Synthesis and characterization of nitrogen-doped graphene hydrogels by hydrothermal route with urea as reducing-doping agents

Abstract

Nitrogen-doped graphene hydrogels (NGHs) were synthesized through a one-pot hydrothermal route with graphene oxide (GO) as raw material and urea as reducing-doping agents. The morphology, structure, and components of the NGHs were characterized by scanning electron microscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, methylene blue adsorption, thermogravimetric analysis and electrical conductivity measurements. The results demonstrated that nitrogen was doped into the graphene plane at the same time as the GO sheets were reduced, and the nitrogen content incorporated into the graphene lattice was in the range of 3.95 to 6.61 at.% with pyrrolic N as the main component. The NGHs contained about 97.6 wt% water and have a large specific surface area (SSA) of >1300 m 2 g À1 in the wet state. In addition, the electrochemical performance of the NGHs was investigated. The sample NGHs-4 with a nitrogen content of 5.86 at.% and SSA of 1521 AE 60 m 2 g À1 in the wet state showed excellent capacitive behavior (308 F g À1 at 3 A g À1 ) and superior cycling stability (92% retention after 1200 cycles) in 6 mol L À1 KOH. The experimental results indicated that not only the N-content but also the N-type have very significant impact on the capacitive behavior.Furthermore, NGHs strongly influenced the electrochemical properties because of their high SSAs and mesoporous structure.

Metal−Organic Framework‐Derived Nitrogen‐Doped Core‐Shell‐Structured Porous Fe/Fe3C@C Nanoboxes Supported on Graphene Sheets for Efficient Oxygen Reduction Reactions

“…Previous studies showed that the decomposition of N precursors could contribute to the formation of N dopants [ 11b ] and the substitution of carbon atoms with graphitic nitrogen could cause n-type doping, resulting in the down-shift of the G band. [ 17 ] The above results provide an evidence for the incorporation of N atoms into RGO. The chemical structure of the N-doped Fe/Fe 3 C@C/RGO was further studied by infrared spectroscopy (IR).…”

NO gas sensing ability of activated carbon fibers modified by an electron beam for improvement in the surface functional group

“…3a. The peaks at 284.5 eV and 532.8 eV correspond to the C1s and O1s signals, respectively [21]. The O1s peak increased in intensity after E-beam irradiation in an aqueous solution, as shown in Table 3.…”

MnS nanocomposites based on doped graphene: simple synthesis by a wet chemical route and improved electrochemical properties as an electrode material for supercapacitors

“…The N1s spectrum of MnS/NG-9 nanocomposite could be tted with two peaks at a binding energy of 398.5 and 400.1 eV corresponding to pyridinic nitrogen and pyrrolic nitrogen atoms in graphene. 36 The strong intensity peaks suggests a good level of nitrogen doping in graphene. The presence of pyrrolic and pyridinic nitrogen in graphene can increase the electrochemical activity of graphene in electrochemical process.…”