7.4 Molten Salt-Assisted Conversion of PET into Carbon …
125
Fig. 7.10 a SEM and EDX analysis of the nanostructured carbon produced by the reactive molten
salt treatment of PET at 1300 °C in air. The carbon material is characterized by the presence of
exfoliated graphene nanolayers with a low amount of oxygen. b Nitrogen adsorption–desorption
isotherms of the nanostructured carbon, reproduced from Ref. [24], copyright 2019, with permission
from Elsevier
The graphitized nature of the nanostructured carbon could be further explored by
TEM microscopy observations, such as shown in Fig. 6.11. The upper left panel in
Fig. 7.11 shows a low magnification TEM micrograph, exhibiting the hierarchical
morphology of the carbon material, which consists of a mixture of intergraded and
fragmented nanosheets. The upper right panel in Fig. 7.11 shows a high magnification image taken on the fragmented nanosheets, revealing the crystalline fringes
of these nanostructures. As it can be observed in the inset of Fig. 7.11, upper-right
panel, the fast Fourier transform (FFT) analysis recorded on carbon fragments shows
a halo ring indicating an interplanar spacing of 3.5 Å, which corresponds to the (002)
crystalline planes of hexagonal carbon. The TEM observations confirm the nanocrystalline nature of the carbon material produced by the reactive molten salt treatment
of PET. This nanostructured carbon has a remarkably high level of crystallinity,
as can be realized from the high-resolution TEM (HRTEM) micrographs shown in
Fig. 7.11, down panels. The FFT pattern recorded on a highly crystalline nanosheet,
(down-left panel in Fig. 7.11), exhibits spots corresponding to the graphitic (002)
planes. The crystalline nanosheets produced are very thin, typically less than 10 nm.
Two nanosheets with a thickness of 5.6 and 8.5 nm are identified in the micrograph
shown in the down-right panel. Further, TEM observations revealed that the majority
of carbon sheets consisted of 4–20 layers [24]. These results confirm that the reactive molten salt treatment of PET leads to the formation of a nanostructured carbon,
which consists of crystalline graphitic nanosheets and sheet fragments with a high
surface area and a thickness of less than 10 nm.
125
Fig. 7.10 a SEM and EDX analysis of the nanostructured carbon produced by the reactive molten
salt treatment of PET at 1300 °C in air. The carbon material is characterized by the presence of
exfoliated graphene nanolayers with a low amount of oxygen. b Nitrogen adsorption–desorption
isotherms of the nanostructured carbon, reproduced from Ref. [24], copyright 2019, with permission
from Elsevier
The graphitized nature of the nanostructured carbon could be further explored by
TEM microscopy observations, such as shown in Fig. 6.11. The upper left panel in
Fig. 7.11 shows a low magnification TEM micrograph, exhibiting the hierarchical
morphology of the carbon material, which consists of a mixture of intergraded and
fragmented nanosheets. The upper right panel in Fig. 7.11 shows a high magnification image taken on the fragmented nanosheets, revealing the crystalline fringes
of these nanostructures. As it can be observed in the inset of Fig. 7.11, upper-right
panel, the fast Fourier transform (FFT) analysis recorded on carbon fragments shows
a halo ring indicating an interplanar spacing of 3.5 Å, which corresponds to the (002)
crystalline planes of hexagonal carbon. The TEM observations confirm the nanocrystalline nature of the carbon material produced by the reactive molten salt treatment
of PET. This nanostructured carbon has a remarkably high level of crystallinity,
as can be realized from the high-resolution TEM (HRTEM) micrographs shown in
Fig. 7.11, down panels. The FFT pattern recorded on a highly crystalline nanosheet,
(down-left panel in Fig. 7.11), exhibits spots corresponding to the graphitic (002)
planes. The crystalline nanosheets produced are very thin, typically less than 10 nm.
Two nanosheets with a thickness of 5.6 and 8.5 nm are identified in the micrograph
shown in the down-right panel. Further, TEM observations revealed that the majority
of carbon sheets consisted of 4–20 layers [24]. These results confirm that the reactive molten salt treatment of PET leads to the formation of a nanostructured carbon,
which consists of crystalline graphitic nanosheets and sheet fragments with a high
surface area and a thickness of less than 10 nm.