scholarly journals Enhancement of Visible Light-Responsive Photocatalytic Efficiency by Using a Laccaic Acid-Modified Titanium Dioxide Photocatalyst

2022 ◽  
Author(s):  
Montri Aiempanakit ◽  
Jariyaporn Sangkaworn ◽  
Nattawan Worawannotai ◽  
Kritapas Laohhasurayotin ◽  
Weerachai Sangchay ◽  
...  
Keyword(s):  
Visible Light ◽  
Anatase Phase ◽  
Visible Region ◽  
Nitrogen Adsorption ◽  
Hydroxyl Groups ◽  
Impregnation Method ◽  
Sem Images ◽  
Tio2 Sample ◽  
X Ray ◽  
Xrd Patterns

In this study, a laccaic acid-modified TiO2 photocatalyst (Lac-TiO2) was prepared via an impregnation method with 0.50, 1.00, 2.50, and 5.00 wt.% laccaic acid. The products’ physical properties were examined through X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoemission spectroscopy (XPS), UV-Vis diffused reflectance spectroscopy (DRS), Fourier-transform infrared spectroscopy (FTIR), nitrogen adsorption/desorption, and photoluminescence (PL) spectroscopy. A possible photocatalytic mechanism was also proposed. XRD patterns revealed the anatase phase of TiO2 and Lac-TiO2 samples. High-magnification FE-SEM images showed that the TiO2 and Lac-TiO2 samples exhibited spherical-like structures. XPS results complementarily confirmed the presence of Ti, O, and C as the main elements of the Lac-TiO2 samples. Interestingly, the DRS spectra of the Lac-TiO2 samples extended into the visible region. FTIR spectra presented the characteristic bands of TiO2 and hydroxyl groups on the TiO2 surface. Instead of hydroxyl groups, the characteristic bands of laccaic acid were observed on the surface of the Lac-TiO2 samples. The photocatalytic properties of the Lac-TiO2 samples were evaluated in terms of methyl orange degradation under visible light irradiation. The Lac-TiO2 samples showed higher photocatalytic performance than the TiO2 sample.

Photocatalytic Activity of Sol-Gel Derived Bi2O3-TiO2 Nanocomposite

2012 ◽  
Vol 712 ◽  
pp. 73-83 ◽  
Author(s):  
C. Karunakaran ◽  
P. Magesan ◽  
P. Gomathisankar
Keyword(s):  
Visible Light ◽  
Deep Level ◽  
Anatase Phase ◽  
Sol Gel ◽  
Spherical Shape ◽  
Tween 80 ◽  
Electron Microscopic ◽  
Sem Images ◽  
X Ray ◽  
Crystallite Sizes

Bi2O3-TiO2 nanocomposites were obtained by sol-gel method using tween 80 (T-80) or polyvinyl pyrrolidone-polyethylene glycol (PVP-PEG) as templating agent. The powder X-ray diffraction (XRD) patterns of both the composites reveal the crystal structure of Bi2O3 as primitive tetragonal and TiO2 is in anatase phase. The energy dispersive X-ray (EDX) spectra provide the composition of Bi2O3 in Bi2O3-TiO2 (T-80) and Bi2O3-TiO2 (PVP-PEG) as 3.8 and 20.4 mol. %, respectively. The average crystallite sizes of Bi2O3-TiO2 (T-80) and Bi2O3-TiO2 (PVP-PEG), derived from XRD, are 9 and 17 nm, respectively. The scanning electron microscopic (SEM) images show the spherical shape of Bi2O3-TiO2 (T-80) and the composites are polycrystalline. The diffuse reflectance spectra (DRS) of the composites display faint absorption of visible light and strong absorption in UV-A region. The photoluminescence (PL) spectra of both the composites are similar and the observed near band gap emission (NBE) and deep level emission (DLE) agree with those of TiO2. The impedance spectra show that the charge-transfer resistances of the composites do not differ significantly. The visible light photoimpedance spectra display the photoconductance of Bi2O3-TiO2 (PVP-PEG) but not that of Bi2O3-TiO2 (T-80). Although the visible light-photocatalytic activities of the two nanocomposites to degrade dye do not differ significantly Bi2O3-TiO2 (T-80) under UV-A light degrades dyes faster than Bi2O3-TiO2 (PVP-PEG).

scholarly journals Visible Light Induced Photocatalytic Degradation of Methyl Red with Codoped Titania

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Susmitha Thota ◽  
Siva Rao Tirukkovalluri ◽  
Sreedhar Bojja
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Anatase Phase ◽  
Sol Gel ◽  
Visible Region ◽  
Oxygen Demand ◽  
Analytical Techniques ◽  
Active Species ◽  
Methyl Red ◽  
X Ray

Photocatalysis using semiconductor oxides was being investigated extensively for the degradation of dyes in effluent water. This paper reports our findings on visible light induced photocatalytic degradation of azo dye, methyl red mediated nitrogen and manganese codoped nano-titanium dioxide (N/Mn-TiO2). The codoped samples with varying weight percentages were synthesized by sol-gel method and characterized by various analytical techniques. The X-ray diffraction data showed that the synthesized samples were in anatase phase with 2θ at 25.3°. UV-visible diffuse reflectance spectral analysis revealed that the presence of dopants in TiO2 caused a significant absorption shift towards visible region and their presence was confirmed by X-ray photoelectron spectral data. The release of hydroxyl radical (major active species in photocatalytic degradation) by the photocatalyst in aqueous solution under visible light irradiation was quantitatively investigated by the photoluminiscent technique (PL). The effect of various experimental parameters like dopant concentration, pH, catalyst dosage, and initial dye concentrations was investigated and optimum conditions were established. The extent of mineralization of methyl red was studied by chemical oxygen demand (COD) assays and the results showed complete mineralization of the dye.

scholarly journals Mesoporous Ce-doped Ti:Ash Photocatalyst Investigation in Visible Light Photocatalytic Water Pretreatment Process

2020 ◽  
Vol 15 (2) ◽  
pp. 367-378
Author(s):  
Abdulkarim Abdulrahman Mohamed Suliman ◽  
Ruzinah Isha ◽  
Mazrul Nizam Abu Seman ◽  
Abdul Latif Ahmad ◽  
Jamil Roslan
Keyword(s):  
Visible Light ◽  
Visible Region ◽  
Impregnation Method ◽  
Wet Impregnation ◽  
X Ray ◽  
Weight Percentage ◽  
Water Pretreatment ◽  
Defect Sites ◽  
Adsorption Desorption ◽  
Wet Impregnation Method

The treatment of organic pollutants in water including semiconductor photocatalysis is a promising approach to disinfect water. The objective of this study is to investigate the effect of Ce loaded on mesoporous Ti:Ash catalyst for water pretreatment process. The mesoporous Ti:Ash catalyst that doped with Ce was synthesized through wet impregnation method with 5%, 10%, and 15% weight percentage of Ce doped on 40:60 Ti:Ash. The photocatalytic properties were characterized through X-ray powder diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy, N2 adsorption-desorption studies and diffuse reflectance UV–vis absorption spectroscopy. It is found that the Ti:Ash nanocomposites doped with Ce shifted the light absorption band-edge position to the visible region. Moreover, the Ce doped Ti:Ash has large surface area and pore diameter. The Ce doping could significantly improve the absorption edge of visible light and adjust the cut-off absorption wavelength from 404 nm to 451, 477 and 496 nm for 5%, 10% and 15% Ce-doped mesoporous Ti:Ash catalysts, respectively. As the Ce doping ratio increased, the band gaps decreased from 3.06 eV to 2.53 eV. The most contaminant reduction up to 45% was achieved when Ti:Ash:Ce 40:55:5 was used. Higher Ce loading on the photocatalyst may reduce the photocatalyst performance because supernumerary metal loading on TiO2 can block TiO2 defect sites which are necessary for the adsorption and photoactivation. The OPFA also acts as an adsorbent for some pollutants besides, reducing the water salinity. It can be deduced that the hybrid TiO2 photocatalyst that synthesized with OPFA and doped with Ce has huge potential to treat seawater prior to commercial seawater desalination process. Copyright © 2020 BCREC Group. All rights reserved 

scholarly journals MoS2/Cu/TiO2 nanoparticles: synthesis, characterization and effect on photocatalytic decomposition of methylene blue in water under visible light

2018 ◽  
Vol 2017 (1) ◽  
pp. 184-193 ◽  
Author(s):  
Desireé M. de los Santos ◽  
Sara Chahid ◽  
Rodrigo Alcántara ◽  
Javier Navas ◽  
Teresa Aguilar ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Tio2 Nanoparticles ◽  
Visible Region ◽  
Pure Tio2 ◽  
Photocatalytic Decomposition ◽  
Tio2 Sample ◽  
X Ray ◽  
Vis Spectroscopy

Abstract Photodegradation processes are of great interest in a range of applications, one of which is the photodecomposition of pollutants. For this reason, analysing nanoparticles that improve the efficiency of these processes under solar radiation are very necessary. Thus, in this study, TiO2 was doped with Mo and Cu using low-temperature hydrolysis as the method of synthesis. Pure TiO2 and x%MoS2/Cu/TiO2 nanoparticles were prepared, where x is the theoretical quantity of MoS2 added (0.0%, 1.0%, 5.5%, 10.0%), setting the nominal quantity of Cu at 0.5 wt.%. The samples obtained were characterized by X-ray diffraction, Raman spectroscopy, X-ray electron spectroscopy and UV-Vis spectroscopy in diffuse reflectance mode. The results suggest that the TiO2 structure was doped with the Mo6+ and Cu2+ ions in the position of the Ti4+. The x%MoS2/Cu/TiO2 samples presented lower band gap energy values and greater optical absorption in the visible region than the pure TiO2 sample. Lastly, the photocatalytic activity of the samples was assessed by means of the photodegradation of methylene blue under visible light. The results show that when the quantity of Mo in the co-doped samples increased (x%MoS2/Cu/TiO2) there were significant increases of up to 93% in the photocatalytic activity.

Study on Magnetic Mn0.2Co0.8Fe2O4/Silicalite-2 Catalyst and its Electro-Catalytic Property

2013 ◽  
Vol 669 ◽  
pp. 30-33
Author(s):  
Yue Cheng ◽  
Shun Long Pan ◽  
Yuan Zhou
Keyword(s):  
Impregnation Method ◽  
Dye Wastewater ◽  
Nano Particle ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Heterogeneous Catalytic ◽  
Initial Ph ◽  
Xrd Patterns ◽  
Electrolysis System

Silicalite-2 zeolite was hydrothermally synthesized and Mn0.2Co0.8Fe2O4 magnetic nano-particle based on the Silicalite-2 zeolite carrier was prepared by a coprecipitation-impregnation method. The morphologies and microstructures of synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM). The heterogeneous catalytic oxidation electrolysis system of Mn0.2Co0.8Fe2O4/silicalite-2 was built by dispersing the catalysts in glass reactor for treating cationic brilliant red X-5GN wastewater. The SEM images showed that the structure of silicalite-2 zeolite remained its original after the introduction of Mn0.2Co0.8Fe2O4 magnetic particle. The XRD patterns revealed that Mn0.2Co0.8Fe2O4 oxides could not be observed on the surface of the silicalite-2 zeolite carrier. The experimental results showed that the dye wastewater with a satisfied decolorization rate (79.1%) was obtained when the initial pH was 6, the magnetic catalyst dosage was 0.4g/L, the electrolysis voltage was 2V, electrolytic time was 45min, respectively.

SYNTHESIS OF MESOPOROUS OF NyTi1–xCexO2–y STRUCTURES AND ITS VISIBLE LIGHT INDUCED PHOTOCATALYTIC PERFORMANCE

NANO ◽  
2013 ◽  
Vol 08 (05) ◽  
pp. 1350051 ◽  
Author(s):  
R. RANGEL ◽  
J. D. GARCÍA-ESPINOZA ◽  
I. ESPITIA ◽  
P. QUINTANA ◽  
P. BARTOLO-PÉREZ ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Anatase Phase ◽  
Visible Region ◽  
Textural Properties ◽  
Band Gap Energy ◽  
X Ray ◽  
Xrd Diffraction

The present work was addressed to study the visible light induced performance as photocatalysts of mesoporous N y Ti 1–x Ce x O 2–y structures obtained under microwave irradiation. The titanium dioxide ( TiO 2) was doped with cerium and nitrogen in order to improve the quantum efficiency of the TiO 2 and to shift its adsorption spectra to the visible region. The prepared meso-powders were analyzed by means of X-ray diffraction (XRD), scanning Electron microscopy (SEM), infrared (IR) spectroscopy, transmission electronic microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The surface area was evaluated by means of the Brunauer-Emmett-Teller (BET) method and ultraviolet (UV)-visible diffuse reflectance measurements were performed in order to determine the band gap energy. In addition, the photocatalytic activity of the samples was evaluated by monitoring the photodegradation of methylene blue (MB) under UV and visible light energy irradiation. The results show that our methodology is an effective way for incorporating cerium and nitrogen into TiO 2 compound, which in turn, increases its photocatalytic activity. The diffuse reflectance analysis confirms that the absorption edge was shifted towards the visible region of the optical spectrum. The XRD diffraction patterns indicate homogeneous solid solutions in which prevails the anatase phase. It was observed a reduction in crystal size from 13.1 nm to 7.7 nm for N y Ti 0.98 Ce 0.02 O 2–y in comparison to TiO 2. The textural properties of the synthesized compounds were determined, by means of adsorption isotherms indicating the formation of mesoporous structures. IR spectra show characteristic vibration signals attributed to Ti–O–Ti bonds, as well as vibrations assigned to cerium and nitrogen bonds. The XPS analyses evidence the presence of Ce 3+/ Ce 4+ redox couple and Ti–N bonds. The photocatalityc efficiency was evaluated in the degradation of MB monitoring the absorbance change at 664 nm. The degradation of this compound was 91.4% using N y Ti 0.98 Ce 0.02 O 2–y as photocatalyst under UV energy in 90 min. Also 38.7% of MB degradation was achieved in 150 min under visible light radiation.

Preparation of Visible Light Responsive Photocatalyst from Titanium Dioxide Nanotubes Modified with Antimony Trisulfide

2018 ◽  
Vol 792 ◽  
pp. 98-103
Author(s):  
Narudon Saijaioup ◽  
Puangrat Kajitvitchyanukul ◽  
Apichon Watcharenwong
Keyword(s):  
Titanium Dioxide ◽  
Visible Light ◽  
Anatase Phase ◽  
Visible Region ◽  
Light Response ◽  
Ethanol Solution ◽  
Halogen Lamp ◽  
X Ray ◽  
Self Organized ◽  
Anodization Process

Titanium dioxide (TiO2) nanotubes with a highly ordered structure were grown by a self-organized anodization process. The photodeposition process was used to improve the visible light response of titanium dioxide (TiO2) nanotubes. The irradiation was carried out with 500 W halogen lamp for 1, 5, 15, 30 and 60 min in the mixed ethanol solution of antimony trisulfide (Sb2S3). The obtained samples were annealed at 250 °C for 30 min. The morphology of the fabricated sample was characterized by a field emission scanning electron microscope (FE-SEM). The phase of samples was determined by X- ray diffractometer (XRD). The weight percentages of a component in the sample were measured by X-ray fluorescence spectrometry (XRF). UV-Vis diffuse reflectance spectra (DRS) of the samples were recorded. All titanium dioxide (TiO2) nanotube samples prepared by anodization process were anatase phase. All composite titanium dioxide (TiO2) nanotube /Sb2S3samples were a crystalline phase. The percentage of Sb and S increase with increasing of photodeposition’s time. The increasing photodeposition of antimony trisulfide (Sb2S3) on titanium (TiO2) nanotubes from 1 to 60 min lead to increasing of photoabsorption property of the material in the visible region.

scholarly journals Preparation of Cerium Modified Titanium Dioxide Nanoparticles and Investigation of Their Visible Light Photocatalytic Performance

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Jinfeng Liu ◽  
Haiyan Li ◽  
Qiuye Li ◽  
Xiaodong Wang ◽  
Min Zhang ◽  
...  
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Titanium Dioxide Nanoparticles ◽  
Spectral Response ◽  
Anatase Phase ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Bet Surface Area ◽  
X Ray ◽  
Adsorption Desorption

Mesoporous CeOx/TiO2nanoparticles have been successfully synthesized using titanate nanotubes as precursor through the hydrothermal-calcination method. The as-prepared materials were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), UV-vis diffuse reflectance spectra and nitrogen adsorption-desorption isotherm analysis. All the obtained CeOx/TiO2materials exhibit anatase phase. Ce element existed in two valance states of Ce3+and Ce4+. Introduction of Ce species can effectively extend the spectral response from UV to visible light region. N2adsorption-desorption analysis revealed that all the samples belong to mesoporous structure and have large BET surface area compared with P25. The CeOx/TiO2nanoparticles showed excellent photocatalytic activity in the degradation of MB under visible light irradiation.

scholarly journals Photocatalytic Degradation of Dichlorvos in Visible Light byMg2+-TiO2Nanocatalyst

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
T. Siva Rao ◽  
Teshome Abdo Segne ◽  
T. Susmitha ◽  
A. Balaram Kiran ◽  
C. Subrahmanyam
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Visible Region ◽  
Sem Images ◽  
Xps Spectra ◽  
X Ray ◽  
Adsorption Desorption

Photocatalytic activity of TiO2was studied by doping with magnesium (Mg2+-TiO2) with varying magnesium weight percentages ranging from 0.75–1.5 wt%. The doped and undoped samples were synthesized by sol-gel method and characterized by X-ray diffraction (XRD), N2adsorption-desorption (BET), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (DRS), and scanning electron microscopy (SEM). The XRD data has shown that anatase crystalline phase in Mg2+-TiO2catalysts, indicating that Mg2+ions did not influence the crystal patterns of TiO2. The presence of magnesium ions in TiO2matrix has been determined by XPS spectra. DRS spectra showed that there is a significant absorption shift towards the visible region for doped TiO2. The SEM images and BET results showed that doped catalyst has smaller particle size and highest surface area than undoped TiO2. The photocatalytic efficiency of the synthesized catalysts was investigated by the photocatalytic degradation of aqueous dichlorvos (DDVP) under visible light irradiation, and it was found that the Mg2+-doped catalysts have better catalytic activity than undoped TiO2. This can be attributed that there is a more efficient electron-hole creation in Mg2+-TiO2in visible light, contrary to undoped TiO2which can be excited only in UV irradiation. The effect of dopant concentration, pH of solution, dosage of catalysts, and initial pesticide concentration has been studied.

scholarly journals Synthesis of N/Fe Comodified TiO2Loaded on Bentonite for Enhanced Photocatalytic Activity under UV-Vis Light

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Xi Cao ◽  
Chen Liu ◽  
Yandi Hu ◽  
Wenli Yang ◽  
Jiawei Chen
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Sol Gel ◽  
Visible Region ◽  
Nitrogen Adsorption ◽  
Single Element ◽  
Photocatalytic Efficiency ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Contaminant Degradation

To improve the efficiency of TiO2as a photocatalyst for contaminant degradation, a novel nanocomposite catalyst of (N, Fe) modified TiO2nanoparticles loaded on bentonite (B-N/Fe-TiO2) was successfully prepared for the first time by sol-gel method. The synthesized B-N/Fe-TiO2catalyst composites were characterized by multiple techniques, including scanning electron microscope (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), X-ray fluorescence (XRF), nitrogen adsorption/desorption, UV-Vis diffuse reflectance spectra (DRS), and electron paramagnetic resonance (EPR). The results showed that bentonite significantly enhanced the dispersion of TiO2nanoparticles and increased the specific surface area of the catalysts. Compared with nondoped TiO2, single element doped TiO2, or unloaded TiO2nanoparticles, B-N/Fe-TiO2had the highest absorption in UV-visible region. The photocatalytic activity of B-N/Fe-TiO2was also the highest, based on the degradation of methyl blue (MB) at room temperature under UV and visible light irradiation. In particular, the synthesized B-N/Fe-TiO2showed much greater photocatalytic efficiency than N/Fe-TiO2under visible light, the newly synthesized B-N/Fe-TiO2is going to significantly increase the photocatalytic efficiency of the catalyst using sun light.

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