Boron-doped Graphene Research Articles

Electrical field-induced selective adsorption behaviours on graphene/Ni heterostructured surfaces: A theoretical study

Graphene is a promising candidate as an ideal reinforcing phase for metal matrix, but the grain growth mechanism within functional graphene/metal composite is still unclear. In our work, the interface microstructures evolution process of graphene/Ni composites is proposed from a theoretical perspective using the first-principles method based on density functional theory (DFT). Specifically, the adsorption and diffusion behaviours of Ni atoms on the graphene/Ni heterostructured surfaces and the selective adsorption sites under external electrical field are comprehensively investigated. Strong interactions are verified by population analysis and charge difference density. To elucidate the influence from the external electrical field, the intensity and the direction of the external electric field are considered. Moreover, the adsorption behaviours of Ni on the boron-doped graphene are studied. It can be concluded that the preferable adsorption sites are near the edge of graphene, and the presence of graphene is favourable for fine grains, and the introduction of boron will decrease adsorption capability. It is expected that our results could provide the underlying insights to reveal the role of graphene in structural evolution and offer some theoretical guidance to rationally design graphene/metal composites.

Evaluation of adsorption performance and mechanisms of a highly effective 3D boron-doped graphene composite for amitriptyline pharmaceutical removal

Three-dimensional heteroatom-doped graphene presents a state-of-the-art approach for effective remediation of pharmaceutical wastewater on account of its distinguished adsorption and physicochemical attributes. Amitriptyline is an emerging tricyclic antidepressant pollutant posing severe risks to living habitats through water supply and food chain. With ultra-large surface area and plentiful chemical functional groups, graphene oxide is a favorable adsorbent for decontaminating polluted water. Herein, a new boron-doped graphene oxide composite reinforced with carboxymethyl cellulose was successfully developed via solution-based synthesis. Characterization study revealed that the adsorbent was formed by graphene sheets intertwined into a porous network and engrafted with 13.37 at% of boron. The adsorbent has a zero charge at pH 6 and contained various chemical functional groups favoring the attachment of amitriptyline. It was also found that a mere 10 mg of adsorbent was able to achieve relatively high amitriptyline removal (89.31%) at 50 ppm solution concentration and 30 °C. The amitriptyline adsorption attained equilibrium within 60 min across solution concentrations ranging from 10 to 300 ppm. The kinetic and equilibrium of amitriptyline adsorption were well correlated to the pseudo-second-order and Langmuir models, respectively, portraying the highest Langmuir adsorption capacity of 737.4 mg/g. Notably, the predominant mechanism was chemisorption assisted by physisorption that contributed to the outstanding removal of amitriptyline. The saturated adsorbent was sufficiently regenerated using ethanol eluent. The results highlighted the impressive performance of the as-synthesized boron-doped adsorbent in treating amitriptyline-containing waste effluent.

Remediation of Amitriptyline Pharmaceutical Wastewater by Heteroatom-Doped Graphene Oxide: Process Optimization and Packed-Bed Studies

Amitriptyline residue released into the aquatic ecosystem can have detrimental consequences on marine organisms and human wellbeing via consumption of polluted water. With a uniquely large surface area and abundant functionalities, graphene oxide adsorption offers a remediation solution for such water pollution. This study focused on synthesizing a novel graphene-based adsorbent via ice-templating of boron-doped graphene substrate. The batch adsorption performance of the as-synthesized adsorbent was explored by central composite design (CCD), while its potential large-scale application was evaluated with a packed-bed column study. The CCD optimized conditions of 12.5 mg dosage, 32 min adsorption time, 30 °C operating temperature and 70 ppm concentration produced the highest removal efficiency of 87.72%. The results of the packed-bed study indicated that continuous adsorption of amitriptyline was best performed at a graphene bed of 3.5 cm in height, with 100 ppm of the pharmaceutical solution flowing at 2 mL/min. Furthermore, the breakthrough curve was effectively portrayed by the Log Bohart–Adams model. The as-synthesized adsorbent showed a high regeneration potential using ethanol eluent via multiple adsorption–desorption cycles. The results suggest the boron-doped graphene adsorbent in packed-bed as a highly effective system to remediate amitriptyline in an aqueous environment.

Excitation-depended fluorescence emission of boron-doped graphene quantum dot as an optical probe for detection of oxytetracycline in food and information encryption patterns.

The boron-doped graphene quantum dot (HSE-GQD-B) was prepared by thermal pyrolysis of the mixture of citric acid, histidine, serine and ethylenediamine and boric acid. The resulting HSE-GQD-B is composed of tiny graphene sheets with an average sheet size of 4.2 ± 0.16 nm and exhibits an excitation-depended fluorescence emission behavior. The HSE-GQD-B produces the strongest blue fluorescence of 450 nm wavelength under the excitation of 365-nm ultraviolet light and the strongest yellow fluorescence of 550-nm wavelength under the excitation of 470-nm visible light. The interaction of HSE-GQD-B with oxytetracycline molecule induces a sensitive blue fluorescence quenching process. Based on this characteristic, a fluorescence method was established for optical detection of oxytetracycline. The analytical method offers a better sensitivity, selectivity, and repeatability compared with previously reported methods. The detection of oxytetracycline attains a wide linear range of 0.02-50 μM and a detection limit of 0.0067 μM. It has been successfully applied to fluorescence detection of oxytetracycline in food samples. In addition, the HSE-GQD-B was also used as a multicolor fluorescence probe for information encryption patterns.

Arc discharge synthesis of graphene with enhanced boron doping concentration for electrochemical applications

The physicochemical properties of graphene, such as the bandgap and electrical conductivity, can be tuned when the carbon atoms are replaced with other heteroatoms. In addition to nitrogen, boron is a dopant that can compensate for the properties lacking in graphene; however, boron-doped graphene has not received significant attention owing to its low doping rate. In this study, we report an improvement in the doping efficiency of arc graphene by utilizing a boron precursor and graphene oxide as anode carbon fillers. X-ray photoelectron spectroscopy revealed that the doping level of the synthesized graphene flakes (5.7at.%) was significantly higher than that of boron-doped arc graphene reported in the literature (3at.%). Cyclic voltammetry, electrochemical impedance spectroscopy, and constant-current charge/discharge experiments were performed to investigate the electrochemical properties of boron-doped graphene. The synthesized boron-doped graphene exhibited an areal capacitance of 66 μF cm−2, which is superior to that of other doped carbon materials. The electrochemical activity of boron-doped graphene is affected more by functionalized doping than by substitutional doping, because of the improved wettability displayed by the former. Boron-doped graphene flakes required for various applications can be easily obtained by arc discharge synthesis.

Hydrothermal Synthesis of Boron-Doped Graphene for High-Performance Zinc-Ion Hybrid Capacitor Using Aloe Vera Gel Electrolyte

The great interest in developing emerging zinc-ion capacitors (ZIC) for energy storage applications is due to their inexpensiveness and the future necessity for hybrid electrical energy storage devices. The Zn-ion hybrid capacitor device was assembled using boron (B)-doped reduced graphene oxide (B-RGO) material, which acts as the cathode, and pure zinc metal as an anode. This research work aims to study the influence of B-doped reduced graphene oxide (B-RGO) with Aloe vera gel as an electrolyte. The reduced graphene oxide (RGO) and B-RGO electrode active materials were confirmed through X-ray diffraction (XRD), RAMAN, Fourier transformation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and field emission-transmission electron microscopy (FE-TEM) analysis. The surface morphological images reveal that a few-layered nanostructure B-RGO was used in the Zn-ion hybrid capacitor device. The electrochemical performance of the Zn-ion hybrid capacitor was evaluated through cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurements, with a wide active potential range of 0–2 V versus Zn/Zn+. The mixture composition of Aloe vera extract and 1M ZnSO4 electrolyte generated a stable voltage and exhibited good capacitive behavior. The fabricated ZIC coin cell device with the Aloe vera gel semi-gel electrolyte containing ZnSO4 demonstrated improved Zn+ ionic exchange and storage efficiency. Moreover, the B-RGO electrode active material exhibited excellent cycle stability. The simple one-step electrochemical technique is the most suitable process for boron doping into graphene nanosheets for future energy storage applications.

Impact of supporting electrolyte on electrochemical performance of borophene-functionalized graphene sponge anode and degradation of per- and polyfluoroalkyl substances (PFAS)

Graphene sponge anode functionalized with two-dimensional (2D) boron, i.e., borophene, was applied for electrochemical oxidation of C4-C8 per- and polyfluoroalkyl substances (PFASs). Borophene-doped graphene sponge outperformed boron-doped graphene sponge anode in terms of PFASs removal efficiencies and their electrochemical degradation; whereas at the boron-doped graphene sponge anode up to 35% of the removed PFASs was recovered after the current was switched off, the switch to a 2D boron enabled further degradation of the electrosorbed PFASs. Borophene-doped graphene sponge anode achieved 32–77% removal of C4-C8 PFASs in one-pass flow-through mode from a 10 mM phosphate buffer at 230 A m−2 of anodic current density. Higher molarity phosphate buffer (100 mM) resulted in lower PFASs removal efficiencies (11–60%) due to the higher resistance of the graphene sponge electrode in the presence of phosphate ions, as demonstrated by the electrochemical impedance spectroscopy (EIS) analyses. Electro-oxidation of PFASs was more efficient in landfill leachate despite its high organic loading, with up to 95% and 75% removal obtained for perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), versus 77% and 57% removal in the 10 mM phosphate buffer, respectively. Defluorination efficiencies as determined relative to the electrooxidized fraction of PFASs indicated up to 69% and 82% of defluorination of PFOS and PFOA in 10 mM phosphate buffer, which was decreased to 16 and 29% defluorination, respectively, for higher buffer molarity (100 mM) due to the worsened electrochemical performance of the sponge. In landfill leachate, relative defluorination efficiencies of PFOS and PFOA were 33% and 45%, respectively, indicating the inhibiting effect of complex organic and inorganic matrix of landfill leachate on the C-F bond breakage. This study demonstrates that electrochemical degradation of PFASs is possible to achieve in complex and brackish streams using a low-cost graphene sponge anode, without forming toxic chlorinated byproducts even in the presence of >7 g L−1 of chloride.

Investigation of boron-doped graphene oxide anchored with copper sulphide flowers as visible light active photocatalyst for methylene blue degradation

The non-biodegradable nature of waste emitted from the agriculture and industrial sector contaminates freshwater reserves. Fabrication of highly effective and low-cost heterogeneous photocatalysts is crucial for sustainable wastewater treatment. The present research study aims to construct a novel photocatalyst using a facile ultrasonication-assisted hydrothermal method. Metal sulphides and doped carbon support materials work well to fabricate hybrid sunlight active systems that efficiently harness green energy and are eco-friendly. Boron-doped graphene oxide-supported copper sulphide nanocomposite was synthesized hydrothermally and was assessed for sunlight-assisted photocatalytic degradation of methylene blue dye. BGO/CuS was characterized through various techniques such as SEM–EDS, XRD, XPS, FTIR, BET, PL, and UV–Vis DRS spectroscopy. The bandgap of BGO-CuS was found to be 2.51 eV as evaluated through the tauc plot method. The enhanced dye degradation was obtained at optimum conditions of pH = 8, catalyst concentration (20 mg/100 mL for BGO-CuS), oxidant dose (10 mM for BGO-CuS), and optimum time of irradiation was 60 min. The novel boron-doped nanocomposite effectively degraded methylene blue up to 95% under sunlight. Holes and hydroxyl radicals were the key reactive species. Response surface methodology was used to analyze the interaction among several interacting parameters to remove dye methylene blue effectively.

Hydrogen adsorption on magnesium-decorated (3, 3) and (5, 0) boron nitride nanotubes

Hydrogen is one of the cleanest ways to store energy in a post-fossil fuel economy. However, it can be dangerous as bulk gas and additional methods for hydrogen storage are needed. Physisorption on graphene sheets and nanotubes has been proposed as an effective approach due to their exceedingly high surface area and storage capacity similar to, or exceeding, highly compressed gas. Magnesium-doping has been demonstrated to significantly enhance hydrogen storage on boron-doped graphene sheets, but Mg-doped boron nitride nanotubes (BNNT), a potentially far more promising material due to the inherent dipoles in the surface providing stronger affinity for hydrogen, remain unexplored. In this in silico investigation, both the armchair (3,3) and zigzag (5,0) BNNT architectures, doped with Mg atoms, were examined for hydrogen storage capacity using first-principles density functional theory. Our calculations revealed that highly Mg-doped armchair and zigzag polymorphs of BNNTs could adsorb up to 9.65 and 8.77 weight percent hydrogen respectively, above the targets sought by the US Department of Energy for future hydrogen storage materials.

Efficient Photocatalytic Degradation of Tetracycline on the MnFe2O4/BGA Composite under Visible Light.

In this work, the MnFe2O4/BGA (boron-doped graphene aerogel) composite prepared via the solvothermal method is applied as a photocatalyst to the degradation of tetracycline in the presence of peroxymonosulfate. The composite's phase composition, morphology, valence state of elements, defect and pore structure were analyzed by XRD, SEM/TEM, XPS, Raman scattering and N2 adsorption-desorption isotherms, respectively. Under the radiation of visible light, the experimental parameters, including the ratio of BGA to MnFe2O4, the dosages of MnFe2O4/BGA and PMS, and the initial pH and tetracycline concentration were optimized in line with the degradation of tetracycline. Under the optimized conditions, the degradation rate of tetracycline reached 92.15% within 60 min, whereas the degradation rate constant on MnFe2O4/BGA remained 4.1 × 10-2 min-1, which was 1.93 and 1.56 times of those on BGA and MnFe2O4, respectively. The largely enhanced photocatalytic activity of the MnFe2O4/BGA composite over MnFe2O4 and BGA could be ascribed to the formation of type I heterojunction on the interfaces of BGA and MnFe2O4, which leads to the efficient transfer and separation of photogenerated charge carriers. Transient photocurrent response and electrochemical impedance spectroscopy tests offered solid support to this assumption. In line with the active species trapping experiments, SO4•- and O2•- radicals are confirmed to play crucial roles in the rapid and efficient degradation of tetracycline, and accordingly, a photodegradation mechanism for the degradation of tetracycline on MnFe2O4/BGA is proposed.

Effect of Charge on Carbon Support on the Catalytic Activity of Cu2O toward CO2 Reduction to C2 Products

Electrochemical carbon dioxide (CO2) reduction for C2 products has been studied on a series of supported Cu-based catalysts; however, the charge-promotion effects from the substrates for the selectivity of CO2 reduction are still unclear. Here we localize nanosized Cu2O on three carbon-based substrates that provide different charge-promotion effects: positively charged boron-doped graphene (BG), negatively charged nitrogen-doped graphene (NG), and weak negatively charged reduced graphene oxide (rGO). We demonstrate that the charge-promotion effects lead to an increase in faradaic efficiency (FE) for C2 products with an order of rGO/Cu < BG/Cu < pure Cu < NG/Cu and an FEC2/FEC1 ratio from 0.2 to 7.1. By performing in situ characterization, electrokinetic investigations, and density functional theory (DFT) calculations, we reveal that the negatively charged NG is favorable for stabilizing Cu+ species under CO2 reduction, which strengthens CO* adsorption to further boost C-C coupling for C2 products. As a result, we achieve a high C2+ FE of ∼68% at high current densities of 100-250 mA cm-2.

Can Li Atoms Anchored on Boron and Nitrogen Doped Graphene Catalyze Dinitrogen Molecule to Ammonia? A DFT Study.

Most successful electrochemical conversion of ammonia from dinitrogen molecule reported to date is Li mediated mechanism. In the framework of the above fact and that Li anchored graphene is an experimentally feasible system, the present work is a computational experiment to identify the potential of Li anchored graphene as a catalyst for N2 to NH3 conversion as a function of (a) minimum number of Li atoms needed for anchoring on graphene sheets and (b) role of chemical modification of graphene surfaces. Li anchored graphene sheets are potential catalysts for ammonia conversion with preferential adsorption of N2 through end-on configuration on Li atoms anchored on doped and pristine graphene surfaces. This mode of adsorption being characteristic of Nitrogen Reduction Reaction (NRR) through enzymatic pathway, examination of the same followed by analysis of electronic properties demonstrates that tri-Li atoms (Tri Atom Catalysts, TACs) are more efficient as catalysts for NRR as compared to two Li atoms (Di Atom Catalysts, DACs). Either way, the rate determining step was found to be *NH2 → *NH3 step (mixed pathway) with ∆Gmax = 1.02 eV and *NH2-*NH3→ *NH2 step (enzymatic pathway) with ∆Gmax = 1.11 eV for 1B doped TAC and DAC on graphene sheet, respectively.

Enhanced formic acid oxidation with Pd nanoparticles deposited on boron-doped graphene: A comprehensive electrochemical and spectroscopic investigation

Herein, nanostructured Pd electrocatalysts with boron-doped graphene (Pd/B-G) are prepared towards the formic acid oxidation. The catalysts are characterized by Raman spectroscopy, X-ray powder diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma optical emission spectrometer (ICP-OES). The boron atoms have been successfully doped into graphene in the forms of BC3, BC2O and BCO2 to create abundant defect sites, which contributes to subsequent dispersion of Pd nanoparticles (NPs). The TEM results confirm that more fine and homogeneous distribution of Pd NPs on B-G than those on native graphene. XPS-Pd3d band shows a little shift to lower binding energy and the higher metallic Pd content on Pd/B-G compared with to not doping boron (Pd/G) due to the electrons transfer from B-G to Pd. The electrochemical evaluation shows that Pd/B-G catalyst achieves much enhanced activity as well as improved catalytic stability compared to those of Pd/G and commercial Pd/C. The enhanced performance is not only ascribed to the higher dispersion the utilization efficiency of Pd, but also attributed to the electronic interaction between Pd NPs and B-G support. This co-effect also can facilitate the formation of metallic Pd and provide more active sites, as well as lowers d-band center of Pd and thus weakens the absorption of the COads on Pd.

Binary Sulfiphilic Nickel Boride on Boron-Doped Graphene with Beneficial Interfacial Charge for Accelerated Li-S Dynamics.

The "shuttle effect" and slow conversion kinetics of lithium polysulfides (LiPSs) are stumbling block for high-energy-density lithium-sulfur batteries (LSBs), which can be effectively evaded by advanced catalytic materials. Transition metal borides possess binary LiPSs interactions sites, aggrandizing the density of chemical anchoring sites. Herein, a novel core-shelled heterostructure consisting of nickel boride nanoparticles on boron-doped graphene (Ni3 B/BG), is synthesized through a graphene spontaneously couple derived spatially confined strategy. The integration of Li2 S precipitation/dissociation experiments and density functional theory computations demonstrate that the favorable interfacial charge state between Ni3 B and BG provides smooth electron/charge transport channel, which promotes the charge transfer between Li2 S4 -Ni3 B/BG and Li2 S-Ni3 B/BG systems. Benefitting from these, the facilitated solid-liquid conversion kinetics of LiPSs and reduced energy barrier of Li2 S decomposition are achieved. Consequently, the LSBs employed the Ni3 B/BG modified PP separator deliver conspicuously improved electrochemical performances with excellent cycling stability (decay of 0.07% per cycle for 600 cycles at 2 C) and remarkable rate capability of 650 mAh g-1 at 10 C. This study provides a facile strategy for transition metal borides and reveals the effect of heterostructure on catalytic and adsorption activity for LiPSs, offering a new viewpoint to apply boride in LSBs.

Superconducting Energy Gap in Hole-Doped Graphene Beyond the Migdal's Theory

In this work we analyze impact of non-adiabatic effects on the superconducting energy gap in the hole-doped graphene. By using the Eliashberg formalism beyond the Migdal's theorem, we present that the non-adiabatic effects strongly influence the superconducting energy gap in the exemplary boron-doped graphene. In particular, the non-adiabatic effects, as represented by the first order vertex corrections to the electron-phonon interaction, supplement Coulomb depairing correlations and suppress the superconducting state. In summary, the obtained results confirm previous studies on superconductivity in two-dimensional materials and show that the corresponding superconducting phase may be notably affected by the non-adiabatic effects.

Phosphorous- and Boron-Doped Graphene-Based Nanomaterials for Energy-Related Applications.

Doping is a great strategy for tuning the characteristics of graphene-based nanomaterials. Phosphorous has a higher electronegativity as compared to carbon, whereas boron can induce p-type conductivity in graphene. This review provides insight into the different synthesis routes of phosphorous- and boron-doped graphene along with their applications in supercapacitors, lithium- ions batteries, and cells such as solar and fuel cells. The two major approaches for the synthesis, viz. direct and post-treatment methods, are discussed in detail. The former synthetic strategies include ball milling and chemical vapor discharge approaches, whereas self-assembly, thermal annealing, arc-discharge, wet chemical, and electrochemical erosion are representative post-treatment methods. The latter techniques keep the original graphene structure via more surface doping than substitutional doping. As a result, it is possible to preserve the features of the graphene while offering a straightforward handling technique that is more stable and controllable than direct techniques. This review also explains the latest progress in the prospective uses of graphene doped with phosphorous and boron for electronic devices, i.e., fuel and solar cells, supercapacitors, and batteries. Their novel energy-related applications will continue to be a promising area of study.

Scalable synthesis of Ta1.1O1.05/biomass carbon composite with multiple structure engineering by boron-doped graphene quantum dot for high-energy supercapacitor

Low intrinsic conductivity and insufficient electroactive sites hinder wide applications of tantalum oxide in supercapacitors. The study reports scalable synthesis of Ta1.1O1.05/biomass carbon (C) composite with multiple structure engineering by boron-doped graphene quantum dot (B-GQD). B-GQD was orderly coordinated with Ta(V) ion to produce Ta-B-GQD complex, sucked into cotton and dried. Followed by annealing at 900 °C in N2 to obtain B-GQD-Ta1.1O1.05/C. Experimental result and theoretical calculation demonstrate that the introduction of B-GQD results in formation of Ta1.1O1.05 nanorods with low valence, small size, highly exposed high-index crystal faces, oxygen vacancies and PN junction. The structure dramatically improves the intrinsic conductivity, electroactive sites and voltage window range. The B-GQD-Ta1.1O1.05/C electrode exhibits high capacitance of 528.3 F g−1 at 0.5 A/g, which is more than that of Ta1.1O1.05 electrode (130.9 F g−1). The flexible symmetrical supercapacitor provides ultrahigh capacitance of 374.1 F g−1 at 1 A/g, high-rate capacity of 207.8 F g−1 at 50 A/g, capacity retention of 98.7 % after 10,000 cycles at 10 A/g and energy density of 113.9 W h Kg−1 at 521.2 W kg−1. The supercapacitor has been successfully applied in the self-powered attitude sensor driven via friction nanogenerator to monitor human walking posture.

Machine-learning-assisted discovery of boron-doped graphene with high work function as an anode material for Li/Na/K-ion batteries.

Work function (WF) modulation is a crucial descriptor for carbon-based electrodes in optoelectronic, catalytic, and energy storage applications. Boron-doped graphene is envisioned as a highly promising anode material for alkali metal-ion batteries (MIBs). However, due to the large structural space concerning various doping concentrations, the lack of both datasets and effective methods hinders the discovery of boron-doped graphene with a high WF that generally leads to strong adsorption. Herein, we propose a machine-learning-assisted approach to discover the target, where a Crystal Graph Convolutional Neural Network was developed to efficiently predict the WF for all possible configurations. As a result, the B5C27 structure is found to have the highest WF in the entire space containing 566 211 structures. In addition, it is revealed that the adsorption energy of alkali metals is linearly related to the WF of the substrate. Therefore, the screened B5C27 is investigated as an anode for Li/Na/K-ion batteries, and it possesses a higher theoretical specific capacity of 2262/2546/1131 mA h g-1 for Li/Na/K-ion batteries compared with that of pristine graphene and other boron-doped graphene. Our work provides an effective way to locate possible high-WF structures in heteroatom-doped systems, which may accelerate future screening of promising adsorbents for alkali metals.

Evidence of ferromagnetism in boron doped graphene oxide synthesized by hydrothermal method

[Enhancing graphene's ferromagnetic properties is important for a variety of applications, including spintronics, magnetic memory, and other electromagnetic devices. A modified version of Hummer's approach was used to synthesize reduced graphene oxide. Boron-doped graphene oxide with different dopant concentrations (1,3,5 and 7 wt%) has been synthesised using the hydrothermal method. Powder X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy are used to characterize the structure. The results of the XRD analysis show that reduced graphene oxide and boron-doped graphene oxide have been formed. The existence of boron atoms at the carbon lattice has been confirmed by observation of the FTIR and Raman spectra. The presence of dopant concentrations was calculated using X-ray photo electron spectroscopy. To further analyze the magnetic characteristics of doped samples, vibrating sample magnetometer investigations are used. The samples shows significant ferromagnetism at room temperature. It has been found that the saturation magnetization(Ms) increases with an increase in boron content. For the sample with the highest boron content, the saturation magnetization(Ms) reaches 0.03 emu/g at room temperature and the coercive force(Hc) reaches 73.9 Oe. Due to the improvement in the ferromagnetic property of boron doped graphene, these materials can be used for nonmagnetic applications and other electromagnetic devices.]

Thermodynamic mechanism of controllable growth of two-dimensional uniformly ordered boron-doped graphene.

Two-dimensional (2D) boron-doped graphene (B-G) exhibits remarkable properties for advanced applications in electronics, sensing and catalysis. However, the synthesis of large-area uniformly ordered 2D B-G remains a grand challenge due to the low doping level and uncontrolled distribution of dopants or even the phase separation from the competitive growth of boron polymorphs and graphene. Here, we theoretically explored the mechanism of the epitaxial growth of 2D uniformly ordered B-G on a metal substrate via ab initio calculations. We show that, by establishing the substrate-mediated thermodynamic phase diagrams, the controllable growth of 2D ordered B-G with different B/C stoichiometry can be achieved on appropriate substrates within distinct chemical potential windows of the feedstock by beating the competitive growth of graphene and other impurity phases. It is suggested that a suitable substrate for the controllable epitaxial growth of 2D ordered B-G can be efficiently screened based on the symmetry match and interaction between 2D B-G and the surfaces. Importantly, by carefully considering the chemical potential of boron/carbon as a function of temperature and partial pressure of the feedstock with the aid of the standard thermochemical tables, the optimal experimental parameters for the controllable growth of 2D ordered B-G are also suggested accordingly. This work provides a comprehensive and insightful understanding of the mechanism of controllable growth of 2D B-G, which will guide future experimental design.