Kuriakose Elias College

Kottayam, India

Kuriakose Elias College

Kottayam, India
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Thomas A.K.,St Berchmans College | Abraham K.,St Berchmans College | Thomas J.,Kuriakose Elias College | Saban K.V.,St Aloysius College
Journal of Asian Ceramic Societies | Year: 2017

Polycrystalline samples of Na0.5La0.25Sm0.25Cu3Ti4O12 ceramics were prepared by solid state sintering. Its crystallographic structure, electrical properties and dielectric behaviour are investigated over wide ranges of temperature (30–325 °C) and frequency (42 Hz–1 MHz). Rietveld refinement of the powder diffraction data has confirmed a cubic, single phase structure with space group Im3. This ceramic material exhibits colossal value of dielectric constant with very low values of loss factor, over wide frequency ranges and thus highlights the quality of the sample to be used for the fabrication of capacitive devices. Impedance spectroscopic studies have revealed that the compound is electrically heterogeneous. The scaling behaviour of Z″ suggests a temperature independent distribution of relaxation time. The mismatch in the peak frequencies of Z″/Zmax ″ and M″/Mmax ″ suggest that the relaxation mechanism is dominated by short range movement of charge carriers. © 2017 The Ceramic Society of Japan and the Korean Ceramic Society


Radhika S.,Kuriakose Elias College | Thomas J.,Kuriakose Elias College
Journal of Environmental Chemical Engineering | Year: 2017

In this study, nano ZnO photocatalyst with rod like morphology was synthesised using low temperature hydrothermal method. Visible light driven catalytic activity of the synthesised ZnO nanorods was enhanced by incorporating different photosensitive molecules like heteropoly phosphotungstic acid (HPA), fluorescein, perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) and porphyrin and their structural and optical properties were characterized. UV-vis diffuse reflectance spectra (DRS) of the synthesised samples supported that these samples absorb visible light as well as ultra violet light. They exhibit efficient photocatalytic activity under sunlight towards the degradation of common textile waste water pollutants like methylene blue (MB), rhodamine B (RhB), eosin yellow (EY) and also for the degradation of endocrine disruptors like resorcinol. Among the different ZnO photocatalysts, PTCDA sensitized ZnO nanorods showed highest photocatalytic activity indicating that PTCDA-ZnO would be very useful for cleaning polluted surface water by solar light driven photocatalysis. © 2017 Elsevier Ltd.


Thomas J.,Kuriakose Elias College | Ambili K.S.,Kuriakose Elias College | Radhika S.,Kuriakose Elias College
Catalysis Today | Year: 2017

Sm3+-doped g-C3N4 nanosheets with efficient solar photocatalytic activity were synthesized and their structural and optical properties were characterized. UV-vis diffuse reflectance spectral studies revealed that the absorption edge is red shifted in all Sm3+-doped samples and Sm3+-doping decreases the band gap of g-C3N4, thereby increases visible light absorption. The separation efficiency of the electrons and holes was obtained from PL spectral studies. The solar photocatalytic activity of the synthesized catalysts was assessed by studying the degradation of different dyes under sunlight. The synthesized photocatalyst was applied for the degradation of a synthetic dye effluent and an endocrine disrupting organic compound, salicylic acid under sunlight and showed more efficiency than the commercial photocatalyst, Degussa P-25. Studies revealed that hydroxyl radicals and holes play significant role in the degradation of dye effluent under sunlight. Further, the possible mechanism of the photocatalytic degradation of pollutants using Sm3+-doped graphitic carbon nitride is also proposed. © 2017 Elsevier B.V.


Jesty T.,Kuriakose Elias College | Ambili K.S.,Kuriakose Elias College | Baby A.M.,Kuriakose Elias College | Sonyamol S.,Kuriakose Elias College
Journal of Applied Spectroscopy | Year: 2017

Two new luminescent hybrid materials were synthesized using para-aminobenzoic acid (PABA), europium nitrate, and titania. Characterization of the synthesized hybrid materials using infrared spectroscopy and CHN elemental analysis revealed the bonding sites and compositions of the two hybrid materials. The homogenous nature of the hybrid materials was confirmed by scanning electron microscopy. The optical properties of these synthesized materials were studied using UV-visible absorption spectroscopy and photoluminescence spectroscopy. Thermogravimetric analysis revealed that the hybrid materials are thermally stable. © 2017 Springer Science+Business Media New York


Thomas J.,Kuriakose Elias College | Radhika S.,Kuriakose Elias College | Yoon M.,Chungnam National University | Yoon M.,JNT Inc.
Journal of Molecular Catalysis A: Chemical | Year: 2016

Different Nd3+-doped TiO2 nanoparticles incorporated with heteropoly phosphotungstic acid (HPA) (Nd3+-TiO2-HPA nanocomposites) were synthesized, and their structure and optical properties were characterized. UV-vis diffuse reflectance spectra of Nd3+-TiO2-HPA nanocomposites supported that the nanocomposites absorb visible light as well as ultra violet light. Consequently they exhibit efficient photocatalytic degradation of methylene blue (MB) upon illumination by the solar simulator, and the photocatalytic efficiency was found to depend on neodymium doping and heteropoly acid incorporation. These new photocatalysts were applied to the complete degradation of the organochlorine toxic chemical, 4-chlorophenol (4-CP) in water within 60 min upon sunlight illumination, indicating that Nd3+-TiO2-HPA nanocomposites would be very useful for cleaning polluted surface water by sunlight through the advanced oxidation process. Photocatalytic degradation pathway of 4-chlorophenol was examined using mass spectral analysis. © 2015 Elsevier B.V.


Vellanikaran J.J.,Kuriakose Elias College | Thomas A.P.,Kerala University
Asian Journal of Microbiology, Biotechnology and Environmental Sciences | Year: 2012

Mosquito menace in rural and urban India has reached alarming proportions. Improper urban development has compounded the problem. Extensive use of synthetic insecticides during the last few decades have resulted in environmental hazards and led to the development of physiological resistance in major vector species. Aedes aegypti is seen to transmit Dengue fever. From a selected twelve plant species of Umbelliferae family, extracts of five could induce significant mortality of A. aegypti larvae. Differential larvicidal activity was seen for various solvent extracts and both Hydrocotyle rotundifolia and Eryngium foetidum were found lethal to the larvae , the former was more effective. Synergic effect was observed when the crude extracts of H. rotundifolia and E. foetidum were used together. These two species are potential sources for larvicidal phytochemicals which may be used in mosquito control and eradication of Dengue fever. Crude extracts of three species - Ferula assa, Foetida, E. foetidum and H. rotundifolia exhibited potential larvicidal action. Development of safe biocides in future, may be done by isolation of the active principles from the crude extracts of Umbelliferae family. © Global Science Publications.


Thomas J.,Kuriakose Elias College | Ambili K.S.,Kuriakose Elias College
Science of Advanced Materials | Year: 2014

A novel inorganic-organic hybrid material (HQ-Sm-Z) was synthesized by grafting 8-hydroxy quinolinesamarium complex (HQ-Sm) on zeolite Y through hydrothermal or solvothermal route. FTIR analysis reveals that the organic and inorganic components were covalently linked through the Si O bond of zeolite Y in the hybrid material. Optical properties of 8-hydroxy quinoline-samarium complex and the hybrid material were studied by using UV-visible spectroscopy and photoluminescence spectroscopy. We found that the 8-hydroxy quinoline-samarium complex grafted on zeolite through solvothermal route has better optical properties than the complex grafted on zeolite through hydrothermal route. The solid samarium complex and the hybrid material give both ligand based emission and the characteristic fluorescence of Sm3+ ion emission at room temperature. The SEM analysis shows that the hybrid material is homogenous. The mechanism of direct excitation and energy transfer scheme is also discussed. © 2014 by American Scientific Publishers.


Thomas A.K.,Smart Materials Analytical Research and Technology SMART Laboratory | Abraham K.,Smart Materials Analytical Research and Technology SMART Laboratory | Thomas J.,Kuriakose Elias College | Saban K.V.,Mary Matha Arts and Science College
Ceramics International | Year: 2015

Abstract The effect of doping the A site (Ca) with La and B site (Ti) with Nb, on the grain formation, crystallographic structure, electrical properties and dielectric behaviour of CaCu3Ti4O12 is investigated over wide ranges of temperature (27-150°C) and frequency (50 Hz to 5 MHz). Microstructure investigation of the cast compound, Ca(1-3x)La2xCu3Ti(4-5x)Nb4xO12 (x=0, 0.02 and 0.04), using Scanning Electron Microscopy (SEM) showed that co-doping would result in grain growth inhibition. Rietveld refinement of the powder diffraction data confirmed a cubic, single phase structure with space group Im3. The steady increase in the lattice volume with increasing dopant concentration confirms the incorporation of the bigger dopant molecules in the lattice. Dielectric studies using HIOKI 3552-50 LCR Hi-Tester show that the room temperature dielectric constant would considerably increase due to co-doping. Impedance spectroscopic studies reveal that the compound is electrically heterogeneous, with semi conductive grain interior and insulating grain boundaries. Doping resulted in a decrease in grain boundary resistance and consequent increase in dielectric loss at low frequency. The dielectric behaviour of compound is explained on the basis of the Internal Barrier Layer Capacitance (IBLC) model. © 2015 Elsevier Ltd and Techna Group S.r.l.


Thomas J.,Kuriakose Elias College | Ambili K.S.,Kuriakose Elias College
Journal of Molecular Structure | Year: 2015

A new metal-organic framework with empirical formula C43H30NO12Sm was solvothermally synthesized using SmCl(, fluorescein and N, N-Dimethyl formamide (DMF) and characterized by single crystal X-ray diffraction, powder X-ray diffraction, infrared spectroscopy, UV-Visible spectroscopy, scanning electron microscopy, optical microscopy, photoluminescence spectroscopy, CHN elemental analysis and thermogravimetric analysis. Single crystal X-ray diffraction revealed that the crystal structure belongs to the triclinic system, P-1 space group with a = 12.113 (6) Å, b = 12.1734 (7) Å, c = 13.2760(8) Å, α = 67.930(3)<>, β = 87.779(3)< >, γ = 77.603(3)< > and V = 1769.71 (17) Å3. The photoluminescence spectrum showed emission peaks at 550 nm, 600 nm and 647 nm due to the characteristic transitions 4G5/2 to 6H5/2, 4G5/2 to 6H7/2 and 4G5/2 to 6H9/2 respectively, when excited at 398 nm. © 2015 Elsevier B.V. All rights reserved.


Thomas J.,Kuriakose Elias College | Chitra K.R.,Kuriakose Elias College
Advanced Materials Research | Year: 2014

Novel nanogold doped TiO2 nanoparticles are found to be highly efficient for the photocatalytic degradation of organic pollutants. TiO2 nanoparticles were synthesized from titanium (IV) isopropoxide through hydrothermal route. Gold nanoparticles were prepared by chemical reduction and stabilization employing D-glucosamine, and were doped in TiO2 nanoparticles. The analysis revealed that the diameter of gold nanoparticles used for doping is around 5 nm. Undoped and gold doped samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, UVVis diffuse reflectance spectra (DRS) and field emission scanning electron microscopy (SEM). DRS study showed that nanogold doping in titania nanoparticles induces a shift of absorption edge to the visible range and reduces the band gap. Complementing our earlier finding that noble metal doping in titania nanoparticles enable photocatalytic activity in the visible region, it is showed that gold doping enhances photocatalytic activity of the titania nanoparticles. This was confirmed by the degradation of the dye methylene blue repeatedly using gold doped nanoparticles under direct sunlight. Further, the nanoparticles were used to study the degradation of the persistent organic pollutant, β endosulfan, and near complete degradation were observed in an hour. Regenerated nanoparticles were found effective for the degradation of the pesticide for more than three cycles. © (2014) Trans Tech Publications, Switzerland.

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