Nitrogen-doped Graphene Aerogel Research Articles

Naturally Dried, Double Nitrogen-Doped 3D Graphene Aerogels Modified by Plant Extracts for Multifunctional Applications

Two-dimensional graphene has become one of the most intensively explored carbon allotropes in materials science owing to its attractive features, such as its outstanding physicochemical properties. To advance its practical application, the fabrication of self-assembled 2D graphene sheets into 3D nitrogen-doped graphene aerogels (NGA) with novel functions is becoming essential. Herein, the first attempts to modify graphene with Plectranthus amboinicus (PA), to introduce double nitrogen doping, and to prepare NGA by a natural drying (ND) method are reported. Natural drying was achieved by increasing the pore structure of NDPA-NGA using PA to simultaneously cross-link the graphene sheets and increase the stiffness of the sample. Meanwhile, we used ammonia and urea as double nitrogen sources to achieve an N-doping amount as high as 12.06 atom %. In addition, NDPA-NGA exhibited superelastic properties (with 95% maximal strain and almost no loss after 60 replicates), a high oil absorption capacity, and an excel...

Amino acid-mediated N-doped graphene aerogels and its electrochemical properties

Three-dimensional porous nitrogen-doped graphene aerogels (NGAs) were synthesized via a facile and green hydrothermal process by using graphene oxide and different amino acids as nitrogen source. The morphology and structure of the as-prepared NGAs were characterized by means of FESEM, XRD, FTIR, Raman and XPS spectroscopy. The microstructure, nitrogen content and doping configuration of NGAs could be facilely controlled by selecting different amino acids. The formation mechanism of different nitrogen doping configurations was proposed. It has been proved that the NGAs prepared with amino acids as nitrogen doping source had enhanced electrochemical performance than pristine graphene aerogels. The pyrrolic N as main doping configuration plays important role in determining the electrochemical performance of NGAs. The NGA with pyrrolic N (content up to 13.82 at.%) exhibited a high specific capacitance, superior rate capability and excellent cycling life. This study gives inspiration to fabricate NGAs for a broad range of technological applications.

Facile synthesis of three-dimensional lightweight nitrogen-doped graphene aerogel with excellent electromagnetic wave absorption properties

The widespread use of communication facilities and electronic devices has increased the demand for novel high-efficiency and lightweight microwave absorption materials. In this work, we propose using N-doped graphene (NG)/wax composites, where an interconnected 3D graphene network is used as filler in a wax matrix. Nitrogen atoms were substitutionally doped into the graphene lattice by hydrothermal method. It was found that controlling the amount of NG could effectively modulate the electrical properties of graphene. Inspection of the samples prepared showed that to a large extent, the vacuum infusion method effectively retained the graphene intact 3D structure. Samples filled with 3.6 wt% NG exhibited the most prominent microwave absorption properties; the minimum reflection loss registered was 53.25 dB at 13.10 GHz for a sample thickness of 3.3 mm, and the bandwidth of the reflection loss less than 10 dB (90% absorption) can reach up to 8.15 GHz. The result indicates that the nitrogen-doped graphene can greatly improve the dielectric loss of electromagnetic wave absorber. More importantly, the work presented provides the framework for a unique facile approach to manufacture low-cost NG/wax composites with strong electromagnetic wave absorption ability at very low filler loading.

Nitrogen-doped graphene aerogel as both a sulfur host and an effective interlayer for high-performance lithium–sulfur batteries

Lithium–sulfur batteries have attracted great concern because of the high theoretical capacity of sulfur (1675 mA h g−1). However, the poor electrical conductivity and volumetric expansion of sulfur along with the dissolution of lithium polysulfides largely limit their practical application. In this study, nitrogen-doped graphene aerogel (NGA) with high nitrogen content and porosity is used as a host for the impregnation of sulfur. The effects of sulfur impregnation on the specific surface area, pore volume, and microstructure of NGA supported sulfur composite (S@NGA) are well investigated. Furthermore, NGA is also processed into a NGA film, which is sandwiched between a separator and S@NGA cathode. The lithium–sulfur battery with such a configuration delivers a high reversible capacity of 1514 mA h g−1 at 0.1 C, excellent rate performance (822 mA h g−1 at 2.0 C), and good cycling stability (946 mA h g−1 at 0.5 C even after 100 cycles). The enhanced electrochemical performance can be ascribed to the introduction of the NGA interlayer, the unique interconnected porous structure, and strong interaction between the three-dimensional nitrogen-doped graphene network and the homogeneously dispersed sulfur and/or lithium polysulfides.

Dopamine and L-arginine tailored fabrication of ultralight nitrogen-doped graphene aerogels for oil spill treatment

Ultralight and nitrogen doped graphene aerogels (UNGAS) are developed by a hydrothermal method in the presence of graphene, dopamine (DA) and L-arginine. Analysis shows that DA can functionalize the graphene surface and also embed nitrogen atoms onto the graphene sheets upon pyrolysis, and the values of pH on the hydrothermal fabrication of UNGAS have great influence on the formation of UNGAS. By adjusting the amount of L-arginine and dopamine in the precursor mixture, UNGAS with a density as low as 2.54 mg/cm3 can be prepared. The UNGAS show high absorption capacity for various oils due to low density, N doping and large surface area.

Edge‐Abundant Porous Fe3O4 Nanoparticles Docking in Nitrogen‐Rich Graphene Aerogel as Efficient and Durable Electrocatalyst for Oxygen Reduction

AbstractA novel Fe3O4 nanoparticles/nitrogen‐doped graphene aerogel (denoted as Fe3O4@NGA) hybrid material with high porosity was prepared by using iron‐based metal‐organic frameworks (MOFs), [Fe3O(H2N‐BDC)3] (H2N‐BDC=2‐aminoterephtalic acid), denoted as MIL‐88B‐NH2, as templates and nitrogen‐doped graphene aerogel (NGA) as the substrate. The obtained Fe3O4 nanoparticles demonstrate a rich edge area with abundant exposed active sites and defects, indicating great potential for oxygen adsorption and activation. When used as an electrocatalyst in alkaline solution, the Pt‐free Fe3O4@NGA exhibited excellent oxygen reduction reaction (ORR) performance and dramatically enhanced durability and tolerance towards methanol compared to commercial Pt/C catalyst, revealing its great viability and potential in practical application.

3D nitrogen-doped graphene aerogel nanomesh: Facile synthesis and electrochemical properties as the electrode materials for supercapacitors

Nitrogen-doped graphene aerogel nanomesh (N-GANM) has been hydrothermally prepared from graphene oxide and ammonium hydroxide using iron nitrate as the etching agent. The results showed that N-GANM with an interesting nanomesh structure on the graphene sheets maintained the 3D architecture of graphene aerogel (GA). Furthermore, it exhibited excellent electrochemical capacitive behavior and the specific capacitance value (290.0Fg−1 at 1Ag−1) remained approximately 90.3% after 2000 cycles in the three-electrode system. In addition, N-GANM displayed an energy density of 30.9Whkg−1 at the power density of 450.3Wkg−1 and excellent cycling stability retention (98%) after 10,000 cycles in the two-electrode symmetric device. The resulting N-GANM was expected to be a much favorable supercapacitor electrode material due to the heteroatom-doping and its unique porous structure.

High-Performance Supercapacitors of N-Doped Graphene Aerogel and Its Nanocomposites

Nitrogen-doped graphene aerogel (NGae) with three-dimensional interconnected structure was synthesized by a hydrothermal reduction of graphene oxide with hydrazine and a following freezing-dry method. The 3D morphology of conductive NGae provides diffusion pathways for electron and ion transportation. Also, the nitrogen-containing groups can store charges via surface redox reactions. The as-fabricated NGae symmetric supercapacitor (CR2016) in 1 M H2SO4 electrolyte provides a specific capacitance of 470.45 F g- 1 at an applied current of 1 mA with maximum energy density and power density of 41.71 Wh kg- 1 and 2442.47 W kg- 1, respectively. Incorporating MnO2 and polyaniline to NGae structure can provide higher specific power and/or energy. The as-fabricated supercapacitors in this work may be practically used in high energy and power applications.

3D free-standing nitrogen-doped reduced graphene oxide aerogel as anode material for sodium ion batteries with enhanced sodium storage

Sodium ion batteries have drawn extensive attentions for large-scale energy storage to replace lithium ion batteries primarily due to the natural abundance of sodium resource and low cost, but their energy density and electrochemical performance are hindered by the sluggish diffusion kinetics of sodium ion. Herein, free-standing nitrogen-doped graphene aerogel has been fabricated via hydrothermal reaction as the potential anode material for sodium ion batteries. The three dimensional porous network structure of the graphene aerogel provides sufficient interstitial space for sodium ion accommodation, allowing fast and reversible ion intercalation/de-intercalation. The nitrogen doping could introduce defects on the graphene sheets, making the feasible transport of large-sized sodium ion. Benefiting from the effective structure and nitrogen doping, the obtained material demonstrates high reversible capacities, good cycling performance (287.9 mA h g−1 after 200 cycles at a current density of 100 mA g−1), especially superior rate capability (151.9 mA h g−1 at a high current density of 5 A g−1).

Mesoporous nitrogen-doped graphene aerogels with enhanced rate capability towards high performance supercapacitors

Abstract In this work, a novel preparation method and architecture of mesoporous nitrogen-doped graphene aerogels (GAs) using electrostatic attraction are reported. The sacrificial template, positively charged SiO 2 nanoparticles by using (3-Animopropyl) triethoxysilane (3-APTS), can significantly decrease the spacing between graphene oxide sheets, due to the strong electrostatic attraction between the graphene oxide and SiO 2 . After the etching of templates, the ratio of mesopores is greatly increased, and the electrochemical performances of electrodes are enhanced. The mesoporous GAs yield an enhanced specific capacitance of 203 F/g at a current density of 1 A/g, and a capacitance fade of only 8.95% at a high current density of 20 A/g, indicating improved ion transport in mesoporous architecture. The controllable synthesized method can be further applied to prepare other mesoporous materials and such mesoporous nitrogen-doped GAs have great potential in high rate performance supercapacitors.

Facile Synthesis of Nitrogen‐Doped Graphene Aerogels for Electrode Materials in Supercapacitors

AbstractThree‐dimensional porous nitrogen‐doped graphene aerogels (NGAs) were synthesized by using graphene oxide (GO) and chitosan (CS) via a self‐assembly process by one‐pot hydrothermal method. The morphology and structure of the as‐prepared materials were characterized by means of scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, XPS spectroscopy, Raman spectroscopy, nitrogen adsorption/desorption measurement and Fourier transform infrared spectroscopy. The electrochemical performance of NGAs was studied by cyclic voltammetry, galvanostatic charge/discharge and impedance spectroscopy measurements. The microstructure, surface area and capacitance of NGAs could be facilely controlled by adding different amounts of chitosan. The prepared NGA‐4 showed a specific capacitance of 148.0 F/g at the discharge current density of 0.5 A/g and also retained 95.3% of the initial capacitance after 5000 cycles at the scan rate of 10 mV/s. It provided a possible way to obtain graphene based materials with high surface area and capacitance.

Nonenzymatic glucose sensing by CuO nanoparticles decorated nitrogen-doped graphene aerogel

CuO nanoparticles decorated N-doped graphene aerogel (NGA-CuO) was facilely synthesized via a mild hydrothermal method followed by freeze-drying and calcination, which was characterized by TEM, FT-IR, XPS, XRD and electrochemical impedance spectroscopy (EIS). The obtained NGA-CuO was used for the construction of a nonenzymatic sensing platform for glucose, exhibiting wide linear range, low detection limit, high sensitivity, reproducibility, selectivity and stability. The excellent analytical performances of the NGA-CuO based glucose sensor might be attributed to the synergistic effect of CuO nanoparticles and N-doped graphene aerogel (NGA). The practical applications of the proposed sensor was verified by determining glucose concentrations in five human serum samples, and the obtained results were quite comparable to those measured on the standard clinical instrument.

Performance of nitrogen-doped graphene aerogel particle electrodes for electro-catalytic oxidation of simulated Bisphenol A wastewaters

The treatment of effluent containing Bisphenol A (BPA) was investigated experimentally using nitrogen-doped graphene aerogel (NGAs) as particle electrodes in a three-dimensional electrode reactor for the electrochemical treatment was studied. The effects of the cell voltage, pH, the ratio of NGAs mass to solution volume and repeated times on the removal efficiency were investigated. Compared with commercial carbon particle electrodes, the NGAs exhibited stronger activity to remove BPA simulated wastewater. For 15mgL−1 of BPA solution, the degradation rate of BPA exceeded 90% after treatment for only 30min under the optimum conditions. The CODCr removal rate of BPA was 85%. Moreover, in the process of reused 50 times, the degradation rate of BPA can be kept in more than 85%. The CODCr removal rate was stable at about 73%. The intermediate products of electrochemical degradation of BPA were identified by liquid chromatography-mass spectrometry liquid chromatography (LC–MS), and a probable BPA degradation pathway was proposed. It was considered that OH radicals by water electrolysis could constantly attack the aromatic ring to form various intermediates such as hydroxylated-BPA, isopropylphenol, hydroquinone, phenol and butantetraol, maleic acid, oxalic acid. These compounds were eventually mineralized by electrolysis into CO2 and H2O.

Facile synthesis of nitrogen-doped graphene aerogels functionalized with chitosan for supercapacitors with excellent electrochemical performance

Three-dimensional porous nitrogen-doped graphene aerogels (NGAs) were synthesized by using graphene oxide (GO) and chitosan via a self-assembly process by a rapid method. The morphology and structure of the as-prepared aerogels were characterized. The results showed that NGAs possesed the hierarchical pores with the wide size distribution ranging from mesopores to macropores. The NGAs carbonized at different temperature all showed excellent electrochemical performance in 6mol/L KOH electrolyte and the electrochemical performance of the NGA-900 was the best. When working as a supercapacitor electrode, NGA-900 exhibited a high specific capacitance (244.4F/g at a current density of 0.2A/g), superior rate capability (51.0% capacity retention) and excellent cycling life (96.2% capacitance retained after 5000 cycles).

Nitrogen-doped graphene aerogels-supported cobaltosic oxide nanocrystals as high-performance bi-functional electrocatalysts for oxygen reduction and evolution reactions

A hybrid material consisting of cobaltosic oxide (Co3O4) nanocrystals grown on nitrogen-doped graphene aerogels (N-GAs), denoted as Co3O4/N-GAs, is fabricated via a simple one-pot hydrothermal process and utilized as a high-performance bi-functional electrocatalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The Co3O4/N-GAs hybrid for the ORR displays an outstanding electrocatalytic performance toward the ORR comparable with commercial Pt/C catalyst in an alkaline medium. Furthermore, our proposed hybrid is also highly active for the OER, making it a promising bi-functional catalyst for both ORR and OER. The obviously enhanced catalytic activity is ascribed to the synergistic effect between Co3O4 and N-GAs.

Fabrication of an arbitrary-shaped and nitrogen-doped graphene aerogel for highly compressible all solid-state supercapacitors

Herein, we report a new template method for fabricating an arbitrary-shaped compressible nitrogen-doped graphene aerogel (GA).

Facile synthesis of 3D nitrogen-doped graphene aerogel nanomeshes with hierarchical porous structures for applications in high-performance supercapacitors

3D N-GANMs with hierarchical pores are firstly synthesized using iron nitrate as the etching agent, which display excellent supercapacitive performances.

Retracted Article: A facile strategy to fabricate nitrogen-doped graphene aerogel supported Fe3N nanoparticles as efficient electrocatalysts for the oxygen reduction reaction

Retracted Article: A facile strategy to fabricate nitrogen-doped graphene aerogel supported Fe₃N nanoparticles as efficient electrocatalysts for the oxygen reduction reaction

Coassembly and high ORR performance of monodisperse Pt nanocrystals with a mesopore-rich nitrogen-doped graphene aerogel

Monodisperse Pt nanocrystals in NGA with a large specific surface area and high N content yield high ORR performance.

Retraction: A facile strategy to fabricate nitrogen-doped graphene aerogel supported Fe3N nanoparticles as efficient electrocatalysts for the oxygen reduction reaction

Retraction of ‘A facile strategy to fabricate nitrogen-doped graphene aerogel supported Fe3N nanoparticles as efficient electrocatalysts for the oxygen reduction reaction’ by Shufeng Wang et al., New J. Chem., 2017, DOI: 10.1039/c6nj04114k.