This document summarizes the preparation, characterization, and photocatalytic activity of nitrogen-doped titanium dioxide (TiO2). Yellow nitrogen-doped TiO2 was prepared through a sol-gel method using titanium isopropoxide and urea as precursors. Characterization with XRD, BET, TEM, XPS, and UV-Vis showed the materials were crystalline anatase TiO2 with nitrogen doping extending light absorption into the visible range. Photocatalytic testing demonstrated that nitrogen-doped TiO2 had higher activity for degrading the pesticide 2,4-D under visible light irradiation compared to undoped TiO2.
Visible Light Induced Selective Photocatalytic Oxidation of Benzyl Amine to N...IJERA Editor
Irradiated semiconductor catalysis in the presence of molecular oxygen can be considered as an innovative and sustainable technique for organic transformations. The present work reports the preparation ofGraphene oxide/TiO2composite by improved Hummer’s method followed by hydrothermal technique. The prepared system was characterized by various physico-chemical techniques such as X-Ray diffraction, IR-Spectroscopy, UV-DRS, XPS, SEM and TEM Analysis.On reaction, benzylamine in CH3CN yieldedN-benzylidene-1-phenylmethanamine as the sole product. The reaction was monitored by GC-MS Analysis.
Visible light assisted photocatalytic reduction of CO2 using a graphene oxide...Pawan Kumar
A new heteroleptic ruthenium complex containing 2-thiophenyl benzimidazole ligands was synthesized using a microwave technique and was immobilized to graphene oxide via covalent attachment. The synthesized catalyst was used for the photoreduction of carbon dioxide under visible light irradiation without using a sacrificial agent, which gave 2050 μmol g−1 cat methanol after 24 h of irradiation
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.
Photocatalytic Degradation of Azo Dye (Methyl Red) In Water under Visible Lig...IJEAB
Commercial TiO2 (P25) co-doped with bimetallic silver and nickel nanoparticles (Ag-Ni/TiO2) was prepared by g-irradiation method. The properties of Ag-Ni/TiO2 were characterized by X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), energy dispersive X-ray spectroscopy techniques (EDX) and surface area measurement by Brunauer-Emmett-Teller (BET) method. The size of silver and nickel nanoparticles was determined by TEM to be of 1-2 nm.The photo-catalytic degradation of azo dye methyl red in the aqueous suspensions of TiO2 and Ag-Ni/TiO2 under visible light was carried out to evaluate the photo-catalytic activity. Results showed that Ag-Ni/TiO2 was found to enhance photo-degradation efficiency of azo dye metyl red compared to commercial TiO2. The results showed that Ag 3% (w/w) and Ni 1.5% (w/w) co-doped TiO2 had the highest photoactivity among all studied samples under visible light. Thus, g-irradiation method can be suitably applied to prepare photo-catalyst of Ag-Ni/TiO2with highly photocatalytic activity.
Photocatalytic degradation of some organic dyes under solar light irradiation...Iranian Chemical Society
Nanoparticles of the ZnO and TiO2 were synthesized and the physicochemical properties of the compounds were characterized by IR, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD patterns of the ZnO and TiO2 nanoparticles could be indexed to hexagonal and rutile phase, respectively. Aggregated nanoparticles of ZnO and TiO2 with spherical-like shapes were observed with particle diameter in the range of 80-100 nm. These nanoparticles were used for photocatalytic degradation of various dyes, Rhodamine B (RhB), Methylene blue (MB) and Acridine orange (AO) under solar light irradiation at room temperature. Effect of the amount of catalyst on the rate of photodegradation was investigated. In general, because ZnO is unstable, due to incongruous dissolution to yield Zn(OH)2 on the ZnO particle surfaces and thus leading to catalyst inactivation,the catalytic activity of the system for photodegradation of dyes decreased dramatically when TiO2 was replaced by ZnO.
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
Visible Light Induced Selective Photocatalytic Oxidation of Benzyl Amine to N...IJERA Editor
Irradiated semiconductor catalysis in the presence of molecular oxygen can be considered as an innovative and sustainable technique for organic transformations. The present work reports the preparation ofGraphene oxide/TiO2composite by improved Hummer’s method followed by hydrothermal technique. The prepared system was characterized by various physico-chemical techniques such as X-Ray diffraction, IR-Spectroscopy, UV-DRS, XPS, SEM and TEM Analysis.On reaction, benzylamine in CH3CN yieldedN-benzylidene-1-phenylmethanamine as the sole product. The reaction was monitored by GC-MS Analysis.
Visible light assisted photocatalytic reduction of CO2 using a graphene oxide...Pawan Kumar
A new heteroleptic ruthenium complex containing 2-thiophenyl benzimidazole ligands was synthesized using a microwave technique and was immobilized to graphene oxide via covalent attachment. The synthesized catalyst was used for the photoreduction of carbon dioxide under visible light irradiation without using a sacrificial agent, which gave 2050 μmol g−1 cat methanol after 24 h of irradiation
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.
Photocatalytic Degradation of Azo Dye (Methyl Red) In Water under Visible Lig...IJEAB
Commercial TiO2 (P25) co-doped with bimetallic silver and nickel nanoparticles (Ag-Ni/TiO2) was prepared by g-irradiation method. The properties of Ag-Ni/TiO2 were characterized by X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), energy dispersive X-ray spectroscopy techniques (EDX) and surface area measurement by Brunauer-Emmett-Teller (BET) method. The size of silver and nickel nanoparticles was determined by TEM to be of 1-2 nm.The photo-catalytic degradation of azo dye methyl red in the aqueous suspensions of TiO2 and Ag-Ni/TiO2 under visible light was carried out to evaluate the photo-catalytic activity. Results showed that Ag-Ni/TiO2 was found to enhance photo-degradation efficiency of azo dye metyl red compared to commercial TiO2. The results showed that Ag 3% (w/w) and Ni 1.5% (w/w) co-doped TiO2 had the highest photoactivity among all studied samples under visible light. Thus, g-irradiation method can be suitably applied to prepare photo-catalyst of Ag-Ni/TiO2with highly photocatalytic activity.
Photocatalytic degradation of some organic dyes under solar light irradiation...Iranian Chemical Society
Nanoparticles of the ZnO and TiO2 were synthesized and the physicochemical properties of the compounds were characterized by IR, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD patterns of the ZnO and TiO2 nanoparticles could be indexed to hexagonal and rutile phase, respectively. Aggregated nanoparticles of ZnO and TiO2 with spherical-like shapes were observed with particle diameter in the range of 80-100 nm. These nanoparticles were used for photocatalytic degradation of various dyes, Rhodamine B (RhB), Methylene blue (MB) and Acridine orange (AO) under solar light irradiation at room temperature. Effect of the amount of catalyst on the rate of photodegradation was investigated. In general, because ZnO is unstable, due to incongruous dissolution to yield Zn(OH)2 on the ZnO particle surfaces and thus leading to catalyst inactivation,the catalytic activity of the system for photodegradation of dyes decreased dramatically when TiO2 was replaced by ZnO.
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
Physical and Magnetic Properties of Manganese Ferrite NanoparticlesIJERA Editor
In this paper, manganese ferrite (MnFe2O4) nanoparticles were synthesized using chemical bath deposition (CBD) method and characterized by XRD and TEM to determine different properties of nanoparticles. The results obtained showed the formation of manganese ferrite nanoparticles with an average particle size are in good agreement with previous reported experimental results and displayed good magnetic properties. Magnetic properties was determined using Vibrating Sample Magnetometer(VSM). Due to simplicity and low cost of this process, it could be used for synthesis of ferrites nanoparticles. These materials may be used in drug delivery systems, electronic devices and water remediation.
Si-Imidazole-HSO4 Functionalized Magnetic Fe3O4 Nanoparticles as an Efficient...Iranian Chemical Society
An efficient and simple method for the preparation of Si-Imidazole-HSO4 functionalized magnetic Fe3O4 nanoparticles (Si-Im-HSO4 MNPs) and used as an efficient and reusable magnetic catalysts for the regioselective ring opening of epoxides under green conditions in water. This catalyst was used for the ring opening of epoxide corresponding to the thiocyanohydrins and azidohydrines. Compared to the classical ring opening of epoxides, this new method consistently has the advantage of excellent yields, short reaction times, and methodological simplicity.
The Low-Background HPGE Γ-Spectrometer OBELIX for the Investigation of the Do...IOSRJAP
A new ultra-low-background spectrometer based on a HPGe detector with a sensitive volume of 600 cm 3 was developed to investigate rare nuclear processes, such as resonant neutrino-less double electron capture (0νEC/EC) and double beta decay processes (2ν2β – , 2νβ+EC, 2νEC/EC) to the excited states of daughter nuclei. The spectrometer was installed at the Modane underground laboratory (LSM, France, 4800 m w.e.). Sensitivity of the spectrometer and its background were tested. A new method for the efficiency calibration in measurements of low-active samples was developed. A spectrometer was used for the measurements of low active materials and samples. Results obtained in 395 h investigation of resonant 0νEC/EC decay of 106Cd to the 2718 keV and 2741 keV excited states of 106Pd with ~23.2 g of enriched 106Cd, β +EC, EC/EC decays of 58Ni in measurements of ~21.7 kg sample of natural nickel and 2ν2β – decay of 100Mo sample with the mass of 2588 g to the 0+ , 1130 keV and 2+ , 539.5 keV excited states of 100Ru are presented.
Enhancing the photocatalytic activity of commercial P25 퐓퐢퐎 powder by combin...IJECEIAES
Titanium dioxide ( TiO 2 ) is the most popular photocatalytic material. However, its operation is limited to UV light only. In this paper, we tried to improve the visible light responsiveness of TiO by doping Nickel (Ni) using the sol-gel method. By combining Ni-doped TiO 2 powder with commercially available P25 TiO 2 2 powder to make photocatalytic thin films, significant improvement in photocatalytic activity has been obtained. Furthermore, we also studied the relationship between the surface condition of photocatalytic thin films and their photocatalytic activity. The surface condition was improved by the multilayer electrophoresis deposition method. Based on experimental results, by combining 10 20 wt% Ni-doped TiO with P25 TiO , we could significantly enhance the photocatalytic activity of P25 TiO 2 .
All about Radiations, Different energy particles- starting from Basics to New methods of analysis also includes DIfferent applications related to it.
Medha Thakur
(M.Sc Chemistry)
A highly efficient, recyclable and magnetically separable core-shell structured CuZnO@Fe3O4 microsphere
wrapped with reduced graphene oxide (rGO@CuZnO@Fe3O4) photocatalyst has been developed and used
for the photoreduction of carbon dioxide with water to produce methanol under visible light irradiation.
Owing to the synergistic effect of the components and to the presence of a thin Fe2O3 layer on Fe3O4,
rGO@CuZnO@Fe3O4 4 exhibited higher catalytic activity as compared to the other possible combinations
such as CuZnO@Fe3O4 2 and GO@CuZnO@Fe3O4 3 microspheres. The yield of methanol in case of using
2 and 3 as photocatalyst was found to be 858 and 1749 mol g−1 cat, respectively. However, the yield
was increased to 2656 mol g−1 cat when rGO@CuZnO@Fe3O4 4 was used as photocatalyst under similar
experimental conditions. This superior photocatalytic activity of 4 was assumed to be due to the
restoration of the sp2 hybridized aromatic system in rGO, which facilitated the movement of electrons
and resulted in better charge separation. The synthesized heterogeneous photocatalyst could readily be
recovered by external magnet and successfully reused for six subsequent cycles without significant loss
in the product yield
PHOTOCATALYTIC DEGRADATION OF RB21 DYE BY TIO2 AND ZNO UNDER NATURAL SUNLIGHT...IAEME Publication
The present work aims to degrade the RB21 dye from synthetic wastewater using
semiconductors TiO2 and ZnO. The activity of photocatalytic degradation process of dye was
carried out using different light sources of 900 W/m
2
intensity in natural sunlight from 02:00 to
04:00 pm with 48°C temperature in Ahmedabad city in the month of May, 600 Watt microwave
oven and high pressure UV-light photocatalytic reactor of wavelength 200-450 nm. All the
experiments were performed with dye concentration 50 mg/L, catalyst dosage 0.8 g, pH 7, room
temperature, irradiation time 240 min followed by 30 min in dark. All the samples were collected at
different time intervals of 30, 60, 90, 120, 150, 180, 210, 240 min for the analysis of COD
degradation and color removal. The best performances was achieved using high pressure UVphotocatalytic
reactor using TiO2. The successful result obtained using TiO2is 80% COD
degradation and 99% color removal followed by 75% COD and 99% color removal with ZnO.
Chemical kinetics was found to follow first order mechanism. The formation of intermediate
compounds and identification of the final products were carried out using LCMS/MS analysis and
FT-IR techniques.
degradation of pollution and photocatalysisPraveen Vaidya
The presentation deals with the use of conduction of photocatalytic reaction using the transition metal doped transparent semiconducting thinfilms. The precursor to film is prepared by the SILAR method, which is a chemical method.
Alkali P-Nitrophenolates for Short Wavelength Laser GenerationEditor IJCATR
Single crystals of alkali p-Nitrophenolates namely sodium p-nitrophenolate dihydrate (SPNP), potassium p- nitrophenolate
monohydrate (PPNP) and lithium p-nitrophenolate trihydrate (LPNP) using Group I elements (Na, K, Li) and p-nitrophenols were grown
by solvent evaporation method. Single crystal XRD analysis shows that SPNP and LPNP crystallize in noncentrosymmetric space group
while PPNP is centrosymmetric. Using Autox software, all the peaks in the recorded powder XRD spectrum of the samples were identified
and indexed. The FT – IR spectra of the sample reveals the characteristic vibrations of the functional groups present in alkalinitrophenolates.
A weak absorption band around the region 1589–1641 cm-1 confirms the presence of the phenolic ring. A broad
intermolecular hydrogen bonded OH stretching at 3325 cm-1 of p- nitrophenol is shifted which shows the increase in the polarizable nature
of p–nitrophenol and thus easily forms a metal (sodium/ potassium/ lithium) coordination compound. UV-Vis spectrum shows that all the
crystals are transparent above 400 nm and has a wide optical window in the visible region. Intense absorption peak in the UV region may
be due to the colored nature of the compound. Addition of metal ion (sodium/potassium) modifies the optical transparency of the original
molecule (p-nitro phenol) and consequently introduces a bath chromic shift of 90/40 nm in the crystal transparency of the samples. Kurtz
powder technique result shows that the relative SHG efficiency of SPNP and LPNP was nearly 5 and 9.25 times of KDP.
Characterization of Clay/Chitosan Nanocomposites and their Use for Adsorption...Editor IJCATR
In this study, composites films were prepared from Chitosan biopolymer and Montmorillonite nanoclay (MMT) by dispersion of MMT into Chitosan solution with different weight percentage (2.5, 5, 7.5, 10, 12.5, 15 and 75% wt. /wt. nanoclay/chitosan), using both sonication and casting technique methods to obtain good dispersion of nanoclay. The structural properties of these nanocomposites samples examined by XRD and FTIR . The XRD patterns indicating that formation of an intercalated nanostructure as exfoliated and flocculated structure . Also the complexion of the dopant with the biopolymer was examined by FTIR studies. The experiments of Mn(ΙΙ) ions adsorption were carried out on MMT/chitosan nanocomposites. The effect of various parameters such as pH, contact time, adsorption mass, initial Mn(ΙΙ) concentration and temperature on the adsorption of Mn(ΙΙ) removal onto MMT/chitosan nanocomposites was investigated. Two adsorption isotherm models were applied Freundlich and Langmuir to fit the experimental data. Langmuir isotherm modeling was suitable for description the data at equilibrium state. The kinetic isotherm was found to follow the pseudo-second-order model. Also, the thermodynamics parameters of the adsorption such as Gibbs free energy∆G^o, entropy ∆S^o and enthalpy ∆H^o were discussed and the results demonstrate that the adsorption process is spontaneous and endothermic.
Physical and Magnetic Properties of Manganese Ferrite NanoparticlesIJERA Editor
In this paper, manganese ferrite (MnFe2O4) nanoparticles were synthesized using chemical bath deposition (CBD) method and characterized by XRD and TEM to determine different properties of nanoparticles. The results obtained showed the formation of manganese ferrite nanoparticles with an average particle size are in good agreement with previous reported experimental results and displayed good magnetic properties. Magnetic properties was determined using Vibrating Sample Magnetometer(VSM). Due to simplicity and low cost of this process, it could be used for synthesis of ferrites nanoparticles. These materials may be used in drug delivery systems, electronic devices and water remediation.
Si-Imidazole-HSO4 Functionalized Magnetic Fe3O4 Nanoparticles as an Efficient...Iranian Chemical Society
An efficient and simple method for the preparation of Si-Imidazole-HSO4 functionalized magnetic Fe3O4 nanoparticles (Si-Im-HSO4 MNPs) and used as an efficient and reusable magnetic catalysts for the regioselective ring opening of epoxides under green conditions in water. This catalyst was used for the ring opening of epoxide corresponding to the thiocyanohydrins and azidohydrines. Compared to the classical ring opening of epoxides, this new method consistently has the advantage of excellent yields, short reaction times, and methodological simplicity.
The Low-Background HPGE Γ-Spectrometer OBELIX for the Investigation of the Do...IOSRJAP
A new ultra-low-background spectrometer based on a HPGe detector with a sensitive volume of 600 cm 3 was developed to investigate rare nuclear processes, such as resonant neutrino-less double electron capture (0νEC/EC) and double beta decay processes (2ν2β – , 2νβ+EC, 2νEC/EC) to the excited states of daughter nuclei. The spectrometer was installed at the Modane underground laboratory (LSM, France, 4800 m w.e.). Sensitivity of the spectrometer and its background were tested. A new method for the efficiency calibration in measurements of low-active samples was developed. A spectrometer was used for the measurements of low active materials and samples. Results obtained in 395 h investigation of resonant 0νEC/EC decay of 106Cd to the 2718 keV and 2741 keV excited states of 106Pd with ~23.2 g of enriched 106Cd, β +EC, EC/EC decays of 58Ni in measurements of ~21.7 kg sample of natural nickel and 2ν2β – decay of 100Mo sample with the mass of 2588 g to the 0+ , 1130 keV and 2+ , 539.5 keV excited states of 100Ru are presented.
Enhancing the photocatalytic activity of commercial P25 퐓퐢퐎 powder by combin...IJECEIAES
Titanium dioxide ( TiO 2 ) is the most popular photocatalytic material. However, its operation is limited to UV light only. In this paper, we tried to improve the visible light responsiveness of TiO by doping Nickel (Ni) using the sol-gel method. By combining Ni-doped TiO 2 powder with commercially available P25 TiO 2 2 powder to make photocatalytic thin films, significant improvement in photocatalytic activity has been obtained. Furthermore, we also studied the relationship between the surface condition of photocatalytic thin films and their photocatalytic activity. The surface condition was improved by the multilayer electrophoresis deposition method. Based on experimental results, by combining 10 20 wt% Ni-doped TiO with P25 TiO , we could significantly enhance the photocatalytic activity of P25 TiO 2 .
All about Radiations, Different energy particles- starting from Basics to New methods of analysis also includes DIfferent applications related to it.
Medha Thakur
(M.Sc Chemistry)
A highly efficient, recyclable and magnetically separable core-shell structured CuZnO@Fe3O4 microsphere
wrapped with reduced graphene oxide (rGO@CuZnO@Fe3O4) photocatalyst has been developed and used
for the photoreduction of carbon dioxide with water to produce methanol under visible light irradiation.
Owing to the synergistic effect of the components and to the presence of a thin Fe2O3 layer on Fe3O4,
rGO@CuZnO@Fe3O4 4 exhibited higher catalytic activity as compared to the other possible combinations
such as CuZnO@Fe3O4 2 and GO@CuZnO@Fe3O4 3 microspheres. The yield of methanol in case of using
2 and 3 as photocatalyst was found to be 858 and 1749 mol g−1 cat, respectively. However, the yield
was increased to 2656 mol g−1 cat when rGO@CuZnO@Fe3O4 4 was used as photocatalyst under similar
experimental conditions. This superior photocatalytic activity of 4 was assumed to be due to the
restoration of the sp2 hybridized aromatic system in rGO, which facilitated the movement of electrons
and resulted in better charge separation. The synthesized heterogeneous photocatalyst could readily be
recovered by external magnet and successfully reused for six subsequent cycles without significant loss
in the product yield
PHOTOCATALYTIC DEGRADATION OF RB21 DYE BY TIO2 AND ZNO UNDER NATURAL SUNLIGHT...IAEME Publication
The present work aims to degrade the RB21 dye from synthetic wastewater using
semiconductors TiO2 and ZnO. The activity of photocatalytic degradation process of dye was
carried out using different light sources of 900 W/m
2
intensity in natural sunlight from 02:00 to
04:00 pm with 48°C temperature in Ahmedabad city in the month of May, 600 Watt microwave
oven and high pressure UV-light photocatalytic reactor of wavelength 200-450 nm. All the
experiments were performed with dye concentration 50 mg/L, catalyst dosage 0.8 g, pH 7, room
temperature, irradiation time 240 min followed by 30 min in dark. All the samples were collected at
different time intervals of 30, 60, 90, 120, 150, 180, 210, 240 min for the analysis of COD
degradation and color removal. The best performances was achieved using high pressure UVphotocatalytic
reactor using TiO2. The successful result obtained using TiO2is 80% COD
degradation and 99% color removal followed by 75% COD and 99% color removal with ZnO.
Chemical kinetics was found to follow first order mechanism. The formation of intermediate
compounds and identification of the final products were carried out using LCMS/MS analysis and
FT-IR techniques.
degradation of pollution and photocatalysisPraveen Vaidya
The presentation deals with the use of conduction of photocatalytic reaction using the transition metal doped transparent semiconducting thinfilms. The precursor to film is prepared by the SILAR method, which is a chemical method.
Alkali P-Nitrophenolates for Short Wavelength Laser GenerationEditor IJCATR
Single crystals of alkali p-Nitrophenolates namely sodium p-nitrophenolate dihydrate (SPNP), potassium p- nitrophenolate
monohydrate (PPNP) and lithium p-nitrophenolate trihydrate (LPNP) using Group I elements (Na, K, Li) and p-nitrophenols were grown
by solvent evaporation method. Single crystal XRD analysis shows that SPNP and LPNP crystallize in noncentrosymmetric space group
while PPNP is centrosymmetric. Using Autox software, all the peaks in the recorded powder XRD spectrum of the samples were identified
and indexed. The FT – IR spectra of the sample reveals the characteristic vibrations of the functional groups present in alkalinitrophenolates.
A weak absorption band around the region 1589–1641 cm-1 confirms the presence of the phenolic ring. A broad
intermolecular hydrogen bonded OH stretching at 3325 cm-1 of p- nitrophenol is shifted which shows the increase in the polarizable nature
of p–nitrophenol and thus easily forms a metal (sodium/ potassium/ lithium) coordination compound. UV-Vis spectrum shows that all the
crystals are transparent above 400 nm and has a wide optical window in the visible region. Intense absorption peak in the UV region may
be due to the colored nature of the compound. Addition of metal ion (sodium/potassium) modifies the optical transparency of the original
molecule (p-nitro phenol) and consequently introduces a bath chromic shift of 90/40 nm in the crystal transparency of the samples. Kurtz
powder technique result shows that the relative SHG efficiency of SPNP and LPNP was nearly 5 and 9.25 times of KDP.
Characterization of Clay/Chitosan Nanocomposites and their Use for Adsorption...Editor IJCATR
In this study, composites films were prepared from Chitosan biopolymer and Montmorillonite nanoclay (MMT) by dispersion of MMT into Chitosan solution with different weight percentage (2.5, 5, 7.5, 10, 12.5, 15 and 75% wt. /wt. nanoclay/chitosan), using both sonication and casting technique methods to obtain good dispersion of nanoclay. The structural properties of these nanocomposites samples examined by XRD and FTIR . The XRD patterns indicating that formation of an intercalated nanostructure as exfoliated and flocculated structure . Also the complexion of the dopant with the biopolymer was examined by FTIR studies. The experiments of Mn(ΙΙ) ions adsorption were carried out on MMT/chitosan nanocomposites. The effect of various parameters such as pH, contact time, adsorption mass, initial Mn(ΙΙ) concentration and temperature on the adsorption of Mn(ΙΙ) removal onto MMT/chitosan nanocomposites was investigated. Two adsorption isotherm models were applied Freundlich and Langmuir to fit the experimental data. Langmuir isotherm modeling was suitable for description the data at equilibrium state. The kinetic isotherm was found to follow the pseudo-second-order model. Also, the thermodynamics parameters of the adsorption such as Gibbs free energy∆G^o, entropy ∆S^o and enthalpy ∆H^o were discussed and the results demonstrate that the adsorption process is spontaneous and endothermic.
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.
Transparent and Conducting TiO2 : Nb Thin Films Prepared by Spray Pyrolysis T...arj_online
To date, only sputtering and pulsed laser deposition (PLD) techniques have been employed
successfully to fabricate highly conducting and transparent TiO2:Nb (TNO) films. In this article, we demonstrate
that transparent and conducting
TiO2
: Nb
films can be made by the spray pyrolysis technique. The films were
deposited on Corning 7059 glass substrates at 500
15˚C using an alcoholic precursor solution consisting of
titanium (iv) isopropoxide and
NbCl5
. The influence of increasing
Nb
concentration on the electrical, optical
and structural properties was investigated. The minimum resistivity, 3.36
-3 10
Ω cm, for
Ti1-xNbxO2
film (x
= 0.15) was obtained after 1 hour post deposition annealing in hydrogen atmosphere at 500˚C. The x-ray
diffraction of hydrogen annealed films showed a polycrystalline anatase (004)-oriented phase without any second
phases. The optical band gap for undoped and doped films lay in the range 3.38 – 3.47 eV. Using dispersion
analysis, optical constants were determined from spectro-photometric measurements for films on glass.
Photo-electrocatalytic activity of TiO2 nanotubes prepared with two-step anod...Iranian Chemical Society
To improve the photo-catalytic degradation of salicylic acid, we reported the fabrication of ordered TiO2 nanotube arrays by a simple and effective two-step anodization method and then these TiO2 nanotubes treated in a methanol solution under UV light irradiation. The TiO2 nanotubes prepared in the two-step anodization process showed better photo-catalytic activity than TiO2 nanotubes prepared in one-step anodization process. Also, compared with TiO2 nanotubes without the UV pretreatment, the TiO2 nanotubes pretreated in a methanol solution under UV light irradiation exhibited significant enhancements in both photocurrent and activity. The treated TiO2 nanotubes exhibited a 5-fold enhancement in photocurrent and a 2.5-fold increase in the photo-catalytic degradation of salicylic acid. Also the effect of addition of persulfate and periodate on the photo-catalytic degradation of salicylic acid were investigated. The results showed that the degradation efficiency of salicylic acid increased with increasing persulfate and periodate concentrations. These treated TiO2 nanotubes are promising candidates for practical photochemical reactors.
Synthesis Of Cobalt Doped Titania Nano Materials Assisted By Anionic Heteroge...IJERA Editor
: This paper presents about the synthesis of (0.25-1.0) wt.% cobalt doped titania nanomaterials
without surfactants: pure Co2+/TiO2 and in presence of 1,4-Butane sultone and 1,3-Propane sultone Anionic
Gemini surfactants and CTAB (Heterogemini surfactant)-0.5wt.%Co2+/TiO2-HgS(1&2).The synthesized nano
photocatalysts have been characterized by using various advanced techniques like X-Ray Diffraction (XRD),
Ultraviolet-visible Diffuse Reflection Spectroscopy (UV-Vis DRS), X-ray Photoelectron Spectroscopy (XPS),
Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), Fourier Transform Infrared
Spectroscopic Studies (FT-IR), Transmission Electron Microscopy (TEM). From the characterization studies all
the catalysts synthesized were reported in anatase phase. TEM indicates the particles size of prepared catalysts
reported with 7-10 nm and 15 nm for pure Co2+/ TiO2 catalyst. From XPS studies Cobalt was found to be in +2
oxidation state. From BET results the surface area was reported to be-89.51 and 77.93 (m2
/g) for Co2+/TiO2-
HgS(1)& Co2+/TiO2-HgS(2). From UV-DRS studies absorbance band shifted more towards visible region (red
shift). In order to find out the efficiency of the synthesized photocatalyst the photocatalytic activity studies were
carried out by degradation of Acid Red as a model azo dye pollutant in presence of the visible light irradiation.
The antibacterial activity of the synthesized catalysts against Escherichia coli was also studied. Thus from the
results 0.5wt.% Co2+/TiO2-HgS(1) exhibited highest photocatalytic activity for the degradation of azo dye Acid
Red as well as proved to be an excellent antibacterial agent
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.
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.
Preparation of Mixed Phase (Anatase/Rutile) TiO2 Nanopowder by Simple Sol Gel...IJLT EMAS
TiO2 nanopowder having both anatase and rutile
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Titanium isopropoxide was used as a titania source and mixed
with methanol and TiO2 nanopowder was obtained after
annealing at 6000C for 1 hour in air. The specimens made from
this powder were characterized by X-ray diffraction (XRD),
Thermogravimetric analyzer (TGA) and Transmission electron
microscopy (TEM). XRD studies revealed the presence of both
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5 nm. No significant weight loss up to 7000 C was observed by
TGA curve which indicates that TiO2 nanopowder is thermally
stable. TEM revealed the presence of a number of crystalline
grains in a structured matrix and selected electron diffraction
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1. IOSR Journal of Applied Chemistry (IOSR-JAC)
e-ISSN: 2278-5736.Volume 4, Issue 3 (May. – Jun. 2013), PP 27-33
www.iosrjournals.org
www.iosrjournals.org 27 | Page
Preparation, Characterization and Photocatalytic Activity of
N doped TiO2
Dhanya T.P.1
, Sugunan S.2
1
(Department of Chemistry, NSS College, Ottapalam, India)
2
(Departmenof Applied Chemistry,Cochin University of Science and Technology, India)
Abstract : In order to utilize visible light in a photocatalytic reaction, yellow nitrogen-doped titania was
prepared by sol-gel method in mild condition, with the elemental nitrogen source from urea.The titania catalysts
were characterized by XRD, BET Surface area, UV-Vis DRS,TEM and XPS . The results showed that all titania
catalysts were anatase and doping of nitrogen extended the absorption into visible light region. Photocatalytic
activity of the catalysts was evaluated based on the photodegradation of 2,4-D in aqueous solution under visible
light. The experiments demonstrated that the nitrogen-doped titania exhibited higher visible-light activity
compared to undoped one.
Keywords – anatase, 2,4-D, nitrogen doped, photocatalytic activity, titania
I. Introduction
AOPs were based on the generation of very reactive species such as hydroxyl radicals (•OH) that
oxidize a broad range of pollutants quickly and non selectively. Among AOPs, heterogeneous photocatalysis
using TiO2 as photo-catalyst appears as the most emerging destructive technology [1]. The key advantage of it is
its inherent destructive nature: it does not involve mass transfer; it can be carried out under ambient conditions
(atmospheric oxygen is used as oxidant) and may lead to complete mineralization of organic carbon into CO2
[2,3]. Moreover, TiO2 photocatalyst is largely available, inexpensive, non-toxic and show relatively high
chemical stability [4].
However, because of the relatively high intrinsic band gap of anatase TiO2 (3.2 eV), only 4% of the
incoming solar energy on the Earth’s surface can be utilized [5,6]. On the other hand, the hole and electron
excited by the UV light can recombine easily, which will reduce the efficiency of photons. How to reduce the
band gap to produce the visible-light photocatalysis and suppress the recombination of hole-electron pairs has
been one of the most challenging topics [7].
Therefore, considerable efforts have been made to extend the photoactivity of titania-based systems
into the visible-light region, using dopants. Asahi et al. [8] reported that nitrogen- doped titania could induce the
visible-light activity and the doped nitrogen was responsible for the visible light sensitivity because of the
narrowing of the band gap. It has initiated a new research area to extend the photo absorbance into the visible-
light region using nitrogen-doped titania [7].
In this study, yellowish nitrogen doped titania was produced through sol-gel method in mild condition,
using titanium tetra isopropoxide(TTIP) as the titanium source and urea as the nitrogen source. The titania
catalysts were characterized by XRD, BET, TEM, XPS and UV-Vis diffuse reflectance spectroscopy. The
photocatalytic activity was studied by the mineralization of a pesticide 2,4-D in aqueous solution. The nitrogen-
doped titania photocatalysts was found to be more active for 2,4-D degradation under visible-light irradiation
compared to undoped one. The effect of time, light source and dopant on the photocatalytic activity was also
discussed.
II. Experimental
2. 1 Preparation of nitrogen doped titania.
Nitrogen doped TiO2 catalyst was prepared through sol gel method using Titanium isopropoxide
(TTIP) and urea. In this method titanium isopropoxide and urea was taken in the mole ratio 1:5. The urea
solution was added drop wise to a mixture of titanium isopropoxide and ethanol. After stirring for 24 hours at
room temperature it was dried at 60o
C .The dried solids were ground in an agate mortar until fine and
homogeneous powder was obtained. Before characterization, all the samples were calcined in air at 400o
C for 4
hours. Different N doped catalysts with TTIP: urea in the mole ratio 1:2, 1:5 and 1:10mole ratios were prepared
by the same method and were signed as U1, U2 and U3. Pure titania catalyst (signed as T) was also prepared to
compare the results with the doped one.
2. Preparation, Characterization and Photocatalytic Activity of N doped TiO2
www.iosrjournals.org 28 | Page
2.2 Characterization Methods
The crystal phases of the catalysts were determined by X-ray diffraction (XRD) analysis. XRD patterns
of the samples were obtained using Bruker AXS D8 advance X ray diffractometer using CuKα radiation. Data
were collected over the angle of 2 between 10° to 70o
. Crystallite size was determined by using Scherrer’s
equation : D=0.9λ /β(П/180)cosθ (1) where D is the crystallite size λ is the wavelength of X ray radiation, β is
the full width of half maximum and θ is the diffraction angle. BET Surface area was measured using
Micrometritics Tristar 3000 surface area analyzer. The samples were activated at 90o
C for 30 minutes and
degassed at 350o
C for 4 hours. The UV- DRS were obtained in the range 300-800nm on Labomed UV VIS
DOUBLE BEAM UVD 500 Spectrophotometer equipped with an integrating sphere assembly using BaSO4 as
reflectance standard. The wavelength at the onset of reflection was taken and band gap was calculated using the
equation: Ebg=1240/λ (2) where is the wavelength in nanometer . The SEM micrographs of the samples were taken
using JOEL Model JSM -6390LV scanning electron microscope with a resolution of 1.38eV. The TEM analysis was
carried out in an ultra high resolution analytical electron microscope JOEL3010. XPS data were recorded in an
indigenously developed electron spectrometer equipped with Thermo VG Clamp-2 Analyser and a Mg Kα X-
ray source (1253.6 eV, 30mA × 8 kV). A thin sample wafer of 12 mm in diameter was used in these studies. As
an internal reference for the absolute binding energy of C 1s peak at 284.6 eV was used.
2.3 Photocatalytic Activity Studies
Photocatalytic activity of the prepared samples was measured by studying the degradation 2,4-D in
aqueous solution. The experiment was carried out using an Oriel Uniform Illuminator 150 W Xe ozone free
lamp with filters. 280-420nm dichoric mirror for UV light, and 420-630nm dichoric mirror (cold mirror) for
visible irradiation were used. The studies were carried out by taking 20 ml of 10-4
M solution of pesticide and
1g/L of catalyst. The solution was stirred for 30 minutes before irradiation to attain the adsorption desorption
equilibrium. After irradiation the solution was centrifuged the percentage mineralisation was studied using TOC
analysis. TOC was analysed using an Elemental Vario TOC analyser.
The percentage mineralisation= (TOCo –TOCt/ TOCo) x 100 (3) where TOCo is the value of TOC for
initial solution, TOCt is the value after time t. The effects of operational parameters, such as time, light source,
dopants were examined.
The structure of 2,4-D as follows
Fig. 1 Structure of 2,4-D
III. Results and Discussion
a. Structure and Properties of Photocatalysts
The XRD patterns of the synthesised N doped TiO2 are shown in Fig. 2.
Fig.2 XRD pattern of N doped titania
10 20 30 40 50 60 70
T
Intensity%
Two theta
U1
U2
U3
3. Preparation, Characterization and Photocatalytic Activity of N doped TiO2
www.iosrjournals.org 29 | Page
The diffraction peak at 25.4 corresponds to anatase phase of titania. Usually amorphous–anatase
transformation may complete in the temperature range 250-400o
C. The peak positions are same and no
extra peaks except for anatase TiO2 was observed, suggesting that the structure of TiO2 is not changed [9].
No peak was observed for dopants, may be due to the low amount of doped nitrogen so that it cannot be
detected by XRD. The materials show a very high degree of crystallinity of fully anatase phase. The
crystallite size of the sample are in arrange of 11-13, which is promising since nanocrystalline anatase is
considered as the more photoactive form of titania [9,10].
Specific surface area is one of the important properties of photocatalyst, a greater surface area is
generally favourable to yield a higher photoactivity [10]. In case of N doped catalysts the surface area first
increases with dopant concentration and then decreases. It can be concluded that the present sol gel method
adopted is a good route for the preparation of photocatalyst with high surface area, which is favourable in
enhancing the photoactivity of TiO2 based photocatalyst. The crystallite size and surface area of the catalysts are
given in Table 1.
Table 1 Crystallite size and surface area of prepared catalysts
Catalyst Crystallite size(nm) BET surface area (m2
/g)
T 13.4 77
U1 12 91
U2 11.7 121
U3 11.6 46
Extending the absorption edge of TiO2 to the visible region is considered as one of the main objective in this
study. The UV-Vis diffuse reflectance spectroscopy method was used to record absorbance capacity of the
powders and to estimate band-gap energies of the prepared TiO2 samples .The minimum wavelength required to
promote an electron depends upon the band-gap energy, Ebg, of the photocatalyst . The band gap of pure titania
is 3.2eV (Fig.3) corresponding to a wavelength of 389nm which falls in the UV region [10,11].
Fig. 3. UV-Vis.DRS of T
The UV DRS spectra were recorded for N doped catalysts (Fig.4). The doped samples are yellow in colour.
The change in colour of the nanoparticles upon N incorporation demonstrates a profound effect on their optical
response in the visible wave length [12].
Fig.4 UV-Vis.DRS of N doped titania catalysts
300 350 400 450 500 550 600
10
20
30
40
50
60
70
80
90
100
%Reflectance
Wavelength nm
300 400 500 600
20
30
40
50
60
70
80
90
100
300 400 500 600
20
30
40
50
60
70
80
90
100
300 400 500 600
20
30
40
50
60
70
80
90
100
300 400 500 600
20
30
40
50
60
70
80
90
100
300 400 500 600
20
30
40
50
60
70
80
90
100
U3
U2
%Reflectance
Wavelength (nm)
U1
4. Preparation, Characterization and Photocatalytic Activity of N doped TiO2
www.iosrjournals.org 30 | Page
As shown in Fig.4, N doping obviously affects light absorption characteristics of TiO2. Unmodified
TiO2 nanoparticles hardly absorb visible light, while N-doped TiO2 nanomaterials show a clear red shift towards
visible light region, suggesting the formation of an energy level within the band gap. Moreover, the absorption
in this range increases with the increase of doped N content. This clearly indicates a decrease of the band gap
energy of TiO2. N doping can extend the wavelength response range to the visible region and increase the
number of photogenerated electrons and holes to participate in the photocatalytic reaction, which would enhance
the photocatalytic activity of TiO2. However there is no direct relation between light absorption and
photocatalytic activity of samples, that stronger absorption of visible light does not mean the higher degradation
of pollutants [9,13]. The band gap of N doped titania(U2) is 2.25eV corresponding to 550 nm. Various
mechanisms have been proposed to explain the light absorption and photoactivity of N-doped TiO2. Di Valentin
et al. provided theoretical evidence that [14] in the case of substitutional N-doped anatase TiO2, the visible light
response arises from occupied N 2p localized states slightly above the valence band edge [15].Hashimoto and
co-workers [16,17] provided the explanation that a localized N 2p state formed above the valence band was the
origin for the visible light response of the nitrogen-doped TiO2.
The surface morphology was studied by SEM analysis. Fig. 5 shows the SEM image of undoped TiO2.
Fig. 6 shows the SEM image of N doped catalyst. The images show that particles are somewhat spherical in
nature. But most of them are in agglomerated form.
Fig.5 SEM image of undoped titania(T) Fig.6 SEM image of U2
The TEM image of U2 is shown in Fig.7.The particles are agglomerated and exhibit spherical or rectangular
shape. The HRTEM image of U2 is shown in Fig.8. The image indicates that particles are well ordered and
highly crystalline in nature. The catalysts give the same d value (0.352nm) which is in correlation with the d
value obtained from XRD and corresponds to101 anatase planes. This again confirms the presence of anatase
phase. Fig.9 shows the selected area electron diffraction pattern of U2 catalyst. The electron diffraction image
shows well distinct spots due to the high crystallinity of titania indicated as anatase phase with major 101 planes
Fig.7 TEM image of U2 Fig.8 HRTEM image of U2
5. Preparation, Characterization and Photocatalytic Activity of N doped TiO2
www.iosrjournals.org 31 | Page
Fig.9 SAED image of U2
The XPS spectrum of nitrogen in U2 is shown in Fig.12. There are obvious nitrogen signals in the N-doped
sample, although peak intensities are not so strong.
450 455 460 465 470 475 480 485
500
1000
1500
2000
2500
3000
3500
4000
Intensity(a.u.)
B.E. (eV)
Ti
Fig.10 Ti 2p spectrum of sample U2
Fig.11 O 1s spectrum of sample U2
Fig. 12 N 1s spectrum of sample U2
515 520 525 530 535 540 545 550 555
1000
2000
3000
4000
5000
6000
Intensity(a.u.)
B.E. (eV)
O
375 380 385 390 395 400 405
380
400
420
440
460
480
500
520
540
Intensity(a.u.)
B.E. (eV)
N
6. Preparation, Characterization and Photocatalytic Activity of N doped TiO2
www.iosrjournals.org 32 | Page
There were two peaks for Ti 2p (Fig.10) at 458.2 and 464.2 eV. According to the literatures [18-20], the
peak at 458.2 eV was attributed to Ti2p3/2 and the peak at 464.2 eV was assigned to Ti2p1/2, indicating that Ti
remained in an octahedral environment [21]. Binding Energy values of Ti are attributed to its 4+ oxidation state.
A shoulder seen in O 1s spectrum at higher B.E at ~ 531 eV (Fig.11) is associated with surface hydroxyl groups
while the main peak at ~529. 3 is due to oxygen associated with titania[22]. Nitrogen 1s peak at ~ 399.2 eV
appears to be very broad has relatively lower intensity. The XPS peak around 399.2 eV which is due to the
formation of an O-Ti-N bond, suggesting that the nitrogen is doped in the lattice as an anion by the bond formation
(O-Ti-N). This peak therefore can be attributed to the 1s electron binding energy of the N atom in the O-Ti-N
environment [12,18] .This O-Ti-N bond formation occurs by the replacement of the lattice oxygen by nitrogen in
[TiO6]2-
octahedra [23,24].
3.2 Photocatalytic Activity of the Catalyst
The effect of time on the degradation of 2,4-D was examined under visible light irradiation in the reaction
time ranging from 30 to 180 minutes. Samples were withdrawn at different time intervals after photodegradation and
centrifuged immediately and percentage mineralisation was studied using TOC analysis. The results of percentage
mineralisation at different times are shown in Fig. 13.
Fig.13 % Mineralisation of 2,4-D against time
Amount of catalyst 1g/L; Pesticide concentration 20ml of 10-4
M
Results show that as time increases the percentage mineralisation increases. It has been observed that the
mineralisation of the compound proceeds much more rapidly in the presence of N doped catalyst in visible light.
It was found that 78% TOC was removed after 3 hours when U2 was used as catalyst in visible light .The reason
for better photoactivity could be attributed to the fact that the catalyst is composed of nanocrystalline anatase
form. The bandgap energy is lower than that of pure titania, it shows a stronger absorption in visible light region
and the presence of dopant prevents the recombination of photogenerated electrons and holes leading to better
photocatalytic activity. In the case of N doped catalysts highest activity was observed with catalyst prepared in
1:5 mole ratio of TTIP and urea (U2). However, when the concentrations of dopant ions are above the optimum
ratio, the dopant atoms become the recombination centres [25]. This can be seen from the reduced
photocatalytic efficiency of the catalyst with doping ratio above the optimum value. The existence of the
optimum value can also be associated with the amount of active sites on TiO2. These active sites however will
be easily blocked if the amount of dopants is too high or above the optimum value. So even though the U4
catalyst shows more absorption in visible region the photocatalytic activity is very low.
The effect of light source of different wavelength on the photodegradation of 2,4-D using undoped and
doped TiO2 also studied. When only UV light is used, degradation takes place slowly using the doped catalyst.
Control experiment was performed by employing visible light irradiated blank solution. The degradation of 2,4-
D was negligible when the aqueous solution was irradiated without TiO2. Negligible mineralisation was
observed when studies were carried out in absence of light. All these results suggest that mineralization of this
compound takes place through photocatalytic mechanism [26].
20 40 60 80 100 120 140 160 180 200
10
20
30
40
50
60
70
80
90
100
20 40 60 80 100 120 140 160 180 200
10
20
30
40
50
60
70
80
90
100
20 40 60 80 100 120 140 160 180 200
10
20
30
40
50
60
70
80
90
100
%Mineralisation
U2
T
Time (min)
7. Preparation, Characterization and Photocatalytic Activity of N doped TiO2
www.iosrjournals.org 33 | Page
Table 2 %Mineralisation of 2,4-D against light source
Irradiation time 1hour; Amount of catalyst 1g/L; Pesticide concentration 20ml of 10-4
M
Light
% mineralisation
U2 T
Visible light (420-630 nm) 66 37
UV light (280- 400nm) 52 48
Table 3 % Mineralisation of 2,4-D in absence of light/catalyst
Irradiation time 3hours; Amount of catalyst 1g/L; Pesticide concentration 20ml of 10-4
M
studies
% mineralisation
2,4-D
Without catalyst 3
Without light 5
IV. Conclusions
Yellowish nitrogen-doped titania catalysts, with the elemental nitrogen source from urea, were
prepared using the sol-gel method in mild condition. The nitrogen-doped titania had larger surface area than
pure titania. The UV-Vis DRS results showed that the presence of small amount of nitrogen in the catalyst gives
rise to a red shift of its absorbance wavelength and decreases the band gap of titania. The nitrogen incorporation
in the lattice of TiO2 formed a narrow N 2p band above the valence band, which exhibited a higher visible light
absorption and was responsible for the higher visible-light activity by considering 2,4-D mineralisation.
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