From the FTIR spectral analysis, the typical peaks corresponding to functional groups

present in GO comprised of O–H stretching (3,400 cm⁻¹), C–H stretching (2,910 cm⁻¹),

C=O stretching (1,687, 1,710 cm⁻¹), C=C stretching (1,542, 1,568 cm⁻¹), C–O stretching

(1,208 cm⁻¹), C–OH stretching (1,113 cm⁻¹), C–O–H bending (1,409 cm⁻¹), and C–H

system stretching (2,875 cm⁻¹).

Ultraviolet-visible spectroscopy (UV-vis) is the most appropriate method to confirm the

effective synthesis of graphene and GO. The graphitic structure generally exhibits an

absorption peak at ~262 nm while a monolayer of GO exhibits absorption at ~230 nm in

the UV-vis spectrum, which is accredited to the π–π^∗ transitions of aromatic C–C bond.

X-ray photoelectron spectroscopy (XPS) is a surface-sensitive and prevailing quantitative

spectroscopic technique and can be used to characterize the chemical state, elemental

composition, and electronic state of the elements present on the surface of graphene. XPS is

regarded as a precise technique to determine the quantity of carbon and oxygen compared

to elemental analysis. It has become the standard method to prove the successful doping of

heteroatoms on the surface of graphene. X-ray diffraction (XRD) and X-ray absorption near-

edge spectroscopy (XANES) measurements are enlightening tools to investigate the

structure, oxidation state, and local symmetry. From the X-ray absorption fine structure

(XAFS) and extended X-ray absorption fine structure (EXAFS) spectroscopy, the accurate

percentage of specific bonds present in graphene can be determined.

The morphological characteristics, structural excellence, and crystallinity of graphene

and its derivatives can be investigated from the microscopic analysis. The frequently used

microscopic methods are scanning electron microscopy (SEM), transmission electron

FIGURE 16.4

Schematic diagram of characterization techniques for graphene-based materials.

Source: (Reproduced from AIMS Materials Science, 4(3): 755–788. DOI: 10.3934/matersci.2017.3.755: licensed

under creative commons attribution license ( http://creativecommons.org/licenses/by/4.0).

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