Distance engineering between $TiO_2$ nanoparticles and graphene quantum dots to enhance photocatalytic activity광촉매 활성 향상을 위한 이산화 티타늄 나노 입자와 그래핀 양자점 사이의 거리 조절

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Titanium dioxide ($TiO_2$) is the most widely used semiconductor photocatalyst due to its strong oxidation power and photochemical stability. However, since pristine $TiO_2$ has critical limitations such as a narrow absorption spectrum and a high recombination rate, it is still difficult to use itself as a photocatalyst. Graphene quantum dots (GQDs), which intentionally open the bandgap by reducing the size of graphene, have arisen as a candidate for sensitizer of $TiO_2$ photocatalyst via band structure modulation. In particular, GQDs fabricated from graphite intercalation compounds (GICs) have a wide and discrete bandgap due to low defects and oxidation content, which can cause effective ligand-to-metal charge transfer (LMCT) with $TiO_2$. GQDs decorated $TiO_2$ form proper band alignment, leading to the charge transfer from the HOMO level of GQDs to the conduction band of $TiO_2$. However, strong orbital coupling induced by a direct chemical bonding of GQDs and $TiO_2$ hinders the delocalization of excited electrons transferred from GQDs to $TiO_2$, resulting in fast back electron transfer (BET). Herein, the distance between $TiO_2$ and GQDs was engineered using the organic linkers to improve the photocatalytic efficiency by suppressing BET. As a result, TA6G with a computational distance of about 1.7 nm between GQDs and $TiO_2$ shows the most effective methylene blue degradation, which can be expected as a significant improvement in the inhibition of BET and charge separation at that distance.
Advisors
Jeon, Seokwooresearcher전석우researcher
Description
한국과학기술원 :신소재공학과,
Publisher
한국과학기술원
Issue Date
2023
Identifier
325007
Language
eng
Description

학위논문(석사) - 한국과학기술원 : 신소재공학과, 2023.2,[vi, 29 p. :]

Keywords

Titanium dioxide ($TiO_2$)▼aGraphene quantum dos (GQDs)▼aPhotocatalyst▼aCharge separation▼aOrganic linker; 이산화 티타늄▼a그래핀 양자점▼a광촉매▼a전하 분리▼a유기 링커

URI
http://hdl.handle.net/10203/308997
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=1033095&flag=dissertation
Appears in Collection
MS-Theses_Master(석사논문)
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