Papers by Selvam Kaliyamoorthy
New Journal of Chemistry, 2015
Photoexcitation of TiO2 loaded with Pd particles produces secondary amines from azobenzenes and a... more Photoexcitation of TiO2 loaded with Pd particles produces secondary amines from azobenzenes and alcohols with almost quantitative yields, via consecutive photocatalytic and catalytic actions.
ZnO nanocrystals have been synthesized by thermal decomposition of zinc oxalate without using any... more ZnO nanocrystals have been synthesized by thermal decomposition of zinc oxalate without using any additives or solvent and characterized by XRD, BET, FE-SEM, DRS and HR-TEM techniques. The XRD analysis showed that the synthesized catalyst has hexagonal wurtzite type polycrystalline structure. HR-TEM analysis revealed the formation of ZnO nanocrystals and the increase in size of ZnO nanoparticle from 40 to 100 nm during the formation. FE-SEM indicates the presence of a nano chain like structures. Nano ZnO is more advantageous than commercial ZnO in the degradation of RO 4 because (i) it has maximum efficiency at pH 7, (ii) its antiphotocorrosion property is higher than commercial ZnO, (iii) it is stable and reusable. The mineralization of Reactive Orange 4 was also confirmed by TOC analysis.
A comparative study was carried out on the efficiency of titanium dioxide specimens Wackherr TiO ... more A comparative study was carried out on the efficiency of titanium dioxide specimens Wackherr TiO 2 , prepared TiO 2 and Aeroxide P25 toward the photocatalytic synthesis of pharmaceutically important 2-methylquinolines. TiO 2 Wackherr induced significantly faster conversion of nitrobenzene to 2-methylquinoline than Aeroxide P25 when high photocatalyst loadings and high substrate concentrations were used. Photocatalytic synthesis of 2-methylquinolines from substituted nitrobenzenes and anilines show that the product yield is not significantly influenced by the substituents. Low cost TiO 2 Wackherr is more useful when high photocatalyst loading is required at high substrate concentration.
N-Doped TiO2 using a new nitrogen precursor hydrazine hydrate was synthesized by a simple wet met... more N-Doped TiO2 using a new nitrogen precursor hydrazine hydrate was synthesized by a simple wet method.
Tetrahedron Letters, 2010
ABSTRACT A convenient eco-friendly photocatalytic synthesis of quinaldines has been developed by ... more ABSTRACT A convenient eco-friendly photocatalytic synthesis of quinaldines has been developed by a simple one-pot reaction of anilines in ethanol solution with Au-loaded TiO2 under UV irradiation. Upon irradiation in the presence of Au-TiO2, aniline and oxidation products derived from ethanol undergo condensation–cyclization to afford quinaldines.
Synthetic Communications, 2011
Product selectivity in the dehydrazonation of benzophenone hydrazone by photocatalytic oxidation ... more Product selectivity in the dehydrazonation of benzophenone hydrazone by photocatalytic oxidation with various semiconductor photocatalysts has been investigated using ultraviolet-A light. TiO2-P25 shows greater product selectivity of benzophenone formation with 93.9% conversion. Doping of metals on TiO2 selectively enhances the formation of azine from hydrazone. Solvents such as dichloromethane, chloroform, and dichloroethane also enhance the formation of azine.
Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 2013
ABSTRACT Nitrogen-doped TiO2 was synthesized by a simple wet method using a nitrogen precursor hy... more ABSTRACT Nitrogen-doped TiO2 was synthesized by a simple wet method using a nitrogen precursor hydrazine hydrate and nano TiO2. This photocatalyst was characterized by X-ray diffraction, high-resolution transmission electron microscopy, diffused reflectance spectra, photoluminescence, and X-ray photoelectron spectroscopy. XPS analysis indicates the incorporation of anionic nitrogen in TiO2 lattice as O-Ti-N linkage. N2 adsorption–desorpion isotherm indicates the mesoporous nature of N-TiO2 with the surface area 130.0 m2/g. Sizes of N-TiO2 particles are found to be in the range of 5–30 nm by HRTEM images. DRS spectra reveal the extended absorption to the visible range. N-TiO2 is found to be more efficient than Ag-TiO2, Au-TiO2, and Pt-TiO2 in quinaldine synthesis under visible light.
Separation and Purification Technology, 2007
The photocatalytic C F bond cleavage in pentafluorobenzoic acid (PFBA) with ZnO using UV-C light ... more The photocatalytic C F bond cleavage in pentafluorobenzoic acid (PFBA) with ZnO using UV-C light has been investigated under different conditions. Strong C F bond is completely cleaved with ZnO under 150 min of UV-C light irradiation. The defluoridation is more with UV/ZnO process than with UV/TiO 2 process at pH 5. The oxidants such as IO 4 − , BrO 3 − , S 2 O 8 2− and ClO 3 − ions enhance the defluoridation rate of PFBA. On the contrary the addition of H 2 O 2 decreases the rate. The order of their activities is IO 4 − > S 2 O 8 2− > BrO 3 − > ClO 3 −. The C F cleavage is also influenced by the addition of inorganic anions and metal ions. The GC-MS analysis of PFBA solution after irradiation with ZnO reveals the formation of pentafluorobenzene, pentafluorophenol and tetrafluoroquinone as intermediates.
Separation and Purification Technology, 2007
A combined homogeneous and heterogeneous photocatalytic decolourisation and degradation of a chlo... more A combined homogeneous and heterogeneous photocatalytic decolourisation and degradation of a chlorotriazine azo dye reactive orange 4 (RO 4) have been carried out using ferrous sulphate/ferrioxalate with H 2 O 2 and TiO 2-P25 nanoparticles. Enhancement in the photo-Fenton processes has been observed by the addition of TiO 2-P25. UV/ferrous/H 2 O 2 /TiO 2 and UV/ferrioxalate/H 2 O 2 /TiO 2 processes are found to be more efficient than the individual photo-Fenton and UV/TiO 2-P25 processes. The use of ferrioxalate in the combined process is found to be more advantageous. The effects of various experimental parameters such as pH, initial H 2 O 2 , Fe 2+ , Fe 3+ and TiO 2 concentrations on these combined photocatalytic processes have been investigated. All these parameters strongly influenced the removal rate. The optimum operating conditions of these combined processes are reported.
Separation and Purification Technology, 2008
Photocatalytic degradation of Direct Red 23 (DR23) by nano-Ag doped TiO 2 has been investigated u... more Photocatalytic degradation of Direct Red 23 (DR23) by nano-Ag doped TiO 2 has been investigated under different conditions. Photodeposition of 1.5% Ag on the surface of TiO 2 enhanced its photoactivity in DR23 degradation. Optimal experimental conditions on catalyst amount, pH and dye concentration have been determined. Addition of some inorganic oxidizing species such as H 2 O 2 , (NH 4)S 2 O 8 and KBrO 3 up to a certain concentration increased the rate of degradation. The higher photoactivity of Ag-TiO 2 than TiO 2 under UV irradiation can be ascribed to the effect of silver deposits acting as electron traps on the Ag-TiO 2 surface.
Research on Chemical Intermediates, 2012
Dihydrobenzofurans containing carbomethoxy-ethenyl at 2-position and phenyl and hydroxyl at 3-pos... more Dihydrobenzofurans containing carbomethoxy-ethenyl at 2-position and phenyl and hydroxyl at 3-position were synthesized by photochemical methods and screened for antibacterial activity. These dihydrobenzofurans were moderately active against bacteria, both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa), while compound 3-(6-chloro-3-hydroxy-3-phenyl-2,3-dihydrobenzofuran-2-yl)acrylic acid methyl ester showed promising activity against both the Gram-positive and Gram-negative bacteria.
Journal of Molecular Catalysis A: Chemical, 2010
The activated carbon loaded TiO2-P25 catalysts were prepared and characterized by diffuse reflect... more The activated carbon loaded TiO2-P25 catalysts were prepared and characterized by diffuse reflectance spectra (DRS), FT-IR, scanning electron micrograph (SEM), X-ray diffraction (XRD) and BET surface area analysis. The photocatalytic efficiency of activated carbon loaded TiO2-P25 (AC-TiO2-P25) was evaluated by UV assisted photodefluoridation of pentafluorobenzoic acid (PFBA) in aqueous medium. The catalyst exhibited higher photo defluoridation efficiency of PFBA than that of bare TiO2-P25. The various experimental parameters like concentration of PFBA, addition of oxidants, amount of catalyst and solution pH for efficient defluoridation are reported. The higher efficiency of AC-TiO2-P25 is due to synergy effect of activated carbon.
Journal of Molecular Catalysis A: Chemical, 2011
In order to get materials with enhanced adsorption and photocatalytic performance, nanosized silv... more In order to get materials with enhanced adsorption and photocatalytic performance, nanosized silver particles loaded TiO2 was prepared by a facile photodeposition. This catalyst was characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller surface area (BET) and diffuse reflectance spectroscopy (DRS). XRD patterns revealed that the crystal structure of Ag–TiO2 resembled anatase phase of TiO2. Visible light absorption increases with the increase in Ag loading. Photoluminescence spectra indicate the suppression of recombination of the photogenerated electron-hole pairs by the loaded silver on TiO2. XPS measurements reveal the presence of silver particles mainly in metallic form. 1.5% Ag loaded TiO2 is found to be most efficient for selective one-pot synthesis of quinaldines from nitroarenes in ethanol using UV light. Ag–TiO2 on irradiation induces a combined redox reaction with nitroarene and alcohol and this is followed by condensation-cyclization of aniline and oxidation products to give quinaldines.
Journal of Hazardous Materials, 2009
Photocatalytic activity of surface fluorinated TiO(2)-P25 (F-TiO(2)-P25) in the degradation of a ... more Photocatalytic activity of surface fluorinated TiO(2)-P25 (F-TiO(2)-P25) in the degradation of a chlorotriazine azo dye Reactive Orange 4 (RO 4) under ambient conditions was investigated in this study. Characterization of F-TiO(2)-P25 reveals that the catalyst has a strong absorption in the UV range and the presence of F atom in the catalyst. The degradation rate of RO 4 with surface fluorinated TiO(2)-P25 is three times faster than bare TiO(2)-P25. The quantum yield of UV/TiO(2)-P25 process is largely decreased by the increase of initial dye concentration, whereas in UV/F-TiO(2)-P25 process, the influence of initial dye concentration is less. Surface fluorination of TiO(2)-P25 enhanced the adsorption of RO 4 dye, while improving overall degradation rate. The optimum operating conditions of UV/F-TiO(2)-P25 process for efficient degradation are reported.
Journal of Hazardous Materials, 2009
Pt-doped TiO 2 has been prepared and characterized by various surface analytical methods such as ... more Pt-doped TiO 2 has been prepared and characterized by various surface analytical methods such as BET surface area, scanning electron micrographs (SEM), X-ray diffraction (XRD), energy dispersive X-ray micro analysis (EDX) and diffuse reflectance spectroscopy (DRS). Photodefluoridation of pentafluorobenzoic acid (PFBA) to fluoride ions has been carried out using TiO 2 and Platinum doped TiO 2 with UV-C (200-300 nm) light. The defluoridation was monitored by the ionometer with fluoride ion selective electrode. Photodeposition of 1.5% Platinum on the surface of TiO 2 enhances its photoactivity in pentafluorobenzoic acid defluoridation. In order to optimize the working conditions, effects of pH and initial PFBA concentration were analyzed. Addition of inorganic oxidizing species KIO 4, H 2 O 2 , (NH 4)S 2 O 8 and KBrO 3 strongly influenced the photocatalytic defluoridation of PFBA. The significant enhancement in the Pt-TiO 2 photoactivity under UV irradiation can be ascribed to the platinum deposits, acting as electron traps on the Pt-TiO 2 surface. The fluoride ions formed during photodefluoridation can be used for the production of CaF 2 .
Desalination and Water Treatment, 2010
The photodegradation of Acid Black 1 (AB 1) using ZnO as photocatalyst in aqueous solution has be... more The photodegradation of Acid Black 1 (AB 1) using ZnO as photocatalyst in aqueous solution has been investigated under different conditions. The degradation is higher with UV/ZnO process than with UV/TiO 2-P25 process at neutral pH 7. The influence of operational parameters such as the amount of photocatalyst, dye concentration and initial pH on degradation by ZnO has been analyzed. At pH 7, maximum degradation efficiency is observed and the leaching of Zn 2þ due to photocorrosion is also significantly reduced when compared to pH 3 and 5. The addition of oxone increases the dye removal where as KIO 4, KIO 3 and H 2 O 2 fails. The degradation of AB 1 follows pseudo-first-order kinetics according to the Langmuir-Hinshelwood model. GC-MS analysis reveals the formation of azobenzene, 3-aminobenzene-1,2-diol, 2-aminobenzene-1,4-diol and 5-aminobenzene-1,3-diol as intermediates. The degradation of AB 1 has also been confirmed by COD measurements.
Desalination, 2010
The mineralization of pentafluorophenol (C6F5OH) in water using UV-C light and Fe(II) sulfate/Fe(... more The mineralization of pentafluorophenol (C6F5OH) in water using UV-C light and Fe(II) sulfate/Fe(III) oxalate with H2O2 was examined to develop a technique to counteract persistent and bioaccumulative C6F5OH to harmless species. Photo-Fenton process led to efficient degradation of C6F5OH to fluoride ions and CO2. Compared with the Fe(II)sulfate photo-Fenton process, the Fe(III) oxalate process is more efficient. The effects of
Dalton Transactions, 2013
Chemistry Letters, 2007
Benzimidazole derivatives were synthesized in good yield from 1,2-phenylenediamine (PD) and vario... more Benzimidazole derivatives were synthesized in good yield from 1,2-phenylenediamine (PD) and various alcohols by photocatalytic cyclization with TiO 2 /acidic clay composite catalyst using UV-A and solar light. Doping silver on TiO 2 enhances product yield and selectivity of the photocatalytic synthesis of benzimidazoles. The higher efficiency of nano-Ag-doped TiO 2 in solar light makes this synthesis a green chemical process.
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Papers by Selvam Kaliyamoorthy