2021, Volume 9, Issue 1, Pages: 224-232  
J. Environ. Treat. Tech.  
ISSN: 2309-1185  
Journal web link: http://www.jett.dormaj.com  
Graphene-Carbon Nanotube Hybrids: Synthesis  
and Application  
Khadije Yousefi*  
Department of Materials Science and Engineering, School of Engineering, Shiraz University, 71348-51154 Shiraz, Iran  
Received: 06/08/2020  
Accepted: 08/11/2020  
Published: 20/03/2021  
Graphene and CNTs have gained considerable concern and research attention. In addition to preventing the aggregation of these  
carbon compounds, graphene CNT hybridization would also make full use of the synergistic relationship between graphene and CNT.  
This chapter discusses the different carbon nanomaterials and their special properties, and a thorough analysis of the graphene-CNT  
derivatives is observed. It would also discuss in detail the methods and their properties used to create graphene-CNT hybrids. Their  
applications are also described particularly in device sensing, energy/supercapacitors, and material science.  
Keywords: Carbon nanotubes, graphene, CNT-graphene hybrid  
are highly satisfactory(10). Theoretical and experimental  
studies on individual SWCNT show significantly strong tensile  
strength (150180 GPa) and tensile modulus (640 GPa1  
TPA), more powerful than popular carbon fibers (11). Also,  
they display off enormous thermal and electric properties a  
number of the great mechanical properties associated with  
CNTs: thermally stable in vacuum up to 2800°C, thermal  
conductivity two times as proper as concrete, electronic present  
day output 1000 extra times than copper wires (12). CNTs may  
be single-walled or multi-walled structures, figure 1 shows an  
image of MWCNT nanostructure transmission electron  
microscope (TEM), in which several graphical carbon layers  
and a hollow core appear.  
Completely carbon-based products from activated carbon,  
carbon nanotubes (CNTs) to graphene have gained widespread  
prominence due to their intricate nanostructures, physical and  
chemical characteristics of high quality. Such features involve  
a range of materials (powders, fabrics, aerogels, composites,  
boards, monoliths, columns, etc.), extremely inert  
electrochemistry, fast storage, and porosity regulation (1-3).  
Graphene and CNTs generated tremendous attention and  
involvement in science due to their remarkable physical  
residences, such as extreme electrical conductivity, equal  
thermal stability, and excellent mechanical efficiency (4).  
Conversely, due to the powerful vanderWaals forces among  
them, the agglomeration of carbon materials, especially  
graphene and CNTs, is unavoidable. Graphene CNT  
hybridization often does not help to inhibit the association of  
such carbon compounds, but may also show synergistic results  
between graphene and CNT(5, 6). Research has shown that  
hybrid graphene-CNT nanomaterials have more electrical  
conductivity, superior surface structure, and improved catalytic  
properties relative to standard CNT or graphene (6, 7). The  
hybrid system is efficient and can be assembled using a range  
of techniques like simple solution assembly, chemical vapor  
deposition, and CNT discharge (8, 9). This chapter  
demonstrates and discusses methods for hybridizing CNTs  
with graphene, characterization, and hybrid alertness.  
3 Graphene Nanosheets  
Graphene is a 2D single-atom-thick film of carbon atoms  
assembled hexagonally(13, 14). The carbon bonds are sp  
hybridized where the in-plane σCC bond is one of the most  
strong links to the substance and the out-of-plane relation is  
responsible for the conduction of graphene electron  
contributing to a delocalized electron network. Graphene has  
shown remarkable physical properties due to the specific  
structural qualities which have provided substantial attention to  
research in both science and technology communities (15-18).  
Graphene has been used as a building block for many of such  
carbon allotropes in extraordinary lengths, as visible in  
Figure.2 (19). For example, with a spacing of 0.330.34 nm,  
D graphite is composed of graph nanosheets layered at each  
Carbon Nanotubes  
other's pinnacle. One-dimensional (1D) carbon allotropes,  
CNTs which include SWCNTs and MWCNTs can be produced  
in miles by rolling the graphene into single or multi-walled  
tubular nanostructures. Wrapping a piece of graphene like a  
ball often has effects in zero-dimensional (0D) fullerenes.  
Carbon nanotubes are visible cylinders with one or two  
additional graphene layers open or near ends (de-called  
SWCNT, or MWCNT). The diameters of SWCNT and  
MWCNT are usually 0.82 nm and 520 nm respectively,  
whereas the diameters of MWCNT maybe 100 nm,  
respectively. CNTs have low mass density, immoderate  
durability, and high issue ratio (usually about 3001000),  
leading in mechanical, thermal, and electrical properties that  
Corresponding author: Khadije Yousefi, Department of Materials Science and Engineering, School of Engineering, Shiraz  
University, 71348-51154 Shiraz, Iran. E-mail: khadije.yousefi@gmail.com