SYNTHESIS OF COAL-DERIVED REDUCED GRAPHENE OXIDE FORSUPERCAPACITOR ELECTRODE APPLICATION
The increasing use of renewable energy, especially solar panels and electric cars, encourages the development of energy storage system technology, one of which is supercapacitors. In supercapacitor materials, graphite plays a vital role, but about 80% of its global reserves and production are con...
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id-itb.:784492023-09-20T09:43:12ZSYNTHESIS OF COAL-DERIVED REDUCED GRAPHENE OXIDE FORSUPERCAPACITOR ELECTRODE APPLICATION Sulaiman, Aziz Indonesia Final Project coal, reduced graphene oxide, electrode, L-ascorbic acid INSTITUT TEKNOLOGI BANDUNG https://digilib.itb.ac.id/gdl/view/78449 The increasing use of renewable energy, especially solar panels and electric cars, encourages the development of energy storage system technology, one of which is supercapacitors. In supercapacitor materials, graphite plays a vital role, but about 80% of its global reserves and production are concentrated in China, so graphite is categorized as a critical material. This encourages the exploration of alternative graphite materials as supercapacitor raw materials. Coal has the potential to be converted as a precursor due to its structure and composition. However, there are several challenges in the process such as high ash content, use of hazardous reagents, and long reduction time. Therefore, to support the energy transition as well as the downstreaming of Indonesian coal, this research focuses on a faster and environmentally friendly synthesis process of reduced graphene oxide from Indonesian coal. Graphene oxide was synthesized from subbituminous coal B. The experiment started with sieving the coal to obtain -200 mesh particles (RC). Then RC was pretreated by stepwise leaching using 1 M HF and 0.5 M HNO3, followed by carbonization at 900 °C for 2 hours (PTR). The PTR sample was used to synthesize graphene oxide (GO) via the modified Hummers method using concentrated H2SO4 and KMnO4 for 8.5 hours. Then GO was reduced using L-ascorbic acid at pH 7 (RGO7) and pH 9 (RGO9) in the microwave for 5 minutes. RGO7 and RGO9 were then subjected to thermal annealing at 300°C to produce RGO7A and RGO9A samples. RC, PTR, GO, RGO, and RGOA samples were characterized using fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope- energy dispersive spectroscopy (SEM-EDS). GO, RGO, and RGOA samples were also tested for electrochemical performance using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD). The results showed that stepwise leaching effectively reduced the ash content (3.21% to 0.55% wt%, db), while carbonization increased the fixed carbon content (47.42% to 95.91% wt%, db). The results of the GO electrochemical performance test showed a capacitance value of 106.28 F/g at a current density of 0.5 A/g, with interlayer spacing d002 = 3.74 nm, and an increase in carbonyl groups which indicates that the synthesis process has taken place well. The reduction process at alkaline pH was able to increase the capacitance value of RGO from 173.13 (RGO7) to 200.63 F/g (RGO9) at a current density of 0.5 A/g. However, the thermal annealing process has not succeeded in increasing the capacitance value, namely 121.88 (RGO7A) and 81.88 F/g (RGO9A) at a current density of 0.5 A/g. FTIR results show the formation of aromatic carbon functional groups on GO which are retained after the reduction process. text |
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The increasing use of renewable energy, especially solar panels and electric cars,
encourages the development of energy storage system technology, one of which is
supercapacitors. In supercapacitor materials, graphite plays a vital role, but about
80% of its global reserves and production are concentrated in China, so graphite is
categorized as a critical material. This encourages the exploration of alternative
graphite materials as supercapacitor raw materials. Coal has the potential to be
converted as a precursor due to its structure and composition. However, there are
several challenges in the process such as high ash content, use of hazardous
reagents, and long reduction time. Therefore, to support the energy transition as
well as the downstreaming of Indonesian coal, this research focuses on a faster and
environmentally friendly synthesis process of reduced graphene oxide from
Indonesian coal.
Graphene oxide was synthesized from subbituminous coal B. The experiment
started with sieving the coal to obtain -200 mesh particles (RC). Then RC was
pretreated by stepwise leaching using 1 M HF and 0.5 M HNO3, followed by
carbonization at 900 °C for 2 hours (PTR). The PTR sample was used to synthesize
graphene oxide (GO) via the modified Hummers method using concentrated H2SO4
and KMnO4 for 8.5 hours. Then GO was reduced using L-ascorbic acid at pH 7
(RGO7) and pH 9 (RGO9) in the microwave for 5 minutes. RGO7 and RGO9 were
then subjected to thermal annealing at 300°C to produce RGO7A and RGO9A
samples. RC, PTR, GO, RGO, and RGOA samples were characterized using fourier
transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning
electron microscope- energy dispersive spectroscopy (SEM-EDS). GO, RGO, and
RGOA samples were also tested for electrochemical performance using cyclic
voltammetry (CV) and galvanostatic charge-discharge (GCD).
The results showed that stepwise leaching effectively reduced the ash content
(3.21% to 0.55% wt%, db), while carbonization increased the fixed carbon content
(47.42% to 95.91% wt%, db). The results of the GO electrochemical performance
test showed a capacitance value of 106.28 F/g at a current density of 0.5 A/g, with
interlayer spacing d002 = 3.74 nm, and an increase in carbonyl groups which
indicates that the synthesis process has taken place well. The reduction process at
alkaline pH was able to increase the capacitance value of RGO from 173.13 (RGO7)
to 200.63 F/g (RGO9) at a current density of 0.5 A/g. However, the thermal
annealing process has not succeeded in increasing the capacitance value, namely
121.88 (RGO7A) and 81.88 F/g (RGO9A) at a current density of 0.5 A/g. FTIR
results show the formation of aromatic carbon functional groups on GO which are
retained after the reduction process. |
format |
Final Project |
author |
Sulaiman, Aziz |
spellingShingle |
Sulaiman, Aziz SYNTHESIS OF COAL-DERIVED REDUCED GRAPHENE OXIDE FORSUPERCAPACITOR ELECTRODE APPLICATION |
author_facet |
Sulaiman, Aziz |
author_sort |
Sulaiman, Aziz |
title |
SYNTHESIS OF COAL-DERIVED REDUCED GRAPHENE OXIDE FORSUPERCAPACITOR ELECTRODE APPLICATION |
title_short |
SYNTHESIS OF COAL-DERIVED REDUCED GRAPHENE OXIDE FORSUPERCAPACITOR ELECTRODE APPLICATION |
title_full |
SYNTHESIS OF COAL-DERIVED REDUCED GRAPHENE OXIDE FORSUPERCAPACITOR ELECTRODE APPLICATION |
title_fullStr |
SYNTHESIS OF COAL-DERIVED REDUCED GRAPHENE OXIDE FORSUPERCAPACITOR ELECTRODE APPLICATION |
title_full_unstemmed |
SYNTHESIS OF COAL-DERIVED REDUCED GRAPHENE OXIDE FORSUPERCAPACITOR ELECTRODE APPLICATION |
title_sort |
synthesis of coal-derived reduced graphene oxide forsupercapacitor electrode application |
url |
https://digilib.itb.ac.id/gdl/view/78449 |
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