scholarly journals Synthesis and Characterization of Electrospun Nanocomposite Nanofibers with Ag Nanoparticles for Photocatalysis Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Srujan Mishra ◽  
S. Phillip Ahrenkiel
Keyword(s):  
Photocatalytic Activity ◽  
Ag Nanoparticles ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Dark Field ◽  
Mixed Phase ◽  
Methyl Red ◽  
Fiber Morphology ◽  
Electrospinning Technique ◽  
Red Dye

Polycrystalline mixed-phase TiO2nanofibers embedded with 2.0% w/v Ag nanoparticles was prepared by the electrospinning technique. Calcination of dry Ag nanoparticles-titanium (IV) isopropoxide/PVP electrospun nanofiber mats in air at for 24 h yielded polycrystalline TiO2/Ag nanofibers. The morphology and distribution of silver nanoparticles were observed by transmission electron microscopy (TEM), scanning TEM (STEM), and high-angle annular dark-field (HAADF) imaging. Mixed-phase anatase and rutile TiO2nanofibers were produced with Ag nanoparticles. High-resolution TEM lattice-fringe measurements showed good agreement with Ag (111), anatase (101), and rutile (110) phases. The photocatalytic activity of TiO2/Ag nanofibers was compared to the photocatalytic activity of pure TiO2nanofibers by studying the photodegradation of methyl red dye under UV light irradiation, in a photoreactor. UV-visible absorbance spectra showed that the rate of decay of the dye in case of photodegradation by TiO2/Ag nanofibers was 10.3 times higher than that by pure TiO2nanofibers. The retaining of the fiber morphology along with the increased surface area due to the addition of Ag nanoparticles can be believed to enhance the photocatalytic oxidation of methyl red dye.

Hydrogen Generation and Pollution Degradation from Wastewater Using TiO2–CuO Nanocomposite

2020 ◽  
Vol 20 (9) ◽  
pp. 5970-5975
Author(s):  
Hassan Koohestani ◽  
Amirabbas Kheilnejad
Keyword(s):  
Hydrogen Production ◽  
Hydrogen Generation ◽  
Uv Light ◽  
Nano Particles ◽  
Methyl Red ◽  
Cyanide Ion ◽  
Electron Hole ◽  
Production Of Hydrogen ◽  
Red Dye ◽  
Photocatalytic Processes

Simultaneous production of hydrogen and degradation of cyanide ion and methyl red dye were successfully accomplished by employing nano-particles of TiO2–CuO under the radiation of UV light. Exploiting composites improves the electron–hole separation and consequently optimizes photocatalytic processes. Furthermore, the simultaneity of several photocatalytic processes decreases the rate of electron–hole recombination. According to the results, more hydrogen was produced in lower pHs. Up to the initial concentration of 0.3 and 0.8 mol/L for methyl red and cyanide ion respectively, the presence of pollutants increased hydrogen production remarkably, while in more concentrations, hydrogen production was independent of concentrations. The rate of hydrogen production decreased with the pass of time which is due to the consumption of holes by pollutants’ molecules, and the effective participation of the electrons in hydrogen production. Accordingly, after 210 min, the amounts of cyanide ion and methyl red declined and the hydrogen production rate decreased from from 17–22 μmol H2/min to 2–3 μmol H2/min.

Preparation and Photocatalytic Activity of Silver Doped TiO2 Nanotubes

2014 ◽  
Vol 618 ◽  
pp. 14-18
Author(s):  
Ying Cao Xu ◽  
Hong You
Keyword(s):  
Acetic Acid ◽  
Photocatalytic Activity ◽  
Light Intensity ◽  
Anodic Oxidation ◽  
Ag Nanoparticles ◽  
Uv Light ◽  
Effect Factors ◽  
Glycerol Water ◽  
Surface Modified

In this paper, highly ordered TiO2 nanotubes were performed by the method of anodic oxidation, using glycerol / water, NH4F as the electrolyte, and Oxidation voltage to 25v for 1h. TiO2 nanotube surface modified by Ag nanoparticles, by using UV light to restore Ag+ to Ag, the Ag+ from AgNO3 solution sputted out by ultrasonic. Ag-doped TiO2 was used to degrade acetic acid concentrations under UV light. Different Ag/TiO2, HAc concentration, and light intensity were selected as effect factors, TiO2 as contrast test.

scholarly journals Volatile Organic Compound (VOC) Removal via Photocatalytic Oxidation Using TiO2 Coated Nanofilms

2017 ◽  
Vol 15 (7) ◽  
pp. 491-501
Author(s):  
Sunun KHAMI ◽  
Wipawee KHAMWICHIT ◽  
Ratthapol RANGKUPAN ◽  
Kowit SUWANNAHONG
Keyword(s):  
Bacterial Cellulose ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Average Particle Size ◽  
Average Particle ◽  
Experimental Conditions ◽  
Electrospinning Technique ◽  
Photocatalytic Reactor ◽  
Toluene Concentration ◽  
Spinning Process

In this paper, toluene removal via photocatalytic oxidation using TiO2 dip coated nanofilms is presented. Nanofilms were synthesized from bacterial cellulose using the electrospinning technique. The physical properties of the nanofilms were analyzed by scanning electron microscopy (SEM). The ratio of bacterial cellulose/nylon used in the spinning process was 0.165:1. The results from SEM showed that the structure of the TiO2 composite nanofilms was rutile crystalline with an average particle size of 20 nm, and synthesized nanofilms had an average size of 20 - 30 nm. The band gap energies of TiO2-dip coated nanofilms ranged from 3.18 - 3.21 eV. SEM results of TiO2 coated nanofilms suggested that the TiO2 was rather uniformly distributed onto the surface of the nanofilms. The actual amount of TiO2 coated on the nanofilms was estimated using thermogravimetric analysis (TGA) for 1x1 cm2 surface area. It was found that 0.1852, 0.2897 and 0.7275 mg of TiO2 were coated on the surface of the nanofilms for 1, 2.5 and 5 % (weight) TiO2 dosage, respectively. The photocatalytic activity of the nanofilms was tested for the removal of gaseous toluene in a photocatalytic reactor. Experimental conditions were set as follows: UV light intensity of approximately 2.7 mW.cm-2, flow rate of 0.2 L.min-1, and an initial toluene concentration of about 200±20 ppm, and a retention time at 200 min. The degradation rate of toluene increased with increasing dosage of TiO2 from 1, 2.5 and 5 %. The nanofilms at a 5 % dosage yielded the highest removal efficiency of 92.71 %, followed by the 2.5 and 1 % dosage, respectively.

scholarly journals Synthesis of NiFe2O4-LDH Composites with High Adsorption and Photocatalytic Activity for Methyl Orange Degradation

Inorganics ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 98 ◽  
Author(s):  
Cristian Valencia-Lopez ◽  
Mario Zafra-Calvo ◽  
María Martín de Vidales ◽  
Verónica Blanco-Gutierrez ◽  
Evangelina Atanes-Sanchez ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Oh Radicals ◽  
Methyl Orange Degradation ◽  
Light Emitting ◽  
Multifunctional Material ◽  
Double Hydroxide ◽  
Remediation Process

The presence of hazardous chemicals in wastewater produced by industrial activities and human metropoles is threating the availability of safe drinking water. The development of a multifunctional material coupling adsorption and photocatalytic activity is hereby particularly promising for the removal of pollutants. We have proved the adsorption and catalytic activity of NiFe2O4-layered double hydroxide (LDH) composite through the degradation of methyl orange (MO) at room temperature under visible light. This degradation is enhanced by using a set of small light-emitting diodes (LEDs) providing a uniform 405 nm UV light. The remediation process is based on a first-step rapid adsorption of MO molecules by the LDH structures followed by the photocatalytic oxidation of the pollutant by the (·OH) radicals produced by the NiFe2O4 semiconductor nanoparticles (NPs). The magnetic properties of the ferrite NPs allow a facile separation of the composite from the liquid media via a simple magnet. NiFe2O4-LDH composite could find wide application as a highly effective adsorbent/oxidizing catalyst operating under visible or near UV light.

scholarly journals Synthesis and Characterization of CeO2-SiO2Nanoparticles by Microwave-Assisted Irradiation Method for Photocatalytic Oxidation of Methylene Blue Dye

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
R. M. Mohamed ◽  
E. S. Aazam
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Irradiation Time ◽  
High Surface ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
Microwave Assisted ◽  
Small Pore

CeO2-SiO2nanoparticles were synthesized for the first time by a facile microwave-assisted irradiation process. The effect of irradiation time of microwave was studied. The materials were characterized by N2adsorption, XRD, UV-vis/DR, and TEM. All solids showed mesoporous textures with high surface areas, relatively small pore size diameters, and large pore volume. The X-ray diffraction results indicated that the as-synthesized nanoparticles exhibited cubic CeO2without impurities and amorphous silica. The transmission electron microscopy (TEM) images revealed that the particle size of CeO2-SiO2nanoparticles, which were prepared by microwave method for 30 min irradiation times, was around 8 nm. The photocatalytic activities were evaluated by the decomposition of methylene blue dye under UV light irradiations. The results showed that the irradiation under the microwave produced CeO2-SiO2nanoparticles, which have the best crystallinity under a shorter irradiation time. This indicates that the introduction of the microwave really can save energy and time with faster kinetics of crystallization. The sample prepared by 30 min microwave irradiation time exhibited the highest photocatalytic activity. The photocatalytic activity of CeO2-SiO2nanoparticles, which were prepared by 30 min irradiation times was found to have better performance than commercial reference P25.

Enhanced Photocatalytic Activity of N/Li2MoO4 Co-doped TiO2 Nanoparticles under Visible Light

2021 ◽  
Author(s):  
Jutarat Kwakkaew ◽  
Matthana Khangkhamano ◽  
Rungrote Kokoo ◽  
Weerachai Sangchay
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Tio2 Nanoparticles ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Visible Region ◽  
Strong Light ◽  
Doped Tio2 ◽  
Vis Spectroscopy ◽  
Wide Range

TiO2-based nanomaterials have been extensively synthesized and used in a wide range of photocatalytic applications. The photocatalytic oxidation process, however, is only activated by irradiation with ultraviolet (UV) light which limits its indoor applications. Herein, to improve such limitations, N/Li2MoO4-doped TiO2 nanoparticles were prepared via sol-gel method. Li2MoO4 concentration was varied. The catalysts were characterized by XRD, XPS, FE-SEM, and UV-Vis spectroscopy. As-synthesized N/Li2MoO4-doped TiO2 catalysts exhibited their crystal sizes of as fine as 20 nm in diameter whereas that of the pure TiO2 was about 35 nm. The absorption ranges of the N/ Li2MoO4-doped catalysts were relocated from UV region toward visible light region. The catalyst with 1 mol% Li2MoO4 offered the highest degradation rate of methylene blue (MB) solution upon visible light irradiation. Its fine crystal size, narrow band gap energy (2.82 eV), high defect concentration, and strong light absorption in visible region are responsible for the enhanced photocatalytic activity of the 1 mol% Li2MoO4.

scholarly journals Photocatalytic Decomposition of Methyl Red Dye by Using Nanosized Zinc Oxide Deposited on Glass Beads in Various pH and Various Atmosphere

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
H. R. Ebrahimi ◽  
M. Modrek
Keyword(s):  
Zinc Oxide ◽  
Uv Light ◽  
Photocatalytic Decomposition ◽  
Methyl Red ◽  
Uv Light Irradiation ◽  
Nanosized Catalysts ◽  
Nanosized Zinc Oxide ◽  
Wastewater Samples ◽  
Red Dye ◽  
Nanosized Zno

Photocatalytic decomposition of methyl red (MR) as a pollutant in wastewater samples is investigated in this study. This photodegradation was investigated in water in neutral, alkaline, and acidic media under external UV light irradiation by zinc oxide nanosized catalysts on granule glass. The effect of four atmosphere types including air, nitrogen, oxygen, and argon was investigated. Finally, it was found that photodecomposition using nanosized ZnO layered on glass is a new alternative route for efficient wastewater treatment. The results showed that the titled dye is degraded by various rate under different atmosphere and pH.

Photocatalytic Degradation of Acetaldehyde by Sol-Gel TiO2 Nanoparticles: Effect of the Physicochemical Properties on the Photocatalytic Activity

2011 ◽  
Vol 691 ◽  
pp. 92-98 ◽  
Author(s):  
R. Carrera ◽  
A.L. Vázquez ◽  
S. Castillo ◽  
E.M. Arce Estrada
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Photocatalytic Oxidation ◽  
Crystal Size ◽  
Uv Light ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Synthesis Method

Nowadays, nanostructured semiconductor materials offer promising opportunities for a new generation of materials such as TiO2nanoparticles with improved properties for their application in the environmental catalysis field. It is well known that the phocatalytic activity of the TiO2nanoparticles is strongly dependent on the surface area, crystal size, phase composition and synthesis method. Thus, the preparation conditions clearly affect the photocatalytic activity of the TiO2nanoparticles. This work deals with the study of the structure of TiO2nanoparticles that were synthesized by the sol-gel method (using isopropanol as solvent), and calcined at 200 and 500°C. The obtained samples were characterized by the XRD-Rietveld refinement, BET and TEM techniques; and tested in the photodecomposition of acetaldehyde. The evaluations were carried out at room temperature by using CH3CHO (300 ppmv), O2(2.0 %) in helium balance in a quartz glass photoreactor (gas phase) with a 365-UV light lamp. According to the results, the sample that presented the highest activity in the photocatalytic oxidation of acetaldehyde (96.4%) was the one annealed at 200 °C. This sample showed the following proportion of phases: anatase (62.88%) with a tetragonal structure (a=0.3790926, b=0.3790926, c=0.9495732) nm; and b) brookite (37.12%) with an orthorhombic structure (a=0.9167624, b=0.5416461, c=0.5210546) nm. The surface area was 189 m2/g and the average crystal size was 7.03 nm. From the results, it can be seen that this material showed high activity in the photocatalytic degradation of acetaldehyde because of: the presence of a mixture of the anatase (higher proportion) and brookite phases, nanometric crystal size and high surface area obtained in this TiO2material. According to the aforementioned, this material can be considered as a good option for the decomposition of acetaldehyde and other volatile organic compounds (VOCs) in confined spaces.

scholarly journals Enhanced Photocatalytic Activity of Powders (P25) via Calcination Treatment

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Guohong Wang ◽  
Lin Xu ◽  
Jun Zhang ◽  
Tingting Yin ◽  
Deyan Han
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Bet Surface Area ◽  
Photocatalytic Activities ◽  
Before And After ◽  
Different Temperatures ◽  
Uv Visible ◽  
Adsorption Desorption ◽  
Calcination Treatment

P25 TiO2powders were calcined at different temperatures in a muffle furnace in air. The P25 powders before and after calcination treatment were characterized with XRD FTIR, UV-visible diffuse reflectance spectra, SEM, TEM, HRTEM, and N2adsorption-desorption measurements. The photocatalytic activity was evaluated by the photocatalytic oxidation of methyl orange aqueous solution under UV light irradiation in air. The results showed that calcination treatment obviously influenced the microstructures and photocatalytic activity of the P25 TiO2powders. The synergistic effect of the phase structure, BET surface area, and crystallinity on the photocatalytic of TiO2powders (P25) after calcination was investigated. An optimal calcination temperature () was determined. The photocatalytic activity of TiO2powders calcined at was nearly 2 times higher than that of the uncalcined P25 TiO2. The highest photocatalytic activities of the calcined samples at for 4 h might be ascribed to the enhancement of anatase crystallization and the optimal mass ratio (ca. 1 : 2) of rutile to anatase.

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