Dimensional evolution of graphene-based nanomaterials for sensor and supercapacitor applications
The versatility of graphene and its derivatives from inventive synthesis method have evolved throughout the years, which provided avenues that precisely tune their structure and functionality for specific applications. Nevertheless, there are only several graphene-based products that have been su...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2018
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/68684/1/FS%202018%2027%20-%20IR.pdf |
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| Summary: | The versatility of graphene and its derivatives from inventive synthesis method have
evolved throughout the years, which provided avenues that precisely tune their
structure and functionality for specific applications. Nevertheless, there are only
several graphene-based products that have been successfully commercialized into
the market. The main reason behind this is the lack of concrete performance metrics
of graphene and its derivatives demonstrating their true value proposition in other
segments. In this thesis, the investigation and justification of the evolution process
of graphene derivatives were discussed in terms of graphene in different dimensions,
which ultimately provide significant insights into diverse industrial applications.
In the first evolution stage, graphene with its natural 2D nanosheet structure was
being employed as an “electronic blanket” in photoelectrochemical (PEC) sensing
platform. The existence of 2D graphene (rGO) blanket in cadmium sulfide (CdS)
modified carbon cloth (CC) electrode increased the photocurrent intensity by two
orders of magnitude, compared to that of without graphene. 2D graphene blanket can
also provide intimate integration between the nanoparticles and current collector
substrate, thus contributing to a sensitive copper ion detector with a linear detection
range of 0.1 to 40.0 μM and a detection limit of 0.05 μM.
In the second evolution stage, graphene was modified with nickel cobaltite (NCO) to
produce a hierarchical 3D rGO/NCO nanostructure. Upon modification, the
morphology of the graphene evolved from nanosheet into a petal-like nanostructure.
This petal-like rGO/NCO nanostructure exhibits excellent supercapacitive
performance (282.95 F g-1), which is 1.5 times higher than that of pure NCO. Besides,
intimate integration of NCO on the rGO nanosheet resulted in an efficient contact between the electrode/electrolyte interface, thus contributing to superior capacitance
retention, which is 46% better than that of pure NCO.
In the third evolution stage, graphene was self-assembled and reinforced with
polypyrrole (Ppy) into a free-standing 3D aerogel matrix. The self-agglomeration and
oxidative polymerization of rGO and Ppy occurred synergistically in a controlled
water bath environment, which resulted in an elastic and conductive compression
sensor. The presence of flexible rGO nanosheets as an aerogel backbone provided a
strong mechanical support which could be compressed more than 50% and recovered
to its original structure in less than 5 seconds with minor mechanical deformations.
Lastly, in the final stage of evolution, graphene modified polylactic acid (PLA) was
employed to develop a 3D printed electrode (3DE) using a commercial 3D printer.
Graphene provided additional electrical conductivity properties to the insulating PLA
matrix, which then proficiently fabricated into a supercapacitor and PEC sensor. They
had a photocurrent response that exceeded expectations (~724.1 μA) and a lower
detection limit (0.05 μM) than an ITO/FTO glass electrode.
In conclusion, the neoteric findings in this research provide a significant leap in
functional graphene nanomaterial fabrications. Even though graphene has been
extensively employed in laboratory research, the evolution and modification of
graphene nanomaterials can eventually reveal its true potential in other industrial
applications. |
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