• Title, Summary, Keyword: Photocatalytic degradation

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Neodymium doped mixed metal oxide derived from CoAl-layered double hydroxide: Considerable enhancement in visible light photocatalytic activity

  • Khodam, Fatemeh;Amani-Ghadim, Hamid Reza;Aber, Soheil;Amani-Ghadim, Ali Reza;Ahadzadeh, Iraj
    • Journal of Industrial and Engineering Chemistry
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    • v.68
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    • pp.311-324
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    • 2018
  • Herein,the Neodymium ion ($Nd^{3+}$) doped CoAl-LDH have been successfully prepared via co-precipitation method and was used as a precursor of Nd-doped CoAl-mixed metal oxides (MMO). The photocatalytic activity of doped LDH and MMO was investigated in the degradation of an azo dye, C.I. Acid Red 14, under visible light irradiation. DRS and PL analysis demonstrated decreasing in the band gap energy and recombination of photo-induced charge carriers of Nd-doped LDH and MMO compared with the pristine CoAL-LDH. Due to significant difference in photocatalytic performance. A power law empirical kinetic model was obtained for predicting the photocatalytic degradation efficiency.

Spray pyrolysis synthesis of mesoporous TiO2 microspheres and their post modification for improved photocatalytic activity

  • Choi, Jaehyung;Yoo, Kye Sang;Kim, Jinsoo
    • The Korean Journal of Chemical Engineering
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    • v.35 no.12
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    • pp.2480-2486
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    • 2018
  • Mesoporous $TiO_2$ microspheres were prepared by spray pyrolysis for photocatalysis. Post modification of $TiO_2$ by heat treatment was performed to optimize its photocatalytic performance. First, spherical $TiO_2$ particles with mesoporous structure were synthesized at pyrolysis temperatures of 500, 600, and $700^{\circ}C$. After characterization by XRD, SEM, and $N_2$ adsorption, a sample prepared at $500^{\circ}C$ was found to possess desirable properties for photocatalytic performance through post-modification. In methylene blue degradation, mesoporous $TiO_2$ microspheres synthesized at $500^{\circ}C$ outperformed other microspheres. Furthermore, samples obtained by spray pyrolysis at $500^{\circ}C$ were calcined at various temperatures as a post-modification process. The sample calcined at $350^{\circ}C$ showed improved photocatalytic activity due to optimal anatase crystallinity and surface area.

Enhanced sunlight photocatalytic activity of silver nanoparticles decorated on reduced graphene oxide sheet

  • Baskey, Moni (Sen);Ghosh, Sanjukta
    • The Korean Journal of Chemical Engineering
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    • v.34 no.7
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    • pp.2079-2085
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    • 2017
  • A facile and straightforward method has been developed to synthesize silver nanoparticles decorated on reduced graphene oxide (RGO) nanosheets through hydrothermal reaction. The composite was characterized by XRD, UV-Visible spectroscopy, SEM and TEM techniques. In this synthesized RGO-Ag nanocomposite, the Ag nanoparticles size ranges 30-50 nm. Moreover, the RGO-Ag composites exhibited excellent photocatalytic activity towards the degradation of methylene blue (MB) in presence of sunlight. This photocatalytic reaction is completed within 20 min and the rate of reaction depends on the amount of RGO present in the nanocomposites.

Effect of ACF and WO3 from ACF/WO3/TiO2 Composite Catalysts on the Photocatalytic Degradation of MO Under Visible Light

  • Meng, Ze-Da;Song, Da-Ye;Zhu, Lei;Park, Chong-Yeon;Choi, Jong-Geun;Oh, Won-Chun
    • Journal of the Korean Ceramic Society
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    • v.48 no.4
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    • pp.282-287
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    • 2011
  • ACF and $WO_3$ modified $TiO_2$ composites (ACF/$WO_3$/$TiO_2$) were prepared using a sol-gel method. The composites were characterized by Brunauer.Emmett.Teller (BET) surface area measurements, X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis and scanning electron microscope (SEM) analysis. A methyl orange (MO) solution under visible light irradiation was used to determine the photocatalytic activity. The degradation of the MO was determined using UV/Vis spectrophotometry. An increase in photocatalytic activity was observed and attributed to an increase of the photo-absorption effect by the $WO_3$ and the cooperative effect of the ACF.

Preparation of CdS-AC/TiO2 Composites Designed for a High Photonic Effect and their Photocatalytic Activity Under Visible Light

  • Park, Chong-Yeon;Choi, Jong-Geun;Ghosh, Trisha;Oh, Won-Chun
    • Journal of the Korean Ceramic Society
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    • v.48 no.5
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    • pp.433-438
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    • 2011
  • In this study, CdS combined activated carbon/$TiO_2$ (CdS-AC/$TiO_2$) composites were prepared by a sol-gel method to improve the photocatalytic performance of $TiO_2$. These composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and UV-vis analysis. The photocatalytic activities were examined by the degradation of methylene blue (MB) under visible light irradiation. The photodegradation rate of MB under visible light irradiation reached 90.1% in 120 min. The kinetics of MB degradation was plotted alongside the values calculated from the Langmuir-Hinshelwood equation. The 0.2 CAT sample showed the best photocatalytic activity, which might be due to an increase in the photo-absorption effect by activated carbon and the cooperative effect of CdS.

Preparation and Characterization of ZnO-ACF/TiO2 Composite Catalysts for the Photocatalytic Degradation of MO under Visible Light

  • Sun, Qian;Zhu, Lei;Meng, Ze-Da;Ullah, Kefayat;Ye, Shu;Oh, Won-Chun
    • Journal of the Korean Ceramic Society
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    • v.50 no.4
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    • pp.269-274
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    • 2013
  • ACF and ZnO modified $TiO_2$ composite materials (ZnO-ACF/$TiO_2$) were prepared by a sol-gel method. The composites were characterized by X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis and scanning electron microscope (SEM) analysis. A methyl orange (MO) solution under visible light irradiation was used to determine the photocatalytic activity. The degradation of the MO was determined using UV spectrophotometers. An increase in the photocatalytic activity was observed and attributed to an increase of the photo-absorption effect by the ZnO and the cooperative effect of the ACF.

Catalytic Activity of BiVO4-graphene Nanocomposites for the Reduction of Nitrophenols and the Photocatalytic Degradation of Organic Dyes

  • Li, Jiulong;Ko, Jeong Won;Ko, Weon Bae
    • Elastomers and Composites
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    • v.51 no.3
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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.

Preparation of Bi/Bi2MoO6 Plasmonic Photocatalyst with High Photocatalytic Activity Under Visible Light Irradiation

  • Zou, Chentao;Yang, Zhiyuan;Liang, Mengjun;He, Yunpeng;Yang, Yun;Yang, Shuijin
    • Nano
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    • v.13 no.11
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    • pp.1850127.1-1850127.13
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    • 2018
  • Bi metal deposited on $Bi_2MoO_6$ composite photocatalysts have been successfully synthesized via a simple reduction method at room temperature with using $NaBH_4$ as the reducing agent. The photocatalytic activity of the composite was evaluated by degradation of rhodamine B (RhB) and bisphenol A (BPA) solution under visible light. The rate constant of $Bi/Bi_2MoO_6$ composite to RhB is 10.8 times that of $Bi_2MoO_6$, and the degradation rate constant of BPA is 6.9 times of that of $Bi_2MoO_6$. Nitrogen absorption-desorption isotherm proved that the increase of specific surface area is one of the reasons for the improvement of photocatalytic degradation activity of $Bi/Bi_2MoO_6$ composites. The higher charge transfer efficiency of $Bi/Bi_2MoO_6$ is found through the characterization of the photocurrent and impedance, which are attributed to the surface plasmon resonance (SPR) effect produced by the introduction of the metal Bi monomer in the composite. Free radical capture experiments proved that cavitation is the main active species. Based on the above conclusions, a possible mechanism of photocatalytic degradation is proposed.

Construction of Strontium Titanate/Binary Metal Sulfide Heterojunction Photocatalysts for Enhanced Visible-Light-Driven Photocatalytic Activity

  • Yu, Yongwei;Yang, Qing;Ma, Jiangquan;Sun, Wenliang;Yin, Chong;Li, Xiazhang;Guo, Jun;Jiang, Qingyan;Lu, Zhiyuan
    • Nano
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    • v.13 no.11
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    • pp.1850130.1-1850130.12
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    • 2018
  • A novel strontium titanate/binary metal sulfide ($SrTiO_3/SnCoS_4$) heterostructure was synthesized by a simple two-step hydrothermal method. The visible-light-driven photocatalytic performance of $SrTiO_3/SnCoS_4$ composites was evaluated in the degradation of methyl orange (MO) under visible light irradiation. The photocatalytic performance of $SrTiO_3/SnCoS_4-5%$ is much higher than that of pure $SrTiO_3$, $SnCoS_4$, $SrTiO_3/SnS_2$ and $SrTiO_3/CoS_2$. The $SrTiO_3/SnCoS_4$ composite material with 5 wt.% of $SnCoS_4$ showed the highest photocatalytic efficiency for MO degradation, and the degradation rate could reach 95% after 140 min irradiation time. The enhanced photocatalytic activity was ascribed to not only the improvement of visible light absorption efficiency, but also the construction of a heterostructure which make it possible to effectively separate photoexcited electrons and holes in the two-phase interface.

Template-free preparation of TiO2 microspheres for the photocatalytic degradation of organic dyes

  • Al Ruqaishy, Mouza;Al Marzouqi, Faisal;Qi, Kezhen;Liu, Shu-yuan;Karthikeyan, Sreejith;Kim, Younghun;Al-Kindy, Salma Mohamed Zahran;Kuvarega, Alex Tawanda;Selvaraj, Rengaraj
    • The Korean Journal of Chemical Engineering
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    • v.35 no.11
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    • pp.2283-2289
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    • 2018
  • $TiO_2$ microspheres were successfully synthesised by simple solution phase method by using various amount of titanium butoxide as precursor. The prepared $TiO_2$ were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance absorption spectra (UV-DRS), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). XRD analysis revealed that the as-synthesized $TiO_2$ microsphere poses an anatase phase. The photocatalytic degradation experiments were carried out with three different dyes, such as methylene blue, brilliant black, reactive red-120 for four hours under UV light irradiation. The results show that $TiO_2$ morphology had great influence on photocatalytic degradation of organic dyes. The experimental results of dye mineralization indicated the concentration was reduced by a high portion of up to 99% within 4 hours. On the basis of various characterization of the photocatalysts, the reactions involved to explain the photocatalytic activity enhancement due to the concentration of titanium butoxide and morphology include a better separation of photogenerated charge carriers and improved oxygen reduction inducing a higher extent of degradation of aromatics.