scholarly journals The Simplest Way to Iodine-Doped Anatase for Photocatalysts Activated by Visible Light

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Václav Štengl ◽  
Tomáš Matys Grygar
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Aqueous Suspension ◽  
Organometallic Compounds ◽  
Orange Ii ◽  
Iodine Doping ◽  
Doped Titania

Iodine-doped TiO2was prepared by thermal hydrolysis of aqueous solutions of the titanium peroxo-complex, which includes no organic solvents or organometallic compounds. The synthesized samples were characterized by X-ray diffraction (XRD), Raman spectroscopy (RS), infrared spectroscopy (IR), specific surface area (BET), and porosity determination (BJH). The morphology and particle size was determined by high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED). All prepared samples have a red-shifted band-gap transition, well crystalline anatase structure, and porous particles with a 100–200 m2 g−1specific surface area. The photocatalytic activity of iodine-doped titania samples was determined by decomposition of Orange II dye during irradiation at 365 nm and 400 nm. Iodine doping promotes the titania photocatalytic activity very efficiently under visible light irradiation. The titania sample with 0.32 wt.% I has the highest catalytic activity during the photocatalyzed degradation of Orange II dye in an aqueous suspension in the UV and visible regions.

Enhanced photocatalytic activity of a hollow TiO2–Au–TiO2 sandwich structured nanocomposite

RSC Advances ◽  
2016 ◽  
Vol 6 (23) ◽  
pp. 18958-18964 ◽  
Author(s):  
Qianqian Ding ◽  
Yunxia Zhang ◽  
Guozhong Wang ◽  
Hongjian Zhou ◽  
Haimin Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Large Specific Surface Area

The hollow mesoporous TiO2–Au–TiO2 nanospheres with stability, large specific surface area can enhance visible-light-induced photocatalytic activity.

TiO2 composite films on different substrates with enhanced visible light photocatalytic performance

2020 ◽  
Vol 13 (07) ◽  
pp. 2051037
Author(s):  
Ke Han ◽  
Guobao Li ◽  
Fang Li ◽  
Mingming Yao
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Composite Films ◽  
Methyl Green ◽  
Photogenerated Electrons

For the sake of improving the photocatalytic performance of TiO2, we prepared the B/Ag/Fe tridoped TiO2 films on common glass and stone substrates by the sol–gel method. In this work, the optical absorption, recombination of photogenerated electrons (e−) and holes (h[Formula: see text]), crystal types, thermal stability, composition, specific surface area and photocatalytic activity of the modified TiO2 films were investigated. The results indicated that B/Ag/Fe tridoping not only enhanced the absorption of visible light by TiO2, but inhibited the recombination of electron–hole (e−/h[Formula: see text]) pairs. The tridoping also promoted the formation of anatase and prevented the transformation of anatase to rutile at high temperature. The composite TiO2 has a large specific surface area, about three times that of pure TiO2. The photocatalytic activity of the TiO2 films were evaluated by methyl green (MG) and formaldehyde degradation. In all samples, the B/Ag/Fe tridoped TiO2 film exhibited the highest degradation rate of MG under both ultraviolet and visible light irradiation. The improvement of photocatalytic performance of TiO2 films is due to the synergistic effect of the B/Ag/Fe tridoping, which enhances the absorption of visible light and prolongs the lifetime of e−/h[Formula: see text] pairs and facilitates transfer of interface charge.

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 Three-Dimensional Zn0.5Cd0.5S/Reduced Graphene Oxide Hybrid Aerogel: Facile Synthesis and the Visible-Light-Driven Photocatalytic Property for Reduction of Cr(VI) in Water

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Wei Xiao ◽  
Wenjie Zhou ◽  
Yanhua Zhang ◽  
Liangliang Tian ◽  
Hongdong Liu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Visible Light ◽  
Specific Surface ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Specific Surface Area ◽  
Three Dimensional ◽  
Reduced Graphene ◽  
Visible Light Driven

A series of three-dimensional ZnxCd1-xS/reduced graphene oxide (ZnxCd1-xS/RGO) hybrid aerogels was successfully synthesized based on a one-pot hydrothermal approach, which were subsequently used as visible-light-driven photocatalysts for photoreduction of Cr(VI) in water. Over 95% of Cr(VI) was photoreduced by Zn0.5Cd0.5S/RGO aerogel material within 140 min, and such photocatalytic performance was superior to that of other ZnxCd1-xS/RGO aerogel materials (x≠0.5) and bare Zn0.5Cd0.5S. It was assumed that the enhanced photocatalytic activity of Zn0.5Cd0.5S/RGO aerogel was attributed to its high specific surface area and the preferable synergetic catalytic effect between Zn0.5Cd0.5S and RGO. Besides, Zn0.5Cd0.5S/RGO aerogel materials were robust and durable enough so that they could be reused several times with merely limited loss of photocatalytic activity. The chemical composition, phase, structure, and morphology of Zn0.5Cd0.5S/RGO aerogel material were carefully examined by a number of techniques like XRD, SEM, TEM, BET, Raman characterizations, and so on. It was found that Zn0.5Cd0.5S/RGO aerogel possessed hierarchically porous architecture with the specific surface area as high as 260.8 m2 g−1. The Zn0.5Cd0.5S component incorporated in Zn0.5Cd0.5S/RGO aerogel existed in the form of solid solution nanoparticles, which were uniformly distributed in the RGO matrix.

scholarly journals Development of a novel photocatalyst for the photocatalytic treatment of industrial wastewater

2021 ◽  
Author(s):  
Mohsen Nasirian
Keyword(s):  
Photocatalytic Activity ◽  
Transition Metal ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mass Ratio ◽  
Thermal Synthesis ◽  
Composite Photocatalyst ◽  
X Ray

Heterogeneous semiconductor photocatalysts have been shown to be efficient for the degradation of refractory organics into simple compounds. Among all photocatalysts, TiO2 is the most used one. Two issues that arise with the use of unmodified TiO2 as a photocatalyst are the unwanted fast recombination of electron/hole pairs and the lower effectiveness in the presence of visible light irradiation. Doping a transition metal or a non-metal into TiO2 and its combination with another photocatalyst have been used to enhance its photoactivity. This study is to develop a new photocatalyst by the combination of TiO2 with another semiconductor oxide (Fe2O3) and its doping with transition metal such as Ag. Combined photocatalysts of Fe2O3 /TiO2 (with different mass ratio of Fe:TiO2) is synthesized and then silver ion is doped to combine photocatalysts (with different mass ratio of Ag:TiO2) to produce a new composite photocatalyst of Ag/TiO2/Fe2O3. A new method of UV-assisted thermal synthesis is also employed to prepare the new composite photocatalyst. Methyl orange (MO) and Congo red (CR), as model pollutants, are used to test the developed photocatalyst. In addition, nitrogen-doped titanium dioxide photocatalyst (N-TiO2) with heterojunction structures is synthesized by three different approaches including new UV-assisted thermal synthesis, annealing, and microwave techniques. The novel UV-assisted thermal synthesis has produced encouraging results as a preparation method to prepare N-TiO2 at lower temperature and atmospheric pressure as well as a lower cost. Design of Experiment (DOE) along with response surface methodology (RSM) is used to optimize the photocatalytic activity of N-TiO2 as well as the affecting parameters (wavelength, light intensity, pH, and initial TOC) for decomposition of organics. The structure of all synthesized composite photocatalysts are investigated by X-ray diffraction (XRD). Scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS) is employed to evaluate surface characteristics and elemental analysis of synthesized photocatalysts. Specific surface area of photocatalysts is measured based on Brunauer, Emmett and Teller (BET) technique. Results show that bare TiO2 has the lowest photocatalytic activity in degradation of organics. When silver is doped to TiO2, the degradation of MO is slightly enhanced at specific mass ratio. The presence of Fe2O3 in the new composite causes a red shift and enhances the potential to absorb higher range of visible light. Results from XRD confirmed that Fe3+ substitutes with Ti4+ in the crystal lattice of TiO2 and crystal defect occurs. The degradation of MO in presence of Ag/TiO2/Fe2O3 (Ag/TiO2=0.005 w:w and Fe:TiO2= 0.01 w:w) reached to 95.6% under sunlight in three hours with a red shift towards visible light. It is observed that there is an optimum specific surface area of photocatalysts by doping and combining photocatalysts.

scholarly journals Photocatalytic activity of BiFeO3/ZnFe2O4 nanocomposites under visible light irradiation

RSC Advances ◽  
2018 ◽  
Vol 8 (13) ◽  
pp. 6988-6995 ◽  
Author(s):  
B. Safizade ◽  
S. M. Masoudpanah ◽  
M. Hasheminiasari ◽  
A. Ghasemi
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Photocatalytic Efficiency

BiFeO3-25 wt% ZnFe2O4 exhibits a low specific surface area, high magnetization, and maximum photocatalytic efficiency of 97%.

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.

One-Pot Fabrication of K-Doped g-C3N4/SiO2Composite with Enhanced Photocatalytic Activity for Degradation of Tetracycline

2021 ◽  
Vol 43 (2) ◽  
pp. 124-124
Author(s):  
Min keng He Min keng He ◽  
Jin Zhang Jin Zhang ◽  
Fang yan Chen Fang yan Chen ◽  
Ke keShu Ke keShu ◽  
Yu bin Tang Yu bin Tang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Specific Surface Area ◽  
Organic Contaminants ◽  
Raw Materials ◽  
Thermal Polymerization ◽  
One Pot

K-doped g-C3N4/SiO2composite (SiO2/K-CN) was synthesized by a facile thermal polymerization with potassium chloride, melamine and nano-silica as raw materials. The as-prepared SiO2/K-CN was characterized by various measures. The photocatalytic activity of SiO2/K-CN was tested via the photocatalytic degradation of tetracycline under visible-light irradiation. The results showed that the specific surface area of SiO2/K-CN catalyst was 28.16m2/g, which is larger than that of pristine K-doped g-C3N4. Both K-doping and silica-combination can reduce the recombination rate of photo-generated electrons-holes pairs and broaden the region of visible light-harvesting. Compared with the pristine K-doped g-C3N4 and composite SiO2/g-C3N4, SiO2/K-CN exhibits distinctly higher photocatalytic activity for degradation of tetracycline. The enhanced photocatalytic performance of SiO2/K-CN is attributed to the increased specific surface area and the synergistic effect of K-doping and silica-combination in both accelerating separation of charged carries and improving visible light-absorption. During photocatalytic degradation of tetracycline, superoxide radicals play the most important role, followed by holes.SiO2/K-CN complex has excellent stability and shows promising application in photocatalytic degradation of organic contaminants in water.

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