• Title/Summary/Keyword: Graphene-$TiO_2$ mixture

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Preparation of graphene-$TiO_2$ composite by aerosol process and it's characterization for dye-sensitized solar cell (에어로졸 공정에 의한 Graphene-$TiO_2$ 복합체 제조 및 염료감응 태양전지 특성평가)

  • Jo, Eun Hee;Kim, Sun Kyung;Jang, Hee Dong;Chang, Hankwon;Roh, Ki-Min;Kim, Tae-Oh
    • Particle and aerosol research
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    • v.9 no.2
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    • pp.51-57
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    • 2013
  • A graphene(GR)-$TiO_2$ composite was synthesized from colloidal mixture of graphene oxide(GO) nanosheets and $TiO_2$ nanoparticles by an aerosol assisted self-assembly. The morphology, specific surface area and pore size of asprepared GR-$TiO_2$ composite were characterized by FE-SEM, BET, and BJH respectively. The shape of GR-$TiO_2$ composite was spherical. The average particle size was 0.5-1 ${\mu}m$ in diameter and the pore diameter ranged 20-50 nm. Photovoltaic characteristics of a mixture of the GR-$TiO_2$ and $TiO_2$ nanoparticles were measured by a solar simulator under simulated solar light. The highest photoelectric conversion efficiency of the mixture photoanode was 5.1%, which was higher than that of $TiO_2$ photoanode.

Functional graphene sheets-TiO2 nanocomposites and their photocatalytic performance for wastewater treatment

  • R. Aitbelale;A. Timesli;A. Sahibed-dine
    • Advances in nano research
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    • v.15 no.4
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    • pp.295-304
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    • 2023
  • In this paper, a powerful photocatalyst based on carbon nanocomposite is developed in order to obtain a new material applicable in water treatment and especially for the discoloration of effluents used in the textile industry. For that, TiO2-graphene nanocomposites have been successfully synthesized by a mixture of Functionalized Graphene Sheet (FGS) and tetrachlorotitanium complexes to form FGS-TiO2 nanocomposite. In the presence of an anionic surfactant, we used a new chemical process to functionalize graphene sheets in order to make them an excellent medium for blocking and preventing the aggregation of TiO2 nanoparticles. The components of these nanocomposites are characterized by means of X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), which confirms the successful formation of the FGS-TiO2 nanocomposite. It was found that the TiO2 nanoparticles were dispersed uniformly on the graphene plane which possesses better charge separation capability than pure TiO2. The FGS-TiO2 nanocomposites exhibited higher photocatalytic activity compared to pure TiO2 for the removal of three dyes: such as Methylene Blue (MB), Bromophenol Blue (BB) and Alizarin Red-S (AR) in water. The removal process was fast and more efficient with FGS-TiO2 nanocomposite in daylight (in the absence of UV irradiation) compared to pure TiO2 nanoparticles without and under UV in all pH range.

Control of Airborne Organic Pollutants Using Plug-Flow Reactor Coated With Carbon Material-Titania Mixtures Under Visible-Light Irradiation

  • Jo, Wan-Kuen;Kang, Hyun-Jung;Kim, Mo-Keun
    • Journal of Environmental Science International
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    • v.22 no.10
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    • pp.1263-1271
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    • 2013
  • Graphene oxide (GO)-titania composites have emerged as an attractive heterogeneous photocatalyst that can enhance the photocatalytic activity of $TiO_2$ nanoparticles owing to their potential interaction of electronic and adsorption natures. Accordingly, $TiO_2$-GO mixtures were synthesized in this study using a simple chemical mixing process, and their heterogeneous photocatalytic activities were investigated to determine the degradation of airborne organic pollutants (benzene, ethyl benzene, and o-xylene (BEX)) under different operational conditions. The Fourier transform infrared spectroscopy results demonstrated the presence of GO for the $TiO_2$-GO composites. The average efficiencies of the $TiO_2$-GO mixtures for the decomposition of each component of BEX determined during the 3-h photocatalytic processes were 26%, 92%, and 96%, respectively, whereas the average efficiencies of the unmodified $TiO_2$ powder were 3%, 8%, and 10%, respectively. Furthermore, the degradation efficiency of the unmodified $TiO_2$ powder for all target compounds decreased during the 3-h photocatalytic processes, suggesting a potential deactivation even during such a short time period. Two operational conditions (air flow entering into the air-cleaning devices and the indoor pollution levels) were found to be important factors for the photocatalytic decomposition of BEX molecules. Taken together, these results show that a $TiO_2$-GO mixture can be applied effectively for the purification of airborne organic pollutants when the operating conditions are optimized.

Synthesis and Morphology Control of Rod Shaped Potassium Hexatitanate (봉상형 육티탄산칼륨(K2Ti6O13) 제조 및 형상제어)

  • Lee, Chongmin;Chang, Hankwon;Jang, Hee Dong
    • Particle and aerosol research
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    • v.14 no.4
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    • pp.145-151
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    • 2018
  • Rod shaped Potassium hexatitanate ($K_2Ti_6O_{13}$) was synthesized from colloidal mixture of $TiO_2$, KOH and graphene oxide (GO) by aerosol spray drying and post heat treatment. Firstly, $TiO_2-KOH-GO$ composites were fabricated by aerosol spray drying in argon atmosphere. The composites were then calcined to form a rod shaped morphology of potassium titanate (KTO) in the presence of graphene at $900^{\circ}C$ for 3 h in argon atmosphere. Finally, the rod shaped KTO was obtained after removal of graphene (GR) at $800^{\circ}C$ and 3 h in air atmosphere. Characterization of the synthesized $K_2Ti_6O_{13}$ was carried out using the XRD, BET and FE-SEM. The length and diameter of the synthesized $K_2Ti_6O_{13}$ could be controlled by weight fraction of GO in the aerosol precursor. The length of $K_2Ti_6O_{13}$ rod increased with decreasing its diameter as GO concentration increased. The aspect ratio of the synthesized $K_2Ti_6O_{13}$ rod was controlled from 5 to 13.

Synthesis and Characterization of MoS2/Graphene-TiO2 Ternary Photocatalysts for High-Efficiency Hydrogen Production under Visible Light

  • Zhang, Feng-Jun;Kong, Cui;Li, Xuan;Sun, Xian-Yang;Xie, Wen-Jie;Oh, Won-Chun
    • Journal of the Korean Ceramic Society
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    • v.56 no.3
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    • pp.284-290
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    • 2019
  • Ternary MoS2/graphene (G)-TiO2 photocatalysts were prepared by a simple hydrothermal method. The morphology, phase structure, band gap, and catalytic properties of the prepared samples were investigated by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, UV-vis spectrophotometry, and Brunauer-Emmett-Teller surface area measurement. The H2 production efficiency of the prepared catalysts was tested in methanol-water mixture under visible light. MoS2/G-TiO2 exhibited the highest activity for photocatalytic H2 production. For 5 wt.% and 1 wt.% MoS2 and graphene (5MT-1G), the production rate of H2 was as high as 1989 µmol-1h-1. The catalyst 5MT-1G showed H2 production activity that was ~ 11.3, 5.6, and 4.1 times higher than those of pure TiO2, 1GT, and 5MT, respectively. The unique structure and morphology of the MoS2/G-TiO2 photocatalyst contributed to its improved hydrogen production efficiency under visible light.