• 한국염색가공학회지
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• 제25권2호
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• pp.94-101
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• 2013

Poly(acrylonitrile) (PAN) nanofibers containing different amounts of titanium dioxide ($TiO_2$) have been prepared by electrospinning technique. Photocatalytic activity of these electrospun PAN/$TiO_2$ nanofibers and the effect of $TiO_2$ content on the photocatalytic efficiency of PAN/$TiO_2$ nanofibers have been evaluated by monitoring the photodecomposition of fluorescein dye, rhodamine B and methylene blue under UV irradiation with respect to irradiation time. Moreover, the effect of hydrogen peroxide ($H_2O_2$) on the photocatalytic behavior of PAN/$TiO_2$ nanofibers has also been investigated. The results showed that PAN/$TiO_2$ nanofibers are effective photocatalyst and their photocatalytic efficiency increases with the increase of $TiO_2$ content in the PAN/$TiO_2$ nanofibers. It is also observed that the presence of $H_2O_2$ significantly enhances the photocatalytic ability of PAN/$TiO_2$ nanofibers. The morphology and the photocatalytic behavior of the PAN/$TiO_2$ nanofibers containing different amounts of $TiO_2$ nanoparticles have been investigated by field-emission scanning electron microscopy (FE-SEM) and UV/Visible spectroscopy, respectively.

• Advances in nano research
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• 제4권3호
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• pp.157-165
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• 2016

The photocatalytic (PC) activity of anatase titania nanoparticles can be improved through codoping with transition metals and nitrogen. In addition, the PC activity can also be improved by creating monodisperse, mesoporous nanoparticles of titania. The question naturally arose as to whether combining these two characteristics would result in further improvement in the PC activity or not. Herein, we describe the synthesis and photocatalytic characteristics of codoped, monodisperse anatase titania. The transition metals tested in the polydisperse and the monodisperse forms were Mn, Co, Ni, and Cu. In each case, it was found that the monodisperse version had a higher PC activity compared to the corresponding polydisperse version.

• 한국산학기술학회논문지
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• 제6권4호
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• pp.331-336
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• 2005

최근 일본이 광촉매 관련 제품에서의 소비자 보호를 위한 적절한 표준화 규격 제정에 강한 의욕을 보이며, 자국내 JIS 규격 외에 ISO 규격 (ISO/TC 206 fine ceramics)을 제정하기 위하여 노력하고 있다. 이에 국내에서는 산업보호 및 해외시장에서의 종속성을 벗어나기 위하여 2001년부터 선정된 분야에서의 광촉매표준화 시도가 이루어졌다. 그 중의 하나로 본 논문은 광섬유를 빛 전달 매개체와 광촉매 코팅 지지체로 이용해서 광촉매 졸을 구성하는 광촉매 자체의 유기물 분해능을 결정하는 방법을 규정하는 과정과 제안과 관련된 것이다. 이 규격은 코팅 가능한 졸이나 졸로 만들 수 있는 자외선 감응 광촉매 재료에 적용하며, 차후 가시광 및 태양광 감응 광촉매 활성 측정 및 비교에도 응용이 가능할 것으로 판단된다.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.164-174
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• 2018

The purpose of this work designed hybrid-structured and plasma effect photocatalyst of $Ag/In_2O_3/TiO_2/HNTs$ via sol-gel and photo-reduction methods. The structures, morphologies, optical and photoelectric performances of as-prepared photocatalysts were characterized via XRD, TEM, XPS, BET, UV-vis DRS, PL and photocurrents. The photocatalytic activity was evaluated by degradation of TC. The results showed that the hybrid-structure and plasma effect can effectively cause the multi-transfer of electrons and increase the separation rate of electron and hole pairs which obtained high photocatalytic activity. The photocatalytic degradation processes reveal that $^{\bullet}O_2{^-}$ and $h^+$ are major active species.

• 청정기술
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• 제21권3호
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• pp.178-183
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• 2015

PbMoO₄ 산화물을 수열합성법과 마이크로파 공정으로 합성하여 XRD, DRS, BET, Raman, SEM 및 PL 등에 의해 특성분석을 하였고, 자외선 조사 하에서 Rhodamine B의 광분해 반응에서의 활성을 조사하였다. XRD 및 Raman의 분석 결과로부터 대부분의 촉매들은 제조방법과 무관하게 잘 결정화된 PbMoO₄ 구조를 가지고 있었으며 42에서 59 nm의 크기를 나타내었다. 마이크로파 공정으로 제조된 PbMoO₄ 촉매는 통상적인 수열합성법으로 제조된 촉매에 비해 균일한 입자를 가지고 있으며, 높은 광분해 활성을 나타내었다. 마이크로파 주사 시간을 75분으로 제조한 PbMoO₄ 촉매가 가장 높은 광분해 활성을 나타내었다. 모든 촉매들은 530 nm 부근에서 강하고 넓은 PL 흡수밴드가 나타났으며, 이 피크의 세기가 커질수록 광분해 활성이 증가하는 것으로 나타났다.

• 한국분말재료학회지
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• 제27권3호
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• pp.226-232
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• 2020

Bismuth vanadate (BiVO₄) is considered a potentially attractive candidate for the visible-light-driven photodegradation of organic pollutants. In an effort to enhance their photocatalytic activities, BiVO₄ nanofibers with controlled microstructures, grain sizes, and crystallinities are successfully prepared by electrospinning followed by a precisely controlled heat treatment. The structural features, morphologies, and photo-absorption performances of the asprepared samples are systematically investigated and can be readily controlled by varying the calcination temperature. From the physicochemical analysis results of the synthesized nanofiber, it is found that the nanofiber calcines at a lower temperature, shows a smaller crystallite size, and lower crystallinity. The photocatalytic degradation of rhodamine-B (RhB) reveals that the photocatalytic activity of the BiVO₄ nanofibers can be improved by a thermal treatment at a relatively low temperature because of the optimization of the conflicting characteristics, crystallinity, crystallite size, and microstructure. The photocatalytic activity of the nanofiber calcined at 350℃ for the degradation of RhB under visible-light irradiation exhibits a greater photocatalytic activity than the nanofibers synthesized at 400℃ and 450℃.

• Environmental Engineering Research
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• 제20권4호
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• pp.329-335
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• 2015

The effects of ion-doping on $TiO_2$ nanotubes were investigated to obtain the optimal catalyst for the effective decomposition of Rhodamine B (RB) through UV photocatalytic oxidation process. Changing the calcination temperature, which changed the weight fractions of the anatase phase, the average crystallite sizes, the BET surface area, and the energy band gap of the catalyst, affected the photocatalytic activity of the catalyst. The ionic radius, valence state, and configuration of the dopant also affected the photocatalytic activity. The photocatalytic activities of the catalysts on RB removal increased when $Ag^+$, $Al^{3+}$ and $Zn^{2+}$ were doped into the $TiO_2$ nanotubes, whereas such activities decreased as a result of $Mn^{2+}$ or $Ni^{2+}$ doping. In the presence of $Zn^{2+}$-doped $TiO_2$ nanotubes calcined at $550^{\circ}C$, the removal efficiency of RB within 50 min was 98.7%.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2512-2518
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• 2014

The praseodymium-doped $TiO_2$ photocatalyst samples, which could degrade methyl orange under UV irradiation, were prepared by sol-microwave method for improving the photocatalytic activity of $TiO_2$. The resulting materials were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectra, Fourier transform infrared spectra (FTIR) and Ultraviolet-visible diffuse reflectance spectra (UV-vis DRS). It was found Pr doping retarded the growth of crystalline size and the phase transformation from anatase to rutile, and narrowed the band gap energy. Praseodymium doping brought about remarkable improvement in the photoactivity. The optimal dopant amount of Pr was 2% by molar of cement and the calcination temperature was $500^{\circ}C$ for the best photocatalytic activity. The improvement of photocatalytic activity was ascribed to the occurrence of lattice distortion and the effective containment of the recombination of the electron-hole by $Pr^{3+}$.

• Elastomers and Composites
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• 제51권3호
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• pp.240-249
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• 2016

$BiVO_4$ nanomaterial was synthesized from bismuth (III) nitrate pentahydrate [$Bi(NO_3)_3{\cdot}5H_2O$] and ammonium vanadate (V) [$NH_4VO_3$]. The $BiVO_4$-graphene nanocomposite was fabricated by calcining the $BiVO_4$ nanomaterial and graphene under an oxygen-free atmosphere at $700^{\circ}C$. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to characterize structural and morphological properties of samples. The catalytic activity of the $BiVO_4$-graphene nanocomposite was studied for the reduction of 4-nitrophenol, 3-nitrophenol and 2-nitrophenol by sodium borohydride [$NaBH_4$]. The photocatalytic activity of the $BiVO_4$-graphene nanocomposite was demonstrated by the degradation of organic dyes like BG, MB, MO and RhB under irradiation at 365 nm. The catalytic and photocatalytic activity were studied by UV-vis spectrophotometry.

• 공업화학
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• 제18권4호
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• pp.371-375
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• 2007

본 연구에서는 광촉매 활성의 다면성을 체계적으로 조사하고자 5개의 상업용 $TiO_2$ 시료와 9가지의 대상기질을 선정하여 광촉매 분해반응을 수행하였다. 광촉매 활성은 평가 대상기질에 따라 매우 상이하게 측정되는 등 매우 복잡하게 나타났고, 광촉매의 일반적 특성들과 뚜렷한 상관성을 보이지 않았다. 즉, 이러한 광촉매 반응의 기질 특이성 때문에 단일물질에 대한 활성으로 전체 광촉매 활성을 대표할 수 없고, 여러 광촉매 간의 직접적이고 객관적인 활성비교가 어렵게 된다. 따라서, 표준화된 광촉매 활성 평가법 개발을 위해서는 광촉매 반응의 기질 특이성을 이해하고 각 적용분야에 맞게 평가기준을 달리하는 등의 통합적인 노력이 요구된다