scholarly journals Combination of mesoporous titanium dioxide with MoS2 nanosheets for high photocatalytic activity

2017 ◽  
Vol 19 (2) ◽  
pp. 56-60 ◽  
Author(s):  
Loghman Karimi
Keyword(s):  
Electron Microscopy ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Dye Degradation ◽  
Hydrothermal Process ◽  
Bet Analysis ◽  
Mesoporous Titanium Dioxide

Abstract This study presents a facile approach for the preparation of MoS2 nanosheet decorated by porous titanium dioxide with effective photocatalytic activity. Mesoporous titanium dioxide nanostructures first synthesized by a hydrothermal process using titanium (III) chloride and then the MoS2/TiO2 were prepared through mixing of MoS2 nanosheet with mesoporous titanium dioxide under ultrasonic irradiation. The synthesized nanocomposite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), and Brunauer-Emmett-Teller (BET) analysis. The results showed that the nanocomposite has mesoporous structure with specific surface area of 176.4 m2/g and pore diameter of 20 nm. The as-prepared MoS2/TiO2 nanocomposites exhibited outstanding photocatalytic activity for dye degradation under sunlight irradiation, which could be attributed to synergistic effect between the molybdenum disulfide nanosheet and mesoporous titanium dioxide. The photocatalytic performance achieved is about 2.2 times higher than that of mesoporous TiO2 alone. It is believed that the extended light absorption ability and the large specific surface area of the 2D MoS2 nanosheets in the nanocomposite, leading to the enhanced photocatalytic degradation activity.

scholarly journals Titanium dioxide modified with manganese: physicochemical and photocatalytic properties

2021 ◽  
Vol 12 (2-2021) ◽  
pp. 214-218
Author(s):  
S. A. Safaryan ◽  
◽  
M. L. Belikov ◽  
V. A. Krysanova ◽  
◽  
...  
Keyword(s):  
Methylene Blue ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Phase Composition ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Organic Dyes ◽  
Photocatalytic Properties

The article presents the results of the studies of the physicochemical and photocatalytic properties of titanium dioxide modified with manganese, by the example of decomposition of organic dyes — ferroin and methylene blue. The correlations between the specific surface area and phase composition of the composites with their photocatalytic activity are revealed.

scholarly journals Synthesis and Characterization of Uniform Spherical Nanoporous TiO2Aerogel Templated by Cellulose Alcohol-Gel with Enhanced Photocatalytic Activity

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Zhiming Liu ◽  
Peng Wu ◽  
Shaoli Yang ◽  
Haiying Wang ◽  
Chunde Jin
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Thermal Method ◽  
X Ray ◽  
Double Beam ◽  
Methyl Orange Dye

The spherical nanoporous TiO2aerogels were prepared by a simple ethanol-thermal method, using spherical cellulose alcohol-gel as the template. The morphology, crystalline structure, pore size, specific surface area, and the photocatalytic activity of obtained TiO2aerogel were separately characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2adsorption-desorption isotherms, and double beam UV-VIS spectrophotometer. The characteristics of TiO2aerogels presented uniform sphere shape, good internal structural morphology, high specific surface area (ranging from 111.88 to 149.95 m2/g), and good crystalline anatase phase. Moreover, methyl orange dye was used as the target pollutant to characterize the photocatalytic activities and the adsorption performance. The photocatalytic experiment shows that the obtained spherical TiO2aerogels had a higher degradation ratio of 92.9% on methyl orange dye compared with aspherical TiO2aerogels prepared from other concentrations of tetrabutyl orthotitanate (TBOT).

New Silica Supported Titanium Dioxide Catalysts: Characteristics and Photocatalytic Efficiency in Waste Water Depollution

2006 ◽  
Vol 61 (10) ◽  
pp. 1311-1318 ◽  
Author(s):  
Noureddine Kamil ◽  
Mohamed Khalid El Amrani ◽  
Najiba Benjelloun
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Inductively Coupled Plasma ◽  
Aqueous Suspension ◽  
Textile Dye ◽  
Photocatalytic Efficiency

Silica gel supported titanium dioxide photocatalysts were prepared by sintering TiO2/SiO2 mixtures under variations of TiO2 content, calcination temperature and calcination time. The method allowed to obtain catalyst samples, which can be used in aqueous suspension and which were found to be easily separated by decantation after the photocatalytic treatment. The photocatalytic efficiency of the catalysts was tested by carrying out the photooxidation of the textile dye Acid Red 88 (AR88) in aqueous solution, used as “model” water pollutant. The obtained photoefficiency results were correlated to catalyst physicochemical characteristics, as determined by Inductively Coupled Plasma (ICP) analysis, X-ray diffraction, specific surface area (BET) and scanning electron microscopy (SEM). No positive correlation has been observed between titanium dioxide content and photocatalytic efficiency. The decrease of photocatalytic activity at high calcination temperature (1000 °C) is attributed to the phase transition anatase/rutile as well as to the decreasing specific surface area. According to SEM analysis, no significant fixation of TiO2 on silica is observed for catalysts prepared at low temperature (400 °C). The observed photocatalytic activity is consequently due to free TiO2 particles. The best efficiency is observed for photocatalyst prepared at 800 °C and containing around fifty percent titanium dioxide.

scholarly journals Evaluation of the photocatalytic activity of concrete

2021 ◽  
Vol 6 (4) ◽  
pp. 13-20
Author(s):  
E. Krushel'nickaya
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Ultraviolet Radiation ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Concrete Surface ◽  
High Specific Surface Area ◽  
Foreign Manufacturer ◽  
Over Time

Based on the change in the color of an organic dye – rhodamine B, on the surface of concrete under the action of ultraviolet radiation, a theoretical and experimental assessment of the photocatalytic activity of concrete was carried out. Photocatalytic activity was calculated using the obtained coordinates of colorimetry L * a * b *. To assess the performance of the photocatalyst over time, a test was carried out with concrete samples at the age of 7 and 28 days. Titanium dioxide of three types of anatase modification of a foreign manufacturer was used as a photocatalyst in the study. It is shown that the introduction of titanium dioxide into concrete promotes self-cleaning of its surface. The values of discoloration of the dye on the concrete surface were obtained depending on its composition and on the time of exposure to ultraviolet radiation. It was determined that the value of the specific surface area of titanium dioxide affects the photocatalytic activity. It is noted that with the age of concrete samples, there is a noticeable decrease in phototransformation. It was also found that the high specific surface area of titanium dioxide allows it to exhibit its photocatalytic properties over time.

scholarly journals Photocatalytic activity of spectro-pure titanium dioxide: Effects of crystalline structure, specific surface area and sorption properties

2003 ◽  
Vol 5 (3) ◽  
pp. 159-166 ◽  
Author(s):  
Evgeny I. Kapinus ◽  
Tatyana A. Khalyavka ◽  
Valentina V. Shimanovskaya ◽  
Tatyana I. Viktorova ◽  
Vladimir V. Strelko
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pure Titanium ◽  
Specific Rate ◽  
Two Phase ◽  
Photocatalytic Reactions ◽  
Optically Pure

Dispersed optically pure anatase, rutile and two-phase samples of titanium dioxide were prepared using a sol-gel technique. In particle of two-phase samples, the anatase nuclei are surrounded by a rutile envelope. Content of anatase in the two-phase particles varied between 20 and 80%. Particles of all theTiO2samples had a globular shape of diameter between 10 and 30μm. When compared to the corresponding technical-grade samples, the optically pure anatase and rutile demonstrated higher photocatalytic activity in the destruction of tetradecylpyridinium chloride, Methylene Blue and tetrachlorofluorescein as well as in reduction ofCr2O7,MnO4,[Fe(CN)6]3−and[Fe(CN)6]4−. The photocatalytic reactions bring about the reduction of the inorganic anions to yield water insoluble substances and mineralization of the organic compounds. Rate constant of the all above processes do not depend on specific surface area ofTiO2and adsorption of the substrates on theTiO2samples. The rutile calcined at 1027K exhibits the highest specific rate constants. Exposure toγ-radiation increases photocatalytic activity of the dispersedTiO2. The influence ofTiO2and substrate on the photocatalytic reactions is caused by the influence of these factors on the formation of reactive electron hole pair and on the efficiency of the interfacial electron transfer.

scholarly journals Efficient Adsorption of Deoxynivalenol by Porous Carbon Prepared from Soybean Dreg

Toxins ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 500
Author(s):  
Zhiwei Ying ◽  
Di Zhao ◽  
He Li ◽  
Xinqi Liu ◽  
Jian Zhang
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Specific Surface Area ◽  
Porous Carbon ◽  
Carbon Material ◽  
Adsorption Effect ◽  
X Ray ◽  
Bet Analysis

A novel porous carbon adsorbent for the removal of deoxynivalenol was prepared from soybean dreg (SD). The new material was characterized by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) analysis, N2 adsorption/desorption measurement techniques, X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The specific surface area of the SDB-6-KOH was found to be 3655.95 m2 g−1, the pore volume was 1.936 cm3 g−1 and the average pore size was 2.125 nm. The high specific surface area and effective functional groups of the carbon material promoted the adsorption of deoxynivalenol. By comparing the adsorption effect of SDB-6-X prepared with different activators (X: KOH, K2CO3, KHCO3), SDB-6-KOH had the highest adsorption capacity. The maximum adsorption capacity of SDB-6-KOH to deoxynivalenol was 52.9877 µg mg−1, and the removal efficiency reached 88.31% at 318 K. The adsorption kinetic and isotherm data were suitable for pseudo-second-order and Langmuir equations, and the results of this study show that the novel carbon material has excellent adsorptive ability and, thus, offers effective practical application potential for the removal of deoxynivalenol.

scholarly journals Synthesis, Characterization, and Photocatalytic Activity of Zn-Doped SnO2/Zn2SnO4Coupled Nanocomposites

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Tiekun Jia ◽  
Junwei Zhao ◽  
Fang Fu ◽  
Zhao Deng ◽  
Weimin Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Synthesis Method ◽  
Diffuse Reflection Spectroscopy ◽  
Transmission Electron ◽  
20 Nm ◽  
Adsorption Desorption

Zn-doped SnO2/Zn2SnO4nanocomposites were prepared via a two-step hydrothermal synthesis method. The as-prepared samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), UV-vis diffuse reflection spectroscopy, and adsorption-desorption isotherms. The results of FESEM and TEM showed that the as-prepared Zn-doped SnO2/Zn2SnO4nanocomposites are composed of numerous nanoparticles with the size ranging from 20 nm to 50 nm. The specific surface area of the as-prepared Zn-doped SnO2/Zn2SnO4nanocomposites is estimated to be 71.53 m2/g by the Brunauer-Emmett-Teller (BET) method. The photocatalytic activity was evaluated by the degradation of methylene blue (MB), and the resulting showed that Zn-doped SnO2/Zn2SnO4nanocomposites exhibited excellent photocatalytic activity due to their higher specific surface area and surface charge carrier transfer.

scholarly journals Photodegradation of Microcystin-LR Using Visible Light-Activated C/N-co-Modified Mesoporous TiO2 Photocatalyst

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1027 ◽  
Author(s):  
Tamer Khedr ◽  
Said El-Sheikh ◽  
Adel Ismail ◽  
Ewa Kowalska ◽  
Detlef Bahnemann
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Photoelectron Spectroscopy ◽  
Ph Value ◽  
Hydrothermal Process ◽  
Tio2 Photocatalyst ◽  
X Ray

Microcystin-LR (MC-LR), a potent hepatotoxin produced by the cyanobacteria, is of increasing concern worldwide because of severe and persistent impacts on humans and animals by inhalation and consumption of contaminated waters and food. In this work, MC-LR was removed completely from aqueous solution using visible-light-active C/N-co-modified mesoporous anatase/brookite TiO2 photocatalyst. The co-modified TiO2 nanoparticles were synthesized by a one-pot hydrothermal process, and then calcined at different temperatures (300, 400, and 500 °C). All the obtained TiO2 powders were analyzed by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscope (TEM), specific surface area (SSA) measurements, ultraviolet-visible diffuse reflectance spectra (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and photoluminescence (PL) analysis. It was found that all samples contained mixed-phase TiO2 (anatase and brookite), and the content of brookite decreased with an increase in calcination temperature, as well as the specific surface area and the content of non-metal elements. The effects of initial pH value, the TiO2 content, and MC-LR concentration on the photocatalytic activity were also studied. It was found that the photocatalytic activity of the obtained TiO2 photocatalysts declined with increasing temperature. The complete degradation (100%) of MC-LR (10 mg L−1) was observed within 3 h, using as-synthesized co-modified TiO2 (0.4 g L−1) at pH 4 under visible light. Based on the obtained results, the mechanism of MC-LR degradation has been proposed.

scholarly journals Graphene Oxide Hybridised TiO2 for Visible Light Photocatalytic Degradation of Phenol

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1420 ◽  
Author(s):  
Guanyu Wang ◽  
Weijie Guo ◽  
Deping Xu ◽  
Di Liu ◽  
Mengtao Qin
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Visible Light ◽  
Specific Surface ◽  
Tio2 Nanoparticles ◽  
Surface Area ◽  
Specific Surface Area ◽  
Phenol Solution ◽  
X Ray

In industrial pollutants, phenol is a kind of degradation-resistant hazardous compound. It is generated during industrial processes in factories and treatment at sewage plants. In this study, we analyse the photocatalytic activity of TiO2 and rGO as a composite for the degradation of phenol. Hybridised titanium dioxide/reduced graphene oxide (TiO2/rGO) nanocomposites were synthesised by a simple hydrothermal method using flake graphite and tetrabutyl titanate as raw materials. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunauer–Emmet–Teller (BET) specific area analysis, Fourier transform infrared spectroscopy (FTIR), Raman, X-ray photoelectron spectroscopy (XPS), photoelectrochemical analysis, and UV–vis diffuse reflectance spectra (DRS) were employed to characterise the physicochemical properties of the as-prepared nanocomposites. The results showed the TiO2/rGO nanocomposites’ significant anatase phase and a small fraction of the rutile phase the same as that of the as-prepared TiO2 nanoparticles. The spherical TiO2 nanoparticles (diameter 20–50 nm) were agglomerated slightly and the agglomerates were anchored on the rGO sheets and dispersed symmetrically. The specific surface area of TiO2/rGO-4% nanocomposites was 156.4 m2/g, revealing a high specific surface area. Oxygen-containing functional groups that existed in TiO2/rGO-4% nanocomposites were almost removed during hydrothermal processing. The photocurrent response of TiO2/rGO-4% was strongest among the TiO2/rGO nanocomposites, and the bandgap of TiO2/rGO-4% was 2.91 eV, showing a redshift of absorption into the visible region, which was in favour of the high photocatalytic activity of TiO2/rGO nanocomposites under visible light (λ > 420 nm). Moreover, the samples were employed to photodegrade phenol solution under visible light irradiation. TiO2/rGO-4% nanocomposite degraded the phenol solution up to 97.9%, and its degradation rate constant was 0.0190 h−1, which had higher degradation activity than that of other TiO2/rGO nanocomposites. This is a promising candidate catalyst material for organic wastewater treatment.

Preparation and Visible Light Activity of Co-Doped Mesoporous TiO2 Photocatalyst

2013 ◽  
Vol 664 ◽  
pp. 690-695 ◽  
Author(s):  
Yi Dan Han ◽  
Lan Bo Di ◽  
Kai Wang ◽  
Xiu Ling Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Doping Amount ◽  
Xps Spectra ◽  
Bet Analysis ◽  
Light Activity ◽  
Co Doped

Co-doped mesoporous TiO2photocatalyst was successfully prepared by an ionic liquid modified sol-gel method from TBOT and Co(NO3)2·6H2O. The Co-doped mesoporous TiO2samples were characterized by TG-DSC, XRD, XPS, BET, UV-Vis and TEM, respectively. TG-DSC and XRD results showed that the mesoporous TiO2samples exhibited high thermal stability, and the samples calcined at 650 oC indicated well-crystallized anatase structure. XPS spectra proved the Co3O4structure of Co in Co-doped mesoporous samples. Large specific surface area was shown from the BET analysis, and the largest specific surface area was obtained when the Co-doping amount was 0.3%. UV-Vis DRS spectra showed that all of the samples exhibited obvious absorption in the visible light range. Photocatalytic activity of the samples was evaluated by photodegradation of MB under visible light (λ>420 nm). Co-doped mesoporous TiO2exhibited high photocatalytic activity for MB oxidation, and the 0.3% Co/TiO2sample showed the highest visible light activity.

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