Edges Of Nanoribbons Research Articles

Bending-induced enhanced spatial separation of dopants and long-lived conventional nanoribbon p-n junctions.

The spatial separation of dopants is crucial in extending the lifetime of nanoribbon p-n junctions, which is traditionally realized via van der Waals heterostructures at a high cost. In this study, we employ atomistic quantum mechanical simulations to demonstrate that a simple in-plane bending deformation can lead to an enhanced doping preference in conventional nanoribbons. Dopants with larger atomic sizes than those of host atoms tend to reside on the tensile side close to the outermost edge of the bent nanoribbons, while dopants with smaller atomic sizes than those of host atoms tend to reside on the compressive side close to the innermost edge of the bent nanoribbons. We also show that this doping preference induces an enhanced spatial separation of n-type and p-type dopants with different atomic sizes. As conventional nanoribbons are easier to synthesize and cost-effective, our results provide a pathway for modulating dopant distribution and designing long-lived nanoribbon p-n junctions via inhomogeneous strain engineering.

Synthesis and Modular Engineering of Porous Graphene Nanoarchitectures

Bottom-up nanoarchitectonics has demonstrated the capability to control structural parameters of nanomaterials with atomic precision. The surface-assisted synthesis of graphene-based one-dimensional nanostructures à la carte distinctly illustrates the power of this concept. However, despite impressive advances in the synthesis of 1D homostructures, advancing in structural complexity faces major challenges. However, despite impressive advances in the synthesis of 1D homostructures, advancing in structural complexity faces major challenges. The functionalization of edges in nanorib-bons, an effective strategy to tailor their electronic properties and chemical interactions, is a clear example. The concept of inserting the desired functional groups or dopants in the molecular precursor often fails due to their lack of stability during the reaction path. The fabrication of heterostructures is a second example, where the challenge lies on the control of the size and distribution of their com-ponents. A third one is extending the on-surface strategy to two-dimensional structures, where examples of long-range ordered nanoarchitectures are very limited.In this talk I will present different strategies that we have developed to overcome each one of this challenges. I will show introducing our method to synthesize a 2D nanoporous graphene, where the long-range order is achieved by the sequential growth of 1D building blocks and their posterior coupling [1]. I will continue presenting two modular strategies that lead to more complex nanoporous structures. The first consist on the molecular engineering of the coupling bridges. I will show an example where the introduction of phenyl groups in the bridges brings tunability of the quantum electronic coupling and the corresponding in-plane electronic anisotropy [2]. In a final example I will focus on intercalating different 1D ribbon components in periodic arrays for the formation of lateral heterostructure superlattices where the junction is defined with atomic precision [3]. One of the components being a N-doped ribbon, the heterostructure can also be seen as a nanoporous graphene sheet bearing N-doped pores.

(Invited) Computational Design of Low-D Graphene-Based Systems in View of Energy Applications

Graphene-based nanostructures, such as 1D graphene nanoribbons [1-4], and graphene-related 2D materials, such as C3N [5-7], offer extraordinary versatility as next-generation semiconductors for nanoelectronics, optoelectronics and energy devices (e.g. batteries) [8,9], due to their tunable properties, including charge-carrier mobility, optical absorption, excitonic features, electronic bandgap and mechanical properties which are uniquely defined by their chemical structure.We here adopt predictive first-principles computational schemes - based on both density-functional theory and many-body perturbation theory - to acquire a comprehensive understanding of the electronic, optical and vibrational (Raman and IR) excitations of such low-D graphene-based materials, as a function of their structure, functionalization, distortion, and different reaction stage in their fabrication. Our results, often combined to experimental investigations, allow not only to fingerprint their precise structures, but also to physically interpret and predict their spectral features also in view of a material design perspective. N. Cavani, M. De Corato, A. Ruini, D. Prezzi, E. Molinari, A. Lodi Rizzini, A. Rosi, R. Biagi, V. Corradini, X.Y. Wang, X. L. Feng, A. Narita, K. Mullen, V. De Renzi, “Vibrational signature of the graphene nanoribbon edge structure from high-resolution electron energy-loss spectroscopy”, Nanoscale 12, 19681-19688 (2020)D. Rizzo, D. Prezzi, A. Ruini, V. Nagyte, A. Keerthi, A. Narita, U. Beser, F.G. Xu, Y,Y, Mai, X.L. Feng, K. Mullen, E. Molinari, C. Casiraghi, “Multiwavelength Raman spectroscopy of ultranarrow nanoribbons made by solution-mediated bottom-up approach”, Phys. Rev. B 100, 045406 (2019)B. Hu, P. Xie, M.De Corato, A. Ruini, S. Zhao, F. Meggendorfer, L.A. Straaso, L. Rondin, P. Simon, J. Li, J.J. Finley, M.R. Hansen, J.S. Lauret, E. Molinari, X.L. Feng, J.V. Barth, C.A. Palma, D. Prezzi, K. Mullen, A. Narita, “Bandgap Engineering of Graphene Nanoribbons by Control over Structural Distortion”, J. Am. Chem. Soc.140, 7803-7809 (2018)R. Denk, M. Hohage, P. Zeppenfeld, J. M. Cai, C. A. Pignedoli, H. Sode, R. Fasel, X. L. Feng, K. Mullen, S. D. Wang, D. Prezzi, A Ferretti, A. Ruini, E. Molinari, P. Ruffieux, “Exciton-dominated optical response of ultra-narrow graphene nanoribbons”, Nature Communications 5, 4253 (2014).M. Zanfrognini, M. Bonacci, F. Paleari, E. Molinari, A. Ruini, A. Ferretti, M. J. Caldas, D. Varsano, “Quenching of low-energy optical absorption in bilayer polytypes”, Physical Review Materials 7 (6), 064006 (2023)M. Zanfrognini, N. Spallanzani, M. Bonacci, E. Molinari, A. Ruini, M.J. Caldas, A. Ferretti, D. Varsano, “Effect of uniaxial strain on the excitonic properties of monolayer: A symmetry-based analysis”, Physical Review B 107 (4), 045430 (2023)M. Bonacci, M. Zanfrognini, E. Molinari, A. Ruini, M. J Caldas, A. Ferretti, D. Varsano, “Excitonic effects in graphene-like C3N”, Phys. Rev. Mat. 6, 034009 (2022)M. A. Salvador, R. Maji, F. Rossella, E. Degoli, A. Ruini, R. Magri, “Structural and Dynamic Characterization of Li–Ionic Liquid Electrolyte Solutions for Application in Li-Ion Batteries: A Molecular Dynamics Approach”, Batteries 9 (4), 234 (2023)R. Maji, M. A. Salvador, A. Ruini, R. Magri, E. Degoli, “A first-principles study of self-healing binders for next-generation Si-based lithium-ion batteries”, Materials Today Chemistry 29, 101474 (2023)

Effects of nanocutting environments on the electronic structure of armchair-type graphene nanoribbons: the first-principles study

In order to investigate the effect of nanocutting environment on the electronic structure of armchair-type graphene nanoribbons, this paper adopts a first-principle computational approach to study the effect of different substrates and solutions, such as on the motion of electrons in the middle and outer orbitals of graphene nanoribbons, by observing the energy band structure, the value of the band gap, and the density of the split-wave states. The results show that the adsorption of Si and C atoms at the edge of the nanoribbon leads to a decrease in the band gap value. The adsorption of Al and O atoms at the edges of graphene nanoribbons leads to a decrease in the nanoribbon band gap value to 0 eV. Different substrate atoms mainly affect the p-orbital electron motion in the nanobelt. Bare-edge graphene nanoribbons are indirect bandgap structures, and graphene nanoribbons with H, O and OH atoms adsorbed at the edges of the nanoribbons are direct bandgap structures. Edge O-isation leads to a nanobelt band gap of 0, which exhibits metallic properties. The edge H-isation nanoribbon band gap is higher than the bare edge nanoribbon band gap. Nanoribbon edge OH-isation reduces the nanoribbon band gap value. Nanoribbon edge adsorption of atoms in solution affects p-orbital electron motion. The formation energy of five-ring defects and seven-ring defects is low, and the defects are easier to form. The edges containing defects all reduce the band gap values of graphene nanoribbons. The defects mainly affect the p-orbital electron motion, leading to differences in the band gap values. The bandgap decreases with increasing nanobelt width, and the bandgap value conforms to 3 N+2<3 N<3 N+1, with regular fluctuations in the curve with period 3. The larger the band gap, the smaller the curvature of the curve at the extremes, and the sparser the curve. In this paper, the electronic structures of different edge structures are analysed from a quantum mechanical point of view, and the synthesis of these results will provide theoretical guidance for obtaining high-quality semiconductor nanoribbons by mechanochemical nanocutting.

Morphology evolution of supramolecular aggregates from C3-symmetric peptide amphiphiles

During the aging of supramolecular systems, new stable materials with different morphologies, molecular packing, and hierarchical organization may form from the initial assembly. Understanding the mechanisms and pathways accompanying age-related changes may allow for the controlled synthesis of multiple materials from a single molecule in a nature-inspired manner. Herein, we demonstrate the multi-stage evolution of a single solution of C3-symmetric peptide amphiphile containing diphenylalanine fragment and benzyl-1,3,5-tricarboxamide core. Transmission electron microscopy reveals the rapid formation of 20–40 nm wide nanoribbons in an aqueous solution within 60 s after preparation. The lateral edges of nanoribbons contain solvent-exposed aromatic residues that tend to merge via an unconventional edge-to-edge zipping mechanism, leading to the nanoribbon’s growth in width. After reaching a critical width and flexibility, “sticky edges” on the same nanoribbon may merge via a self-zipping mechanism, forming rigid nanotubes. Eventually, mechanical perturbations cause buckling and fracture of nanotubes into shorter nanotubes via flexural or tensile failure. This work reports new evolution pathways in soft 2D assemblies and introduces solution ageing as a promising method to control morphology of peptide amphiphiles.

Formation of Metal Atom Chains at the Edges of Graphene Nanoribbons Supported by Graphene

Formation of Metal Atom Chains at the Edges of Graphene Nanoribbons Supported by Graphene

Nanoscale terahertz conductivity and ultrafast dynamics of terahertz plasmons in periodic arrays of epitaxial graphene nanoribbons

The dynamics of plasmons in nanoribbons of (hydrogen intercalated) quasi-freestanding single-layer graphene is studied by terahertz spectroscopy both in the steady state and upon photoexcitation by an ultrashort near infrared laser pulse. The use of two-dimensional frequency-domain analysis of the optical pump–terahertz (THz) probe signals allows us to determine the evolution of carrier temperature and plasmon characteristics with ∼100 fs time resolution. Namely, we find that the carrier temperature decreases from more than 5000 K to the lattice temperature within about 7 ps and that during this evolution the carrier mobility remains practically constant. The time-resolved THz conductivity spectra suggest that graphene nanoribbons contain defects which act as low potential barriers causing a weak localization of charges; the potential barriers are overcome upon photoexcitation. Furthermore, the edges of graphene nanoribbons are found to slightly enhance the scattering of carriers. The results are supported by complementary measurements using THz scanning near-field microscopy, which confirm a high uniformity of the THz conductivity across the sample and demonstrate high enough sensitivity to resolve even the impact of nanometric terrace steps on SiC substrate under the graphene monolayer. Published by the American Physical Society 2024

Room temperature thermal rectification in suspended asymmetric graphene ribbon

Thermal rectifiers are essential in optimizing heat dissipation in solid-state devices to enhance energy efficiency, reliability, and overall performance. In this study, we experimentally investigate the thermal rectification phenomenon in suspended asymmetric graphene ribbons (GRs). The asymmetry within the graphene is introduced by incorporating periodic parallel nanoribbons on one side of the GR while maintaining the other side in a pristine form. Our findings reveal a substantial thermal rectification effect in these asymmetric graphene devices, reaching up to 45% at room temperature and increasing further at lower environmental temperatures. This effect is attributed to a significant thermal conductivity contrast between pristine graphene and nanoribbon graphene within the asymmetric structure. We observe that the incorporation of nanoribbons leads to a notable reduction in thermal conductivity, primarily due to phonon scattering and bottleneck effects near the nanoribbon edges. These findings suggest that graphene structures exhibiting asymmetry, facilitated by parallel nanoribbons, hold promise for effective heat management at the nanoscale level and the development of practical phononic devices.

Micromechanical effects of substrate hardness on graphene nano-cutting quality

In the nanocutting process of graphene, the mechanism on the atomic scale of the effect of substrate hardness on the edge quality of graphene nanoribbons has not been thoroughly investigated. In this paper, we construct a diamond probe (radius of 5 Å) to cut graphene (190 Å × 113 Å) models with different substrates (silicon/sapphire/silicon carbide), molecular dynamics simulations were used to study the effect of substrate hardness and cutting depth on the atomic structure of graphene nanoribbon edges by observing the atomic morphology, the number of C-C bonds, the radial distribution function and friction. The results show that during the nanoindentation stage, when graphene is in the critical damage state, the substrate with high hardness has high deformation strength, the substrate deformation is small, and graphene undergoes deformation is also small, but the force Fz on the probe, the critical graphene stress σz and the equivalent stress are all large, and the number of C atoms with CN=3 is large; At the nano-cutting stage, the breakage of C-C bonds and the generation of edge defects are caused by local stress concentration, and the graphene stress σxx along the x-direction has a clear directionality. With the same cutting depth (critical damage depth of silicon substrate), silicon substrate hardness is small, the graphene nanoribbon obtained has less number of circular defects generated at the edge, less total number of defective atoms, more number of CN=3 atoms, large peak of radial distribution function of graphene after cutting, and graphene integrity is better. The hardness of the silicon carbide substrate is large, and the number of C-C bond breaks in graphene during the cutting process is high. Each substrate is cut at its own critical damage depth, and the substrate hardness has no significant effect on the number of C-C bond breaks, the number of circular defects, the total number of defective atoms, and the number of CN=3 atoms in graphene. When the silicon substrate was used, the stable force of the probe is small, the edge structure of graphene has little impact, the edge effect obtained is good. The cutting depth and substrate hardness have little effect on the graphene temperature during the nano-cutting process. In this paper, the atomic structure of graphene edges after cutting is analysed and investigated on the atomic scale, and the above results are combined to provide theoretical guidance for obtaining efficient and high-quality and low-damage graphene nanoribbon cutting.

Impact of uniaxial strain on physical properties of zigzag graphene nanoribbons with topological defects

The synergistic regulation mechanism of uniaxial strain, topological defects, edge passivation atom and nanoribbon width on the geometric and electronic structures of zigzag graphene nanoribbons have been studied systematically by first-principles. It is found that the average formation energy and strain energy of X-N 1 N 2-LD-ZGNR (X = H, F and O, as well as, N 1 = N 2 = 3, 4 and 5) increase with the increase of uniaxial strain, and this relationship is also dependent of edge passivation atom species and nanoribbon width. And the edge of 55-LD-ZGNR passivating with O and F atoms is more beneficial than H atom for system stability. The stress–strain curve shows that the limiting strain of zigzag graphene nanoribbon depends on edge passivation atom species and nanoribbon width. The Young’s modulus in the case of ε > 3% and Poisson’s ratio except O-33-LD-ZGNR at ε = 1% of X-N 1 N 2-LD-ZGNR decrease with the increase of the tensile strain, and is dependent of nanoribbon width and edge atom species. And O-55-LD-ZGNR is easier than F-55-LD-ZGNR and H-55-LD-ZGNR to be stretched or compressed. The magnetism is induced in both H-55-LD-ZGNR and F-55-LD-ZGNR, and remains with the increases of uniaxial tension strain. What is more, magnetic property of O-55-LD-ZGNR can be regulated by applying uniaxial strain, and the band gap of the O-N 1 N 2-LD-ZGNR (N 1 = N 2 = 3, 4 and 5) system can be regulated by adjusting the uniaxial tensile strain and nanoribbon width. Our research provides a new method to open the graphene band gap, which can provide some new theoretical guidance for the application of graphene in electronic devices and other fields. The band gap of the O-LD-ZGNDR system is opened as the uniaxial tensile strain increases.

Modulation of dual-spin filtering by edge-hybridized pairing of β-SiC7 nanoribbons

Atomic capping is a common approach in edge modification to tune band engineering and can be achieved experimentally through hydrogen plasma etching. Based on first-principles calculations, nine symmetric and asymmetric structures are constructed with different numbers of hydrogen atoms passivated at the edge of β-SiC7 nanoribbons. An in-depth study reveals that different edge hydrogenations realize the transition from semiconductors to half-metals to metals, firstly, because different numbers of hydrogen atoms lead to different edge atomic orbital hybridizations, and, more importantly and specifically, because the bands around the Fermi level of β-SiC7 nanoribbons are all derived from the spatially separated edge states, so that arbitrary pairings of upper and lower edge hybridizations are able to diversify the bands near the Fermi level and bring about a richer electronic properties. We also design the metallic H-zSiC7NR-H and semiconducting 2H-zSiC7NR-H into a heterojunction, which possesses good dual spin filtering properties at low bias, can achieve a spin polarization transition from -100 % to 100 %, and exhibits the NDR phenomenon. These findings suggest that β-SiC7 nanoribbons have promising applications in the field of spintronics.

Gallium phosphide nanoribbon-based carbon monoxide sensors: insights from first principles study

The priority of research efforts over the past two decades has been focused on the effective detection of harmful gases and the development of small, efficient, and reliable nanodimensional sensors. The adsorption of carbon monoxide (CO) gas molecules on zigzag gallium phosphide nanoribbons (zGaPNRs) has been studied using first-principle calculations within the context of Density Functional Theory (DFT). Here, we have evaluated the potential of single-atom thick zGaPNRs in different configurations of nanoribbons for the detection of CO. Many possible configurations of studying the CO molecule adsorption on zGaPNRs have been explored. It is established that the interaction of CO molecules has an impact on the electrical and transport properties of zGaPNRs. The H-GaP-H is the most stable structure with the binding energy ([Formula: see text]) of −5.70[Formula: see text]eV. The stability is compromised with CO adsorption with CO-GaP-CO being the least stable structure. Pristine structure is semiconducting with the energy band gap ([Formula: see text]) of −3.95[Formula: see text]eV. The computed sensitivity (S) values are found to be highest for Co-GaPNRs with the S value of [Formula: see text] and the least sensitive structure is H-GaP-CO with the computed S as [Formula: see text]. Additionally, it is noted that CO molecules always establish a stable chemical bond with the nanoribbon edges through the C-side. The unique behavior is revealed by the transport characteristics, which demonstrates that when CO adsorption occurs near the Ga edge, the current magnitude is noticeably greater. Our research demonstrates the potential of specific CO adsorption and detection for the development of nanosensors.

Enhanced reduction of CO to C2 products on MoS2 nanoribbons by edge engineering

Engineering the edge of MoS2 nanoribbons promotes selective CO reduction to C2 products.

Structure-search-revealed edge reconstruction in two-dimensional materials: The case of phosphorene nanoribbons

The edge structures of two-dimensional materials are important for the property control of corresponding nanoribbons, but possible edge reconstructions are difficult to resolve. Taking phosphorene nanoribbons as an example, we have employed the structure-searching program IM2ODE to discover new structures for both zigzag and armchair edges of bare phosphorene nanoribbons. The edge atoms of these low-energy nanoribbons are generally 3-fold coordinated, and the edge energies are significantly lower than those directly cut from the monolayer. Moreover, we can build low-energy sinuous edges along the diagonal direction based on the bonding features of phosphorus atoms. Further electronic structure studies also reveal that zigzag phosphorene nanoribbons undergo cell doubling and metal-insulator transition similar to Peierls distortion, indicating that the edges experience self-passivation and become stabilized. As similar edge reconstructions can exist in many other two-dimensional materials and it may be difficult to construct the edges by hand, our structure-searching approach provides reliable insights and certain rules can be discovered to elucidate various structure reconstructions.

Edge Magnetism in MoS2 Nanoribbons: Insights from a Simple One-Dimensional Model.

Edge magnetism in zigzag nanoribbons of monolayer MoS2 has been investigated with both density functional theory and a tight-binding plus Hubbard (TB+U) Hamiltonian. Both methods revealed that one band crossing the Fermi level is more strongly influenced by spin polarization than any other bands. This band originates from states localized on the sulfur edge of the nanoribbon. Its dispersion closely resembles that of the energy branch obtained in a linear chain of atoms with first-neighbor interaction. By exploiting this resemblance, a toy model has been designed to study the energetics of different spin configurations of the nanoribbon edge.

Structural and electronic properties of novel BeN4/MgN4 nanoribbons

Nanostructures of novel materials are capable of altering the properties of materials quite drastically. Recently discovered Dirac monolayer BeN4 has drawn much attention since this Nitrogen-based material’s electronic structure is very similar to graphene. In this work, we have analyzed various possiblities of nanoribbons structures of MN4 (M=Be, Mg) monolayer materials. We have proposed several possible geometries of BeN4 and MgN4 nanoribbon structures. More specifically, we have proposed armchair nanoribbons with three possible edge configurations as well as zigzag nanoribbons based on edge geometry. Owing to the changes in coordination environment of nanoribbon edge atoms, the resulting bonding characteristics gets altered at the edges, leading to interesting electronic properties. The electronic structures of these nanoribbons are quite different from monolayer and reveal fascinating edge states that exclusively depend on the edge configuration. Though the armchair nanoribbons are found to be metallic, the electronic structure of zigzag nanoribbons exhibits band gap which lead to huge tunability potential of the investigated nanostructures. Therefore, these nanoribbons can function both, metallic as well as semiconducting as required in device applications which can be tuned by modulating the material geometry.

Electronic and spin transport in Bismuthene with magnetic impurities

Topological insulators have remained as candidates for future electronic devices since their first experimental realization in the past decade. The existence of topologically protected edge states could be exploited to generate a robust platform and develop quantum computers. In this work we explore the role of magnetic impurities in the transport properties of topological insulators, in particular, we study the effect on the zigzag bismuthene nanoribbon edge states conductivity. By means of realistic abinitio calculations we simulate the interaction between magnetic adatoms and topological insulators, furthermore, our main goal is to obtain the transport properties for large samples as it would be possible to localize edge states at large scales.

Stiffer Bonding of Armchair Edge in Single-Layer Molybdenum Disulfide Nanoribbons.

The physical and chemical properties of nanoribbon edges are important for characterizing nanoribbons and applying them in electronic devices, sensors, and catalysts. The mechanical response of molybdenum disulfide nanoribbons, which is an important issue for their application in thin resonators, is expected to be affected by the edge structure, albeit this result is not yet being reported. In this work, the width-dependent Young's modulus is precisely measured in single-layer molybdenum disulfide nanoribbons with armchair edges using the developed nanomechanical measurement based on a transmission electron microscope. The Young's modulus remains constant at ≈166GPa above 3nm width, but is inversely proportional to the width below 3nm, suggesting a higher bond stiffness for the armchair edges. Supporting the experimental results, the density functional theory calculations show that buckling causes electron transfer from the Mo atoms at the edges to the S atoms on both sides to increase the Coulomb attraction.

Photoinduced edge-specific nanoparticle decoration of two-dimensional tungsten diselenide nanoribbons

Metallic nanoparticles are widely explored for boosting light-matter coupling, optoelectronic response, and improving photocatalytic performance of two-dimensional (2D) materials. However, the target area is restricted to either top or bottom of the 2D flakes. Here, we introduce an approach for edge-specific nanoparticle decoration via light-assisted reduction of silver ions and merging of silver seeds. We observe arrays of the self-limited in size silver nanoparticles along tungsten diselenide WSe2 nanoribbon edges. The density of nanoparticles is tunable by adjusting the laser fluence. Scanning electron microscopy, atomic force microscopy, and Raman spectroscopy are used to investigate the size, distribution, and photo-response of the deposited plasmonic nanoparticles on the quasi-one-dimensional nanoribbons. We report an on-surface synthesis path for creating mixed-dimensional heterostructures and heterojunctions with potential applications in opto-electronics, plasmonics, and catalysis, offering improved light matter coupling, optoelectronics response, and photocatalytic performance of 2D materials.

Theoretical insights into the methane catalytic decomposition on graphene nanoribbons edges.

Catalytic methane decomposition (CMD) is receiving much attention as a promising application for hydrogen production. Due to the high energy required for breaking the C-H bonds of methane, the choice of catalyst is crucial to the viability of this process. However, atomistic insights for the CMD mechanism on carbon-based materials are still limited. Here, we investigate the viability of CMD under reaction conditions on the zigzag (12-ZGNR) and armchair (AGRN) edges of graphene nanoribbons employing dispersion-corrected density functional theory (DFT). First, we investigated the desorption of H and H2 at 1200K on the passivated 12-ZGNR and 12-AGNR edges. The diffusion of hydrogen atom on the passivated edges is the rate determinant step for the most favourable H2 desorption pathway, with a activation free energy of 4.17eV and 3.45eV on 12-ZGNR and 12-AGNR, respectively. The most favourable H2 desorption occurs on the 12-AGNR edges with a free energy barrier of 1.56eV, reflecting the availability of bare carbon active sites on the catalytic application. The direct dissociative chemisorption of CH4 is the preferred pathway on the non-passivated 12-ZGNR edges, with an activation free energy of 0.56eV. We also present the reaction steps for the complete catalytic dehydrogenation of methane on 12-ZGNR and 12-AGNR edges, proposing a mechanism in which the solid carbon formed on the edges act as new active sites. The active sites on the 12-AGNR edges show more propensity to be regenerated due lower free energy barrier of 2.71eV for the H2 desorption from the newly grown active site. Comparison is made between the results obtained here and experimental and computational data available in the literature. We provide fundamental insights for the engineering of carbon-based catalysts for the CMD, showing that the bare carbon edges of graphene nanoribbons have performance comparable to commonly used metallic and bi-metallic catalysts for methane decomposition.