Pub Date : 2025-12-02DOI: 10.1016/j.cartre.2025.100598
Aisuluu Aitkulova, Markus Gabrysch, Saman Majdi, Nattakarn Suntornwipat, Jan Isberg
The integration of single-layer graphene with diamond substrates offers a promising platform for high-performance electronic devices by utilizing the exceptional properties of both materials. This study describes a fabrication process and transport measurements of single-layer graphene devices on diamond substrates featuring two surface terminations: hydrogen (H-terminated, thermal process) and oxygen (O-terminated, plasma treatment). The carrier transport properties were investigated using Hall effect measurements over a broad temperature range (80–400 K) under high-vacuum conditions ( mbar). Our findings reveal that thermal annealing significantly improves the graphene-diamond interface quality, causing a notable increase in carrier mobility for devices on both H- and O-terminated from 1439 to 1644 cmVs and from 1238 to 1340 cmVs, respectively. We also found that the effect of remote interfacial phonon scattering on high-temperature mobility is affected by the termination type. These findings highlight the importance of substrate surface engineering and offer a pathway for optimizing graphene-diamond heterostructures for advanced electronic applications.
{"title":"Temperature dependence of charge transport in single-layer graphene on surface-terminated diamond","authors":"Aisuluu Aitkulova, Markus Gabrysch, Saman Majdi, Nattakarn Suntornwipat, Jan Isberg","doi":"10.1016/j.cartre.2025.100598","DOIUrl":"10.1016/j.cartre.2025.100598","url":null,"abstract":"<div><div>The integration of single-layer graphene with diamond substrates offers a promising platform for high-performance electronic devices by utilizing the exceptional properties of both materials. This study describes a fabrication process and transport measurements of single-layer graphene devices on diamond substrates featuring two surface terminations: hydrogen (H-terminated, thermal process) and oxygen (O-terminated, plasma treatment). The carrier transport properties were investigated using Hall effect measurements over a broad temperature range (80–400 K) under high-vacuum conditions (<span><math><mrow><mn>1</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math></span> mbar). Our findings reveal that thermal annealing significantly improves the graphene-diamond interface quality, causing a notable increase in carrier mobility for devices on both H- and O-terminated from 1439 to 1644 cm<span><math><mrow><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup><mo>/</mo></mrow></math></span>Vs and from 1238 to 1340 cm<span><math><mrow><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup><mo>/</mo></mrow></math></span>Vs, respectively. We also found that the effect of remote interfacial phonon scattering on high-temperature mobility is affected by the termination type. These findings highlight the importance of substrate surface engineering and offer a pathway for optimizing graphene-diamond heterostructures for advanced electronic applications.</div></div>","PeriodicalId":52629,"journal":{"name":"Carbon Trends","volume":"22 ","pages":"Article 100598"},"PeriodicalIF":3.9,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145738103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.cartre.2025.100594
Philani V. Hlophe , Huanlei Zhao , Guoning Li , Kenate N Nigussa , Shidong Song , Phumlani F. Msomi
The sluggish kinetics of the oxygen reduction reaction (ORR) significantly hinder the performance of proton exchange membrane fuel cells (PEMFCs). Although platinum (Pt)-based catalysts are the current benchmark, their high cost and limited stability demand a more advanced alternative. This critical review examines dual-transition metal-supported high-entropy alloy platinum group metals (HEA-PGM/DTM-MXene), focusing on the structural engineering challenges necessary to unlock their full potential. We argue that the rational design of components, guided by computational pre-screening, combined with the structural confinement offered by the 2D support, represents the primary path forward. We detail the complex synthesis challenges, analyze the performance gaps using representative Pt-alloy/MXene systems in full PEMFC devices, and conclude by defining the critical research questions required to achieve the projected performance targets. This work establishes a materials-centric framework for the future development of these complex electrocatalysts, aligning the structural control of the DTM-MXene with the kinetic tuning of the HEA-PGM.
{"title":"Dual-transition metal MXene-supported high-entropy-alloy platinum group metal catalysts for oxygen reduction reaction: A focused review","authors":"Philani V. Hlophe , Huanlei Zhao , Guoning Li , Kenate N Nigussa , Shidong Song , Phumlani F. Msomi","doi":"10.1016/j.cartre.2025.100594","DOIUrl":"10.1016/j.cartre.2025.100594","url":null,"abstract":"<div><div>The sluggish kinetics of the oxygen reduction reaction (ORR) significantly hinder the performance of proton exchange membrane fuel cells (PEMFCs). Although platinum (Pt)-based catalysts are the current benchmark, their high cost and limited stability demand a more advanced alternative. This critical review examines dual-transition metal-supported high-entropy alloy platinum group metals (HEA-PGM/DTM-MXene), focusing on the structural engineering challenges necessary to unlock their full potential. We argue that the rational design of components, guided by computational pre-screening, combined with the structural confinement offered by the 2D support, represents the primary path forward. We detail the complex synthesis challenges, analyze the performance gaps using representative Pt-alloy/MXene systems in full PEMFC devices, and conclude by defining the critical research questions required to achieve the projected performance targets. This work establishes a materials-centric framework for the future development of these complex electrocatalysts, aligning the structural control of the DTM-MXene with the kinetic tuning of the HEA-PGM.</div></div>","PeriodicalId":52629,"journal":{"name":"Carbon Trends","volume":"21 ","pages":"Article 100594"},"PeriodicalIF":3.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.cartre.2025.100595
Reza Salehi , Mehdi Ebrahimian-Hosseinabadi , Mohammad Rafienia
The ability to develop a polymeric scaffold with suitable electrical conductivity for an ideal nerve tissue engineering scaffold has been a persistent challenge for researchers. In this study, five nanocomposite scaffolds based on polycaprolactone (PCL), a synthetic polymer providing mechanical strength, natural biocompatible chitosan, and graphene quantum dots (GQDs) to enhance conductivity, were fabricated via electrospinning, a technique known for producing thin, uniformly aligned fibers. The scaffolds were characterized structurally using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR), confirming uniform distribution and significant impact of GQDs on fiber structure. Scanning electron microscopy (SEM) and fluorescence microscopy revealed a substantial reduction in fiber diameter by approximately 70 % and the presence of GQDs along the fibers. Electrical testing showed that increasing GQD content from 0.5 to 1 wt% notably decreased electrical resistance (from ∼1883 to 133 Ω), enhancing conductivity. Degradation studies in PBS over two months demonstrated an increase in degradation rate proportional to GQD content, with some scaffolds exhibiting up to 60 % degradation. Mechanical tensile testing indicated improved strength and elastic modulus with 0.5 to 1 wt% GQDs, whereas higher contents caused brittleness and strength reduction. Biological evaluation using PC12 cells showed a 4–7 % increase in cell viability upon adding 0.5 to 2 wt% GQDs, while 4 wt% induced cytotoxicity. Considering the combined biological, physical, and mechanical results, scaffolds S2 and S3 emerged as the best candidates for electrically conductive and biocompatible scaffolds suitable for peripheral nerve tissue engineering. These findings highlight the promising potential of these nanocomposites for nerve tissue repair applications.
{"title":"Fabrication and characterization of polycaprolactone/chitosan/graphene quantum dots nanocomposite scaffolds with potential application in neural tissue engineering","authors":"Reza Salehi , Mehdi Ebrahimian-Hosseinabadi , Mohammad Rafienia","doi":"10.1016/j.cartre.2025.100595","DOIUrl":"10.1016/j.cartre.2025.100595","url":null,"abstract":"<div><div>The ability to develop a polymeric scaffold with suitable electrical conductivity for an ideal nerve tissue engineering scaffold has been a persistent challenge for researchers. In this study, five nanocomposite scaffolds based on polycaprolactone (PCL), a synthetic polymer providing mechanical strength, natural biocompatible chitosan, and graphene quantum dots (GQDs) to enhance conductivity, were fabricated via electrospinning, a technique known for producing thin, uniformly aligned fibers. The scaffolds were characterized structurally using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR), confirming uniform distribution and significant impact of GQDs on fiber structure. Scanning electron microscopy (SEM) and fluorescence microscopy revealed a substantial reduction in fiber diameter by approximately 70 % and the presence of GQDs along the fibers. Electrical testing showed that increasing GQD content from 0.5 to 1 wt% notably decreased electrical resistance (from ∼1883 to 133 Ω), enhancing conductivity. Degradation studies in PBS over two months demonstrated an increase in degradation rate proportional to GQD content, with some scaffolds exhibiting up to 60 % degradation. Mechanical tensile testing indicated improved strength and elastic modulus with 0.5 to 1 wt% GQDs, whereas higher contents caused brittleness and strength reduction. Biological evaluation using PC12 cells showed a 4–7 % increase in cell viability upon adding 0.5 to 2 wt% GQDs, while 4 wt% induced cytotoxicity. Considering the combined biological, physical, and mechanical results, scaffolds S<sub>2</sub> and S<sub>3</sub> emerged as the best candidates for electrically conductive and biocompatible scaffolds suitable for peripheral nerve tissue engineering. These findings highlight the promising potential of these nanocomposites for nerve tissue repair applications.</div></div>","PeriodicalId":52629,"journal":{"name":"Carbon Trends","volume":"21 ","pages":"Article 100595"},"PeriodicalIF":3.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-26DOI: 10.1016/j.cartre.2025.100597
Mohammad Abushuhel , Ramin Javahershenas , Rekha M. M , Shaker Al-Hasnaawei , Kattela Chennakesavulu , Renu Sharma , Aashna Sinha
This work reports a multifunctional nanocatalyst, CNTs-ZnFe₂O₄-IL, designed for efficient, selective, and magnetically recoverable oxidation of alcohols to aldehydes. The catalyst integrates zinc ferrite (ZnFe₂O₄) nanoparticles onto carboxyl-functionalized carbon nanotubes (CNTs) and immobilizes them with an imidazolium-based ionic liquid. Characterization by XRD, FTIR, TEM, TGA, VSM, SEM-EDX, and BET confirms successful synthesis and the advantageous architecture: magnetic ZnFe₂O₄ facilitates easy magnetic separation, CNTs provide high surface area and improved nanoparticle dispersion, and the ionic liquid layer offers unique solvating and activating properties that enhance catalysis. Catalytic performance was demonstrated in the selective oxidation of benzyl alcohol to benzaldehyde using tert‑butyl hydroperoxide (TBHP) as a green oxidant. At 50 °C, the catalyst delivered exceptionally high yields (90–97 %) across a broad substrate scope of 21 substituted benzyl alcohols, displaying strong functional group tolerance and high selectivity toward aldehyde without over-oxidation to benzoic acid. The magnetic nature enables straightforward recovery, and the catalyst-maintained activity and selectivity over six consecutive reuse cycles with negligible performance loss. CNTs-ZnFe₂O₄-IL offers a sustainable, cost-effective protocol for aerobic oxidations, aligning with green chemistry principles by eliminating solvents, minimizing waste, and enabling easy catalyst recycling.
{"title":"Magnetic carbon nanotube-enhanced imidazolium ionic liquid (CNTs-ZnFe2O4-IL); A novel catalyst for selective oxidation of benzyl alcohol to benzaldehyde","authors":"Mohammad Abushuhel , Ramin Javahershenas , Rekha M. M , Shaker Al-Hasnaawei , Kattela Chennakesavulu , Renu Sharma , Aashna Sinha","doi":"10.1016/j.cartre.2025.100597","DOIUrl":"10.1016/j.cartre.2025.100597","url":null,"abstract":"<div><div>This work reports a multifunctional nanocatalyst, CNTs-ZnFe₂O₄-IL, designed for efficient, selective, and magnetically recoverable oxidation of alcohols to aldehydes. The catalyst integrates zinc ferrite (ZnFe₂O₄) nanoparticles onto carboxyl-functionalized carbon nanotubes (CNTs) and immobilizes them with an imidazolium-based ionic liquid. Characterization by XRD, FTIR, TEM, TGA, VSM, SEM-EDX, and BET confirms successful synthesis and the advantageous architecture: magnetic ZnFe₂O₄ facilitates easy magnetic separation, CNTs provide high surface area and improved nanoparticle dispersion, and the ionic liquid layer offers unique solvating and activating properties that enhance catalysis. Catalytic performance was demonstrated in the selective oxidation of benzyl alcohol to benzaldehyde using tert‑butyl hydroperoxide (TBHP) as a green oxidant. At 50 °C, the catalyst delivered exceptionally high yields (90–97 %) across a broad substrate scope of 21 substituted benzyl alcohols, displaying strong functional group tolerance and high selectivity toward aldehyde without over-oxidation to benzoic acid. The magnetic nature enables straightforward recovery, and the catalyst-maintained activity and selectivity over six consecutive reuse cycles with negligible performance loss. CNTs-ZnFe₂O₄-IL offers a sustainable, cost-effective protocol for aerobic oxidations, aligning with green chemistry principles by eliminating solvents, minimizing waste, and enabling easy catalyst recycling.</div></div>","PeriodicalId":52629,"journal":{"name":"Carbon Trends","volume":"22 ","pages":"Article 100597"},"PeriodicalIF":3.9,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-24DOI: 10.1016/j.cartre.2025.100596
Natalia R. Arutyunyan , Alexander A. Tonkikh , Pavel V. Fedotov , Dmitry V. Rybkovskiy , Ekaterina A. Obraztsova , Wanyu Dai , Xiang Rong , Shigeo Maruyama , Elena D. Obraztsova
6- atom-wide armchair graphene nanoribbons (6-AGNRs) are synthesized through two-step process inside a matrix of single-walled carbon nanotubes (SWCNTs) pre-aligned by controlled vacuum filtration method. The typical Raman modes of nanoribbons as radial breathing-like mode at 453 cm-1, edge CH mode at 1245 cm-1 and middle-range mode at 1270 cm-1 appear in the Raman spectra alongside with the modes of carbon nanotubes. Polarized Raman spectra reveal the strong anisotropy of the signal depending on the orientation of the sample, as the alignment of nanoribbons is provided by the alignment of the nanotube host matrix. This result is in agreement with polarized Raman density functional theory (DFT) calculations carried out for the main vibrational modes of the 6-AGNR. The proposed method ensures the alignment of graphene nanoribbons (GNRs) on a macroscale and preserves the anisotropy of their optical properties.
{"title":"Optical anisotropy of 6-A graphene nanoribbons synthesized inside aligned nanotubes","authors":"Natalia R. Arutyunyan , Alexander A. Tonkikh , Pavel V. Fedotov , Dmitry V. Rybkovskiy , Ekaterina A. Obraztsova , Wanyu Dai , Xiang Rong , Shigeo Maruyama , Elena D. Obraztsova","doi":"10.1016/j.cartre.2025.100596","DOIUrl":"10.1016/j.cartre.2025.100596","url":null,"abstract":"<div><div>6- atom-wide armchair graphene nanoribbons (6-AGNRs) are synthesized through two-step process inside a matrix of single-walled carbon nanotubes (SWCNTs) pre-aligned by controlled vacuum filtration method. The typical Raman modes of nanoribbons as radial breathing-like mode at 453 cm<sup>-1</sup>, edge C<img>H mode at 1245 cm<sup>-1</sup> and middle-range mode at 1270 cm<sup>-1</sup> appear in the Raman spectra alongside with the modes of carbon nanotubes. Polarized Raman spectra reveal the strong anisotropy of the signal depending on the orientation of the sample, as the alignment of nanoribbons is provided by the alignment of the nanotube host matrix. This result is in agreement with polarized Raman density functional theory (DFT) calculations carried out for the main vibrational modes of the 6-AGNR. The proposed method ensures the alignment of graphene nanoribbons (GNRs) on a macroscale and preserves the anisotropy of their optical properties.</div></div>","PeriodicalId":52629,"journal":{"name":"Carbon Trends","volume":"22 ","pages":"Article 100596"},"PeriodicalIF":3.9,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-17DOI: 10.1016/j.cartre.2025.100592
Tooran Tavangar, Nick A Eaves
Graphene can be synthesized entirely in the gas phase within microwave-assisted reactors operating at atmospheric pressure. Although these systems are sustained by plasmas with extremely high local temperatures, graphene formation occurs downstream where chemical kinetics govern molecular growth. A one-dimensional plug-flow model coupled with a sectional aerosol framework is used to evaluate how different detailed gas-phase chemical mechanisms influence graphene formation from an ethanol precursor. Five mechanisms commonly used for polycyclic aromatic hydrocarbon (PAH) chemistry—ABF, DLR, CALTECH, KAUST, and CRECK—are compared with experimental measurements of graphene yield and Feret diameter. The mechanisms predict very different onsets of graphene formation. Notably, the KAUST mechanism, despite its unrealistic assumption of irreversible PAH growth, reproduces experimental trends most closely. This outcome suggests that the plasma environment maintains a chemically frozen state where large PAHs behave as effectively irreversible species. Comparison between kinetic and equilibrium calculations confirms that PAH concentrations in the post-plasma region exceed equilibrium predictions by 18–20 orders of magnitude. Because the model itself does not include plasma physics, this kinetic–equilibrium disparity provides indirect, but not exclusive, evidence that plasma-driven processes push the system far from chemical equilibrium and enable the rapid molecular growth required for graphene formation. These findings explain why equilibrium models fail to predict graphene synthesis and demonstrate that model discrepancies can expose hidden nonequilibrium mechanisms.
{"title":"Evidence of plasma-driven nonequilibrium chemistry in graphene formation from gas-phase kinetic modeling","authors":"Tooran Tavangar, Nick A Eaves","doi":"10.1016/j.cartre.2025.100592","DOIUrl":"10.1016/j.cartre.2025.100592","url":null,"abstract":"<div><div>Graphene can be synthesized entirely in the gas phase within microwave-assisted reactors operating at atmospheric pressure. Although these systems are sustained by plasmas with extremely high local temperatures, graphene formation occurs downstream where chemical kinetics govern molecular growth. A one-dimensional plug-flow model coupled with a sectional aerosol framework is used to evaluate how different detailed gas-phase chemical mechanisms influence graphene formation from an ethanol precursor. Five mechanisms commonly used for polycyclic aromatic hydrocarbon (PAH) chemistry—ABF, DLR, CALTECH, KAUST, and CRECK—are compared with experimental measurements of graphene yield and Feret diameter. The mechanisms predict very different onsets of graphene formation. Notably, the KAUST mechanism, despite its unrealistic assumption of irreversible PAH growth, reproduces experimental trends most closely. This outcome suggests that the plasma environment maintains a chemically frozen state where large PAHs behave as effectively irreversible species. Comparison between kinetic and equilibrium calculations confirms that PAH concentrations in the post-plasma region exceed equilibrium predictions by 18–20 orders of magnitude. Because the model itself does not include plasma physics, this kinetic–equilibrium disparity provides indirect, but not exclusive, evidence that plasma-driven processes push the system far from chemical equilibrium and enable the rapid molecular growth required for graphene formation. These findings explain why equilibrium models fail to predict graphene synthesis and demonstrate that model discrepancies can expose hidden nonequilibrium mechanisms.</div></div>","PeriodicalId":52629,"journal":{"name":"Carbon Trends","volume":"22 ","pages":"Article 100592"},"PeriodicalIF":3.9,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-11DOI: 10.1016/j.cartre.2025.100591
Seyyed Ebrahim Mousavi , Mohammad Javad Azarhoosh , Saeed Abbasizadeh , Hassan Pahlavanzadeh , Habib Ale Ebrahim
The catalytic removal of sulfur dioxide (SO₂) was evaluated using methane (CH4) as a reductant, focusing on nickel catalysts supported on activated carbon. Various compositions of nickel oxide on activated carbon were impregnated and tested at temperatures between 550 and 800 °C for the sulfur dioxide reduction reaction with methane. The catalyst containing 15 % nickel showed the highest performance, achieving over 99 % conversion of SO₂ and over 99.5 % selectivity for the desired sulfur product. A comparative analysis was conducted between nickel oxide catalysts supported by activated carbon and alumina. The alumina-supported nickel catalyst demonstrated promising effectiveness in a lifetime test for industrial applications. The impact of activated carbon structure degradation on the performance of catalysts was also evaluated. It was found that as activated carbon structures degrade over time, the formation of new pores enhances carbon availability, thereby increasing the occurrence of undesirable side reactions. These results highlight how important catalyst support materials are in ensuring long-term stability and performance in sulfur dioxide reduction processes.
{"title":"Optimized nickel-activated carbon catalysts for efficient SO2 reduction with methane: Performance and lifetime comparative analysis with alumina","authors":"Seyyed Ebrahim Mousavi , Mohammad Javad Azarhoosh , Saeed Abbasizadeh , Hassan Pahlavanzadeh , Habib Ale Ebrahim","doi":"10.1016/j.cartre.2025.100591","DOIUrl":"10.1016/j.cartre.2025.100591","url":null,"abstract":"<div><div>The catalytic removal of sulfur dioxide (SO₂) was evaluated using methane (CH<sub>4</sub>) as a reductant, focusing on nickel catalysts supported on activated carbon. Various compositions of nickel oxide on activated carbon were impregnated and tested at temperatures between 550 and 800 °C for the sulfur dioxide reduction reaction with methane. The catalyst containing 15 % nickel showed the highest performance, achieving over 99 % conversion of SO₂ and over 99.5 % selectivity for the desired sulfur product. A comparative analysis was conducted between nickel oxide catalysts supported by activated carbon and alumina. The alumina-supported nickel catalyst demonstrated promising effectiveness in a lifetime test for industrial applications. The impact of activated carbon structure degradation on the performance of catalysts was also evaluated. It was found that as activated carbon structures degrade over time, the formation of new pores enhances carbon availability, thereby increasing the occurrence of undesirable side reactions. These results highlight how important catalyst support materials are in ensuring long-term stability and performance in sulfur dioxide reduction processes.</div></div>","PeriodicalId":52629,"journal":{"name":"Carbon Trends","volume":"21 ","pages":"Article 100591"},"PeriodicalIF":3.9,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145571226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-10DOI: 10.1016/j.cartre.2025.100589
Géza I. Márk , Márton Szendrő , Alexandre Mayer , Zoltán Simon , Péter Vancsó
We report a pronounced direction-dependent quantum transport phenomenon across stacking domain boundaries in trilayer graphene, revealed by large-scale wave packet dynamics simulations. Employing molecular statics with realistic interatomic force fields, we construct an ABC–ABA grain boundary geometry with structural features – such as soliton width and corrugation amplitude – that closely match experimental observations. To mimic a transport device geometry, we injected electrons from a graphene electrode into the outer layer of our ABC-ABA junction. We demonstrate that this configuration shows a striking asymmetry in transport behavior: wave packets incident from the rhombohedral (ABC) side transmit with minimal reflection, while those originating from the Bernal (ABA) side are strongly backscattered. The total reflection probability measured in the graphene electrode differs by more than a factor of 20 between the two incidence directions, and the energy-dependent transmission function reveals that the main differences are concentrated within the energy range around the Fermi level. We prove that this rectification is robust across grain boundaries of varying thicknesses and morphologies, as it originates from the distinct electronic structures – effective masses, sublattice-, and layer polarizations – of the two stacking configurations. These differences in the electronic structure of the two stacking configurations are rooted in their lattice symmetries: the mirror-symmetric ABA and the inversion-symmetric ABC trilayers, which give rise to distinct reflection behavior at both the graphene-trilayer contact and the ABA–ABC grain boundary. The precise energy dependence of the reflection function, however, depends on the specific atomic structure of the domain boundary, yet, without altering the overall value of the reflection. Our results show that contacted ABC–ABA stacking domain boundaries could lead to directional quantum transport — opening a pathway toward quantum diode-like functionalities.
{"title":"Robust reflection asymmetry across rhombohedral—Bernal stacking boundaries in trilayer graphene","authors":"Géza I. Márk , Márton Szendrő , Alexandre Mayer , Zoltán Simon , Péter Vancsó","doi":"10.1016/j.cartre.2025.100589","DOIUrl":"10.1016/j.cartre.2025.100589","url":null,"abstract":"<div><div>We report a pronounced direction-dependent quantum transport phenomenon across stacking domain boundaries in trilayer graphene, revealed by large-scale wave packet dynamics simulations. Employing molecular statics with realistic interatomic force fields, we construct an ABC–ABA grain boundary geometry with structural features – such as soliton width and corrugation amplitude – that closely match experimental observations. To mimic a transport device geometry, we injected electrons from a graphene electrode into the outer layer of our ABC-ABA junction. We demonstrate that this configuration shows a striking asymmetry in transport behavior: wave packets incident from the rhombohedral (ABC) side transmit with minimal reflection, while those originating from the Bernal (ABA) side are strongly backscattered. The total reflection probability measured in the graphene electrode differs by more than a factor of 20 between the two incidence directions, and the energy-dependent transmission function reveals that the main differences are concentrated within the <span><math><mrow><mo>±</mo><mn>0</mn><mo>.</mo><mn>5</mn><mspace></mspace><mi>eV</mi></mrow></math></span> energy range around the Fermi level. We prove that this rectification is robust across grain boundaries of varying thicknesses and morphologies, as it originates from the distinct electronic structures – effective masses, sublattice-, and layer polarizations – of the two stacking configurations. These differences in the electronic structure of the two stacking configurations are rooted in their lattice symmetries: the mirror-symmetric ABA and the inversion-symmetric ABC trilayers, which give rise to distinct reflection behavior at both the graphene-trilayer contact and the ABA–ABC grain boundary. The precise energy dependence of the reflection function, however, depends on the specific atomic structure of the domain boundary, yet, without altering the overall value of the reflection. Our results show that contacted ABC–ABA stacking domain boundaries could lead to directional quantum transport — opening a pathway toward quantum diode-like functionalities.</div></div>","PeriodicalId":52629,"journal":{"name":"Carbon Trends","volume":"21 ","pages":"Article 100589"},"PeriodicalIF":3.9,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-08DOI: 10.1016/j.cartre.2025.100588
Ari Gurel, Assya Cheutin, Yasmine Bouaouni, Stéphanie Lau, Sébastien Bellynck, Sophie Nowak, Delphine Schaming
While carbon dots (CDs) have attracted increasing attention these last years as a new family of carbon materials with amazing optical properties and applications in ever-wider fields, many CDs described in the literature come from bottom-up syntheses using organic molecules as precursors. In particular, a very simple and rapid method largely employed consists in the microwaves treatment of an aqueous solution of citric acid and urea using microwaves. This method leads to CDs with a very high fluorescence quantum yield which are generally used for several applications such as catalysis without thorough purifications. In these works, we highlight the formation of a large quantity of molecular organic fluorophores during the synthesis protocol of these CDs. After a purification process based on chromatographic separation and Soxhlet extraction, we isolated purer CDs from the mixture of organic fluorophores. Then, we investigated the catalytic properties of these CDs and these organic fluorophores when associated with ZnO or TiO2 photocatalysts. While CDs are generally described as excellent co-catalysts for protons photoreduction, we evidenced the role of these organic fluorophores in photocatalysis performances generally assigned to CDs while the later used pure seem to deactivate the catalytic properties of semiconductors.
{"title":"Investigation of the synthesis of carbon dots from citric acid and urea: evidence of the formation of organic fluorophores and study of their impact in catalysis","authors":"Ari Gurel, Assya Cheutin, Yasmine Bouaouni, Stéphanie Lau, Sébastien Bellynck, Sophie Nowak, Delphine Schaming","doi":"10.1016/j.cartre.2025.100588","DOIUrl":"10.1016/j.cartre.2025.100588","url":null,"abstract":"<div><div>While carbon dots (CDs) have attracted increasing attention these last years as a new family of carbon materials with amazing optical properties and applications in ever-wider fields, many CDs described in the literature come from bottom-up syntheses using organic molecules as precursors. In particular, a very simple and rapid method largely employed consists in the microwaves treatment of an aqueous solution of citric acid and urea using microwaves. This method leads to CDs with a very high fluorescence quantum yield which are generally used for several applications such as catalysis without thorough purifications. In these works, we highlight the formation of a large quantity of molecular organic fluorophores during the synthesis protocol of these CDs. After a purification process based on chromatographic separation and Soxhlet extraction, we isolated purer CDs from the mixture of organic fluorophores. Then, we investigated the catalytic properties of these CDs and these organic fluorophores when associated with ZnO or TiO2 photocatalysts. While CDs are generally described as excellent co-catalysts for protons photoreduction, we evidenced the role of these organic fluorophores in photocatalysis performances generally assigned to CDs while the later used pure seem to deactivate the catalytic properties of semiconductors.</div></div>","PeriodicalId":52629,"journal":{"name":"Carbon Trends","volume":"22 ","pages":"Article 100588"},"PeriodicalIF":3.9,"publicationDate":"2025-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145625342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-03DOI: 10.1016/j.cartre.2025.100590
Andrea Marangon , Guido Orlando , Elisa Calà , Alessandro Croce , Enrico Avattaneo , Eleonora Cara , Natascia De Leo , Giorgio Gatti
Plant biomass is becoming an increasingly viable alternative for producing activated carbons, compared to fossil sources. The most commonly used biomass sources include agricultural waste, vegetable biomass from the food industry, and biomass waste from the processing of woody materials. Among the biomass that has received attention is bamboo. This grass it is capable of storing large quantities of CO2 during its growth phase, and appears to be a renewable resource with a fast-growing rate that can be utilized as a starting biomass for the production of activated carbon. There are multiple methodologies in the literature for preparing activated carbons from biomass, but each of these methodologies leads to the formation of materials with distinct properties. For this reason, three different pre-activation (two chemical and one physical method) and activation methods (using different KOH ratios and activation temperature) of preparing active carbons were applied and compared with each other. The materials obtained were compared using scanning electron microscopy to assess morphology, infrared spectroscopy to evaluate the surface functional groups, thermogravimetric analysis, and Raman spectroscopy to determine the water contenent and degree of graphitisation of the materials. Finally, through physisorption of nitrogen at 77 K it was possible to determine the surface area and porous volume. The materials produced demonstrated that bamboo can serve as a biomass for the preparation of activated carbons, and that different methodologies lead to the production of materials with different functionalities and chemical-physical properties.
{"title":"Comparison of different activation methods for activated carbon produced using various methods from Phyllostachys edulis (bamboo moso) biomass","authors":"Andrea Marangon , Guido Orlando , Elisa Calà , Alessandro Croce , Enrico Avattaneo , Eleonora Cara , Natascia De Leo , Giorgio Gatti","doi":"10.1016/j.cartre.2025.100590","DOIUrl":"10.1016/j.cartre.2025.100590","url":null,"abstract":"<div><div>Plant biomass is becoming an increasingly viable alternative for producing activated carbons, compared to fossil sources. The most commonly used biomass sources include agricultural waste, vegetable biomass from the food industry, and biomass waste from the processing of woody materials. Among the biomass that has received attention is bamboo. This grass it is capable of storing large quantities of CO<sub>2</sub> during its growth phase, and appears to be a renewable resource with a fast-growing rate that can be utilized as a starting biomass for the production of activated carbon. There are multiple methodologies in the literature for preparing activated carbons from biomass, but each of these methodologies leads to the formation of materials with distinct properties. For this reason, three different pre-activation (two chemical and one physical method) and activation methods (using different KOH ratios and activation temperature) of preparing active carbons were applied and compared with each other. The materials obtained were compared using scanning electron microscopy to assess morphology, infrared spectroscopy to evaluate the surface functional groups, thermogravimetric analysis, and Raman spectroscopy to determine the water contenent and degree of graphitisation of the materials. Finally, through physisorption of nitrogen at 77 K it was possible to determine the surface area and porous volume. The materials produced demonstrated that bamboo can serve as a biomass for the preparation of activated carbons, and that different methodologies lead to the production of materials with different functionalities and chemical-physical properties.</div></div>","PeriodicalId":52629,"journal":{"name":"Carbon Trends","volume":"21 ","pages":"Article 100590"},"PeriodicalIF":3.9,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145465446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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