Nitrogen-doped Graphene Oxide Research Articles

Nitrogen-doped graphene oxide studies aimed at the Bacillus subtillis proliferation

Nitrogen-doped graphene oxide studies aimed at the Bacillus subtillis proliferation

A Tripartite Composite Incorporating Nitrogen-Doped Graphene Oxide, Polypyrrole, and Silica for Lithium-Ion Battery Anodes

In this study, N-doped graphene oxide-polypyrrole-silica (NGO-PPy-SiO2) composite was employed as a possible anode in Li-ion batteries. The chronoamperometric technique was employed to synthesize NGO, and within this study two samples were produced, one characterized by a high polypyrrle content (N1) and the other by a low polypyrrle content (N2). N2 has the maximum initial discharge capacity of 785 mAh g−1 at 0.1 C, which is greater than N1’s capacity of 501 mAh g−1. The initial coulombic efficiency of the first cycle is around 72%, whereas the ICE of N2 is approximately 60%. N1 demonstrates outstanding cycling performance for 100 cycles at high rate (10 C) with maintain capacity as 100% and coulombic efficiency of 100%, as well as extremely stable capacity during the cycling. N2 has a maintain capacity of ≈79% and excellent coulombic efficiency, however the capacity during cycling is not as stable as N1.

Fabrication of SnO2/NGO hybrid nanocomposite as an effective photocatalyst for binary dye degradation under sunlight illumination

We successfully synthesized nitrogen-doped graphene oxide grafting tin oxide nanoparticles (SnO2/NGO nanocomposite). To evaluate the surface, optical and morphology characterization of synthesized SnO2/NGO nanocomposites was done using various analytical techniques. The XRD data indicate the crystallinity of a high-purity SnO2/NGO nanocomposite in nature. The Raman spectra of the resultant SnO2/NGO nanocomposite exhibit moderate graphitization with a ID/IG intensity of 0.98. Under sunlight irradiation, the photocatalytic activity of a produced SnO2/NGO nanocomposite on the breakdown of toxic binary organic dyes (methylene blue/methyl orange) was examined. On MB and MO, the resultant SnO2/NGO nanocomposite had a maximum degradation efficiency of 150mins and 89.4%, 93.7%, respectively. Furthermore, the simple and inexpensive hydrothermal-derived SnO2/NGO nanocomposite exhibits rapid photocatalytic degradation on MB and MO when exposed to sunlight illumination.

Insight on magnetic nitrogen-doped graphene oxide composite electrode constructing heterogeneous Electro-Fenton system for treating organophosphorus pesticide wastewater

The treatment of organic phosphorus pesticide (OPP) wastewater faces challenges such as incomplete degradation and low reaction efficiency. While heterogeneous electro-Fenton (Hetero-EF) has emerged as the preferred technology for addressing these issues due to its high treatment efficiency, further optimization is still necessary. This study used a one-pot hydrothermal method to prepare magnetic nitrogen-doped graphene oxide (Fe3O4@N-GO) composite electrodes to construct a novel Hetero-EF system. Dimethoate (DIM) was chosen as the representative pollutant to investigate the effects of parameters such as current density, pH, electrode spacing, and loading amount on degradation efficiency. The results demonstrated complete degradation of DIM within 40 min. Density functional theory (DFT) calculations and intermediate product analysis revealed that the reactive sites for DIM degradation were the P=S and P=S bonds, involving both hydrolysis and •OH pathways, with a decrease in toxicity of degradation products observed. Compared to graphite electrodes, Fe3O4@N-GO composite electrodes significantly increased H2O2 production, achieving complete DIM degradation even after 5 cycles, with a phosphate conversion rate of 30–40 %. This study highlights the innovative strategy of the Hetero-EF system in its significant application value for OPP treatment.

The correlation between electron exchange capacity of Fenton-like heterogeneous catalyst and catalytic activity

Electron transfer played key role in peroxymonosulfate (PMS) activation for heterogeneous Fenton-like catalysts (HFCs). However, the relationship between electron exchange capacity (EEC) and catalytic activity of HFCs has not been elucidated. Herein, thirteen HFCs reported in our previous studies were selected to measure their EEC via electrochemical methods and to investigate the correlation between EEC and catalytic activity for PMS. The results show that nitrogen-doped graphene oxide had much higher EEC (5.299 mM(e) g−1), followed by reduced graphene oxide (3.23 mM(e) g−1), nitrogen-doped biochar-700 (2.032 mM(e) g−1), graphene oxdie (1.789 mM(e) g−1), nitrogen-doped biochar-300 (1.15 mM(e) g−1), g-C3N4 (0.752 mM(e) g−1) and biochar (0.351 mM(e) g−1). For carbon materials, their catalytic activity was not determined by electron donor capacity (EDC), electron acceptor capacity (EAC) and EEC (EDC + EAC), but was linear correlation with |EDC-EAC| that can characterize the extent of HFCs reacting with PMS. The higher the |EDC-EAC| is, the higher the catalytic activity of HFCs is. For carbonaceous materials, their catalytic activity was not proportional to EAC, but had good linear correlation with EDC and |EDC-EAC|. The discrepancy between carbon materials and carbonaceous materials could be due to the different activation mechanisms. Further analysis found that there was no correlation between EEC and the reactive species derived from PMS, indicating that the produced reactive species was not only controlled by EEC. This study firstly elucidated the correlation between EEC and catalytic activity of HFCs, and |EDC-EAC| could be used as an index for evaluating the catalytic activity of HFCs.

Synthesis of graphene oxide and nitrogen-doped graphene oxide by nanosecond pulsed laser ablation of graphene in liquid for fiber optic gas sensing application

Heteroatom-doped graphene oxide has a wide range of applications in bio-imaging and sensing. In this work, Graphene Oxide (GO) and Nitrogen-doped GO (NG) were synthesized by laser ablation of Graphene in ethanol. The dopant Diethylenetriamine (DETA) is used in different amounts for different nitrogen concentrations. Optical, morphological, structural, and elemental composition studies were done by UV–vis spectroscopy, FT-IR, FE-SEM, XRD, Raman, and EDAX analysis, respectively. The nitrogen doping on the surface of GO was confirmed by FT-IR and EDAX studies. Upon laser ablation with fundamental wavelength, the graphene is converted to spherical GO nanoparticles, and nitrogen doping is done to produce porous nano coral structured NG nanoparticles. The sensitivity and selectivity of GO and NG for ammonia, ethanol, and acetone target gaseous were investigated and compared. NG sample shows excellent sensitivity and selectivity towards acetone gas. And the Nitrogen-doped graphene oxide can be considered an ideal material for gas-sensing applications.

Synthesis of nitrogen-doped graphene oxide by nanosecond pulsed laser ablation of graphene in liquid for bioimaging applications

This work reports the synthesis of graphene oxide (GO) and nitrogen-doped graphene oxide (NGOs) by laser ablating graphene flakes in ethanol, utilizing liquid ammonia solution as the nitrogen source. Raman, FT-IR, and UV reveal the oxidation of graphene by laser ablation. Nitrogen doping was confirmed using FTIR and XPS analysis. XPS reveals the presence of pyrrolic, pyridinic, and graphitic nitrogen. The spherical shape and amorphous nature of NGOs are confirmed by HR-TEM analysis. FE-SEM examined the formation of different nanostructures of GO and NGO, and the average particle size was 40–50 nm. All samples show excitation-dependent PL emission with bluish-green emission, and nitrogen doping enhances the PL emission intensity. Time-resolved spectroscopy analysis shows the average lifetime improved by doping and increasing the nitrogen concentration. NGOs with remarkable quantum yields hold great promise for their application in bioimaging. We conducted cytotoxicity of the NGO samples against HeLa cancer cells using 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and selected the sample with lower cytotoxicity in cancer cells for bioimaging purposes. The NGOs with higher concentrations of nitrogen have less cytotoxicity and high photostability.

Tin disulfide nanoflowers and nitrogen doped graphene oxide based extended gate field effect transistor as immunosensors

Miniaturized biosensor design is widely preferred for its application in integrated platform to provide rapid and sensitive diagnosis. However, there are only few reports which employ extended gate field effect transistors (EG-FET) for immunosensing application. Herein, we designed EG-FET using four level lithography techniques. Further, the gate layer (Au/Ti) of device has been modified with Tin disulfide nanoflowers (SnS2) and nitrogen doped graphene oxide (N-GO) hybrid composite for enhanced electrical sensing. The as-prepared SnS2 and N-GO based nanocomposite (SnS2/N-GO) was characterized by various techniques. The designed SnS2/N-GO based EG-FET was employed as an immunosensor to detect HIgG using anti-HIgG antibody. Under optimum conditions, our miniaturized immunosensor demonstrated the detection of HIgG as low as 4.81 ng/mL. The proposed immunosensor exhibited excellent sensitivity, selectivity and reproducibility towards HIgG detection, thereby suitable for a reliable integrated biosensing platform which can detect protein concentration in real samples for clinical diagnostics.

Boosting ion diffusion kinetics of Fe2O3/MoC@NG via heterointerface engineering and pseudocapacitance behavior: An alternative high-rate anode for high‐capacity lithium dual-ion batteries

Lithium dual-ion batteries (Li-DIBs) technology is expected to become a leader in replacing lithium-ion batteries (LIBs) to carry out high energy/power density energy storage devices. Unfortunately, the sluggish electrochemical reaction kinetics of anode materials critically restricts their practical development. Here, a Li-DIBs is proposed by using a three-dimensional (3D) structure composed of Fe2O3/MoC heterostructure nanoparticals embedded in a hierarchical mesoporous nitrogen-doped reduction graphene oxide (Fe2O3/MoC@NG) as the anode, which has low Li+ ion diffusion barrier (0.098 eV), high Li+ ion diffusion coefficient (4.99 × 10−11 cm2 s−1) and remarkable rate property (879.2 mA h g−1 at 10 A g−1), and choosing nano-graphite as the cathode. Originating from the respective strengths of Fe2O3/MoC@NG anode and the nano-graphite cathode, the as-constructed Li-DIBs full battery displays high reversible capacity and prominent rate property (103.9 mA h g−1 at 0.05 A g−1 and 48.9 mA h g−1 at 2 A g−1). Specifically, taking advantage of density functional theory (DFT) calculations, the exact paths of PF6− ion intercalation into graphite cathode and Li+ ion diffusion into Fe2O3/MoC@NG anode is obtained, namely PF6− ion transmits along the (002) face of nano-graphite and Li+ ion diffuses along the heterointerface of Fe2O3/MoC@NG.

Cathodic membrane with confined interlayer spacing for efficient electrocatalytic dehalogenation of antibiotics

Conventional catalytic membranes often exhibit inadequate catalytic efficiency due to limited retention time for pollutants during filtration. In this study, a single-atom catalyst (Ni-NG) was prepared by dispersing single nickel atoms onto nitrogen-doped graphene oxide sheets. Subsequently, under controlled conditions, the assembly of Ni-NG with reduced graphene oxide (rGO) sheets led to the fabrication of efficient electrocatalytic cathodic membranes (ECMs). The ECMs were designed to concentrate and dehalogenate antibiotics simultaneously by utilizing the confined single nickel atoms within the multilayered ECMs through electrocatalytic reduction. Remarkably, complete degradation of chloramphenicol (CAP, 20 mg L−1) in the solution was achieved within a remarkably short time of 3.0 ms by ECM8 which had an area of 7.1 cm2 and comprised Ni-NG (16.9 μg) and rGO (16.9 μg), with an interlayer spacing of 0.37 nm, during filtration (40 L m−2 h−1). The reaction rate constant (k) for CAP degradation by ECM8 was approximately 3 × 108 min−1, surpassing the highest value in the literature. Furthermore, the ECM demonstrated both high energy efficiency and stability, highlighting the great potential for practical applications. The electrocatalytic cathodic membrane, designed to primarily concentrate pollutants in confined interlayer spaces through the sieving effect, shed lights on the highly efficient dehalogenation of organic compounds in pharmaceutical salt-laden wastewater.

Economical-effective purification of brackish water through an integrated capacitive desalination & boron adsorption system

The escalating scarcity of high-quality water for potable, industrial, and agricultural use necessitates innovative methods to augment freshwater supply from unconventional sources. This study primarily aims to lower boron (B) and chloride (Cl−) levels in brackish water to meet water quality standards of B < 0.5 mg/L and Cl− < 250 mg/L. To meet this goal, an innovative adsorbent, OQAS-AC@NGO, was used for boron removal. It combines organosilicon quaternary ammonium chloride (OQAS) modified activated carbon (AC) within a self-assembled nitrogen-doped graphene oxide (NGO) structure. Before boron removal, a capacitive deionization (CDI) system was used, employing OQAS-AC as the anode and COOH-modified AC as the cathode for chloride ion electrosorption. Through this cooperation procedure, the treated water meets the required quality standards while significantly reducing chemical costs by approximately 13.5 times when compared to conventional ion exchange resin methods for adsorbent regeneration. Moreover, the OQAS-AC@NGO adsorbent sustains its efficiency through multiple cycles, outperforming non-assembled N-GO in terms of yield, performance, and water flux. This underscores the cost-effective adsorbent preparation and enhanced water productivity. Economic analysis endorses the integrated CDI & B adsorption approach, advancing both sustainable water treatment processes and practical industrial applications.

Submicromolar electrochemical sensing platform for fast Fluoxetine quantification based on Nb2CTx MXene and nitrogen-doped graphene oxide nanocomposites

A facile and novel electrochemical determination of Fluoxetine (FLX) at submicromolar concentration Niobium carbide (Nb2CTx) and Nitrogen-doped Reduced Graphene Oxide (NRGO) hybridized electrodes as sensing platform is demonstrated. Herein, Niobium carbide (Nb2CTx) was successfully prepared by etching Nb2AlC and then ultrasonically compounded with Nitrogen-doped Reduced Graphene Oxide (NRGO), to form a well-dispersed Nb2CTx/NRGO composite, which was modified onto a glassy carbon electrode (GCE). The morphology, structure and electrochemical property of the Nb2CTx/NRGO/GCE was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The electrocatalytic activity of the Nb2CTx/NRGO/GCE for FLX oxidation was studied in detail. The peak currents showed two good linear relationships (R2 = 0.9962 and 0.9949) with FLX concentrations (1.0–10 µM and 10–100 µM) and a detection limit of 0.34 µM (S/N = 3). The sensor has good selectivity, repeatability, reproducibility and stability, and is capable of sensitively determining FLX in human serum and urine samples of clinical biological fluids. This work is believed to be of great significance and of broad interest for research on innovative MXene materials development and biomedical sensing applications.

Nitrogen-doped Ti3C2Tx/TiO2-graphene hybrid materials with 3D interconnected structure compatible with ionic liquid-based electrolyte for high performance supercapacitors

Ti3C2Tx, a typical MXene, bears tremendous attention as a type of potential electrode materials for supercapacitors. Regrettably, though Ti3C2Tx electrode has excellent capacitance in aqueous electrolytes, it cannot achieve high energy density due to a narrow operating potential window of the aqueous electrolytes. Herein, we demonstrate a well-designed hybrid material: nitrogen-doped Ti3C2Tx-reduced graphene oxide with in situ formed TiO2 nanopaticles bridged by -NH- (N-Ti3C2Tx/TiO2-RGO), and meanwhile formulate a ternary mixed electrolyte of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EmimTFSI), acetonitrile (ACN), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) to match the hybrid material. The N-Ti3C2Tx/TiO2-RGO hybrid possesses a 3D cross-linked porous structure with rapid transport channels for the electrolyte ions. The formulated ionic liquid-based electrolyte has a wide electrochemical stability window and free lithium ions are able to conduct Faradaic redox reactions. Benefiting from its unique architectural structure, the N-Ti3C2Tx/TiO2-RGO material delivers an enhanced specific capacitance (specific capacity) of 188 F g−1 (338 C g−1) at 1 A g−1 and exhibits a high rate capability. Furthermore, the assembled asymmetrical supercapacitor with the N-Ti3C2Tx/TiO2-RGO-5 anode and the self-synthesized p-phenylenediamine functionalized reduced graphene oxide (PPD-RGO) cathode delivers a high energy density of 46 Wh kg−1 at a high-power density of 1550 W kg−1. This work develops a simple strategy to assemble 2D MXene sheets into 3D porous electrode materials compatible to the ionic liquid-based electrolyte for high performance supercapacitors.

Facile synthesis of N-doped graphene oxide decorated with copper ferrite as an electrode material for supercapacitor with enhanced capacitance

In the past decade, enormous attempts have been made to modify the effective electrode materials for the construction of supercapacitors. Here, we report a cost-effective, simple, and one-pot hydrothermal technique to fabricate a new nanocomposite based on nitrogen-doped graphene oxide (NGO) nanosheets twisted with copper ferrite nanoparticles (CuFe2O4 NPs) as a new supercapacitor material with outstanding performance. A concurrent synthetic route takes advantage of the synergetic impact caused by the high pseudo-capacitance of CuFe2O4 and the superior electrical conductivity of NGO, resulting in a larger performance improvement of the nanocomposite than that of blank CuFe2O4. The as-prepared NGO/ CuFe2O4 electrode significantly shows an excellent specific capacitance of 348 F/g at 1 A/g current density with superior cycling stability, saving 87% of its first capacitance over 2000 GCD cycles. The electrochemical analysis revealed that the NGO provides a continuous conductive pathway for electron/ion transport and a large surface area and alleviates the significant strain resulting from the volume expansion of CuFe2O4. Furthermore, an asymmetrical supercapacitor is produced by NGO/CuFe2O4 as the positive electrode and activated carbon as the negative electrode, which shows superior electrochemical performance, producing a high energy density (35.79 Wh/kg) and a high-power density (883.09 W/kg) with excellent cycling stability. This article aims to provide a rapid and scalable hydrothermal approach for synthesizing NGO/CuFe2O4 nanocomposites with increased electrochemical efficiency for supercapacitor applications.

An aptasensor based on the fluorescence resonance energy transfer of nitrogen-doped carbon quantum dots and graphene oxide to detect fipronil in eggs

An aptasensor based on the fluorescence resonance energy transfer of nitrogen-doped carbon quantum dots and graphene oxide to detect fipronil in eggs

Dried figs like nitrogen-doped graphene oxide anchored cobalt-doped Fe3O4 nanoparticle as sulfur host for high performance Li-S battery

Lithium-sulfur batteries (LSBs) represent a prospective energy storage device because of their low cost and high theoretical energy density. However, the performance of LSBs was largely constrained by the kinetics of polysulfides (LiPSs) conversion and shuttle effect. Thus, a metal-doped metal oxide is proposed as an efficient adsorbent and catalyst for LiPSs. We designed cobalt-doped Fe3O4 nano-catalysts which was in situ grown on the N-doped graphene conductive network as a multifunctional sulfur host. Evidenced by experimental characterization, it is demonstrated that due to the appropriate doping amount (EGO/Co-Fe3O4 (700)), the host exhibits efficient adsorption and rapid catalytic conversion of LiPSs. Compared with the undoped Co catalyst (S@EGO/Fe3O4), The S@EGO/Co-Fe3O4 (700) electrode possesses high initial discharge specific capacity (1488.4 mAh/g, 0.2 C), and superior cycle stability (900.8 mAh/g after 100 cycles). Impressive performances are also attained at lean electrolyte conditions (electrolyte-to-sulfur (E/S) ratio ∼ 7 μL mg−1).

Pink photoluminescent nitrogen-doped graphene oxide nanosheets from Juniperus squamata roots and their cytotoxic potential against human cervical cancer cells (HeLa cells) and Plasmodium falciparum an agent of malaria: A green approach

In this paper, we reported a green synthesis of nitrogen-doped graphene oxide nanosheets (N-GONSs) from Juniperus squamata roots along with its cytotoxic potential against HeLa cells, human cervical cancer cells and Plasmodium falciparum, a causative agent of malaria in humans. The water-soluble and high fluorescent N-GONSs were synthesized by hydrothermal process using Juniperus squamata roots and ethylenediaminetetraacetic acid (EDTA), as carbon and nitrogen sources without any chemical modification. The X-ray photoelectron spectroscopy (XPS) analysis confirmed that the N-GONSs were mainly composed of carbon, oxygen and nitrogen. The synthesized N-GONSs showed pink luminescence behavior under the short wavelength at 250 nm. The viabilities of the HeLa cancer cells for N-GONSs were 76.47%, 43.98%, and 20.55% after 24 h and 48 h, and 72 h, respectively, at the concentration of 50 μg/mL. Also, N-GONSs showed moderate antimalarial activity with IC50 PF3D7 45 μg/mL. Furthermore, they were also nontoxic to VERO cells (C 1008; monkey kidney epithelial cells) up to a concentration of 100 μg/mL. The present study reflected that the N-GONSs show potential cytotoxicity against HeLa cells and Plasmodium falciparum.

Structural, Optical, and Magnetic Properties of Nitrogen-Doped Graphene Oxide Synthesized by Hydrothermal Method

The study examines how different nitrogen doping concentrations affect hydrothermally synthesized graphene oxide’s properties using various analytical techniques. Two analytical spectroscopic techniques were used to investigate UV–visible spectroscopy in dispersed samples, namely Bromo Phenol Blue (BPB) and 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The results showed that the doped graphene samples absorb most light in the visible range between 476 nm and 568 nm in the presence of BPB, and the band gap values obtained using Tauc’s formalism ranged from 2.65 to 4.03 eV. In the presence of DDQ reagent, the formation of charge transfer complexes led to sharp absorption peaks in the ultraviolet region around 310 nm wavelength and a range of energy band gap values between 3.77 and 3.98 electron volts. Empirical Relations-Based Calculation of Refractive Index (n) for Nitrogen-Doped Graphene displayed Optical Absorption Potential in the Visible and UV ranges. Pyrrolic-N Bonding Dominance in Samples as Evident by X-ray Photoelectron Spectroscopy. The VSM results demonstrated that the sample with the highest percentage of Pyrrolic-N exhibited the highest saturation magnetization (0.23 emu gm−1) and coercive field (66.6 H Oe). The improved magnetic properties and optical band gap values observed in nitrogen-doped graphene oxide make them promising materials for use in magneto-optical devices.

Heterogeneous activation of persulfate by macroscopic nitrogen-doped graphene oxide cubes for the degradation of antibiotic contaminants in water

As a sustainable and green approach, carbocatalysis, a metal-free strategy, has shown exceptional results in advanced oxidation processes (AOPs). Nonetheless, the recovery of these catalysts has been a major shortcoming over the years. Herein, three-dimensional nitrogen-doped graphene macrostructures (3D-NGMs), in the form of macro cubes, were synthesised by a simple cross-linking and thermal annealing procedure, after which they were employed in the activation of peroxydisulfate (PS) for the degradation of sulfamethoxazole (SMX). The catalytic cubes were loaded with different amounts of nitrogen precursor to investigate the role of nitrogen configuration in the sp2 hybridised carbon network on AOPs. NGC3 cubes with optimum N-loading exhibited outstanding performance for SMX degradation owing to their optimum N/C ratio. Various reaction parameters were studied to optimise the catalytic system. Comprehensive studies on the radical generation were done and illustrated the dominance of the non-radical pathway leading to the proposal of a possible reaction mechanism for SMX. This study not only suggests the role of nitrogen doping on graphene macrostructures but also provides novel insights into macro catalysis to overcome the recovery challenges posed by nano catalysis.

Mn3O4 nano-octahedrons embedded in nitrogen-doped graphene oxide as potent anode material for lithium-ion batteries.

The online version contains supplementary material available at 10.1007/s11581-023-05035-6.