microscopy (TEM) including high-resolution transmission electron microscopy (HRTEM),

atomic force microscopy (AFM), and scanning tunnelling microscopy (STM). Scanning

electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution

transmission electron microscopy (HRTEM) are typically explored to envisage the mor­

phology and structure of graphene-based materials. In addition to the morphological

geographies of the nanostructures, the SEM scanned images additionally help to find the

possible mechanisms responsible for the formation of specific structural characteristics,

which are correlated to the end property of the material. Energy dispersive spectrometry

(EDS) provided with FE-SEM is frequently used for the elemental composition of graphene-

based nanostructures. The topographical and structural features exposed by the STM help

in perusing the presence of defects, folds, and periodicity in addition to the number of

graphene layers and recognizing the lattice disparity and effect of interface between the

substrate and graphene.

HRTEM is also an operative technique to perceive surface defects of graphene-based

materials. Furthermore, HRTEM elemental mapping is a powerful tool to distinguish

the elemental distribution of graphene-based materials. AFM is broadly used to acquire the

three-dimensional images, lateral dimensions, thickness, and the number of layers present in

graphene films. AFM is also used to characterize the surface roughness, which will provide

some evidence of surface area and the active area available in graphene-based materials.

X-ray fluorescence (XRF, non-destructive) and inductively coupled plasma mass

spectrometry (ICP, destructive) are two exceedingly suggested techniques to investigate

the residual metal concentration present in graphene-based materials. One superficial and

practical technique adopted to analyze the mass loss of the functional groups present in

graphene can be quantitatively estimated from the is thermogravimetric analysis (TGA).

Also, by combining TGA with FTIR or mass spectra (MS), accurate informative data re­

garding the structural characteristics of graphene-related materials can be obtained.

Brunauer–Emmett–Teller (BET) surface achieved from nitrogen adsorption-desorption

experiments at 77 K can quantify the surface area of the graphene-related materials

proficiently and reliably, which can provide indirect support for the layer number

identification qualitatively. The determination of layer number can be partially used to

epitomize the surface area condition and vice versa. The theoretical calculations indicate

that the highest surface area of monolayer graphene is 2,630 m²/g.

The reaction mechanisms of graphene-based materials can be gathered by studying

the mechanism by experimental techniques based on the bulk and surface structure

analysis and chemisorption ability determination, theoretical computations with density

functional theory (DFT), and from the combination of both experimental and theoretical

investigations.

16.5 Properties of Graphene

Graphene holds several outstanding properties in terms of optical transparency, electric

conductivity, mechanical strength, and thermal conductivity. The graphene revolution has

commenced with the development of outstanding electrical and electronics properties.

The properties of graphene materials are extremely contingent on the number of layers

used to create graphene sheets. Graphene is a semi-metal or zero-gap semiconductor

[32,33]. Electronic properties separate graphene from other condensed matter systems.

Graphene Nanostructures

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