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

Cited by 1 | Viewed by 1580

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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15 pages, 4855 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

Cited by 1 | Viewed by 1855

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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14 pages, 2008 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

Cited by 1 | Viewed by 1621

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, 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

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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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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

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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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13 pages, 1309 KB

Open AccessArticle

Thermal Conductivity of Graphene Moiré Superlattices at Small Twist Angles: An Approach-to-Equilibrium Molecular Dynamics and Boltzmann Transport Study

by Lorenzo Manunza, Riccardo Dettori, Antonio Cappai and Claudio Melis

C 2025, 11(3), 46; https://doi.org/10.3390/c11030046 - 30 Jun 2025

Cited by 2 | Viewed by 3232

Abstract

We investigate the thermal conductivity of graphene Moiré superlattices formed by twisting bilayer graphene (TBG) at small angles, employing approach-to-equilibrium molecular dynamics and lattice dynamics calculations based on the Boltzmann Transport Equation. Our simulations reveal a non-monotonic dependence of the thermal conductivity on [...] Read more.

We investigate the thermal conductivity of graphene Moiré superlattices formed by twisting bilayer graphene (TBG) at small angles, employing approach-to-equilibrium molecular dynamics and lattice dynamics calculations based on the Boltzmann Transport Equation. Our simulations reveal a non-monotonic dependence of the thermal conductivity on the twisting angle, with a local minimum near the first magic angle (

θ \sim

1.1°). This behavior is attributed to the evolution of local stacking configurations—AA, AB, and saddle-point (SP)—across the Moiré superlattice, which strongly affect phonon transport. A detailed analysis of phonon mean free paths (MFP) and mode-resolved thermal conductivity shows that AA stacking suppresses thermal transport, while AB and SP stackings exhibit enhanced conductivity owing to more efficient low-frequency phonon transport. Furthermore, we establish a direct correlation between the thermal conductivity of twisted structures and the relative abundance of stacking domains within the Moiré supercell. Our results demonstrate that even very small changes in twisting angle (<2°) can lead to thermal conductivity variations of over 30%, emphasizing the high tunability of thermal transport in TBG. Full article

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18 pages, 1917 KB

Open AccessArticle

Bimetallic Copper–Indium Co-Doped Titanium Dioxide Towards Electrosynthesis of Urea from Carbon Dioxide and Nitrate

by Youcai Meng, Tianran Wei, Zhiwei Wang, Caiyun Wang, Junyang Ding, Yang Luo and Xijun Liu

C 2025, 11(3), 44; https://doi.org/10.3390/c11030044 - 27 Jun 2025

Cited by 1 | Viewed by 1421

Abstract

Electrocatalytic urea synthesis offers great potential for sustainable strategies through CO₂ and NO₃⁻ reduction reactions. However, the development of high-performance catalysts is often hampered by the complexity of synthetic methodologies and the unresolved nature of C-N coupling pathways. In this [...] Read more.

Electrocatalytic urea synthesis offers great potential for sustainable strategies through CO₂ and NO₃⁻ reduction reactions. However, the development of high-performance catalysts is often hampered by the complexity of synthetic methodologies and the unresolved nature of C-N coupling pathways. In this study, we present a copper–indium co-doped titanium dioxide (CuIn-TiO₂) catalyst that exhibits remarkable efficacy in enhancing the synergistic reduction of CO₂ and NO₃⁻ to produce urea. The bimetallic CuIn site functions as the primary active site for the C-N coupling reaction, achieving a urea yield rate of 411.8 μg h⁻¹ mg_cat⁻¹ with a Faradaic efficiency of 6.7% at −0.8 V versus reversible hydrogen electrode (vs. RHE). A body of experimental and theoretical research has demonstrated that the nanoscale particles enhance the density of active sites and improve the feasibility of reactions on the surface of TiO₂. The co-doping of Cu and In has been shown to significantly enhance electronic conductivity, increase the adsorption affinity for *CO₂ and *NO₃⁻, and promote the C-N coupling process. The CuIn-TiO₂ catalyst has been demonstrated to effectively promote the reduction of NO₃⁻ and CO₂, as well as accelerate the C-N coupling reaction. This effect is a result of a synergistic interaction among the catalyst’s components. Full article

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

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17 pages, 5479 KB

Open AccessArticle

Fracture Mechanics of Tetragraphene: Effects of Structural Variations and Loading Conditions

by Elnaz Haddadi and Alireza Tabarraei

C 2025, 11(3), 40; https://doi.org/10.3390/c11030040 - 24 Jun 2025

Cited by 1 | Viewed by 1278

Abstract

Despite the promising electronic properties of graphene, its lack of an intrinsic bandgap limits its applicability in semiconductor technologies. This has catalyzed the investigation of newly developed two-dimensional carbon materials, including tetragraphene (TG), a quasi-2D semiconducting material featuring a combination of hexagonal and [...] Read more.

Despite the promising electronic properties of graphene, its lack of an intrinsic bandgap limits its applicability in semiconductor technologies. This has catalyzed the investigation of newly developed two-dimensional carbon materials, including tetragraphene (TG), a quasi-2D semiconducting material featuring a combination of hexagonal and tetragonal rings. This study aims to investigate the mechanical and fracture behaviors of TG using density functional theory (DFT) and molecular dynamics (MD) simulations, studying two distinct atomic configurations of tetragraphene. DFT simulations assess the mechanical properties, while MD simulations explore the fracture dynamics subjected to mixed mode I (opening mode) and mode II (in-plane shear mode) loading. Our analysis focuses on the influence of loading phase angle, crack edge chirality, crack tip configuration, and temperature on crack propagation paths and critical stress intensity factors (SIFs) in TG structures. Our results show that the critical SIF varies by 12.5–21% depending on the crack chirality. Across all loading conditions, increasing the temperature ranging from 300 K to 2000 K reduces the critical SIF by 10–45%, with the largest reductions observed under pure mode I loading. These outcomes offer important insights into the structural integrity of TG and inform its potential integration into flexible nanoelectronic devices, where mechanical reliability is essential. Full article

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Review

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29 pages, 4706 KB

Open AccessReview

From Production to Market: Challenges and Opportunities of Graphene-Related Materials

by Gimhani Danushika, Pei Lay Yap, Siavash Aghili, Gurleen Singh Sandhu and Dusan Losic

C 2026, 12(2), 35; https://doi.org/10.3390/c12020035 - 22 Apr 2026

Viewed by 795

Abstract

Graphene-related materials (GRMs) possess exceptional electrical, mechanical, thermal, and surface properties, offering significant potential across broad sectors and applications in electronics, energy storage, composites, and environmental technologies. Despite extensive investment in academic research and translation, large-scale industrial adoption of GRMs remains slower than [...] Read more.

Graphene-related materials (GRMs) possess exceptional electrical, mechanical, thermal, and surface properties, offering significant potential across broad sectors and applications in electronics, energy storage, composites, and environmental technologies. Despite extensive investment in academic research and translation, large-scale industrial adoption of GRMs remains slower than projected. This review systematically analyzes the global graphene manufacturing landscape using available data from 100 commercial producers, with a focused evaluation of manufacturing technology, types and forms of produced GRMs, raw material sources, product forms, industrial quality control and characterization practices. Graphite-based production routes, particularly graphene oxide (GO) and reduced graphene oxide (rGO), dominate in the market due to their scalability and cost advantages. However, substantial inconsistencies in the quality of produced GRMs, characterization and standardization depth, analytical evidence, and technical data sheets (TDSs) remain widespread. A SWOT (strengths, weaknesses, opportunities and threats) analysis of emerging graphene in the industry highlights technological maturity and expanding market demand but reveals critical weaknesses and challenges in quality, standardization and cost–performance alignment. Overall, quality of manufactured materials, quality control transparency, and standardization rather than material manufacturing limitations emerge as the primary barriers to the widespread commercial realization of graphene. Full article

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

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21 pages, 1834 KB

Open AccessReview

Porous Carbon Materials for Organophosphate Removal—Implications for Long-Term Neurotoxicity Exposure

by Tamara Lazarević-Pašti, Vedran Milanković, Nevena Radivojević and Tamara Terzić

C 2026, 12(1), 25; https://doi.org/10.3390/c12010025 - 18 Mar 2026

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Abstract

Organophosphate pesticides (OPs) are widespread contaminants in agricultural and aquatic environments. Growing evidence indicates that even low-level, chronic exposure to OPs is associated with neurotoxic effects and long-term neurological risks. Over the past decade, substantial progress has been made in developing porous carbon [...] Read more.

Organophosphate pesticides (OPs) are widespread contaminants in agricultural and aquatic environments. Growing evidence indicates that even low-level, chronic exposure to OPs is associated with neurotoxic effects and long-term neurological risks. Over the past decade, substantial progress has been made in developing porous carbon materials capable of efficiently removing OPs from water, food systems, and other environmental matrices. However, adsorption studies have largely focused on equilibrium performance metrics rather than on conditions relevant to real exposure scenarios. This review introduces an exposure-oriented perspective for evaluating porous carbon materials for OP mitigation by linking adsorption science with exposure-driven neurotoxicity considerations. By analysing recent studies on OP adsorption, we demonstrate that equilibrium adsorption capacity alone is often a poor predictor of real-world exposure mitigation. Instead, adsorption kinetics at low concentrations, pore accessibility, and surface chemical heterogeneity emerge as key factors governing sustained OP sequestration. The review further highlights how hierarchical pore architectures and balanced surface functionalization can enhance adsorption efficiency under environmentally realistic conditions. By integrating environmental carbon research with exposure-relevant considerations, this work outlines design principles for carbon adsorbents to reduce long-term OP exposure and associated neurological risks. Full article

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

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41 pages, 5104 KB

Open AccessReview

Spin Covalent Chemistry of Carbon

by Elena F. Sheka

C 2026, 12(1), 20; https://doi.org/10.3390/c12010020 - 28 Feb 2026

Viewed by 953

Abstract

This review presents the covalent chemistry of carbon from the point of the spin-radical concept of electron interaction in the framework of the unrestricted molecular orbitals (UHF MO) theory. Using the language of valence bond trimodality, the regions of classical spinless spin-symmetric covalence [...] Read more.

This review presents the covalent chemistry of carbon from the point of the spin-radical concept of electron interaction in the framework of the unrestricted molecular orbitals (UHF MO) theory. Using the language of valence bond trimodality, the regions of classical spinless spin-symmetric covalence and its spin-dependent asymmetric counterpart are defined. Carbon is the only element exhibiting spin covalent chemistry. Classical covalent chemistry of carbon of molecular substances whose valence bond structure includes segregate or chained single sp³

C - C

bonds meet its spin counterpart only at these bonds breaking. Substances with double sp²

C = C

and triple sp¹

C \equiv C

bonds are the subject of spin covalent chemistry of carbon. The mathematical apparatus of the UHF MO allows forming algorithms controlling the chemical modification of carbon substances, polymerization processes, and catalysis involving them, making it possible to supplement the empirical spin covalent chemistry of carbon with its virtual analog. Full article

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

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18 pages, 667 KB

Open AccessReview

Reassessed Ability of Carbon-Based Physisorbing Materials to Keep Pace with Evolving Practical Targets for Hydrogen Storage

by Patrick L. Langlois, Chavdar P. Chilev and Farida D. Lamari

C 2026, 12(1), 9; https://doi.org/10.3390/c12010009 - 21 Jan 2026

Viewed by 796

Abstract

This study provides a comprehensive overview of research and advancements on carbon materials with regard to practical targets for hydrogen storage in terms of gravimetric and volumetric capacities. For the sake of clarity, only the most relevant references on hydrogen storage by adsorption [...] Read more.

This study provides a comprehensive overview of research and advancements on carbon materials with regard to practical targets for hydrogen storage in terms of gravimetric and volumetric capacities. For the sake of clarity, only the most relevant references on hydrogen storage by adsorption are presented, although the study was conducted in the same exhaustive manner as the one initially carried out by Anne C. Dillon and Michael J. Heben in 2001 with a particular emphasis on emerging technologies and potential applications in various sectors. This study also focuses on the importance of carbon-based materials with high specific surface areas and porous structures optimised to maximise adsorption—including at high pressure—while primarily limiting references herein to experimentally validated results. It therefore offers insights into the porous materials, as well as the methodologies—including a fully comprehensive and so-far proven highly transferable intermolecular hydrogen model combining van der Waals’s and Coulomb’s forces—used to improve hydrogen solid storage efficiency. Full article

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

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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

Cited by 3 | Viewed by 3571

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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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

Cited by 2 | Viewed by 2039

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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