In this work, Fe-doped TiO2 nanoparticles ranging from a 0.2 to 1 weight % were grown from
the surface of graphene sheet templates containing –COOH functionalities using sol–gel
chemistry in a green solvent, a mixture of water/ethanol. The assemblies were characterized by a
variety of analytical techniques, with the coordination mechanism examined theoretically using
the density functional theory (DFT). Scanning electron microscopy and transmission electron
microscopy images showed excellent decoration of the Fe-doped TiO2 nanoparticles on the
surface of the graphene sheets >5 nm in diameter. The surface area and optical properties of the
Fe-doped photocatalysts were measured by BET, UV and PL spectrometry and compared to
non-graphene and pure TiO2 analogs, showing a plateau at 0.6% Fe. Interactions between
graphene and Fe-doped anatase TiO2 were also studied theoretically using the Vienna ab initio
Simulation Package based on DFT. Our first-principles theoretical investigations validated the
experimental findings, showing the strength in the physical and chemical adsorption between the
graphene and Fe-doped TiO2. The resulting assemblies were tested for photodegradation under
visible light using 17β-estradiol (E2) as a model compound, with all investigated catalysts
showing significant enhancements in photocatalytic activity in the degradation of E2.
IOSR Journal of Applied Chemistry (IOSR-JAC) is an open access international journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Abstract— 2, 4-dinitrophenol and 2, 4, 6- trinitrophenol were successfully photodegraded using visible light active monoclinic BiVO4 as photocatalyst. 10ppm of dinitrophenol is photodegraded using 50mg BiVO4 under irradiation for 3h. 10ppm trinitrophenol is photodegraded using 100mg BiVO4 under irradiation for 3h. Ease of photodegradation of DNP and TNP varied in the order DNP > TNP for the same amount of photocatalyst. Photoluminescence studies confirmed the formation of •OH free radicals due to irradiation. Synergetic effect is noticed between BiVO4 and H2O2.
Preparation, characterization and application of sonochemically doped fe3+ in...eSAT Journals
Abstract In this present study, mechanistic investigation of ultrasound–assisted dye decolorization/degradation was investigated using sonochemically prepared Fe3+ doped ZnO. Fe3+ doped ZnO nanoparticle was prepared under ultrasound (20 kHz) irradiation using a doping concentration of 2 wt% of Fe(III). To investigate the catalytic activity of Fe3+ doped ZnO, Acid Red 14 (azo dye) was chosen for decolorization/degradation using sonolysis, photocatalysis and sono–photocatalysis processes. To study the influence of dopant onto structure, crystallinity, and optical properties, different analytical analyses were performed such as X–ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Zeta potential, Delsa Nano Particle Size Analyzer (PSA), Vibrating Sample Magnetometer analysis (VSM) and Field Emission Scanning Electron Microscopy (FE–SEM) etc. For photocatalytic experiments, a blended high pressure mercury UV lamp with maximum peak emission at 365 nm was used. The decolorization/degradation of dye with modified photocatalyst showed faster reaction kinetics under sono–photocatalytic process. Ultrasound showed an additive effect for degradation/decolorization process. The maximum decolorization of AR14 was achieved (~ 82%) under sono–photocatlytic process with an initial dye concentration of 20 ppm. The sono–photocatalysis process showed 1.4 – 1.6 higher reaction rates with Fe–doped ZnO than pure ZnO. Index Terms: ZnO, Fe–ZnO, Fe-doped ZnO, Sonocatalytic, Photocatalytic, Advanced Oxidation Process, AOP
IOSR Journal of Applied Chemistry (IOSR-JAC) is an open access international journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Abstract— 2, 4-dinitrophenol and 2, 4, 6- trinitrophenol were successfully photodegraded using visible light active monoclinic BiVO4 as photocatalyst. 10ppm of dinitrophenol is photodegraded using 50mg BiVO4 under irradiation for 3h. 10ppm trinitrophenol is photodegraded using 100mg BiVO4 under irradiation for 3h. Ease of photodegradation of DNP and TNP varied in the order DNP > TNP for the same amount of photocatalyst. Photoluminescence studies confirmed the formation of •OH free radicals due to irradiation. Synergetic effect is noticed between BiVO4 and H2O2.
Preparation, characterization and application of sonochemically doped fe3+ in...eSAT Journals
Abstract In this present study, mechanistic investigation of ultrasound–assisted dye decolorization/degradation was investigated using sonochemically prepared Fe3+ doped ZnO. Fe3+ doped ZnO nanoparticle was prepared under ultrasound (20 kHz) irradiation using a doping concentration of 2 wt% of Fe(III). To investigate the catalytic activity of Fe3+ doped ZnO, Acid Red 14 (azo dye) was chosen for decolorization/degradation using sonolysis, photocatalysis and sono–photocatalysis processes. To study the influence of dopant onto structure, crystallinity, and optical properties, different analytical analyses were performed such as X–ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Zeta potential, Delsa Nano Particle Size Analyzer (PSA), Vibrating Sample Magnetometer analysis (VSM) and Field Emission Scanning Electron Microscopy (FE–SEM) etc. For photocatalytic experiments, a blended high pressure mercury UV lamp with maximum peak emission at 365 nm was used. The decolorization/degradation of dye with modified photocatalyst showed faster reaction kinetics under sono–photocatalytic process. Ultrasound showed an additive effect for degradation/decolorization process. The maximum decolorization of AR14 was achieved (~ 82%) under sono–photocatlytic process with an initial dye concentration of 20 ppm. The sono–photocatalysis process showed 1.4 – 1.6 higher reaction rates with Fe–doped ZnO than pure ZnO. Index Terms: ZnO, Fe–ZnO, Fe-doped ZnO, Sonocatalytic, Photocatalytic, Advanced Oxidation Process, AOP
Synthesis and Characterization of Atmospheric Residue Hydrodemetalization (Ar...IOSR Journals
Synthesis and characterization of atmospheric residue hydrodemetalization (ARDHM) catalyst for crude oil processing have been carried out. The catalyst was synthesized by loading of small amount of Ni and Mo metals onto the Indonesian natural zeolite from Klaten (ZA sample). The natural zeolite was treated with 3M HCl solution to produce the ZAA sample. The Ni and Mo metal was impregnated onto the ZAA sample using (NH4)6Mo7O24.4H2O followed by Ni(NO3)2.6H2O precursor solution, then calcined at 450ºC for 5 h and reduced at 400ºC for 3 h produced the NiMo/ZAA catalyst. The zeolite samples were characterized by means of total acid amount determined by pyridine vapour adsorption, the TO4 site (T = Si or Al) analyzed by Infra Red Spectrometer (IR), Crystallinity by X-ray Diffraction (XRD), and surface performance by Scanning Electron Microscope (SEM), and metal content measured by Atomic Absorption Spectroscopy (AAS). The catalyst activity was tested in hydrodemetalization process using nickel porphyrin, tiophene or pyridine as petroleum residue model compounds carried out at 360, 370, 380 and 390ºC, LHSV 0.2 h-1. The HCl treatment to the ZA sample caused dealumination, did not defect the crystalline matter and increased total acid amount. Loading of Ni and Mo metal onto the ZAA sample increased acidity, did not defect the crystalline of mordenite and also did not block the zeolite pore. Nickel removal from nickel porphyrin (Np) was easier than N remofal from pyridine; on the other hand, nickel removal from nickel porphyrin was more difficult than S removal from pyridine. The spent catalyst was deactivated by coke deposition and it can be regenerated and reused
adsorption of methylene blue onto xanthogenated modified chitosan microbeadsSiti Nadzifah Ghazali
Methylene Blue (MB) is thiazine dyes that widely use to color product in many industry such as textile, printing, leather, cosmetic and paper. Xanthogenated-Modified Chitosan Microbeads (XMCM) is use to observe the new alternative adsorbent in removing MB from water body through adsorption process. The interactions between MB and functional group in XMCM were confirmed by Fourier Transform Infrared (FT-IR) spectra. Several parameters that influence adsorption ability such as the effect of adsorbent dosage of XMCM and the effect of initial pH of MB aqueous solution were studied. This study were done at optimum condition which is at pH 4 of initial pH of MB solution, 0.01 g of initial XMCM dosage, 6 hours stirring time and temperature of (30 ± 2 ℃). The adsorption data fit well Langmuir model more than Freundlich model. Based on Langmuir model, the maximum monolayer adsorption capacity of MB was 21.62 mg g-1 which indicated that XMCM can be a new alternative adsorbent for removing MB.
Photochemistry Mediated Synthesis and Characterization of Thyroxine Capped Si...priyanka raviraj
Objective:
Silver nanoparticles (AgNPs) are one of the noble metal nanoparticles studied due to their amenability of synthesis, functionalization and ease of detection. Synthesis of silver nanoparticles using thyroxine as a reducing and capping agent through the one step photochemical method
Characterization of synthesized silver nanoparticles (Thy-AgNPs)
1. UV-Spectroscopy Analysis
2. Fourier Transforms-Infra Red Spectroscopy (FT-IR)
3. High Resolution Transmission Electron Microscopy(HR-TEM)
4. Field Emission Scanning Electron Microscopy(FE-SEM)
5. Dynamic Light Scattering (DLS)
6. Zeta potential
Uses:
*AgNPs have unique optical, electrical, and thermal properties
*Exhibit high plasmon efficiency
*More sensitive towards localized surface plasmon resonance
*Less time consuming, economic and more ecofriendly
*It is used in electronics, food industry, cosmetics, photochemical, biomedicine and chemistry.
Preparation and photocatalytic activity of alkali titanateSoumya Ranjan Sahoo
Photocatalysts nano A2TinO2n+1 (A = Li, Na, K) were prepared successfully by novel hydrothermal synthesis process. The nano crystals of Li2TiO3 were self-assembled as snowflakes while that of Na2Ti3O7 and K2Ti8O17 were nanorods. The results indicated that alkali titanates as prepared have higher photocatalytic activities compared with P25TiO2 in the degradation of chloroform under UV light irradiation. A combination of K2Ti8O17 and NiO produces a photo catalyst effective for the degradation of chloroform in aqueous solution.
Adsorption Characteristics and Behaviors of Natural Red Clay for Removal of B...ijtsrd
The present study deals with the analysis and adsorption of Basic Yellow 28 BY28 onto low-cost natural red clay NRC . Adsorbent characterized by XRD, SEM, TG DTA, BET and BJH. The effect of the contact time, the temperature, the initial concentration, the pH and the adsorbent mass and on adsorption process were investigated using by batch adsorption technique and then the adsorption isotherm, kinetics, thermodynamics and equilibrium studies were performed. The pH effect on the removal of BY28 efficiency was not important. It was found that the isotherm model best suited to the equilibrium data obtained from the adsorption of BY28 on NRC was the pseudo-second order. It was found that the kinetic model best suited to the data obtained from the adsorption of BY28 on NRC was the Langmuir model. The maximum monolayer adsorption capacity was 370 mg. g-1. In the thermodynamic studies, it can be said that the adsorption of BY28 onto NRC takes place spontaneously, physically and endothermic ally. Finally, the use of NRC shows a greater potential for the removal of cationic dyes, as no costly equipment is required. Omer Lacin | Ali Haghighatnia | Fatih Demir | Fatih Sevim "Adsorption Characteristics and Behaviors of Natural Red Clay for Removal of BY28 from Aqueous Solutions" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-2 , February 2019, URL: https://www.ijtsrd.com/papers/ijtsrd21544.pdf
Paper URL: https://www.ijtsrd.com/engineering/engineering-chemistry/21544/adsorption-characteristics-and-behaviors-of-natural-red-clay-for-removal-of-by28-from-aqueous-solutions/omer-lacin
V mn-mcm-41 catalyst for the vapor phase oxidation of o-xylenesunitha81
The role of V and Mn incorporated mesoporous molecular sieves was
investigated for the vapor phase oxidation of o-xylene. Mesoporous monometallic
V-MCM-41 (Si/V = 25, 50, 75 and 100), Mn-MCM-41 (Si/Mn = 50) and bimetallic
V-Mn-MCM-41 (Si/(V ? Mn) = 100) molecular sieves were synthesized by
a direct hydrothermal (DHT) process and characterized by various techniques such
as X-ray diffraction, DRUV-Vis spectroscopy, EPR, and transmission electron
microscopy (TEM). From the DRUV-Vis and EPR spectral study, it was found that
most of the V species are present as vanadyl ions (VO2?) in the as-synthesized
catalysts and as highly dispersed V5? ions in tetrahedral coordination in the calcined
catalysts. The activity of the catalysts was measured and compared with each other
for the gas phase oxidation of o-xylene in the presence of atmospheric air as an
oxidant at 573 K. Among the various catalysts, V-MCM-41 with Si/V = 50
exhibited high activity towards production of phthalic anhydride under the experimental
condition. The correlation between the phthalic anhydride selectivity and
the physico-chemical characteristics of the catalyst was found. It is concluded that
V5? species present in the MCM-41 silica matrix are the active sites responsible for
the selective formation of phthalic anhydride during the vapor phase oxidation of
o-xylene.
Electrooxidation of methanol on carbon supported pt ru nanocatalysts prepared...suresh899
Carbon Supported PtRu nanocatalysts have been prepared by simple impregnation reduction method in which Pt and Ru precursors are reduced by ethanol under reflux conditions for different reaction times. The prepared nanocatalysts were characterized by means of XRD, EDAX, ICP-AAS, FESEM and TEM. XRD analyses showed that all nanocatalysts exhibited f.c.c crystal structure, the structure characteristic for pure Pt, except for that reduced at prolonged reaction time of 4h which showed the presence of characteristic peak for Ru metal. The lattice constant calculations indicate that all catalysts are present in unalloyed phase and the average particle size as determined by TEM was in the range of 3.7 nm. The electrocatalytic activities and stability for the prepared nanocatalysts methanol electro-oxidation reaction (MOR) were studied by cyclic voltammetry. The catalysts prepared at 2h reduction time showed higher electrocatalytic activity in terms of mass specific activity and good stability over potential sweep for 100 cycles for methanol electro-oxidation. The results showed that the prepared nanocatalysts are considered as promising electrode catalyst (anode catalyst) for electro-oxidation of methanol in direct methanol fuel cells.
Using Tunisian Phosphate Rock and Her Converted Hydroxyapatite for Lead Remov...IJERA Editor
Natural and synthesis apatites represent a cost effective soil amendment, which can be used for in situ reduction of lead bioavailability and mobility. In our previous work, we selected Tunisian Phosphate Rock (TPR) and Hydroxyapatite (CaHAp) as promising minerals for the removal of lead from aqueous solutions. X-ray powder diffraction patterns (DRX), Infra Red (IR), Thermogravimetric analysis (TGA) and Scanning Electron Microscopy (SEM) were used to characterize TPR and CaHAp. CaHAp was prepared from TPR and employed for the removal of Pb2+ ions at different concentrations from aqueous solution to determine the adsorption properties of CaHAp and compare them with those of a TPR. The kinetic data obtained indicated that the adsorption performances of the adsorbents depended both on their specific surface area and crystallinity. Complexation of lead ion on the adsorbent surface favoured the dissolution of hydroxyapatites characterized by a Ca/Pb molar ratio of 1.69. The maximum adsorption capacity of CaHAp for Pb2+ ions at 25 °C was 1.806 mmol /g relative to 1.035 mmol /g for TPR at the same temperature. The higher capacity of CaHAp was explained in terms of its porosity and crystallinity. The Pb2+ ions sorption results could be modelled by the Langmuir and Freundlich isotherms. The simulations of adsorption isotherms of Pb2+ on CaHAp allow us to conclude that there is a good correlation between the experimental data and the Langmuir model. On TPR, we show a good correlation between the experimental data and the Langmuir and Freundlich model.
HfO2 nanodots incorporated in TiO2 and its hydrogenation for high performance...Devika Laishram
Black titania (H-TiO2) as a photoanode material has attracted huge attention due to its extremely high
optical absorption in the visible region. Herein, black TiO2 doped with HfO2 shows 45.7% higher photoconversion efficiency than H-TiO2 under identically similar conditions. The incorporation of HfO2
nanodots increased the optical scattering in H-TiO2 only when it underwent hydrogenation along with
TiO2. Hafnia-doped TiO2 (HfO2/TiO2) is synthesized by a combination of simple sol–gel and
hydrothermal method followed by thermal annealing under controlled hydrogen atmosphere. The
hydrogenated H-(TiO2/HfO2) exhibited very high optical absorption but slightly lower than H-TiO2 due
to light scattering by HfO2 nanodots. We observed a sharp decrease in optical band gap of TiO2/HfO2
from 3.2 to 2.4 eV up on hydrogen annealing, which is important in solar applications as demonstrated
by the fabrication of high efficiency dye sensitized solar cells (DSSC)
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Photocatalytic application of TiO2/SiO2-based magnetic nanocomposite (Fe3O4@S...Iranian Chemical Society
In this research we have developed a treatment method for textile wastewater by TiO2/SiO2-based magnetic nanocomposite. Textile wastewater includes a large variety of dyes and chemicals and needs treatments. This manuscript presents a facile method for removing dyes from the textile wastewater by using TiO2/SiO2-based nanocomposite (Fe3O4@SiO2/TiO2) under UV irradiation. This magnetic nanocomposite, as photocatalytically active composite, is synthesized via solution method in mild conditions. A large range of cationic, anionic and neutral dyes including: methyl orange, methylene blue, neutral red, bromocresol green and methyl red are used for treatment investigations. Neutral red and bromocresol green have good results in reusing treatment. The high surface area of nanocomposites improve the kinetic of wastewater treatment. In this method, by using the magnetic properties of Fe3O4 nanoparticles, TiO2-based photocatalyst could be separated and reused for 3 times. The efficiency of this method is respectively 100% and 65% for low concentration (10 ppm) and high concentration (50 ppm) of neutral red and bromocrosol green after 3 h treatment. The efficiency of treatment using the second used nanocomposite was 90% for 10 ppm of the same dyes.
Synthesis and Characterization of Atmospheric Residue Hydrodemetalization (Ar...IOSR Journals
Synthesis and characterization of atmospheric residue hydrodemetalization (ARDHM) catalyst for crude oil processing have been carried out. The catalyst was synthesized by loading of small amount of Ni and Mo metals onto the Indonesian natural zeolite from Klaten (ZA sample). The natural zeolite was treated with 3M HCl solution to produce the ZAA sample. The Ni and Mo metal was impregnated onto the ZAA sample using (NH4)6Mo7O24.4H2O followed by Ni(NO3)2.6H2O precursor solution, then calcined at 450ºC for 5 h and reduced at 400ºC for 3 h produced the NiMo/ZAA catalyst. The zeolite samples were characterized by means of total acid amount determined by pyridine vapour adsorption, the TO4 site (T = Si or Al) analyzed by Infra Red Spectrometer (IR), Crystallinity by X-ray Diffraction (XRD), and surface performance by Scanning Electron Microscope (SEM), and metal content measured by Atomic Absorption Spectroscopy (AAS). The catalyst activity was tested in hydrodemetalization process using nickel porphyrin, tiophene or pyridine as petroleum residue model compounds carried out at 360, 370, 380 and 390ºC, LHSV 0.2 h-1. The HCl treatment to the ZA sample caused dealumination, did not defect the crystalline matter and increased total acid amount. Loading of Ni and Mo metal onto the ZAA sample increased acidity, did not defect the crystalline of mordenite and also did not block the zeolite pore. Nickel removal from nickel porphyrin (Np) was easier than N remofal from pyridine; on the other hand, nickel removal from nickel porphyrin was more difficult than S removal from pyridine. The spent catalyst was deactivated by coke deposition and it can be regenerated and reused
adsorption of methylene blue onto xanthogenated modified chitosan microbeadsSiti Nadzifah Ghazali
Methylene Blue (MB) is thiazine dyes that widely use to color product in many industry such as textile, printing, leather, cosmetic and paper. Xanthogenated-Modified Chitosan Microbeads (XMCM) is use to observe the new alternative adsorbent in removing MB from water body through adsorption process. The interactions between MB and functional group in XMCM were confirmed by Fourier Transform Infrared (FT-IR) spectra. Several parameters that influence adsorption ability such as the effect of adsorbent dosage of XMCM and the effect of initial pH of MB aqueous solution were studied. This study were done at optimum condition which is at pH 4 of initial pH of MB solution, 0.01 g of initial XMCM dosage, 6 hours stirring time and temperature of (30 ± 2 ℃). The adsorption data fit well Langmuir model more than Freundlich model. Based on Langmuir model, the maximum monolayer adsorption capacity of MB was 21.62 mg g-1 which indicated that XMCM can be a new alternative adsorbent for removing MB.
Photochemistry Mediated Synthesis and Characterization of Thyroxine Capped Si...priyanka raviraj
Objective:
Silver nanoparticles (AgNPs) are one of the noble metal nanoparticles studied due to their amenability of synthesis, functionalization and ease of detection. Synthesis of silver nanoparticles using thyroxine as a reducing and capping agent through the one step photochemical method
Characterization of synthesized silver nanoparticles (Thy-AgNPs)
1. UV-Spectroscopy Analysis
2. Fourier Transforms-Infra Red Spectroscopy (FT-IR)
3. High Resolution Transmission Electron Microscopy(HR-TEM)
4. Field Emission Scanning Electron Microscopy(FE-SEM)
5. Dynamic Light Scattering (DLS)
6. Zeta potential
Uses:
*AgNPs have unique optical, electrical, and thermal properties
*Exhibit high plasmon efficiency
*More sensitive towards localized surface plasmon resonance
*Less time consuming, economic and more ecofriendly
*It is used in electronics, food industry, cosmetics, photochemical, biomedicine and chemistry.
Preparation and photocatalytic activity of alkali titanateSoumya Ranjan Sahoo
Photocatalysts nano A2TinO2n+1 (A = Li, Na, K) were prepared successfully by novel hydrothermal synthesis process. The nano crystals of Li2TiO3 were self-assembled as snowflakes while that of Na2Ti3O7 and K2Ti8O17 were nanorods. The results indicated that alkali titanates as prepared have higher photocatalytic activities compared with P25TiO2 in the degradation of chloroform under UV light irradiation. A combination of K2Ti8O17 and NiO produces a photo catalyst effective for the degradation of chloroform in aqueous solution.
Adsorption Characteristics and Behaviors of Natural Red Clay for Removal of B...ijtsrd
The present study deals with the analysis and adsorption of Basic Yellow 28 BY28 onto low-cost natural red clay NRC . Adsorbent characterized by XRD, SEM, TG DTA, BET and BJH. The effect of the contact time, the temperature, the initial concentration, the pH and the adsorbent mass and on adsorption process were investigated using by batch adsorption technique and then the adsorption isotherm, kinetics, thermodynamics and equilibrium studies were performed. The pH effect on the removal of BY28 efficiency was not important. It was found that the isotherm model best suited to the equilibrium data obtained from the adsorption of BY28 on NRC was the pseudo-second order. It was found that the kinetic model best suited to the data obtained from the adsorption of BY28 on NRC was the Langmuir model. The maximum monolayer adsorption capacity was 370 mg. g-1. In the thermodynamic studies, it can be said that the adsorption of BY28 onto NRC takes place spontaneously, physically and endothermic ally. Finally, the use of NRC shows a greater potential for the removal of cationic dyes, as no costly equipment is required. Omer Lacin | Ali Haghighatnia | Fatih Demir | Fatih Sevim "Adsorption Characteristics and Behaviors of Natural Red Clay for Removal of BY28 from Aqueous Solutions" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-2 , February 2019, URL: https://www.ijtsrd.com/papers/ijtsrd21544.pdf
Paper URL: https://www.ijtsrd.com/engineering/engineering-chemistry/21544/adsorption-characteristics-and-behaviors-of-natural-red-clay-for-removal-of-by28-from-aqueous-solutions/omer-lacin
V mn-mcm-41 catalyst for the vapor phase oxidation of o-xylenesunitha81
The role of V and Mn incorporated mesoporous molecular sieves was
investigated for the vapor phase oxidation of o-xylene. Mesoporous monometallic
V-MCM-41 (Si/V = 25, 50, 75 and 100), Mn-MCM-41 (Si/Mn = 50) and bimetallic
V-Mn-MCM-41 (Si/(V ? Mn) = 100) molecular sieves were synthesized by
a direct hydrothermal (DHT) process and characterized by various techniques such
as X-ray diffraction, DRUV-Vis spectroscopy, EPR, and transmission electron
microscopy (TEM). From the DRUV-Vis and EPR spectral study, it was found that
most of the V species are present as vanadyl ions (VO2?) in the as-synthesized
catalysts and as highly dispersed V5? ions in tetrahedral coordination in the calcined
catalysts. The activity of the catalysts was measured and compared with each other
for the gas phase oxidation of o-xylene in the presence of atmospheric air as an
oxidant at 573 K. Among the various catalysts, V-MCM-41 with Si/V = 50
exhibited high activity towards production of phthalic anhydride under the experimental
condition. The correlation between the phthalic anhydride selectivity and
the physico-chemical characteristics of the catalyst was found. It is concluded that
V5? species present in the MCM-41 silica matrix are the active sites responsible for
the selective formation of phthalic anhydride during the vapor phase oxidation of
o-xylene.
Electrooxidation of methanol on carbon supported pt ru nanocatalysts prepared...suresh899
Carbon Supported PtRu nanocatalysts have been prepared by simple impregnation reduction method in which Pt and Ru precursors are reduced by ethanol under reflux conditions for different reaction times. The prepared nanocatalysts were characterized by means of XRD, EDAX, ICP-AAS, FESEM and TEM. XRD analyses showed that all nanocatalysts exhibited f.c.c crystal structure, the structure characteristic for pure Pt, except for that reduced at prolonged reaction time of 4h which showed the presence of characteristic peak for Ru metal. The lattice constant calculations indicate that all catalysts are present in unalloyed phase and the average particle size as determined by TEM was in the range of 3.7 nm. The electrocatalytic activities and stability for the prepared nanocatalysts methanol electro-oxidation reaction (MOR) were studied by cyclic voltammetry. The catalysts prepared at 2h reduction time showed higher electrocatalytic activity in terms of mass specific activity and good stability over potential sweep for 100 cycles for methanol electro-oxidation. The results showed that the prepared nanocatalysts are considered as promising electrode catalyst (anode catalyst) for electro-oxidation of methanol in direct methanol fuel cells.
Using Tunisian Phosphate Rock and Her Converted Hydroxyapatite for Lead Remov...IJERA Editor
Natural and synthesis apatites represent a cost effective soil amendment, which can be used for in situ reduction of lead bioavailability and mobility. In our previous work, we selected Tunisian Phosphate Rock (TPR) and Hydroxyapatite (CaHAp) as promising minerals for the removal of lead from aqueous solutions. X-ray powder diffraction patterns (DRX), Infra Red (IR), Thermogravimetric analysis (TGA) and Scanning Electron Microscopy (SEM) were used to characterize TPR and CaHAp. CaHAp was prepared from TPR and employed for the removal of Pb2+ ions at different concentrations from aqueous solution to determine the adsorption properties of CaHAp and compare them with those of a TPR. The kinetic data obtained indicated that the adsorption performances of the adsorbents depended both on their specific surface area and crystallinity. Complexation of lead ion on the adsorbent surface favoured the dissolution of hydroxyapatites characterized by a Ca/Pb molar ratio of 1.69. The maximum adsorption capacity of CaHAp for Pb2+ ions at 25 °C was 1.806 mmol /g relative to 1.035 mmol /g for TPR at the same temperature. The higher capacity of CaHAp was explained in terms of its porosity and crystallinity. The Pb2+ ions sorption results could be modelled by the Langmuir and Freundlich isotherms. The simulations of adsorption isotherms of Pb2+ on CaHAp allow us to conclude that there is a good correlation between the experimental data and the Langmuir model. On TPR, we show a good correlation between the experimental data and the Langmuir and Freundlich model.
HfO2 nanodots incorporated in TiO2 and its hydrogenation for high performance...Devika Laishram
Black titania (H-TiO2) as a photoanode material has attracted huge attention due to its extremely high
optical absorption in the visible region. Herein, black TiO2 doped with HfO2 shows 45.7% higher photoconversion efficiency than H-TiO2 under identically similar conditions. The incorporation of HfO2
nanodots increased the optical scattering in H-TiO2 only when it underwent hydrogenation along with
TiO2. Hafnia-doped TiO2 (HfO2/TiO2) is synthesized by a combination of simple sol–gel and
hydrothermal method followed by thermal annealing under controlled hydrogen atmosphere. The
hydrogenated H-(TiO2/HfO2) exhibited very high optical absorption but slightly lower than H-TiO2 due
to light scattering by HfO2 nanodots. We observed a sharp decrease in optical band gap of TiO2/HfO2
from 3.2 to 2.4 eV up on hydrogen annealing, which is important in solar applications as demonstrated
by the fabrication of high efficiency dye sensitized solar cells (DSSC)
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Photocatalytic application of TiO2/SiO2-based magnetic nanocomposite (Fe3O4@S...Iranian Chemical Society
In this research we have developed a treatment method for textile wastewater by TiO2/SiO2-based magnetic nanocomposite. Textile wastewater includes a large variety of dyes and chemicals and needs treatments. This manuscript presents a facile method for removing dyes from the textile wastewater by using TiO2/SiO2-based nanocomposite (Fe3O4@SiO2/TiO2) under UV irradiation. This magnetic nanocomposite, as photocatalytically active composite, is synthesized via solution method in mild conditions. A large range of cationic, anionic and neutral dyes including: methyl orange, methylene blue, neutral red, bromocresol green and methyl red are used for treatment investigations. Neutral red and bromocresol green have good results in reusing treatment. The high surface area of nanocomposites improve the kinetic of wastewater treatment. In this method, by using the magnetic properties of Fe3O4 nanoparticles, TiO2-based photocatalyst could be separated and reused for 3 times. The efficiency of this method is respectively 100% and 65% for low concentration (10 ppm) and high concentration (50 ppm) of neutral red and bromocrosol green after 3 h treatment. The efficiency of treatment using the second used nanocomposite was 90% for 10 ppm of the same dyes.
Adsorptive/photo-catalytic process for naphthalene removal from aqueous media...NOMADPOWER
The problem being addressed in this study is the removal of naphthalene from aqueous media using an adsorptive/photo-catalytic process. The proposed solution involves the use of an in-situ nickel doped titanium nanocomposite as a catalyst to degrade the naphthalene molecules. The effectiveness of this process is being tested in order to provide a potential solution for the removal of naphthalene from industrial wastewater and other contaminated water sources.
Influence of Synthesis Route on the Formaldehyde Gas Sensing Properties of Ni...IJMERJOURNAL
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Visible Light Assisted Degradation of Eosin Yellow using Heteroatom Functiona...IJERA Editor
10 ppm EY dye were successfully photodegraded using visible light active 0.75wt% Ba & 0.25wt% Zr codoped
TiO2 nanomaterial that were synthesized by Sol-gel method as nanomaterials under irradiation for 20
minutes and characterized by various advanced instrumental techniques. The X-ray Diffraction Spectroscopic
showed that the prepared nanomaterial were in the anatase phase with 2θ at 25.3º. UV-visible Diffuse
Reflectance Spectra analysis explained that the dopants found in the TiO2, imparts a significance absorption
shift towards visible region and their exisistance were confirmed by X-ray Photoelectron Spectral data.
Quantitatively the formation of hydroxyl radical by the nanomaterial in aqueous solution under visible
light irradiation was investigated by the photoluminiscent technique. Finally the effects of different parameters
in the photocatalytic degradation of EY were established in aqueous solution
Synthesis and Characterization Studies of Solvothermally Synthesized Undoped ...IJERA Editor
Nanocrystalline TiO2 was investigated by solvothermal synthetic method using toluene as a solvent. Titanium tetra isopropoxide (TTIP) was used as a precursor, which was decomposed at high temperature and precipitated in toluene. Subsequently, the solution was thermally treated at 250C for five hours in stainless steel autoclave. Amorphous Nano TiO2 was formed. When these amorphous Nano TiO2 was calcinated to 550 C anatase Nano TiO2 crystalline with particle size <20 nm was formed. These amorphous and anatase phase Nano TiO2 was characterized by Powder X-ray diffraction (PXRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS) and Photoluminescence (PL) studies and the results were discussed.
High-performance dye-sensitized solar cell using dimensionally controlled tit...Devika Laishram
The subject of the current study is a concoct of anatase and rutile mixed phase titania synthesized at 40 C and
10 C. At these sub-zero temperatures, highly crystalline, phase-oriented nanostructured titania were formed.
At 40 C, nanocrystals of TiO2 consist of the anatase phase while nanorods dominated by the rutile phase form
at 10 C. These samples are remarkable photoanode materials with excellent photon scattering ability in dyesensitized solar cells (DSSCs). On performance optimization of DSSCs, a composition of 0.5 wt% TiO2 (prepared
at 40 C) and P25 improved the photon harvesting by providing a large number of sites for interaction, resulting
in a high photocurrent of 18.46 mA cm2 and 8.6% photoconversion efficiency.
Similar to Iron Doped Titania Nanostructures Synthesis, DFT modelling and Photocatalysis (20)
IONEEC is a platform that gives the artists the opportunity to control their promotion. Stimulating the Art is an efficient way to discover weekly outstanding artwork as it is based on competitiveness. It is also a tool that helps discover artworks and artists that suffer media coverage. Artists are given the chance to generate an activity in a specific Genre by comparing the artwork weekly. The concept is based on votes, 1: only artists can participate to the competition and, 2: only artist submitting artwork to the competition can vote, 3: artists submitting samples to the competition cannot vote his own artwork. An artist is allowed to give out 3 votes per competing artwork! All the artists are subject to the same rule. Finally the artwork receiving the most votes wins the competition.
- Markov Chain
Random movements, one follow another
- Importance sampling
To sample many points in the region where the Boltzmann factor is large and few elsewhere
- Ergodicity (ensemble average)
Such an average over all possible quantum states of a system
- Detailed Balance
Dipole-directed self-assembly can be used to create robust one-dimensional nanostructures
on silicon. It also provides new insights into interactions between molecules and this important
technological material.
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1,5-dichloropentane on Si(100)-231 was shown to self-assemble at room temperature into molecular lines that grew
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Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
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Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
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Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
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Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
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Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
This pdf is about the Schizophrenia.
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Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Iron Doped Titania Nanostructures Synthesis, DFT modelling and Photocatalysis
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Fe doped TiO
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–graphene nanostructures: synthesis, DFT modeling and photocatalysis
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3. stabilized on its surface to produce more efficient photo-
catalysts [39, 40].
The ability to control nanocrystal growth from gra-
phene’s surface is still under active examination, with many
results from different research studies inconsistent due to a
large variation of experimental conditions investigated. In
addition, very few reports investigate theoretically the inter-
action of nanoparticles and graphene sheets and the
mechanism of charge transfer from graphene to the nano-
crystal. In our previous studies, we decorated the surface of
graphene with both TiO2 nanofibers [41] and Fe doped TiO2
nanofibers [42] in supercritical carbon dioxide (scCO2)
showing high phoyocatalitic properties. We also theoretically
investigated both physical and chemical interaction of TiO2
and graphene sheets using density functional theory (DFT)
resulting in good charge transfer between graphene and TiO2
[43]. Das et al deposited different semiconductor nano-
particles such as TiO2 and ZnO and some magnetic nano-
particles such as Fe3O4 and Ni on graphene. By using first
principle calculations, they showed that charge transfer occurs
between graphene and the deposited nanoparticles [44]. Rojas
et al used DFT calculations for Titanium modified graphene
system for the adsorption of different molecules, showing
considerably improved hydrogen storage capacity [45].
Herein, we synthesize different weight ratios of Fe-doped
TiO2 nanoassemblies ranging from 0.2 to 1% on the surface
of graphene sheets using a sol–gel method in water/ethanol.
The materials are characterized in detail and DFT calculations
are examined to investigate the adsorption of the Fe doped
TiO2 nanocrystals to graphene and the energy transfer
mechanism. Finally, the resulting materials are investigated
for degradation of estrodine (E2) under visible light with the
results compared to catalysts prepared in identical conditions
without graphene.
2. Experimental
2.1. Materials
Graphite flakes nominally sized at 7–10 microns were pro-
vided from Alfa Aesar. Fuming nitric acid (>90%), sulfuric
acid (95–98%), potassium chlorate (98%), hydrochloric acid
(37%), acetic acid, titanium isopropoxide (99.999%) trace
metals basis and iron chloride FeCl3, were purchased from
Sigma-Aldrich (Canada Ltd, Oakville, ON) and used as
received.
2.2. Methods
2.2.1. Preparation of functionalized graphene sheets
(FGSs). Staudenmaier method was used to produce
graphene from graphite oxide [46]. Graphite (5 g) was
reacted with concentrated nitric (45 mL) and sulfuric acid
(90 mL) with potassium chlorate (55 g). To avoid any sudden
increase in temperature, the potassium chlorate was added
slowly over 15 min and mixture was stirred for more than
72 h at room temperature. The mixture was added to water
after completing the reaction, washed with a 5% solution of
HCl, and water repeatedly until the pH of the filtrate was
neutral. The dried graphite oxide was placed in a quartz boat
and inserted into a tubular furnace preheated to 1050 °C and
kept at this temperature for 30 s. The graphite oxide was
reduced to FGSs.
2.2.2. Preparation of Fe doped TiO2/graphene sheet
composites. A simple sol–gel method was used in this
study as reported by Hoffman et al [47]. Acetic acid was
added to 50 ml of distilled water to adjust it’s pH to 2.6.
Previously, we studied different FGSs: TIP ratios and 1:20
was found as an optimum value ratio [41]. In this study, we
used the same FGSs: TIP weight ratio. Graphene sheets
(FGSs/TIP: 1:20) were added to this solution gradually over
10 min to avoid agglomeration. In the next step, the
appropriate amount of Fe was dissolved in 2 ml ethanol and
added to the graphene solution. In another beaker, TiO2 sols
were prepared by drop wise addition of 5 mL of an ethanolic
TIP solution, which had been dissolved in 50 mL of absolute
ethanol, into the first beaker. After continuously stirring for
24 h, the resulting transparent solution was evaporated using a
rotary evaporator at 50 °C and washed with distilled water
and dried in the oven (80 °C) overnight. The obtained powder
was calcined at 450 °C for 2 h under air.
2.3. Characterization
Scanning electron microscopy (SEM) (Model LEO 1530) and
transmission electron microscopy (TEM) (Model JEOL
2010F) were used to examine the morphologies of the sam-
ples. For SEM imaging, samples were prepared by applying
the powder directly to a carbon adhesive tape. The powdered
samples for TEM analysis, were dispersed in methanol by
sonication and then placed on a copper grid covered with
holey carbon film and dried by evaporation. X-ray powder
diffractometer (Rigaku Miniflex XRD, TX, USA), fitted with
a rotating sample holder, a scintillation counter detector and a
divergent beam utilizing a Cu Kα source of x-rays
(λ = 1.5418 Å) was used to analyze structural of the samples.
Different Fe doped TiO2 particles were also prepared on the
graphene sheets with the fraction of rutile (XR) calculated
using the Scherrer equation [47]:
= − + − ×{ }( )X I I(%) 1 1 1.26 1 100, (1)R R A
where IR and IA are the x-ray intensities of the rutile (101) and
anatase (110) peaks, respectively. Raman analysis was per-
formed using a Kaiser optical system (RXN1-785) with 5
times exposure and 20 times accumulation. The X-ray photo-
electron spectroscopy (XPS) analysis was carried out with a
Kratos Axis Ultra spectrometer using a monochromatic AlK
(alpha) source (15 mA, 14 kV). UV spectra were performed
by (Shimadzu 3600) deuterium arc lamp and two different
detectors (PMT, and PbS). In order to measure diffuse
reflectance of these materials, an integrating sphere was
utilized.
2
Nanotechnology 25 (2014) 305601 N Farhangi et al
4. 2.4. Photocatalytic activity measurements
17β-Estradiol (Sigma-Aldrich) was used as a model endocrine
disrupting compound. In this experiment, the visible light
source was a solar simulator (Model: SS1KW, Sciencetech)
with a 1000 watt xenon arc lamp equipped with an air mass
filter (AM filter) AM 1.5 G (λ > 290 nm) and a special UV
cut-off filter (290 ⩽ λ ⩽ 420 nm). In a typical photodegrada-
tion experiment, a mixture of aqueous E2 solution (5 μg L−1
)
and 0.5 g L−1
of catalyst was vigorously stirred for 30 min to
establish an adsorption/desorption equilibrium in the dark
following by irradiation under visible light in an open water-
jacketed vertical photo-reactor which was placed on a mag-
netic stirrer during all experiments, under aerated conditions
[1]. Circulating cooling water was used to control the tem-
perature of the reactions at 22 + 1 °C. At given time intervals,
5 mL aliquots were sampled and centrifuged to remove the
particles. The supernatant was analyzed by HPLC using a
(ICS 300, Dionex), which included a DP pump, an AS auto
sampler, a dc column oven and PDA UV detector, connected
to Chromeleon software. Separations were carried out with an
Acclaim 120 C18 reversed-phase column (150 mm × 4.6 mm
i.d., 5 μm particle size, Dionex, USA). The injection volume
was 40 μL from a 2 mL HPLC vial, capped and sealed with
PTFE lid. The mobile phase was the mixture of acetonitrile
(AcN) and deionized water (Milli-Q) (50 : 50 v/v), delivered
at a flow rate of 1 mL min−1
. The column temperature was
maintained at 30 °C and detection wavelength was set at
280 nm which shows maximum absorbance of E2. The
retention time of E2 in the HPLC column was 5.33 min. The
measurements were repeated for each catalytic system, and
the experimental error was found to be within (±1%).
3. Computational methods
Theoretical bulk structures and binding energy values were
studied using the Vienna ab initio Simulation Package
(VASP) [48, 49] based on DFT. Electronic structure calcu-
lations were carried out using the GGA PW91 [50] functional
implemented with VASP code for all graphene and titania
systems. The electron–ion interactions are described by the
projector-augmented wave scheme [49]. A constant energy
cutoff of 400 eV was used for all the calculations for
consistency in the bond length and angles. A Ti atom was
substituted with a Fe atom in the 48-, 24- and 12-atom
supercells to form the FexTin−xO2n with the corresponding x
doping values of 0.0625, 0.125 and 0.25 respectively, which
represents the titania structures doped with uniformly dis-
tributed Fe atoms. A one-dimensional and periodic single
sheet of 60 carbon atoms supercell passivated with hydrogens
and organic groups have been used for the chemical adsorp-
tion (chemisorption) purposes. A two-dimensional and peri-
odic single sheet of 100 carbon atoms supercell has been used
for the description of physical adsorption (physisorption)
phenomena. Four adsorption sites were considered: top,
bridge, hollow sites on the pure graphene and carboxylate on
the functionalized graphene. Schemes 1(a)–(d) show the
schematic structures of titania species adsorbed on the pos-
sible sites of pure graphene and the carboxylate site of
functionalized graphene.
4. Results and discussion
Different percentages of Fe doped TiO2/FGSs were synthe-
sized by a sol–gel method in a green solvent mixture of water
and ethanol to give decorated graphene sheets. The experi-
mental conditions and resulting properties of the synthesized
materials are summarized in table 1.
Typical morphologies of the as-prepared FGSs are shown
in figures 1(a) and (b) using SEM and TEM imaging. The
SEM image of the FGSs shows the exfoliation of the reduced
Table 1. Synthesis conditions, morphology, BET surface area, pore volume, and pore size distribution of Fe-doped TiO2/functionalized
graphene sheet composites.
Dopant Calcination T (°C) Rutile (%) Bandgap (eV) Surface area (m2
g−1
) Color
TiO2 450 0 3.2 50 White
TiO2/FGSs 450 0 2.9 124 Gray
0.6 % Fe–TiO2 450 0 2.6 68 Yellow
0.2% Fe–TiO2/FGSs 450 0 2.9 130 Light yellow
0.4% Fe-TiO2/FGSs 450 0 2.7 158 Light yellow
0.6% Fe doped TiO2/FGSs 450 0 2.5 188 Yellow
0.6% Fe–TiO2/FGSs 700 53 2.5 98 Yellow
0.8% Fe–TiO2/FGSs 450 0 2.5 190 Orange
1% Fe–TiO2/FGSs 450 0 2.5 193 Orange
Scheme 1. Adsorption sites on pure and functionalized graphene
substrates. TiO2 adsorbates can possibly adsorb on (a) a top site, (b)
a bridge site, (c) a hollow site of pure graphene and (d) a carboxylate
site of functionalized graphene.
3
Nanotechnology 25 (2014) 305601 N Farhangi et al
5. Figure 1. Functionalized graphene sheets (FGSs) (a) SEM, (b) TEM; 0.6% Fe doped TiO2/FGSs (c) SEM and (d).
Figure 2. 0.6% Fe doped TiO2 (a) SEM and (b) TEM, (c) HRTEM image of Fe doped TiO2/FGSs (0.6%) calcined at 450 °C.
4
Nanotechnology 25 (2014) 305601 N Farhangi et al
6. graphite oxides and high porosity of the graphene sheets. A
TEM image of the FGSs is shown in figure 1(b); here a thin
paper-like structure is observed which is not completely flat
showing wrinkles on the edges [51].
Most of the graphene sheets are very thin as has been
previously observed; however some of them stack together
due to van der Waals interactions. In figures 1(c) and (d),
typical SEM and TEM images of the Fe-doped TiO2 grown
on the surface of graphene sheets is shown in which a uniform
dispersion of small nanoparticles on the sheets is clearly
observable. In the TEM images, doped TiO2 nanoparticles
less than 5 nm covered the entire surface of the graphene
sheets with no significant agglomeration of nanoparticles
detected. However, more nanoparticles are observed on the
edges of the graphene sheets as darker spots are obvious on
the graphene edges. This is attributed to a higher number of
functional groups on that area as other researchers have
shown [52]. Our calculations for both TiO2 nanofibers on
graphene sheets [43] and Fe doped TiO2 nanoparticles on
graphene (this paper) are also confirm the existence of strong
chemisorptions between nanoparticles and –COOH groups on
the edges of graphene sheets.
Typical SEM and TEM images of Fe doped TiO2 are
presented in figures 2(a) and (b). When graphene sheets were
not used as a support, the size of TiO2 particles significantly
increased up to 50 nm and some of the particles agglomer-
ated. Hence, it is apparent that the graphene sheets can
facilitate uniform dispersion of the nanoparticles on its sur-
face while controlling their size. As described in detail below,
doped TiO2 particles grown from carboxyl groups on the
surface of the graphene sheets, significantly decrease the
degree of agglomeration. A HRTEM micrograph of the lattice
image of 0.6% Fe doped titania/graphene calcined at 450 °C
is given in figure 2(c), showing uniform dispersion of anatase
with d-spacing 0.35 nm (101) [53]. There was no Fe detected
in the HRTEM micrographs, indicating that all the Fe is
impregnated within the TiO2 lattice. Some amorphous regions
are also observable, corresponding to the presence of gra-
phene sheets in the composites.
The BET surface areas provided in table 1 were deter-
mined using nitrogen adsorption and desorption isotherms.
Synthesized FGSs showed high surface areas (1100 m2
g−1
)
while the BET surface area of the undoped sol–gel synthe-
sized TiO2, which was calcined at 450 °C, was found to be
85 m2
g−1
. The BET surface areas of the Fe-doped TiO2
samples were found to be slightly larger than the undoped
TiO2 (105 m2
g−1
). When Fe-doped TiO2 was grown on the
surface of the graphene sheets, the surface area increased to
180 m2
g−1
. By increasing the amount of Fe in the compo-
sites, the surface area was enhanced (230 m2
g−1
for 0.6% Fe
doped/TiO2/FGSs), which is attributed to producing more
pores inside the composites. By increasing the calcination
temperature to 700 °C, the surface area decreased to
70–112 m2
g−1
which is attributed to the agglomeration of
TiO2 nanoparticles and the collapse of the porous structure.
The FGSs did not show any peaks in XRD which means
that either all stacking is lost or the remaining stacking is
disordered [54]. Figure 3(A) shows the XRD patterns of
different amounts of Fe-doped TiO2/FGSs composites cal-
cined at 450 °C. All spectra show anatase phase, however the
crystallinity varies. By increasing the amount of Fe from 0.2
to 0.6%, the crystallity increases, whereas further increasing
to 1% decreases the crystallity probably because of excess
amount of Fe which can not properly fit inside the TiO2
crystal. In figure 3(B), the XRD patterns of Fe doped TiO2
(0.6%) with and without graphene are compared. The crys-
tallinity is significantly higher when grown on the FGSs. In
explanation, when Fe doped TiO2 nanostructures were grown
on the surface of the graphene sheets, the functional groups
on the graphene sheets acted as templates, enhancing crys-
tallization and resulting in smaller sized TiO2 nanocrystals
being obtained.
Diffuse reflectance UV–Vis spectroscopy was applied to
further study the interactions between the Fe doped TiO2 and
graphene in the composites. The UV–Vis spectra indicates
that Fe doped TiO2/graphene gave strong absorbance in the
UVA-visible region (300–700 nm) with the band gap
decreasing to 2.5 eV, as calculated using the basic energy
Figure 3. XRD spectra of (A) Fe doped 0.2% (a), 0.6% (b) and 1% (c), (B) 0.6 Fe doped TiO2 (a), 0.6 Fe doped TiO2/graphene (b) calcined
at 450 °C.
5
Nanotechnology 25 (2014) 305601 N Farhangi et al
7. equation (E = hc/λ) (table 1). Different studies on TiO2/gra-
phene composites have shown that graphene can narrow the
band gap of TiO2 [36, 55, 56]. Formation of Ti–O–C bonding
between TiO2 and graphene sheets, similar to that observed
with carbon-doped TiO2 composites, is a potential reason for
the red shift in the UV spectra [57].
Metal-doping enhances visible light absorption owing to
the formation of intermediate energy levels, leading to a
decrease in the energy band gap [58]. Figure 4(A) compares
the UV spectra of Fe-doped TiO2 with and without graphene
sheets. By adding graphene to the system, the band gap of Fe
doped TiO2 decreased from 2.6 to 2.5 eV, which helps con-
firm that graphene acts as a photosensitizer. In figure 4(B), the
UV spectra of TiO2 with band gap of 3.2 eV is compared to
TiO2/FGSs with a band gap of 2.9 eV.
Graphene has two characteristic peaks in the Raman
spectra; (figure 5(d)) i.e. a broad D and G band, which are
assigned to the C sp2
atoms and one to C sp3
atoms,
respectively [59]. After functionalization of graphene with
TiO2, the intensity ratio of the D band to G band, which is
proposed as an indication of disorder in the prepared cata-
lysts, increased dramatically indicating good attachment of
the TiO2 nanoparticles to the graphene surface. All doped
TiO2/FGSs samples calcined at 450 °C are present in the
anatase phase, corresponding to characteristic peaks around
143 cm−1
, which are attributed to the main Eg anatase vibra-
tion mode. Crystalline TiO2 showed the vibration peaks at
400 cm−1
(B1g), 519 cm−1
(A1g) and 640 cm−1
(Eg) as well
[60]. The Raman spectra of the prepared Fe-doped TiO2/
FGSs are shown in figures 5(b), (c) which is in good accor-
dance with the XRD patterns as no Fe peak is detected. The
peak position shifts towards a higher wavenumber in the order
of 0.2 and 0.8% Fe doped TiO2/FGSs, indicating an increase
in the number of surface oxygen vacancies. The more oxygen
vacancies induced by Fe-doping could be attributed to the
incorporation of Fe-dopants into the TiO2 lattice. Zhu et al
Fe-doped nanocrystalline was prepared by Zhu et al via a
non-hydrolytic sol–gel method and showed the same shift in
the Raman study [61].
To further investigate nanoparticle linking to graphene,
XPS was examined. The XPS spectra of 0.6% Fe doped TiO2/
FGSs shows 6.1% Fe 2p, 54.7% O1s, 18.7% Ti 2p and 20.5%
C1s (figure 6).
In the high resolution of C1s, the intensity of C=O and
C–OH peaks decreased compared to those of FGSs. Coordi-
nation between Ti and carboxylic acids on the surface of the
graphene sheets resulted in a shift of C=O peak which is
located at 289.25 eV to a lower energy value (288.8 eV). The
O 1s showed a main peak at 530.3 eV which is assigned to the
(Ti–O). Hyroxyl group showed a peak at 533.4 eV in FGSs.
This peak disappeared after functionalization of FGSs with Fe
doped TiO2 , but the peak at 531.4 eV corresponding to the
carbonyl group is still available [62]. As shown in figure 7,
two peaks at 458.4 eV and 464.1 eV which are consistent with
the values of Ti4+
in the TiO2 lattices represent the Ti 2p3/2
and Ti 2p1/2 for Fe doped TiO2 on the graphene surface [63].
Fe3
(2p3/2 and 2p1/2) also represent peaks at 711.9 eV and
724.6 eV , respectively which exhibit a slightly positive shift
compared to those in Fe2O3 (710.7 eV for 2p3/2 and 724.3 eV
for 2p1/2) due to formation of Fe–O–Ti bonding and trans-
ferring the electrons from Fe3+
into the TiO2 lattice [63]. We
observed similar results when comparing Fe-doped TiO2/
FGSs nanowires prepared using scCO2 [42].
Figure 4. Diffuse reflectance UV–Vis spectra of: (A) (a) TiO2 anatase; (b) 0.4% Fe doped TiO2 and (c) 0.4% Fe doped TiO2/FGSs; (B) (a)
TiO2 anatase, (b) TiO2/FGSs.
Figure 5. Raman spectrum of TiO2 (a) Fe doped TiO2/FGSs (0.2%)
(b), Fe doped TiO2 (0.8%) (c), and functionalized graphene sheets
(FGSs) (d).
6
Nanotechnology 25 (2014) 305601 N Farhangi et al
8. 5. Theoretical calculations of adsorption and energy
transfer
Presently, only a few theoretical studies exist on the inter-
actions of TiO2 and graphene sheets [64]. However, most of
these studies have only focused on ideal graphene sheets
(periodic and infinite supercells), without any functional
groups or defective sites interacting with gas phase or
molecular TiO2. We recently studied the interaction of small
size titania nanostructures with pure and functionalized
graphene by DFT [43]. Hence, here we investigate the
interactions of Fe doped TiO2 when in direct contact with
Figure 6. XPS spectra of FGSs, high resolution (a) C (1s) and (b) O (1s).
Figure 7. XPS spectra of 0.6% Fe doped TiO2/FGSs, high resolution (a) O, (b) C, (c) Ti and (d) Fe.
7
Nanotechnology 25 (2014) 305601 N Farhangi et al
9. pure and FGSs, comparing the results with our recent study
of undoped rutile and anatase TiO2 nanostructures [43]. An
initial unit cell of anatase TiO2 (Ti4O8) was used doped with
a Fe cation, which can be can be placed in 4 different
positions of the unit cell. The study was extended adding
two Fe-doped anatase TiO2 adsorbates with much lower
doping concentration. Scheme 1 shows the schematic
structure of Fe-doped anatase titania adsorbates used for
chemical and physical adsorption on graphene. A 12-atom
adsorbate of 0.25 concentration value was initially used
followed by a 24-atom of a 0.125 concentration and a 48-
atom nanostructure of 0.0625 concentration were used to
complete the adsorption study. The FeTi3O8 TiO2 unit cell
was initially calculated in a small rectangular supercell
(3.29 × 3.29 × 10.27 Å3
) for a structural optimization of its
bulk properties. Then the isolated nanostructure had its
wavefunction optimized in a large rectangular supercell
(21.2 × 12.3 × 30.0 Å3
). The same ground states set up was
applied to the FeTi7O16 nanostructures which was initially
calculated in a rectangular unit cell of
(3.26 × 3.26 × 20.02 Å3
) and to the FeTi15O32 nanostructure
in a (3.23 × 6.58 × 20.02 Å3
) unit cell. Spin polarization was
considered in all calculations, and the electronic structures
were optimized to their ground states.
Figure 8 shows three unit cells of Fe doped anatase at
different concentration and specifically where the Fe atom
was doped within the anatase TiO2 structure. Pink spheres
represent the titanium atoms, yellow spheres the iron atom
and red spheres the oxygen atoms. From the XPS results, we
chose (x = 1) as the unit cell, which corresponds to the
formula FeTi3O8, FeTi7O16 and FeTi15O32 and respectively
to concentrations of 25%, 12% and 6% (w%) cation doping
of anatase. Note that the Fe atom is not involved in binding
to the graphene sheet, as the Fe-doping only plays a role in
the electronic structure of anatase. Titanium binds to the
clean and FGS in all cases of physisorption and chemi-
sorption. These adsorption sites are the top, the bridge, the
hollow, and the carboxylate site. Schemes 1(a), (b) and (c)
show these three types of physical adsorptions (physisorp-
tion) while Scheme 1(d) shows the unique chemical
adsorption (chemisorption) site. If anatase TiO2 is rotated
by 90° on graphene, it results in a rotated adsorption site
that may lead to slightly different results, as previously
discussed [43].
All binding energy values of anatase TiO2 adsorbed on
graphene are presented in table 2.
Figure 9 shows a typical adsorption study of titania
nanostructures adsorbed on graphene substrates, figure 9(a)
FeTi15O32 physisorbed on pure graphene and figure 9(b)
FeTi15O32 chemisorbed on functionalized graphene. A 100
carbon atom supercell was used for the physisorption study
(figure 9(a)), while a 60 carbon atom supercell terminated by
hydrogens, alcohol and carboxylates groups was used for the
chemisorption study (figure 9(b)). The adsorption energy can
Figure 8. Schematic structure of Fe-doped anatase TiO2 nanos-
tructures. By the substitution of a Ti atom with Fe on a 12, a 24 and a
48-atom unit cell of anatase titania we obtain respectively (a)
FeTi3O8, (b) FeTi7O16 and (c) FeTi15O32 compounds.
Table 2. Calculated binding energy values for Fe-doped anatase
TiO2 nanostructures adsorbed on graphene substrates.
FeTi3O8 FeTi7O16 FeTi15O32
Adsorption
sites
Eb
(eV)
Ti–C
(Å)
Eb
(eV)
Ti–C
(Å)
Eb
(eV)
Ti–C
(Å)
Top 1.774 2.20 1.845 2.21 1.874 2.18
Bridge 1.742 2.32 1.649 2.28 1.759 2.33
Hollow 2.201 2.47 2.222 2.42 2.398 2.40
Carboxylate 5.785 1.94 5.623 1.96 5.380 1.97
Figure 9. Physisorption and chemisorption of anatase titania on
graphene and functionalized graphene substrates. FeTi15O32 adsorbs
successfully on (a) a top site of pure graphene and (b) a carboxylate
site of functionalized graphene.
8
Nanotechnology 25 (2014) 305601 N Farhangi et al
10. be calculated using the following equation:
= +
−
( )
( )
E E E
E
(graphene) TiO
TiO graphene ,
b 2
2
where Eb(or Eads(> 0)) represents the positive amount of
binding energy. E(graphene) represents the total energy of the
graphene sheet while E(TiO2) represents the total energy of
the anatase (clean or doped) nanostructure. E(TiO2/graphene)
represents the total energy of a system in which both gra-
phene and Titania are interacting. The adsorption energy was
assumed to be favored when the binding energy was positive.
For convenience, the binding energy Eb will be used in place
of Eads in the remaining sections [64].
A summary of the results for the optimized structures for
all Fe-doped TiO2/graphene systems is provided in table 2.
Note that the physisorption is represented by Ti–C interac-
tions and chemisorption by Ti–O interactions.
The three Fe-doped anatase nanostructures were suc-
cessfully adsorbed on graphene and functionalized graphene
on all the adsorption sites described in the above table 2. Fe-
doped anatase TiO2 is generally more favorable while
adsorbed on graphene than pure anatase [43]. For all species,
the chemical adsorption shows a higher binding energy
compared to all physical adsorption sites. In terms of physi-
sorption of Fe-doped titania on graphene, the hollow site
shows a higher binding energy followed by the top site and
the bridge site in every Fe-doped anatase nanostructure. As a
result, Fe-doped anatase TiO2 nanostructures are more likely
to start their growth on the hollow sites of pure graphene.
As can be seen, the shortest separation between an atom
of TiO2 and the closest carbon atom of the graphene layer is
between 2.19 and 2.45 Å in the case of physisorption and
1.92 Å for chemisorption. After doping TiO2 with Fe, all
distances increased by just 0.02 Å. Das et al deposited dif-
ferent nanoparticles such as TiO2, ZnO, Fe3O4, and Ni on
graphene surfaces and reports that the closest distances of
graphene’s carbon and nanoparticles range from 2.4 to
3.0 Å [44].
Interestingly, in physisorption, the relative binding
energies are higher in all Fe-doped TiO2 embedded in gra-
phene than the corresponding undoped nanostructure, almost
by 0.4 eV. The binding energy values remain stable with
different sizes of Fe doped nano-adsorbates. It seems that
when we replace one Ti atom with Fe, some magnetization in
the composites occurs altering the charge transfer between the
deposited nanoparticles and graphene. Das et al studied the
interaction of graphene decorated by semiconducting and
magnetic nanoparticles and found significant electronic and
magnetic interactions facilitating charge transfer between the
nanoparticles and graphene.
Higher binding energies with almost the same Ti–C bond
distances helps confirm strong physisorption occurred
between the Fe doped TiO2 and the graphene sheets. More-
over, the binding energy in the presence of carboxylate
groups on graphene results in slightly decreased chemisorp-
tion. However, the chemisorption value between the Fe doped
TiO2 and graphene surface was relatively strong, i.e. having a
calculated bonding energy of roughly 5.50 eV.
6. Visible light photocatalytic activity of
Fe–TiO2/FGSs
17β-estradiol (E2) was chosen as the model organic com-
pound to evaluate the photoactivity of the prepared Fe doped
TiO2 nanoparticles on graphene sheets under visible light
irradiation (λ > 400 nm). Photocatalytic degradation normally
follows first-order kinetics:
= −
+
C
t
k
K C
K C
d
d 1
(3)r
a
a
(dC/dt) is the degradation rate of E2, C is the concentration of
E2 in the solution, t is reaction time, kr is the reaction rate
constant, and Ka is the adsorption coefficient of the reactant.
When the value of C is very small, KaC is negligible in
equation (3). At t = 0, C = C0, it can be described as
equation (4)
= ×
⎛
⎝
⎜
⎞
⎠
⎟
C
C
K tln . (4)0
app
The photocatalytic activities are shown in table 3, in
which the observed rate constant was increased slightly to
0.003 h−1
in the presence of undoped TiO2. However, Fe-
TiO2 showed significantly enhanced photocatalytic activities
under the visible light irradiation. By increasing the amount
of Fe in the composites from 0.4 to 0.6%, the rate constant
increased from 0.0091 to 0.0123 h−1
. Further increasing the
Table 3. Visible-light photocatalytic activities of Fe-TiO2 and Fe-
TiO2/FGSs samples for the degradation of E2.
Materials
k (h−1
) (cal-
cined at
450 °C) first
cycle
k (h−1
) (cal-
cined at
450 °C) sec-
ond cycle
k (h−1
) (cal-
cined
at 700 °C)
TiO2 0.002 0.0015 0.0012
TiO2/FGSs 0.003 0.0018 0.00176
0.2% Fe
doped TiO2
0.004 0.0032 0.0018
0.2% Fe doped
TiO2/FGSs
00.007 0.0054 0.0037
0.4% Fe
doped TiO2
0.0071 0.0052 0.00501
0.4% Fe doped
TiO2/FGSs
0.0091 0.0076 0.00721
0.6% Fe
dopedTiO2
0.0083 0.0059 0.00521
0.6%Fe doped
TiO2/FGSs
0.0123 0.0096 0.00892
0.8% Fe
doped TiO2
0.0087 0.0062 0.00592
0.8% Fe doped
TiO2/FGSs
0.0122 0.0093 0.00891
9
Nanotechnology 25 (2014) 305601 N Farhangi et al
11. amount of Fe to 0.8% did not affect the rate constant sig-
nificantly (k = 0.0123 h−1
), similar to the results obtained by
UV–Vis. By preparing Fe–TiO2 on the surface of graphene,
the rate constant of E2 photodegradation increased sig-
nificantly (table 2).
To examine recycling, all catalysts were filtered, then
tested for the second cycle. Although the rate constants
decreased, the catalysts were still active. Catalysts calcined at
700 °C were also tested for E2 photodegradation. The rate
constant decreased significantly compared to catalysts cal-
cined at 450 °C. This reduction should be because of catalyst
sintering, i.e. collapsing the pores at high temperature and a
subsequent decreasing of surface area as described above.
7. Conclusions
High performance Fe doped TiO2 on the surface of graphene
sheets were successfully synthesized via a simple sol–gel
process in the green solvent mixture of water/ethanol.
Fe–TiO2/FGSs showed higher visible light absorption, higher
surface areas than corresponding samples prepared without
graphene. The prepared materials were examined for visible
light degradation of E2—an endocrine disrupting hormone,
which showed higher photocatalytic activity compared to
TiO2/graphene and metal doped TiO2 composites. The
observed photocatalytic enhancement can be explained by
enhanced adsorptivity of dyes, extending the photoresponse
range, and enhancing the charge separation and transportation
properties simultaneously. DFT calculations were also per-
formed, indicating possible physical interactions between Fe
doped TiO2 and graphene sheets on three different positions
i.e. the top, the bridging and the hollow sites. The hollow sites
were shown as the most stable configuration. Fe doped TiO2/
graphene composites showed higher stability than TiO2/gra-
phene composites because of higher charge transfer from the
doped semiconductor to the graphene sheets. Fe doped TiO2
decorated on carboxylated graphene sheets were also inves-
tigated which show strong chemical interactions between the
Fe doped TiO2 and graphene. These materials provide new
possibilities in the investigation of TiO2–graphene composites
and promote their practical application in addressing various
environmental issues.
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