Many chemically doped graphene materials exhibit desirable attributes like superior catalytic activity, durable and fast sensing capabilities, and increased magnetic moments. These characteristics can be measured using X-ray photoelectron spectroscopy (XPS), which is an effective technique for evaluating surface doping configurations and oxidation states.
How Nitrogen Doped Graphene Works
Chemical doping is a powerful technique to tune and introduce new properties into carbon materials2. Doping with nitrogen, boron, sulfur, or halogens, has drawn great attention due to its superior performance in supercapacitors3, lithium-ion batteries4, molecular sensors5, and metal-free electro catalysts for oxygen reduction reactions6.
The sensitivity and stability of graphene electrodes are crucial for their applications in sensors, electrochemical capacitors and batteries1. Nitrogen doping significantly enhances the performance of pristine graphene and reduces its degradation over time. Compared to unmodified graphene oxide (GO) and boron doped GO, NG has higher cycling stability with better capacitance retention and specific capacity2.
How Nitrogen Doped Graphene Can Be Used
Nitrogen doping can be used to improve the performance of graphene for various applications. It can increase the electrical conductivity of graphene and tune its Fermi energy. It can also be used to modify its chemical properties. The type of nitrogen doping can also affect its electrochemical behavior.
Xing et al. synthesized three different types of N-doped graphene by using urea as doping and reduction agent for graphene oxide (GO). The synthesis method was hydrothermal, with urea added to the aqueous dispersion of GO before the thermolysis started. The synthesis was performed for different periods of time (3, 8 and 12 h).
Nitrogen Doped Graphene Applications
Graphene and Nitrogen Doped Graphene (N-G) have been explored for supercapacitors2,3, solar fuel6, lithium-ion batteries7, molecular sensors8, and metal-free electro catalysts for oxygen reduction reactions9. The high discharge specific capacity of N-G is due to its atomic doping, but the exact mechanism is still unclear. The precise control of the atomic configuration and spatial arrangement of heteroatoms in doped graphene is critical for high carrier mobility, but this requires sophisticated synthetic approaches.
Nitrogen atoms can be introduced to graphene through chemical vapor deposition (CVD) in both surface-charge transfer and substitutional doping18,28,37. Surface-charge transfer doping involves adsorption of metal ions or gas molecules, while substitutional doping introduces covalently bonded heteroatoms to the graphene lattice38. Both techniques improve the performance of pristine graphene but do not retain its extraordinary properties38,39,40.
N is a popular choice for doping because it has the same periodic table location as C and easily substitutes into the graphene lattice to form p- and n-type doping22,23. In addition, N has five valence electrons in its 2s and 2p orbitals that can form strong bonds with the carbon atoms of graphene24. This doping can be precisely controlled by tuning the growth temperature of graphene. Typically, CVD-grown Nc-G exhibits Shubnikov-de Haas oscillations and well-developed plateaus in magneto transport measurements at room temperature, which is indicative of its high quality. These characteristics make it attractive for industrial applications, such as touch screens.
Nitrogen Doped Graphene Future
Besides the intrinsic properties of graphene, many other features can be tuned by chemical doping. Heteroatom dopants are electron donors or acceptors and can alter the energy band gap of graphene to suit different applications. They can be introduced into graphene in situ during the growth process or ex situ after plasma treatment.
Nitrogen (N) is the most popular dopant because it is a nonmetal element with five valence electrons that can form strong bonds with C atoms. This makes N a popular choice for p-type doping of graphene22,23. For example, Son et al. directly imaged substitution ally doped N atoms in graphene with an areal coverage of a few square micrometers. Thank visiting readnewsblog.com