We report that graphene films with thickness ranging from 1 to 7 layers can be controllably synthesized on the surface of polycrystalline copper by a chemical vapour deposition method. The number of layers of graphene is controlled precisely by regulating the flow ratio of CH 4 and H 2 , the reaction pressure, the temperature and the reaction time. The synthesized graphene films were characterized by scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, X-ray diffraction and Raman spectroscopy. In addition, the graphene films transferred from copper to other substrates are found to have a good optical transmittance that makes them suitable for transparent conductive electrodes.
The high value-added
utilization of fluid catalytic cracking (FCC)
slurry has always been full of challenges and has important practical
significance. Ultralight N-rich porous graphene nanosheets (N-PGNs)
have been synthesized via a chemical vapor deposition method using
FCC slurry as a carbon source and g-C3N4 as
a substrate. The N-PGNs integrate interesting features including high
N doping and large surface area with ultrahigh pore volume, which
leads to intriguing performance in electromagnetic wave absorption
(EMWA) along with broad absorption bandwidth. When the ratio of FCC
slurry and g-C3N4 continues to optimize, the
maximum reflection loss of the N-PGNs can reach −53 dB with
a low filler loading of only 3 wt %, and the effective absorption
bandwidth exceeding −10 dB is 6.8 GHz with a thickness of 3
mm. The excellent property of the N-PGNs and their extraordinary EMWA
performance develop a new pathway for the high value-added utilization
of FCC slurry.
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