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Volume 11
Issue 3
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C, Volume 11, Issue 3 (September 2025) – 33 articles

Cover Story (view full-size image): The disposal of medical device waste is an international problem that has been exacerbated by the increasing prevalence of point of care testing devices. The material composition of the latter is largely based on non-degradable plastics which, when spent, are typically discarded for incineration. There is a pressing need for the development of new biodegradable polymers that can serve as electrode substrates and which, ideally, originate from sustainable sources. The combination of psyllium husk with carbon nano particles could potentially meet such demanding requirements through the ability of the composites to form conductive hydrogels and intricate 3D microneedle structures. Formed from aqueous solution, these novel substrates offer new opportunities for the simple and clean manufacture of disposable electrochemical sensors. View this paper
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20 pages, 21513 KB  
Article
Tribological Properties and Wear Mechanisms of Carbide-Bonded Graphene Coating on Silicon Substrate
by Xiaomeng Zhu, Xiaojun Liu, Lihua Li, Kun Liu and Jian Zhou
C 2025, 11(3), 72; https://doi.org/10.3390/c11030072 - 15 Sep 2025
Viewed by 900
Abstract
Carbide-bonded graphene (CBG) coating, with its unique 3D cross-linked network structure, shows significant potential for protecting silicon substrates. However, a comprehensive understanding of its macroscale tribological properties remains lacking. This study investigated the macroscale friction and wear behaviors of CBG-coated silicon wafers using [...] Read more.
Carbide-bonded graphene (CBG) coating, with its unique 3D cross-linked network structure, shows significant potential for protecting silicon substrates. However, a comprehensive understanding of its macroscale tribological properties remains lacking. This study investigated the macroscale friction and wear behaviors of CBG-coated silicon wafers using reciprocating sliding tests against steel balls under various loads and sliding cycles. The CBG coating exhibited excellent friction-reduction and anti-wear performance, reducing the steady friction coefficient from 0.80 to 0.17 and wear rate by an order of magnitude compared to those of bare silicon. Higher loads slightly decreased both friction coefficients and wear rates, primarily due to the formation of denser tribofilms and transfer layers. Re-running experiments revealed three distinct wear stages—adhesive, abrasive, and accelerated substrate wear—driven by the evolution of tribofilms, transfer layers, and unabraded flat areas. Furthermore, comparative experiments confirmed that these “unabraded flat areas” on the wear track play a critical role in sustaining low friction and prolonging coating life. The findings identify CBG as a robust solid lubricant for high-contact-pressure applications and emphasize the influence of tribo-layer dynamics and wear debris behavior on coating performance. Full article
(This article belongs to the Topic Application of Graphene-Based Materials, 2nd Edition)
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12 pages, 5425 KB  
Article
Effect of Carbon Fixation Time on the Properties of Gangue–Fly Ash Composite Filling Materials: Carbon Fixation Amount and Rheological Properties
by Haiquan Liu, Qiang Guo, Yong Chen, Yifan Zhang, Binbin Huo and Meng Li
C 2025, 11(3), 71; https://doi.org/10.3390/c11030071 - 8 Sep 2025
Viewed by 725
Abstract
Coal-based solid wastes are used for carbon fixation, which can achieve the dual purpose of resource utilization of coal-based solid wastes and CO2 storage, but carbon fixation has a negative impact on the rheological properties of filling slurry. This paper explores the [...] Read more.
Coal-based solid wastes are used for carbon fixation, which can achieve the dual purpose of resource utilization of coal-based solid wastes and CO2 storage, but carbon fixation has a negative impact on the rheological properties of filling slurry. This paper explores the effect of carbon fixation time on the carbon fixation performance and rheological properties of coal gangue (CG)–fly ash (FA) composite filling materials (CFS) through rheometer, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and other testing methods. The results show that, with an increase in the carbon fixation time, the carbon fixation amount of the CFS shows a trend of increasing first and then stabilizing. Considering the carbon fixation amount and rheological properties of the CFS together, the optimal carbon fixation time is 2 h. At this time, the carbon fixation amount of the CFS is 1.18%, and the yield stress and plastic viscosity are 155.93 Pa and 0.17 Pa·s, respectively. However, with a further increase in the carbon fixation time, the carbon fixation amount basically tends to be stable, mainly because the calcium ions in the CFS are gradually consumed by the reaction as the carbon fixation time increases. The research results are of great significance for improving the utilization of coal-based solid waste and CO2 storage. Full article
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15 pages, 3020 KB  
Article
Enhanced Electrocatalytic Activity for ORR Based on Synergistic Effect of Hierarchical Porosity and Co-Nx Sites in ZIF-Derived Heteroatom-Doped Carbon Materials
by Yan Yang, A-Min Tan, Qiu-Xuan Ren and Gai Zhang
C 2025, 11(3), 70; https://doi.org/10.3390/c11030070 - 8 Sep 2025
Viewed by 907
Abstract
The hierarchical porosity and active sites of porous carbon materials have significant impacts on the oxygen reduction reaction (ORR) process. The heteroatom-doped porous carbon materials (Z67-900, Z8-900, Z11-900, Z12-900) were synthesized by pyrolysis of ZIFs to reveal the synergistic effect of hierarchical porosity [...] Read more.
The hierarchical porosity and active sites of porous carbon materials have significant impacts on the oxygen reduction reaction (ORR) process. The heteroatom-doped porous carbon materials (Z67-900, Z8-900, Z11-900, Z12-900) were synthesized by pyrolysis of ZIFs to reveal the synergistic effect of hierarchical porosity and Co-Nx sites. The structures of prepared materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, and nitrogen adsorption. The results of electrocatalytic performance show that Z67-900 has the best performance among the four materials prepared. The onset potential (E0) of Z67-900 is close to commercial Pt/C (20%), and the half-wave potential (E1/2) of Z67-900 is 80 mV positive than that of Pt/C in an O2-saturated 0.1 M KOH solution (1600 rpm) with sweep rate of 5 mV·s−1. Moreover, Z67-900 has better methanol resistance. The hierarchical pore structure of Z67-900 facilitates mass transfer, while the Co-Nx sites provide active catalytic centers. This study provides a solid foundation for the rational design of highly efficient ZIF-derived heteroatom-doped catalysts. Full article
(This article belongs to the Section Carbon Materials and Carbon Allotropes)
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18 pages, 1709 KB  
Article
Formation of Improved Metallurgical Properties and Carbon Structure of Coke by Optimizing the Composition of Petrographically Heterogeneous Interbasin Coal Batches
by Denis Miroshnichenko, Kateryna Shmeltser, Maryna Kormer, Leonid Bannikov, Serhii Nedbailo, Mykhailo Miroshnychenko, Natalya Mukina and Mariia Shved
C 2025, 11(3), 69; https://doi.org/10.3390/c11030069 - 4 Sep 2025
Viewed by 997
Abstract
Given the multi-basin raw material base for coking that has been formed at most industry enterprises, there is an urgent need to optimize the component composition and improve the basic technological methods of coal raw material preparation, taking into account the petrographic characteristics [...] Read more.
Given the multi-basin raw material base for coking that has been formed at most industry enterprises, there is an urgent need to optimize the component composition and improve the basic technological methods of coal raw material preparation, taking into account the petrographic characteristics of coal batches. A comprehensive study of the components included in a coke chemical enterprise’s coking raw material base was carried out. The work used standardized methods for studying coal and coal batches’ technological and plastic–viscous properties. The qualitative characteristics of coke were determined using physical–mechanical and thermochemical methods of studying standardized indicators: crushability (M25), abrasion (M10), reactivity (CRI), post-reaction strength (CSR), and specific electrical resistance (ρ). The results were analyzed using the licensed Microsoft Excel computer program. Based on the results of proximate, plastometric, and petrographic analyses of the studied coal samples and data from experimental industrial coking, proposals were made to optimize the component composition, properties of the coal batch, and technology for its preparation for coking. The established inverse dependence of Gibbs free energy (ΔGf,total) on the reaction capacity of coke CRI and its direct reliance on its post-reaction strength CSR confirmed the feasibility of using ΔGf,total as a thermodynamic predictive parameter for optimizing and compiling coal batches that produce less reactive, stronger coke. This made it possible to improve the quality indicators of metallurgical coke. Thus, according to the M25 crushability index, the mechanical strength increased by 0.6%, and the M10 abrasion decreased by 0.4%. Significant improvements in thermochemical properties and an increase in the orderliness of the carbon structure were recorded: the CRI reactivity decreased by 3.1%, the CSR post-reaction strength increased by 8.3%, and the specific resistance decreased by 8.4%. Full article
(This article belongs to the Topic Advances in Carbon-Based Materials)
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13 pages, 3960 KB  
Article
NaOH-Modified Activated Carbon Materials for Hydrogen Sulfide Removal
by Meriem Abid, Manuel Martínez-Escandell and Joaquín Silvestre-Albero
C 2025, 11(3), 68; https://doi.org/10.3390/c11030068 - 3 Sep 2025
Viewed by 1219
Abstract
A high-surface-area activated carbon material (RG) is used as a platform to create highly concentrated NaOH composites. These materials are tested for the removal of H2S under industrially relevant conditions (800 ppm H2S in CO2-, H2 [...] Read more.
A high-surface-area activated carbon material (RG) is used as a platform to create highly concentrated NaOH composites. These materials are tested for the removal of H2S under industrially relevant conditions (800 ppm H2S in CO2-, H2O- and O2-containing streams). The experimental results show that the breakthrough performance highly depends on the amount of NaOH incorporated and the experimental conditions used (e.g., relative humidity). The most promising material (RG-NaOH-30) reaches a saturation uptake of up to 800 mgH2S/g at 25 °C and atmospheric pressure. This value is among the most promising results reported in the literature for H2S removal, and it is well above traditional commercial samples. Breakthrough column tests confirm the promoting role of humidity in the reaction mechanism. Analysis of the adsorbents after H2S confirms the formation of well-defined sulfur (Sn) microcrystals as the main reaction product. Full article
(This article belongs to the Special Issue Carbons for Health and Environmental Protection (2nd Edition))
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15 pages, 4854 KB  
Article
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
Viewed by 1033
Abstract
Effective ablative thermal protection systems are essential for ensuring the structural integrity of hypersonic vehicles subjected to extreme aerothermal loads. However, the microscopic reaction mechanisms at the gas–solid interface, particularly under non-equilibrium high-enthalpy conditions, remain poorly understood. This study employs reactive molecular dynamics [...] Read more.
Effective ablative thermal protection systems are essential for ensuring the structural integrity of hypersonic vehicles subjected to extreme aerothermal loads. However, the microscopic reaction mechanisms at the gas–solid interface, particularly under non-equilibrium high-enthalpy conditions, remain poorly understood. This study employs reactive molecular dynamics (RMD) simulations with the ReaxFF-C/H/O force field to investigate the atomic-scale ablation behavior of a graphene-based knitted graphene structure impacted by atomic oxygen (AO). By systematically varying the AO incident kinetic energy (from 0.1 to 8.0 eV) and incidence angle (from 15° to 90°), we reveal the competing interplay between catalytic recombination and ablation processes. The results show that the catalytic recombination coefficient of oxygen molecules reaches a maximum at 5.0 eV, where surface-mediated O2 formation is most favorable. At higher energies, the reaction pathway shifts toward enhanced CO and CO2 production due to increased carbon atom ejection and surface degradation. Furthermore, as the AO incidence angle increases, the recombination efficiency decreases linearly, while C-C bond breakage intensifies due to stronger vertical energy components. These findings offer new insights into the anisotropic surface response of knitted graphene structures under hyperthermal oxygen exposure and provide valuable guidance for the design and optimization of next-generation thermal protection materials for hypersonic flight. Full article
(This article belongs to the Special Issue 10th Anniversary of C — Journal of Carbon Research)
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3 pages, 200 KB  
Editorial
Editorial for Special Issue “Carbon-Based Materials Applied in Water and Wastewater Treatment”
by Athanasia K. Tolkou
C 2025, 11(3), 66; https://doi.org/10.3390/c11030066 - 2 Sep 2025
Viewed by 964
Abstract
In the past decade, carbon nanostructures have emerged as one of the most rapidly advancing areas of research [...] Full article
(This article belongs to the Special Issue Carbon-Based Materials Applied in Water and Wastewater Treatment)
14 pages, 2007 KB  
Article
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
Viewed by 992
Abstract
The treatment of organic phosphate ester (OPE) pollutants in water is a challenging but highly necessary task. In this study, an advanced oxidation process through light activation of peroxymonosulfate (PMS) involving graphene oxide (GO) as a promoter was developed to degrade OPE in [...] Read more.
The treatment of organic phosphate ester (OPE) pollutants in water is a challenging but highly necessary task. In this study, an advanced oxidation process through light activation of peroxymonosulfate (PMS) involving graphene oxide (GO) as a promoter was developed to degrade OPE in water, taking triphenyl phosphate (TPhP) as an example. The developed “Light+PMS+GO” system demonstrated good convenience, high TPhP degradation efficiency, tolerance in a near-neutral pH, satisfactory re-usability, and a low toxicity risk of degradation products. Under the investigated reaction conditions, viz., the full spectrum of a 300 W Xe lamp, PMS of 200 mg L−1, GO of 4 mg L−1, and TPhP of 10 μmol L−1, the “Light+PMS+GO” system achieved nearly 100% TPhP degradation efficiency during a 15 min reaction duration with a 5.81-fold enhancement in the reaction rate constant, compared with the control group without GO. Through quenching experiments and electron paramagnetic resonance studies, singlet oxygen was identified as the main reactive species for TPhP degradation. Further studies implied that GO could accumulate both oxidants and pollutants on the surface, providing additional reaction sites for PMS activation and accelerating electron transfer, which all contributed to the enhancement of TPhP degradation. Finally, the TPhP degradation pathway was proposed and a preliminary toxicity evaluation of degradation intermediates was conducted. The convenience, high removal efficiency, and good re-usability indicates that the developed “Light+PMS+GO” reaction system has great potential for future applications. Full article
(This article belongs to the Special Issue 10th Anniversary of C — Journal of Carbon Research)
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15 pages, 5132 KB  
Article
Characterisation of a Biodegradable Electrode Substrate Based on Psyllium Husk–Carbon Nanoparticle Composites
by Cliodhna McCann, Victoria Gilpin, Regan McMath, Chris I. R. Gill, Karl McCreadie, James Uhomoibhi, Pagona Papakonstantinou and James Davis
C 2025, 11(3), 64; https://doi.org/10.3390/c11030064 - 17 Aug 2025
Viewed by 1027
Abstract
Unrefined psyllium husk derived from Plantago ovata constitutes a complex mixture of water-soluble and insoluble polymeric chains that form an interpenetrating network capable of entrapping carbon nanoparticles. While the resulting composite was found to swell in aqueous electrolyte, it exhibited hydrogel-like properties where [...] Read more.
Unrefined psyllium husk derived from Plantago ovata constitutes a complex mixture of water-soluble and insoluble polymeric chains that form an interpenetrating network capable of entrapping carbon nanoparticles. While the resulting composite was found to swell in aqueous electrolyte, it exhibited hydrogel-like properties where the electrochemical activity was retained and found to be stable upon repetitive voltammetric cycling. Planar film systems were characterized by electron microscopy, Raman spectroscopy, tensile testing, gravimetric analysis, contact angle and cyclic voltammetry. A key advantage of the composite lies in its ability to be cast in 3D geometric forms such as pyramidal microneedle arrays (700 μm high × 200 μm base × 500 μm pitch) that could serve as viable electrode sensors. In contrast to conventional composite electrode materials that rely on non-aqueous solvents, the psyllium mixture is processed entirely from an aqueous solution. This, along with its plant-based origins and simple processing requirements, provides a versatile matrix for the design of biodegradable electrode structures that can be manufactured from more sustainable sources. Full article
(This article belongs to the Section Carbon Materials and Carbon Allotropes)
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15 pages, 1152 KB  
Article
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
Viewed by 891
Abstract
The present study deals with hydrate formation with binary gaseous mixtures consisting of carbon dioxide mixed with ethane at varying concentrations. Since the production of hydrates is recognised as a stochastic process and also due to the marked influence that experimental apparatuses often [...] Read more.
The present study deals with hydrate formation with binary gaseous mixtures consisting of carbon dioxide mixed with ethane at varying concentrations. Since the production of hydrates is recognised as a stochastic process and also due to the marked influence that experimental apparatuses often have on the results, the continuous updating of the literature with new experimental data is needed. Hydrates were produced and dissociated in excess water and in unstirred conditions. The dissociation values were collected and tabulated. Each test was plotted and compared with the phase boundary equilibrium conditions of pure ethane and pure carbon dioxide hydrates. The results confirmed the lowering of pressures required for hydrate formation with the increase in ethane concentration in the gas mixture. In detail, the dissociation condition for CO2/C2H6 hydrates was tested within the following thermodynamic ranges: 0.1–13 °C and 11.26–36.75 bar for the 25/75 vol% mixture, 0.1–13 °C and 9.74–35.07 bar for the 50/50 vol% mixture and 7.0–12.9 °C and 17.36–30.05 bar for the 75/25 vol% mixture. When 75 vol% ethane was used, the dissociation of hydrates occurred at conditions corresponding to the phase equilibrium of pure ethane hydrates, denoting that the system reached the most favourable thermodynamic conditions possible despite the presence of 25 vol% CO2. Full article
(This article belongs to the Special Issue 10th Anniversary of C — Journal of Carbon Research)
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34 pages, 10992 KB  
Article
Graphene-like Carbon Materials from King Grass Biomass via Catalytic Pyrolysis Using K3[Fe(CN)6] as a Dual Catalyst and Activator
by Alba N. Ardila Arias, Erasmo Arriola-Villaseñor, Madelyn Ortiz-Quiceno, Lucas Blandón-Naranjo and José Alfredo Hernández-Maldonado
C 2025, 11(3), 62; https://doi.org/10.3390/c11030062 - 14 Aug 2025
Viewed by 1152
Abstract
The potential of king grass biomass as a precursor for carbon-based materials was evaluated through comprehensive physicochemical characterization. The biomass showed high fixed carbon content, reactive oxygenated groups, and favorable atomic ratios, supporting its suitability for conversion into porous carbon structures. This study [...] Read more.
The potential of king grass biomass as a precursor for carbon-based materials was evaluated through comprehensive physicochemical characterization. The biomass showed high fixed carbon content, reactive oxygenated groups, and favorable atomic ratios, supporting its suitability for conversion into porous carbon structures. This study focused on the synthesis of graphene-like materials via high-temperature pyrolysis (~1000 °C), employing FeCl3 and potassium ferricyanide (K3[Fe(CN)6]) as catalytic agents. Although FeCl3 is widely studied, it showed limited capacity to promote graphitic ordering. In contrast, K3[Fe(CN)6] exhibited a synergistic effect, combining iron-based catalytic species (Fe, Fe3C) and potassium-derived activating compounds (K2CO3), which significantly enhanced graphitization and porosity. Characterization by Raman spectroscopy, XRD, and SEM confirmed that materials synthesized with K3[Fe(CN)6] presented improved crystallinity, lower defect densities (ID/IG = 0.37–1.11), and distinct 2D bands (I2D/IG = 0.32–0.80), indicating the formation of few-layer graphene domains. The most promising structure was obtained from cellulose treated with alkaline peroxide and deoxygenated prior to pyrolysis with K3[Fe(CN)6], showing properties comparable to commercial graphene. BET analysis revealed surface areas up to 714.50 m2/g. While non-catalyzed samples yielded higher mass, the catalytic approach with K3[Fe(CN)6] demonstrates a sustainable and efficient pathway for producing graphene-like carbon materials from lignocellulosic biomass. Full article
(This article belongs to the Special Issue Carbon Innovations in Renewable Energy Systems and Environmental Sustainability)
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24 pages, 10422 KB  
Article
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
Viewed by 865
Abstract
The column photobioreactor has become the predominant approach for carbon sequestration by microalgae in power plant settings, owing to its capacity for high-density cultivation and efficient light energy utilization. Due to the dense arrangement of the columnar photobioreactor and its height, insufficient light [...] Read more.
The column photobioreactor has become the predominant approach for carbon sequestration by microalgae in power plant settings, owing to its capacity for high-density cultivation and efficient light energy utilization. Due to the dense arrangement of the columnar photobioreactor and its height, insufficient light became one of the main factors limiting the carbon sequestration rate of microalgae growth. In this paper, a light resource optimization method of reflective baffle and top diffusing glass was proposed. When the angle of reflective baffle on the north and east walls was 35°, and the angle of reflective baffle on the west and south floors was 0°, the overall light radiation intensity of the reactor array became the largest, reaching up to 916.81 W/m2, which was 14.39% higher than that before the optimization. The replacement of the top glass with diffusing material converted the direct radiation of solar radiation into scattered radiation. When the transmittance was 95% and the haze was 95%, the overall average light radiation intensity of the algal solution reached 830.93 W/m2, which was an increase of 3.7%. Four new exhaust air distribution methods were proposed, in which the three-entrance staggered-arrangement type glasshouse had the lowest algal liquid temperature. Full article
(This article belongs to the Special Issue 10th Anniversary of C — Journal of Carbon Research)
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15 pages, 4099 KB  
Article
Pulsed Laser Annealing of Deposited Amorphous Carbon Films
by Arianna D. Rivera, Eitan Hershkovitz, Panagiotis Panoutsopoulos, Manny X. de Jesus Lopez, Bradley Simpson, Honggyu Kim, Rajaram Narayanan, Jesse Johnson and Kevin S. Jones
C 2025, 11(3), 60; https://doi.org/10.3390/c11030060 - 8 Aug 2025
Viewed by 1231
Abstract
Pulsed laser annealing (PLA) was performed on a 0.3 μm thick hydrogenated amorphous carbon (a-C:H) film deposited on silicon substrate by plasma-enhanced chemical vapor deposition (PECVD). The 532 nm, 32 ns PLA ranged in fluence from 0.2 to 0.94 J cm−2. [...] Read more.
Pulsed laser annealing (PLA) was performed on a 0.3 μm thick hydrogenated amorphous carbon (a-C:H) film deposited on silicon substrate by plasma-enhanced chemical vapor deposition (PECVD). The 532 nm, 32 ns PLA ranged in fluence from 0.2 to 0.94 J cm−2. There were no visible signs of film delamination over the entire fluence range for a single pulse. As the fluence increased, graphitization of the amorphous film bulk was observed. However, at the near surface of the film, there was a concomitant increase in sp3 content. The sp3 bonding observed is the result of the formation of a thin diamond-like layer on the surface of the carbon film. Along with increasing laser fluence, the film swelled by 75% up to 0.6 J cm−2. In addition, carbon fiber formation was observed at 0.6 J cm−2, increasing in size and depth up through 0.94 J cm−2. The origin of this transformation may be associated with a rapid outgassing of hydrogen from the amorphous carbon during the PLA step. Additionally, there was a dramatic increase in the visible light absorption of these thin films with increasing laser fluence, despite the films being less than a micron thick. These results suggest that PLA of a-C:H film is a useful method for modifying the surface structure for optical or electrochemical applications without film ablation. Full article
(This article belongs to the Special Issue Carbon Functionalization: From Synthesis to Applications)
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11 pages, 4453 KB  
Article
In Silico Exfoliation of ReaxFF Graphite—Temperature, Speed, Angle Dependence, and the Effect of Gold Overlayer
by Teruki Ando, Seiya Yokokura, Hiroki Waizumi, Hironori Suzuki, Kenji Kawashima and Toshihiro Shimada
C 2025, 11(3), 59; https://doi.org/10.3390/c11030059 - 7 Aug 2025
Viewed by 967
Abstract
Exfoliation of layered materials is an important technique for preparing atomic-layer materials. To provide fundamental mechanistic insights for optimizing this process, we investigated the exfoliation process of nano graphite using molecular dynamics simulations with the ReaxFF force field. The impact of temperature, speed, [...] Read more.
Exfoliation of layered materials is an important technique for preparing atomic-layer materials. To provide fundamental mechanistic insights for optimizing this process, we investigated the exfoliation process of nano graphite using molecular dynamics simulations with the ReaxFF force field. The impact of temperature, speed, and angle of removing the top layer has been examined to gain insight into obtaining thin, uniform layers. The bending rigidity of the ReaxFF graphite is temperature-dependent and affects the cleavage behavior. The impact of the Au overlayer, which has recently been utilized to obtain a large area, was also studied, and it was confirmed to be effective in improving repeatability. Full article
(This article belongs to the Section Carbon Materials and Carbon Allotropes)
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22 pages, 1937 KB  
Review
Carbon Dot Nanozymes in Orthopedic Disease Treatment: Comprehensive Overview, Perspectives and Challenges
by Huihui Wang
C 2025, 11(3), 58; https://doi.org/10.3390/c11030058 - 1 Aug 2025
Viewed by 1157
Abstract
Nanozymes, as a new generation of artificial enzymes, have attracted increasing attention in the field of biomedicine due to their multiple enzymatic characteristics, multi-functionality, low cost, and high stability. Among them, carbon dot nanozymes (CDzymes) possess excellent enzymatic-like catalytic activity and biocompatibility and [...] Read more.
Nanozymes, as a new generation of artificial enzymes, have attracted increasing attention in the field of biomedicine due to their multiple enzymatic characteristics, multi-functionality, low cost, and high stability. Among them, carbon dot nanozymes (CDzymes) possess excellent enzymatic-like catalytic activity and biocompatibility and have been developed for various diagnostic and therapeutic studies of diseases. Here, we briefly review the representative research on CDzymes in recent years, including their synthesis, modification, and applications, especially in orthopedic diseases, including osteoarthritis, osteoporosis, osteomyelitis, intervertebral disc degenerative diseases, bone tumors, and bone injury repair and periodontitis. Additionally, we briefly discuss the potential future applications and opportunities and challenges of CDzymes. We hope this review can provide some reference opinions for CDzymes and offer insights for promoting their application strategies in the treatment of orthopedic disease. Full article
(This article belongs to the Special Issue Carbon Nanohybrids for Biomedical Applications (2nd Edition))
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11 pages, 1936 KB  
Communication
Diffusion of C-O-H Fluids in a Sub-Nanometer Pore Network: Role of Pore Surface Area and Its Ratio with Pore Volume
by Siddharth Gautam and David Cole
C 2025, 11(3), 57; https://doi.org/10.3390/c11030057 - 1 Aug 2025
Viewed by 1002
Abstract
Porous materials are characterized by the pore surface area (S) and volume (V) accessible to a confined fluid. For mesoporous materials NMR measurements of diffusion are used to assess the S/V ratio, because at short times, only [...] Read more.
Porous materials are characterized by the pore surface area (S) and volume (V) accessible to a confined fluid. For mesoporous materials NMR measurements of diffusion are used to assess the S/V ratio, because at short times, only the diffusivity of molecules in the adsorbed layer is affected by confinement and the fractional population of these molecules is proportional to the S/V ratio. For materials with sub-nanometer pores, this might not be true, as the adsorbed layer can encompass the entire pore volume. Here, using molecular simulations, we explore the role played by S and S/V in determining the dynamical behavior of two carbon-bearing fluids—CO2 and ethane—confined in sub-nanometer pores of silica. S and V in a silicalite model representing a sub-nanometer porous material are varied by selectively blocking a part of the pore network by immobile methane molecules. Three classes of adsorbents were thus obtained with either all of the straight (labeled ‘S-major’) or zigzag channels (‘Z-major’) remaining open or a mix of a fraction of both types of channel blocked, resulting in half of the total pore volume being blocked (‘Half’). While the adsorption layers from opposite surfaces overlap, encompassing the entire pore volume for all pores except the intersections, the diffusion coefficient is still found to be reduced at high S/V, especially for CO2, albeit not so strongly as would be expected in the case of wider pores. This is because of the presence of channel intersections that provide a wider pore space with non-overlapping adsorption layers. Full article
(This article belongs to the Section Carbon Cycle, Capture and Storage)
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16 pages, 3508 KB  
Article
Stability of Carbon Quantum Dots for Potential Photothermal and Diagnostic Applications
by María Fernanda Amezaga Gonzalez, Abdiel Ramirez-Reyes, Monica Elvira Mendoza-Duarte, Alejandro Vega-Rios, Daniel Martinez-Ozuna, Claudia A. Rodriguez-Gonzalez, Santos-Adriana Martel-Estrada and Imelda Olivas-Armendariz
C 2025, 11(3), 56; https://doi.org/10.3390/c11030056 - 29 Jul 2025
Cited by 1 | Viewed by 1553
Abstract
Theranostic agents enable the simultaneous diagnosis and treatment of diseases, and they are particularly useful in fluorescent imaging and cancer therapies. In this study, carbon quantum dots were synthesized via a microwave-assisted method using citric acid and bovine serum albumin (BSA) as precursors. [...] Read more.
Theranostic agents enable the simultaneous diagnosis and treatment of diseases, and they are particularly useful in fluorescent imaging and cancer therapies. In this study, carbon quantum dots were synthesized via a microwave-assisted method using citric acid and bovine serum albumin (BSA) as precursors. The resulting CQDs exhibited spherical morphology, an average size of 4 nm, and an amorphous graphitic structure. FT-IR characterization revealed the presence of amide bonds and oxygenated functional groups. At the same time, optical analysis showed excitation at 320 nm and emission between 360 and 400 nm, with fluorescent stability maintained for one month. Furthermore, the CQDs demonstrated good thermal stability and photothermal efficiency, reaching temperatures above 41 °C within 15 min under NIR irradiation, with a mass loss of less than 1%. Their stability was evaluated in media with different pH levels, simulating physiological and tumor environments. While their behavior was affected under acidic conditions, their excellent photothermal conversion capacity and overall stability in triple-distilled water positioned them as promising candidates for theranostic applications in cancer, effectively combining diagnostic imaging and thermal therapy. Full article
(This article belongs to the Special Issue Carbon Nanohybrids for Biomedical Applications (2nd Edition))
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15 pages, 2645 KB  
Article
Carbon Footprint and Uncertainties of Geopolymer Concrete Production: A Comprehensive Life Cycle Assessment (LCA)
by Quddus Tushar, Muhammed A. Bhuiyan, Ziyad Abunada, Charles Lemckert and Filippo Giustozzi
C 2025, 11(3), 55; https://doi.org/10.3390/c11030055 - 28 Jul 2025
Cited by 3 | Viewed by 3443
Abstract
This study aims to estimate the carbon footprint and relative uncertainties for design components of conventional and geopolymer concrete. All the design components of alkaline-activated geopolymer concrete, such as fly ash, ground granulated blast furnace slag, sodium hydroxide (NaOH), sodium silicate (Na2 [...] Read more.
This study aims to estimate the carbon footprint and relative uncertainties for design components of conventional and geopolymer concrete. All the design components of alkaline-activated geopolymer concrete, such as fly ash, ground granulated blast furnace slag, sodium hydroxide (NaOH), sodium silicate (Na2SiO3), superplasticizer, and others, are assessed to reflect the actual scenarios of the carbon footprint. The conjugate application of the life cycle assessment (LCA) tool SimPro 9.4 and @RISK Monte Carlo simulation justifies the variations in carbon emissions rather than a specific determined value for concrete binders, precursors, and filler materials. A reduction of 43% in carbon emissions has been observed by replacing cement with alkali-activated binders. However, the associative uncertainties of chemical admixtures reveal that even a slight increase may cause significant environmental damage rather than its benefit. Pearson correlations of carbon footprint with three admixtures, namely sodium silicate (r = 0.80), sodium hydroxide (r = 0.52), and superplasticizer (r = 0.19), indicate that the shift from cement to alkaline activation needs additional precaution for excessive use. Therefore, a suitable method of manufacturing chemical activators utilizing renewable energy sources may ensure long-term sustainability. Full article
(This article belongs to the Section Carbon Cycle, Capture and Storage)
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24 pages, 3016 KB  
Article
Industrial Off-Gas Fermentation for Acetic Acid Production: A Carbon Footprint Assessment in the Context of Energy Transition
by Marta Pacheco, Adrien Brac de la Perrière, Patrícia Moura and Carla Silva
C 2025, 11(3), 54; https://doi.org/10.3390/c11030054 - 23 Jul 2025
Viewed by 2188
Abstract
Most industrial processes depend on heat, electricity, demineralized water, and chemical inputs, which themselves are produced through energy- and resource-intensive industrial activities. In this work, acetic acid (AA) production from syngas (CO, CO2, and H2) fermentation is explored and [...] Read more.
Most industrial processes depend on heat, electricity, demineralized water, and chemical inputs, which themselves are produced through energy- and resource-intensive industrial activities. In this work, acetic acid (AA) production from syngas (CO, CO2, and H2) fermentation is explored and compared against a thermochemical fossil benchmark and other thermochemical/biological processes across four main Key Performance Indicators (KPI)—electricity use, heat use, water consumption, and carbon footprint (CF)—for the years 2023 and 2050 in Portugal and France. CF was evaluated through transparent and public inventories for all the processes involved in chemical production and utilities. Spreadsheet-traceable matrices for hotspot identification were also developed. The fossil benchmark, with all the necessary cascade processes, was 0.64 kg CO2-eq/kg AA, 1.53 kWh/kg AA, 22.02 MJ/kg AA, and 1.62 L water/kg AA for the Portuguese 2023 energy mix, with a reduction of 162% of the CO2-eq in the 2050 energy transition context. The results demonstrated that industrial practices would benefit greatly from the transition from fossil to renewable energy and from more sustainable chemical sources. For carbon-intensive sectors like steel or cement, the acetogenic syngas fermentation appears as a scalable bridge technology, converting the flue gas waste stream into marketable products and accelerating the transition towards a circular economy. Full article
(This article belongs to the Section Carbon Cycle, Capture and Storage)
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12 pages, 11599 KB  
Article
Dual pH- and Temperature-Responsive Fluorescent Hybrid Materials Based on Carbon Dot-Grafted Triamino-Tetraphenylethylene/N-Isopropylacrylamide Copolymers
by Huan Liu, Yuxin Ding, Longping Zhou, Shirui Xu and Bo Liao
C 2025, 11(3), 53; https://doi.org/10.3390/c11030053 - 22 Jul 2025
Viewed by 766
Abstract
Carbon dots (CDs), a class of carbon-based fluorescent nanomaterials, have garnered significant attention due to their tunable optical properties and functional versatility. In this study, we developed a hybrid material by grafting pH- and temperature-responsive copolymers onto CDs via reversible addition-fragmentation chain-transfer (RAFT) [...] Read more.
Carbon dots (CDs), a class of carbon-based fluorescent nanomaterials, have garnered significant attention due to their tunable optical properties and functional versatility. In this study, we developed a hybrid material by grafting pH- and temperature-responsive copolymers onto CDs via reversible addition-fragmentation chain-transfer (RAFT) polymerization. Triamino-tetraphenylethylene (ATPE) and N-isopropylacrylamide (NIPAM) were copolymerized at varying ratios and covalently linked to CDs, forming a dual-responsive system. Structural characterization using FTIR, 1H NMR, and TEM confirmed the successful grafting of the copolymers onto CDs. The hybrid material exhibited pH-dependent fluorescence changes in acidic aqueous solutions, with emission shifting from 450 nm (attributed to CDs) to 500 nm (aggregation-induced emission, AIE, from ATPE) above a critical pH threshold. Solid films of the hybrid material demonstrated reversible fluorescence quenching under HCl vapor and recovery/enhancement under NH3 vapor, showing excellent fatigue resistance over multiple cycles. Temperature responsiveness was attributed to the thermosensitive poly(NIPAM) segments, with fluorescence intensity increasing above 35 °C due to polymer chain collapse and ATPE aggregation. This work provides a strategy for designing multifunctional hybrid materials with potential applications in recyclable optical pH/temperature sensors. Full article
(This article belongs to the Special Issue Carbon-Based Polymer Composites: Synthesis, Processing, Characterization and Applications (2nd Edition))
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11 pages, 3598 KB  
Article
NMR Spectroelectrochemistry in Studies of Procarbazine Oxidation by Laser-Induced Graphene Thin Films
by Zhe Wang, Xiaoping Zhang, Shihui Xu, Lin Yang, Lina Wang, Yijing Wang, Ahmad Mansoor and Wei Sun
C 2025, 11(3), 52; https://doi.org/10.3390/c11030052 - 21 Jul 2025
Viewed by 786
Abstract
In this paper, nanoscale graphene film electrodes were prepared using laser-induced technology, and an in situ electrochemical cell was constructed. The normalized peak areas at 2.82 ppm for the samples without the in situ electrochemical cell and with an in situ electrochemical cell [...] Read more.
In this paper, nanoscale graphene film electrodes were prepared using laser-induced technology, and an in situ electrochemical cell was constructed. The normalized peak areas at 2.82 ppm for the samples without the in situ electrochemical cell and with an in situ electrochemical cell are 4.02 and 4.41, respectively. Tests showed that this in situ electrochemical cell has minimal interference from the nuclear magnetic resonance (NMR) magnetic field, allowing for high-resolution in situ spectra. Using this in situ electrochemical cell and employing in situ electrochemistry combined with NMR techniques, we investigated the oxidation reaction of 0.01 M procarbazine (PCZ) in real-time. We elucidated the following oxidation mechanism for procarbazine: the oxidation of PCZ first generates azo-procarbazine, which then undergoes a double bond shift to hydrazo-procarbazine. hydrazo-procarbazine undergoes hydrolysis to yield benzaldehyde-procarbazine, and then finally oxidizes to produce N-isopropylterephthalic acid. This confirms that the combination of in situ electrochemistry and nuclear magnetic resonance technology provides chemists with an effective tool for in situ studying the reaction mechanisms of drug molecules. Full article
(This article belongs to the Section Carbon Materials and Carbon Allotropes)
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18 pages, 6572 KB  
Article
Tuning Optical Excitations of Graphene Quantum Dots Through Selective Oxidation: Effect of Epoxy Groups
by Igor V. Ershov, Anatoly A. Lavrentyev, Dmitry L. Romanov and Olga M. Holodova
C 2025, 11(3), 51; https://doi.org/10.3390/c11030051 - 14 Jul 2025
Viewed by 1061
Abstract
Graphene quantum dots (GQDs) have strong potential in optoelectronics, particularly in LEDs, photodetectors, solar cells, and nanophotonics. While challenges remain in efficiency and scalability, advances in functionalization and hybrid material integration could soon make them commercially viable for next-generation optoelectronic devices. In this [...] Read more.
Graphene quantum dots (GQDs) have strong potential in optoelectronics, particularly in LEDs, photodetectors, solar cells, and nanophotonics. While challenges remain in efficiency and scalability, advances in functionalization and hybrid material integration could soon make them commercially viable for next-generation optoelectronic devices. In this work, we assess the stability of various epoxy positions and their impact on the electronic and optical properties of GQDs. The oxygen binding energies and the potential barrier heights at different positions of epoxy groups at the edges and in the core of the GQD were estimated. The effect of possible transformations of epoxy groups into other edge configurations on the structural and optical properties of GQDs was evaluated. The results demonstrate that the functionalization of the GQD surface and edges with an epoxy groups at varying binding sites can result in substantial modification of the electronic structure and absorption properties of the GQDs. The prospects of low temperature annealing for controlling optical properties of epoxidized GQDs were discussed. The present computational work offers atomistic insights that can facilitate the rational design of optoelectronic systems based on GQD materials. Full article
(This article belongs to the Special Issue Carbon-Based Polymer Composites: Synthesis, Processing, Characterization and Applications (2nd Edition))
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18 pages, 1777 KB  
Review
Biochar in Agriculture: A Review on Sources, Production, and Composites Related to Soil Fertility, Crop Productivity, and Environmental Sustainability
by Md. Muzammal Hoque, Biplob Kumar Saha, Antonio Scopa and Marios Drosos
C 2025, 11(3), 50; https://doi.org/10.3390/c11030050 - 11 Jul 2025
Cited by 2 | Viewed by 5205
Abstract
Due to soil nutrient depletion and rising food demand from an increasing global population, it is essential to find sustainable ways to boost crop yields, improve soil health, and address the environmental issues induced by agriculture. The most appropriate approach is to consider [...] Read more.
Due to soil nutrient depletion and rising food demand from an increasing global population, it is essential to find sustainable ways to boost crop yields, improve soil health, and address the environmental issues induced by agriculture. The most appropriate approach is to consider sustainable amendments, such as biochar and its derivatives, which are vital constituents of soil health due to their affordability, low reactivity, large surface area, and reduced carbon footprint. In this context, biochar and its derivatives in farming systems focus on improving soil structure, nutrient holding capacity, microbial activities, and the perpetuation of soil fertility. Despite its benefits, biochar, if it is used in high concentration, can sometimes become highly toxic, causing soil erosion due to reducing surface area, increasing pH levels, and altering soil properties. This review highlights the production methods and sources of feedstocks, emphasizing their important contribution to the soil’s physicochemical and biological properties. Furthermore, it critically evaluates the environmental applications and their impacts, providing data built upon the literature on contaminant removal from soil, economic factors, heavy metal immobilization, carbon sequestration, and climate resilience. This review emphasizes the main challenges and future prospects for biochar use in comparison to modified biochar (MB) to propose the best practices for sustainable farming systems. Full article
(This article belongs to the Special Issue Carbons for Health and Environmental Protection (2nd Edition))
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11 pages, 2969 KB  
Article
First-Principles Study of CO, C2H2, and C2H4 Adsorption on Penta-Graphene for Transformer Oil Gas Sensing Applications
by Min-Qi Zhu and Xue-Feng Wang
C 2025, 11(3), 49; https://doi.org/10.3390/c11030049 - 9 Jul 2025
Cited by 1 | Viewed by 811
Abstract
Penta-graphene, a novel two-dimensional carbon allotrope entirely composed of pentagonal carbon rings, has attracted increasing attention due to its unique geometric structure, mechanical robustness, and intrinsic semiconducting nature. In this study, we systematically investigate the adsorption behavior of three typical dissolved gases in [...] Read more.
Penta-graphene, a novel two-dimensional carbon allotrope entirely composed of pentagonal carbon rings, has attracted increasing attention due to its unique geometric structure, mechanical robustness, and intrinsic semiconducting nature. In this study, we systematically investigate the adsorption behavior of three typical dissolved gases in transformer oil (CO, C2H2, and C2H4) on penta-graphene using first-principles calculations based on density functional theory. The optimized adsorption configuration, adsorption energy, charge transfer, adsorption distance, band structure, density of states, charge density difference, and desorption time are analyzed to evaluate the sensing capability of penta-graphene. Results reveal that penta-graphene exhibits moderate chemical interactions with CO and C2H2, accompanied by noticeable charge transfer and band structure changes, whereas C2H4 shows weaker physisorption characteristics. The projected density of states analysis further confirms the orbital hybridization between gas molecules and the substrate. Additionally, the desorption time calculations suggest that penta-graphene possesses good sensing and recovery potential, especially under elevated temperatures. These findings indicate that penta-graphene is a promising candidate for use in gas sensing applications related to the monitoring of dissolved gases in transformer oils. 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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19 pages, 2749 KB  
Article
Mechanism of Fluorescence Characteristics and Application of Zinc-Doped Carbon Dots Synthesized by Using Zinc Citrate Complexes as Precursors
by Yun Zhang, Yiwen Guo, Kaibo Sun, Xiaojing Li, Xiuhua Liu, Jinhua Zhu and Md. Zaved Hossain Khan
C 2025, 11(3), 48; https://doi.org/10.3390/c11030048 - 7 Jul 2025
Viewed by 1233
Abstract
Zn-doped carbon dots (Zn@C-210 calcination temperature at 210 °C and Zn@C-260 calcination temperature at 260 °C) were synthesized via an in situ calcination method using zinc citrate complexes as precursors, aiming to investigate the mechanisms of their distinctive fluorescence properties. A range of [...] Read more.
Zn-doped carbon dots (Zn@C-210 calcination temperature at 210 °C and Zn@C-260 calcination temperature at 260 °C) were synthesized via an in situ calcination method using zinc citrate complexes as precursors, aiming to investigate the mechanisms of their distinctive fluorescence properties. A range of analytical methods were employed to characterize these nanomaterials. The mechanism study revealed that the coordination structure of Zn-O, formed through zinc doping, can induce a metal–ligand charge-transfer effect, which significantly increases the probability of radiative transitions between the excited and ground states, thereby enhancing the fluorescence intensity. The Zn@C-210 in a solid state and Zn@C-260 in water exhibited approximately 71.50% and 21.1% quantum yields, respectively. Both Zn@C-210 and Zn@C-260 exhibited excitation-independent luminescence, featuring a long fluorescence lifetime of 6.5 μs for Zn@C-210 and 6.2 μs for Zn@C-260. Impressively, zinc-doped CDs displayed exceptional biosafety, showing no acute toxicity even at 1000 mg/kg doses. Zn@C-210 has excellent fluorescence in a solid state, showing promise in anti-photobleaching applications; meanwhile, the dual functionality of Zn@C-260 makes it useful as a folate sensor and cellular imaging probe. These findings not only advance the fundamental understanding of metal-doped carbon dot photophysics but also provide practical guidelines for developing targeted biomedical nanomaterials through rational surface engineering and doping strategies. Full article
(This article belongs to the Special Issue Carbon Nanohybrids for Biomedical Applications (2nd Edition))
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14 pages, 4383 KB  
Article
Optimized Adsorptive Desulfurization Using Waste Tire-Derived Carbon
by Ming-Liao Tsai, An-Ya Lo, Jun-Hao Liu and Yong-Ming Dai
C 2025, 11(3), 47; https://doi.org/10.3390/c11030047 - 7 Jul 2025
Cited by 1 | Viewed by 1209
Abstract
The inclusion of adsorption thermodynamic analysis and performance benchmarking with existing adsorbents reinforces both the theoretical significance and practical applicability of this study. The modified rubber-derived carbon demonstrated a remarkably high DBT adsorption capacity of 254.45 mg/g. These results establish it as a [...] Read more.
The inclusion of adsorption thermodynamic analysis and performance benchmarking with existing adsorbents reinforces both the theoretical significance and practical applicability of this study. The modified rubber-derived carbon demonstrated a remarkably high DBT adsorption capacity of 254.45 mg/g. These results establish it as a promising alternative to conventional materials such as commercial activated carbon, zeolites, and even metal–organic framework materials. In addition to confirming the superior performance of the adsorbent, the findings provide a deeper understanding of the DBT adsorption mechanism and offer a solid scientific basis for large-scale fuel desulfurization applications. This research highlights the potential of transforming end-of-life tire waste into value-added functional materials and contributes to the advancement of sustainable and efficient desulfurization technologies. Future work should focus on optimizing surface functionalization and regeneration strategies to further improve long-term adsorption stability and practical deployment. Full article
(This article belongs to the Special Issue Carbon Functionalization: From Synthesis to Applications)
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13 pages, 1309 KB  
Article
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 1847
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∼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
(This article belongs to the Special Issue 10th Anniversary of C — Journal of Carbon Research)
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14 pages, 18495 KB  
Article
Analysis of Biochar–Cement Composites by SEM/EDS: Interfacial Interactions and Effects on Mechanical Strength
by Rafaela Paula, Jaqueline Carvalho, Antônio Júnior, Filipe Fagundes, Robson de Lima, Evaneide Lima, Carlos Oliveira, Magno de Oliveira, Augusto Bezerra, Osania Ferreira and Alan Machado
C 2025, 11(3), 45; https://doi.org/10.3390/c11030045 - 29 Jun 2025
Cited by 2 | Viewed by 2177
Abstract
Portland cement production is one of the main global sources of CO2 emissions, driving the search for sustainable solutions to reduce its environmental footprint. This study evaluated the use of biochar derived from sugarcane bagasse as a partial cement replacement in cementitious [...] Read more.
Portland cement production is one of the main global sources of CO2 emissions, driving the search for sustainable solutions to reduce its environmental footprint. This study evaluated the use of biochar derived from sugarcane bagasse as a partial cement replacement in cementitious composites, aiming to investigate its effects on mechanical and microstructural properties. Composites were prepared with 0, 2, and 5 (% w w−1) biochar at two water-to-cement (w/c) ratios: 0.28 and 0.35. It was hypothesized that the porous structure and carbon-rich composition of biochar could enhance the microstructure of the cementitious matrix and contribute to strength development. Characterization of the biochar indicated compliance with the European Biochar Certificate (EBC) standard, high thermal stability, and notable water retention capacity. Mechanical testing revealed that incorporating 5% w w−1 biochar increased compressive strength by up to 48% in the 0.35 w/c formulation compared to the control. Microstructural analyses (SEM/EDS) showed good interaction between the biochar and the cementitious matrix, with the formation of hydration products at the interfaces. The results confirm the potential of sugarcane bagasse biochar as a supplementary cementitious material, promoting more sustainable composites with improved mechanical performance and reduced environmental impact. Full article
(This article belongs to the Section Carbon Materials and Carbon Allotropes)
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18 pages, 1917 KB  
Article
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
Viewed by 745
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 mgcat−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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10 pages, 1436 KB  
Article
Theoretical Investigation of O2 and CO2 Adsorption on Small PdNi Clusters Supported on N-Doped Graphene Quantum Dots
by Brenda García-Hilerio, Lidia Santiago-Silva, Pastor T. Matadamas-Ortiz, Alejandro Gomez-Sanchez, Víctor A. Franco-Luján and Heriberto Cruz-Martínez
C 2025, 11(3), 43; https://doi.org/10.3390/c11030043 - 27 Jun 2025
Viewed by 765
Abstract
A density functional theory (DFT) investigation was conducted to study the O2 and CO2 adsorption on very small Pd3−nNin (n = 0–2) clusters supported on N-doped graphene quantum dots (N-GQDs). The study was carried out in two stages. [...] Read more.
A density functional theory (DFT) investigation was conducted to study the O2 and CO2 adsorption on very small Pd3−nNin (n = 0–2) clusters supported on N-doped graphene quantum dots (N-GQDs). The study was carried out in two stages. First, the interaction between Pd3−nNin (n = 0–2) clusters and N-GQDs was analyzed. Subsequently, the adsorption behavior of O2 and CO2 molecules on the supported clusters was examined. The calculated interaction energies (Eint) of Pd3−nNin (n = 0–2) clusters on N-GQDs were found to be higher than those on pristine graphene, indicating enhanced cluster stability on N-GQDs. Furthermore, the adsorption energies (Eads) of the O2 molecule on the Pd3 and Pd2Ni clusters deposited on N-GQDs were similar. Meanwhile, the PdNi2 cluster deposited on N-GQDs exhibited the highest Eads (−1.740). The Eads of CO2 on Pd3−nNin (n = 0–2) clusters embedded in N-GQDs were observed to be close to or exceed 1 eV. Upon adsorption of O2 and CO2 on the Pd3−nNin (n = 0–2) clusters supported on N-GQDs, an elongation of the O–O and C–O bond lengths was observed, respectively. This structural change may facilitate the dissociation of these molecules on the supported clusters. Full article
(This article belongs to the Section Carbon Materials and Carbon Allotropes)
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