Nitrogen doped graphene (NG-Gh) is a type of graphene that is composed of nitrogen doping the surface of the graphene layer, while keeping the bulk of the graphene structure unchanged. Nitrogen doping the graphene improves its electrical conductivity, making it ideal for use in semiconductor devices. N-Gh is used in white light emitting diodes. It also shows potential for use in the field of magnetism and electrocatalytic activity.
XPS analysis of N-Gh
The core level XPS spectrum represents the chemical and physical state of the individual atoms in the sample. It can be obtained from high-resolution scans of the XPS instrument. This guide outlines a few essential strategies and tools to obtain this information.
Peak fitting is an important technique for separating overlapping peaks for quantitative analysis. However, it is an art. Effective peak fitting depends on the type of sample and the complexity of the spectrum.
Photoemission peaks can be fitted with a number of different line shapes. These vary from simple, narrow symmetric shapes to complex, highly symmetric ones. Identifying the correct lineshapes is one of the more difficult parts of the fitting process.
Identifying the best line shape for a photoemission peak requires knowledge of the chemical environment of the sample and appropriate reference spectra. Reference spectra can help determine the position of the peak and the degree of extrinsic processes that affect its structure.
An XPS instrument can acquire data through a variety of scanning modes. Typically, the analyzer is a hemispherical instrument. A typical analyzer uses a lens system to adjust the energy of the photoelectrons.
When identifying peaks, it is important to consider the signal-to-noise ratio of the spectra. This is affected by the chemistry of the sample and the quality of the data acquisition. To improve this, smoothing techniques may be employed. Smoothing techniques can also introduce changes in spectral shape.
The XPS spectrum is composed of two spectral regions. The first is the core region, which includes electrons with binding energies that are greater than 30 eV. The second is the valence band, which includes electrons with binding energies less than 30 eV.
Electrochemical reversibility
In the search for next-generation energy storage devices, graphene has been gaining widespread attention due to its unique properties. In particular, its exceptional electronic conductive capacity and carrier mobility. It also exhibits a strong quantum Hall effect on the honeycomb sp2 carbon lattice.
Nitrogen doping is a promising approach for improving the electrochemical performance of graphene. This is because nitrogen has a similar atomic size as carbon. Also, nitrogen atoms can form covalent bonds with the adjacent C atoms.
Nitrogen doped graphene can increase the specific capacitance. The resulting hybrid materials are classified into conventional capacitors and ultra-capacitors. They can also be incorporated into supercapacitors.
Electrochemical control experiments were carried out at solvent-modified and pure graphene electrodes. GO-modified electrodes showed enhanced reversibility. The improved response was likely related to energetically favourable hydrogen bonding between the C/O functional groups and the electrode.
In addition, the GO-modified electrodes show a smaller EP. These results indicate that GO-modified BPPGs could be used for epinephrine sensing.
An alternating voltage electrochemical technique was applied to study the electrochemical properties of large scale N-doped graphene. The three-electrode system is suitable for analyzing the electron transport properties of N-Gh.
Electrochemical measurements of the N-Gh samples were studied at various scan rates. With the increasing scan rates, the intensity of the corresponding CV files increased. However, the shape of the curves remained broadly stable.
Magnetism
N-doped graphene exhibits significant ferromagnetism at room temperature. However, the emergence of ferromagnetism in the samples is due to defects. Defects can play a vital role in enhancing the magnetic exchange coupling of localized magnetic moments.
The emergence of ferromagnetism is positively correlated to the concentration of nitrogen in the samples. Samples with low nitrogen content have lower ferromagnetism than pristine samples. This can be explained by the defect concentration. A low N concentration may also limit the experimental realization of FM in the NG.
XPS measurements were performed for as-prepared powders and TEM specimens. XPS results showed that samples with higher N content have a higher frequency G band.
Raman spectra were obtained using a 532 nm wavelength laser. This corresponds to 2.34 eV. In addition, X-ray fluorescence was used to confirm the composition.
Samples with highest N content had a high coercive force. Ms values for these samples were comparable to graphene obtained in freestanding MoS2 nanosheets. However, Ms values were decreased with the increase in temperature.
Total ferromagnetic impurities in the samples are 13.9 ppm. These impurities include 8.9 ppm Fe and 5.0 ppm Ni. TPY-G3N (T) is a type of triazine (T) complex.
Antiferromagnetic couplings are present in z1 and a7 configurations. The antiferromagnetic state of TPI-G3N is unstable. Nevertheless, the ferromagnetic contribution is negligible.
N-doped graphene exhibits a narrow coercive force. However, it shows a high saturation magnetization. Saturation magnetizations are given by magnetic hysteresis loops. Fig. 5(b-d) illustrates the derivatives of the M T curve.
At 300 K, the averaged magnetization per site was weaker than the high N concentration limit. For the sample with highest N content, Ms value was 168.8 Oe. Nevertheless, this value is comparable to graphene found in other dopant-free diluted magnetic semiconductors.
Electrocatalytic activity
Nitrogen doped graphene has great potential as an electrocatalyst for oxygen reduction reaction (ORR). In this research, we investigate the catalytic activity of nitrogen doped graphene in oxygen reduction reaction. The results are promising, as the obtained materials show good electrocatalytic activity.
N-doped graphene nanocarbons exhibit excellent durability and high activity in CO2RR process. This material can be applied as electrodes for fuel cells. However, the properties of nitrogen doped graphene can vary from one sample to another. Thus, it is very important to understand the chemical and physical properties of these materials.
XPS analysis revealed the presence of nitrogen, oxygen, and other functional groups. Moreover, nitrogen doped graphene is characterized by its stability and high faradaic efficiency for formate. Moreover, it can convert carbon dioxide into multicarbon hydrocarbons.
For further development, further research may focus on the application of nitrogen doped graphene(NDG) to other processes. Such materials could be a potential replacement for metal catalysts. Moreover, they have environmentally friendly characteristics.
Compared to pyridine-type N-doped olympicene/graphene hybrids, the electrocatalytic activity of the nitrogen doped graphene foams is comparable to Pt(111) surface. Although the pore size is reduced, the specific surface areas are large.
NGQDs for white-light emitting diodes
White LEDs are no longer just a pipe dream, but a reality in the making. These devices boast an impressive power conversion efficiency as well as operating stability. The advent of nanotechnology has also allowed for a more focused approach to agglomerating the necessary components to yield the desired end result. While the task of stacking and resizing the aforementioned components is no small feat, a little effort and clever sourcing can go a long way in ensuring a successful synthesis.
Using the right materials in the right proportions yields a light emitting device fit for a queen. Besides the obvious fluorescents, the trick is balancing the plethora of competing light emitting materials. For the neophytes, a shortlist of promising materials is a must. Among these, carbon quantum dots have garnered much of the spotlight. Some of the more well-studied materials have demonstrated a number of interesting properties, such as the ability to produce a quantum yield of 68.1% in a commercially viable fashion.
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