| Summary: | 碩士 === 國立臺灣大學 === 環境工程學研究所 === 103 === 1970s was known to be the time of oil crisis. Since then, technologies of utilizing light to produce hydrogen energy had drawn much attention. Hydrogen produced from water splitting was considered to be one of the potential candidates of alternative energy owing to the discovery of Honda-Fujishima effect. By applying sacrificial reagents and improving photocatalysts, heterogeneous photocatalytic system of water splitting became possible few years later.
Among various semiconductors, TiO2 is probably the most suitable material for industrial scale photocatalysts in future. TiO2 is cheap, nontoxic and stable. Its properties had also been well studied.
Recently, nanomaterial researchers had been concerned about graphene. Oxidative exfoliation allows graphene oxide (GO) to be synthesized in gram-scale through facile method. Theoretically, reduced GO (rGO) possess good conductivity. Also GO is capable to be manipulated under nanometer scale, which is suitable for composition on TiO2 powder to further enhance photocatalytic activity. Considering various existing reduction methods, here in we synthesized TiO2/rGO by hydrothermal reduction (HrGO), photo-assisted reduction (PrGO) and thermal reduction (TrGO). Under UV irradiation, TiO2/HrGO was discovered to perform best among others, with 2.7 fold hydrogen production for 1%w/w compare with mere TiO2.
In addition, synthesizing TiO2 nanotube (TiNT) with simultaneous composition and reduction of GO had been achieved to produce TiNT/rGO. Crystallinity changed along with nanotube fabrication and subsequent blue shift of absorption edge was observed. As a result, TiNT of 0% and 1%w/w rGO composition possess worse photocatalytic activities than that of TiO2. For the fact that specific surface area of TiNT is much higher than TiO2, hydrogen production rate of 2% composition of rGO on TiNT increased dramatically by 13 fold compare to mere TiO2
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