scholarly journals TiO2/ZnS/CdS Nanocomposite for Hydrogen Evolution and Orange II Dye Degradation

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Václav Štengl ◽  
Daniela Králová
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Hydrogen Evolution ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Nitrogen Adsorption ◽  
Band Gap Energy ◽  
Photocatalytic Decomposition ◽  
Orange Ii ◽  
Adsorption Desorption

TiO2/ZnS/CdS composites for photocatalytic hydrogen production from water were prepared by homogeneous hydrolysis of aqueous solutions mixture of TiOSO4, ZnSO4, and CdSO4with thioacetamide. Hydrogen evolution was observed in the presence of palladium and platinum nanoparticles deposited on TiO2/ZnS/CdS composites. The morphology was obtained by scanning electron microscopy, the nitrogen adsorption-desorption was used for determination of surface area (BET) and porosity. The method of UV-VIS diffuse reflectance spectroscopy was employed to estimate band-gap energies of prepared TiO2/ZnS/CdS nano-composites. The photocatalytic activity of the prepared samples were assessed by photocatalytic decomposition of Orange II dye in an aqueous slurry under UV irradiation at 365 nm wavelength and visible light up to 400 nm wavelength. Doped titanium dioxide by the CdS increased band-gap energy and doping with ZnS increased photocatalytic activity. The best photocatalytic activity for H2evolution shows sample named TiZnCd7 on surface deposited with palladium, which contains 20.21% TiO2, 78.5% ZnS, and 1.29% CdS.

scholarly journals CdS Loaded Activated Carbon: An Efficient, Solar Light Driven Photocatalyst for RhB Dye Degradation

2019 ◽  
Vol 35 (3) ◽  
pp. 1037-1044
Author(s):  
Sagar Kande ◽  
Udhav Ghoshir ◽  
Jayshree Khedkar ◽  
Anil Gambhire
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Xrd Analysis ◽  
Band Gap Energy ◽  
X Ray ◽  
Adsorption Desorption

A series of novel photocatalyst with CdS loaded on activated carbon (xAC/CdS) were successfully synthesized by a simple hydrothermal method. The activated carbon content was varied between 0-7 wt. %. The prepared photocatalysts were characterized by X-ray diffraction, scanning electron microscopy with EDX, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy, N2 adsorption-desorption analysis and photoluminescence spectroscopy. The photocatalytic activity of as-synthesized photocatalysts was studied for RhB dye degradation under natural sunlight irradiation. XRD analysis assigned both cubic and hexagonal morphology for xAC/CdS photocatalysts. The UV-vis DRS studies showed that loading of CdS on activated carbon enhances its visible light absorption with decrease in band gap energy. The lowest photoinduced e/h pair recombination rate in 3wt% AC/CdS results in optimum photocatalytic activity as revealed by photoluminescence study. The enhancement in dye degradation ability (̴ 11 times) of prepared photocatalysts can be attributed to synergistic effect of CdS and activated carbon.

scholarly journals Synthesis of Ag-TiO2/perlite composite for the photodegradation of methylene blue under solar light irradiation

2020 ◽  
Vol 9 (4) ◽  
pp. 42-48
Author(s):  
Nui Pham Xuan ◽  
Hoa Nguyen Thi ◽  
Tien Nguyen Trung ◽  
Tai Le Huu ◽  
Thi Tran Thi Van
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Band Gap Energy ◽  
Light Irradiation ◽  
Solar Light ◽  
Solar Light Irradiation ◽  
Adsorption Desorption

In this research, photocatalytic materials of TiO2, Ag-TiO2, Ag-TiO2/perlite were synthesized by the sol-gel method. By combining the photocatalytic activity between Ag-TiO2 and Perlite mineral, the Ag-TiO2/perlite composite has overcome the disadvantages of pristine TiO2, such as high band gap energy, low light utilization and easy recombination of electrons and holes. The synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherm, UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The photocatalytic activity of the samples was tested for degradation of methylene blue (MB) under solar light irradiation. Photodegradation studies revealed a 95% removal of MB dye via the synthesized Ag-TiO2/perlite after 150 min of irradiation. Reusability of this hybrid photocatalyst system was tested and only a 3% decrease was observed after four cycles.

scholarly journals Synthesis of C-N-S-Tridoped TiO2 from Vietnam Ilmenite Ore and Its Visible Light-Driven-Photocatalytic Activity for Tetracyline Degradation

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Nguyen Thi Lan ◽  
Vo Hoang Anh ◽  
Hoang Duc An ◽  
Nguyen Phi Hung ◽  
Dao Ngoc Nhiem ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Nitrogen Adsorption ◽  
Photocatalytic Decomposition ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Visible Light Driven

In this study, C-N-S-tridoped TiO2 composite was fabricated from TiO2 prepared from ilmenite ore and thiourea by means of hydrothermal method. The obtained material was characterized by X-ray diffraction, Raman scattering spectroscopy, UV-Vis diffuse reflectance spectroscopy, nitrogen adsorption-desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). It was found that C-N-S-tridoped TiO2 material has a large specific surface area, showing good photocatalytic activity on the degradation of antibiotic tetracycline in visible light region. The study on the mechanism of tetracycline photodegradation using the liquid chromatography with mass spectrometry was performed. It was found that tetracycline has been degraded over C-N-S-tridoped TiO2 catalyst into many different intermediates which can eventually be converted into CO2 and H2O. The kinetics of photocatalytic decomposition of tetracycline were investigated. In addition, the obtained material could catalyze well the degradation of other antibiotics (ciprofloxacin and chloramphenicol) and dyes (rhodamine-B, methylene blue, and organe red). The catalyst was stable after five recycles with slight loss of catalytic activity, which indicates great potential for practical application of C-N-S-tridoped TiO2 catalyst in treatment of wastewater containing tetracycline in particular or antibiotics in general.

The Influence of Cr Doped TiO2 on the Optical Property and Photocatalytic Activity under Sunlight Irradiation

2016 ◽  
Vol 13 (1) ◽  
pp. 99
Author(s):  
Siti Zulaikha Suhaili ◽  
Muhamad Kamil Yaakob ◽  
Siti Irma Yuana Saaid ◽  
Umi Sarah Jais
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Diffraction Method ◽  
Band Gap Energy ◽  
Pure Tio2 ◽  
Photocatalytic Efficiency ◽  
Sunlight Irradiation ◽  
Doped Tio2 ◽  
Gap Energy

Pure TiO2 and Cr doped TiO2 (0.1-1.0wt% Cr) nanoparticles were synthesized via sol gel method. This study focuses on narrowing the TiO2 band gap energies in order to enhance the photocatalytic efficiency under visible light. The synthesized samples were characterized by X-Ray diffraction method (XRD), field emmision (FESEM) and also UV-Vis diffuse reflectance spectroscopy (DRS).The photocatalytic activity under sunlight irradiation was demonstrated by photocatalytic decomposition of methylene blue in water using UV/Vis spectrophotometer. The XRD analysis of pure TiO2 and doped TiO2 calcined at 500oC showed a mixture of anatase and rutile phases with decreasing crystallites size from 13.3nm to 11.6nm as the concentration of Cr was increased. The anatase-rutile phase transformation increased from 28.8% to 57.4%. An indication shows that at 0.75wt%, Cr the anatase and rutile phases have equal composition percentage. This study demonstrated that band gap energy of TiO2 was reduced with Cr doping which could enhance the photocatalytic efficiency. Sample containing 1.0wt% exhibit the lowest optical band gap energy at 2.86 eV. The optimum chromium doping concentration was found to be at 0.1 wt% Cr corresponding to band gap energy of 2.87 eV and degradation rate of 84%. 

The Influence of Cr Doped TiO2 on the Optical Property and Photocatalytic Activity under Sunlight Irradiation

2016 ◽  
Vol 13 (1) ◽  
pp. 99
Author(s):  
Siti Zulaikha Suhaili ◽  
Muhamad Kamil Yaakob ◽  
Siti Irma Yuana Sheikh Mohd Saaid ◽  
Umi Sarah Jais
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Diffraction Method ◽  
Band Gap Energy ◽  
Pure Tio2 ◽  
Photocatalytic Efficiency ◽  
Sunlight Irradiation ◽  
Doped Tio2 ◽  
Gap Energy

Pure TiO2 and Cr doped TiO2 (0.1-1.0wt% Cr) nanoparticles were synthesized via sol gel method. This study focuses on narrowing the TiO2 band gap energies in order to enhance the photocatalytic efficiency under visible light. The synthesized samples were characterized by X-Ray diffraction method (XRD), field emmision (FESEM) and also UV-Vis diffuse reflectance spectroscopy (DRS).The photocatalytic activity under sunlight irradiation was demonstrated by photocatalytic decomposition of methylene blue in water using UV/Vis spectrophotometer. The XRD analysis of pure TiO2 and doped TiO2 calcined at 500oC showed a mixture of anatase and rutile phases with decreasing crystallites size from 13.3nm to 11.6nm as the concentration of Cr was increased. The anatase-rutile phase transformation increased from 28.8% to 57.4%. An indication shows that at 0.75wt%, Cr the anatase and rutile phases have equal composition percentage. This study demonstrated that band gap energy of TiO2 was reduced with Cr doping which could enhance the photocatalytic efficiency. Sample containing 1.0wt% exhibit the lowest optical band gap energy at 2.86 eV. The optimum chromium doping concentration was found to be at 0.1 wt% Cr corresponding to band gap energy of 2.87 eV and degradation rate of 84%.

Industrial and agroindustrial wastes: an echotechnological approach to the production of supported photocatalysts

2015 ◽  
Vol 73 (1) ◽  
pp. 28-38 ◽  
Author(s):  
William Leonardo da Silva ◽  
Marla Azário Lansarin ◽  
João H. Z. dos Santos
Keyword(s):  
Zeta Potential ◽  
Rice Husk ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Tap Water ◽  
Nitrogen Adsorption ◽  
Band Gap Energy ◽  
Visible Radiation ◽  
X Ray ◽  
Agroindustrial Wastes

Agroindustrial wastes (rice husk, exhausted bark acacia, and tobacco dust) and foundry sands from the iron foundry industry were employed as a support source for photocatalysts. TiCl4 was used as the titanium precursor in the preparation of the supported photocatalysts. The solids were characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), diffuse reflectance spectroscopy over the ultraviolet range (DRS-UV), X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), nitrogen adsorption–desorption at −196 °C and zeta potential (ZP) measurements. The systems were evaluated for the photodegradation of rhodamine B (RhB). Among the tested systems, the highest percentage of dye degradation was reached by the catalyst prepared with foundry sand supports, with values of 65% under ultraviolet and 39% under visible radiation, whereas under the same conditions, the catalyst prepared with rice husk showed the best photocatalytic performance among the samples prepared with agroindustrial wastes with values of 43% under ultraviolet and 38% under visible radiation. Strong Spearman's correlations among the photocatalytic activity, the zeta potential (ζp > 0.900) and the band gap energy (ζp > 0.895) were observed. Exploratory tests with tap water samples revealed that the system may be sensitive to other analytes present in these environmental samples.

Sol-Gel Synthesis of Na2Ta4O11 Nanocrystals Showing High Efficient Photocatalytic Performance

2014 ◽  
Vol 1058 ◽  
pp. 35-39 ◽  
Author(s):  
Yi Guo Su ◽  
Xu Yang ◽  
Ting Ting Wang ◽  
Bao Ling Zhu ◽  
Xiao Jing Wang
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Active Species ◽  
Gap Energy ◽  
High Efficient ◽  
Sol Gel Synthesis

Semiconductors showing high efficient photocatalytic activity have attracted great interest, because they provide a potential solution to many environmental pollution problems that humankind is currently facing. This work reports on the sol-gel synthesis of Na2Ta4O11 nanocrystals and its photocatalytic performance toward Red G. The samples were carefully characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, and the Barrett–Emmett–Teller technique. By modulating the synthetic condition, the sol-gel reaction yielded pure Na2Ta4O11 nanocrystals with diameter of ~32 nm from the peak broadening of (006) plane using Scherrer formula. It is found that the as-prepared Na2Ta4O11 nanocrystals showed a band gap energy of 3.63 eV, which is much smaller than that of Na2Ta4O11 prepared by flux approach. The relative narrowed band gap energy of Na2Ta4O11 nanocrystals may predict superior photocatalytic activity. By careful photocatalytic test, it is found that Na2Ta4O11 nanocrystals showed excellent photocatalytic activity toward Red G. The photocatalytic degradation efficiency was estimated to be 94.0% within a time intervals of 40 minutes. Controlled experiment by adding active species scavengers gave evidence that the degradation of Red G is dominated by the oxidation reaction of the generated O2-∙ active species taking place on the surface of the photocatalyst.

scholarly journals Study of the Effect of TiO2 Layer on the Adsorption and Photocatalytic Activity of TiO2-MoS2 Heterostructures under Visible-Infrared Light

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
N. Cruz-González ◽  
O. Calzadilla ◽  
J. Roque ◽  
F. Chalé-Lara ◽  
J. K. Olarte ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Nitrogen Adsorption ◽  
High Photocatalytic Activity ◽  
Infrared Light ◽  
Polluted Water ◽  
Light Spectrum ◽  
X Ray

In the last decade, the urgent need to environmental protection has promoted the development of new materials with potential applications to remediate air and polluted water. In this work, the effect of the TiO2 thin layer over MoS2 material in photocatalytic activity is reported. We prepared different heterostructures, using a combination of electrospinning, solvothermal, and spin-coating techniques. The properties of the samples were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms, UV-Vis diffuse reflectance spectroscopy (UV-Vis-DRS), and X-ray photoelectron spectroscopy (XPS). The adsorption and photocatalytic activity were evaluated by discoloration of rhodamine B solution. The TiO2-MoS2/TiO2 heterostructure presented three optical absorption edges at 1.3 eV, 2.28 eV, and 3.23 eV. The high adsorption capacity of MoS2 was eliminated with the addition of TiO2 thin film. The samples show high photocatalytic activity in the visible-IR light spectrum.

Photocatalytic Degradation of Methylene Blue over Co-Ag3VO4 under Visible Light Irradiation

2011 ◽  
Vol 335-336 ◽  
pp. 1385-1390 ◽  
Author(s):  
Shuo Wiei Zhao ◽  
Hui Xu ◽  
Hua Ming Li ◽  
Yuan Guo Xu
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Absorption Edge ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Light Irradiation ◽  
Experimental Conditions ◽  
X Ray

In order to improve the photocatalytic activity, Co was successfully loaded into Ag3VO4 by using impregnation process. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS) and diffuse reflectance spectroscopy (DRS). The XRD and SEM–EDS analyses revealed that Co ion was dispersed on Ag3VO4. The DRS results indicated that the absorption edge of the Co–Ag3VO4 catalyst shifted to longer wavelength. The enhanced photocatalytic activity of Co–Ag3VO4 for Methylene Blue(MB) dye degradation under visible light irradiation was due to its wider absorption edge and higher separation rate of photo-generated electron and holes. In the experimental conditions, it is demonstrated that the MB was effectively degraded by more than 95% within 40 min when the Co–Ag3VO4 catalyst was calcined at 300°C with 1 wt.% Co content.

Enhanced visible-active photocatalytic behaviors observed in Mn-doped BiFeO3

2018 ◽  
Vol 32 (17) ◽  
pp. 1850185 ◽  
Author(s):  
Yun-Hui Si ◽  
Yu Xia ◽  
Ya-Yun Li ◽  
Shao-Ke Shang ◽  
Xin-Bo Xiong ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Mn Doped ◽  
Hole Recombination ◽  
Narrow Band Gap Semiconductors

A series of BiFeO3 and BiFe[Formula: see text]Mn[Formula: see text]O3 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by a hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and UV–Vis diffuse reflectance spectroscopy, and their photocatalytic activity was studied by photocatalytic degradation of methylene blue in aqueous solution under visible light irradiation. The band gap of BiFeO3 was significantly decreased from 2.26 eV to 1.90 eV with the doping of Mn. Furthermore, the 6% Mn-doped BiFeO3 photocatalyst exhibited the best activity with a degradation rate of 94% after irradiation for 100 min. The enhanced photocatalytic activity with Mn doping could be attributed to the enhanced optical absorption, increment of surface reactive sites and reduction of electron–hole recombination. Our results may be conducive to design more efficient photocatalysts responsive to visible light among narrow band gap semiconductors.

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