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008			201023t2 2 m a|||fram|| 000 0 eng d
020			_aTHE0008932(Local) _qhardback
040			_aUMP _beng _cUMP _erda
090			_aFSTI .L56 2019 r Thesis
100	1		_aLim, Wan Sin, _eauthor.
245	1	0	_aEffect of sulphuric acid concentration of hummers’ method in reduced graphene oxide synthesis and its electrochemical study / _cLim Wan Sin
264		1	_aKuantan, Pahang : _bUMP, _c2019
264		4	_c© 2019
300			_axv, 80 pages : _billustrations (some color) ; _c30 cm. + _e1 CD-ROM
336			_atext _2rdacontent
336			_atext _2rdacontent
337			_aunmediated _2rdamedia
337			_acomputer _2rdamedia
338			_avolume _2rdacarrier
338			_acomputer disc _2rdacarrier
347			_atext file _bPDF _2rda
500			_aFaculty of Industrial Sciences and Technology
502			_aThesis (Master of Science) -- Universiti Malaysia Pahang – 2019
504			_aIncludes bibliographical references
520	3		_aSulphuric acid is an intercalation agent that commonly utilized during the chemical oxidation process in the modified Hummers’ method. The presence of sulphuric acid serves as intercalated molecules that significant to enhance the reactive of graphite surface for further oxidation. The aims of the study are to prepare graphene oxide (GO) through modification of the Hummers’ method by controlling the sulphuric acid concentration during the first step of oxidation and determine the electrochemical performance of the reduced graphene oxide (rGO). Ultraviolet-visible spectroscopy (UV-Vis), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS) and Field Emission Scanning Electron Microscope (FESEM) were used to characterize the composition and morphology of GO samples. After reduction by hydrazine monohydrate, rGO was characterized using XPS and Brunauer-Emmett-Teller (BET) surface area analysis. Then the electrochemical studies of rGO have been evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) using the three-electrode system. Based on XPS results, it was found that in the case of 98 % (GO98) and 90 % (GO90), the edge oxidized GO was dominant. After reduced the edge oxidized GO (rGO98 and rGO90) reached the specific capacitance 160 and 185 F g-1 at current density 0.5 A g-1. With the further reduction of the sulphuric acid concentration to 80 % (GO80) and 70 % (GO70), basal oxidized GO was obtained. However, the specific capacitance reduced to 146 and 120 F g-1. The EIS revealed that rGO90 has higher electron mobility and lower resistance than rGO98, rGO80 and rGO70. The stability of rGO90 after 10000 cycles showed 94 % capacitance retention which is higher than rGO98, rGO80, and rGO70 with capacitance retention 86, 85, and 80 %, respectively. Hence, it demonstrated that sulphuric acid concentration significantly influences on oxygen oxidized location either edge or basal plane during GO formation and also its electrochemical performance after reduction.
610	2	0	_aFaculty of Industrial Sciences and Technology _xDissertations
650		0	_aUniversities and colleges _xDissertations
650		0	_aTheses
942			_2lcc _cRESTRICT