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SnS2 exhibits lower photocatalytic activity against organic dyes without N N double bonds due to the SnIV/SnII transition which decreases its degradation efficiency due to the decreased formation of O 2 ∗ − and OH∗ radicals. To upgrade the photocatalytic ability of SnS2 against dyes without N N bonds, NiO coupling has been adopted and the results obtained are furnished in this paper. By adopting precipitation method, SnS2, NiO and SnS2 NiO nanocomposite was synthesized. Structural, morphological, compositional, functional group analyses of SnS2, NiO and SnS2 NiO nanocomposite were performed by adopting techniques such as XRD, SEM, TEM, XPS, FTIR and PL. The magnetic property of pure SnS2 got enhanced by coupling with NiO thereby making it suited for magnetic devices. Photocatalytic activities were performed against MB and RhB dyes under visible light. The enhanced degradation ability of the SnS2 NiO composite may be due to its enhanced oxidation/reduction ability of the electrons and holes generated under the effect of visible light.

The present work aims to synthesize CdO Al2O3 nanocomposite and to study its visible light activated photocatalytic performance against metanil yellow dye. Precipitation method was employed to synthesize pure CdO, Al2O3 and CdO Al2O3 nanoparticles. Diffraction peaks related to cubic CdO and monoclinic θ-Al2O3 were observed in the XRD pattern of the composite. XPS spectrum confirmed the presence of Cd, Al and O in the composite. Peaks related to Cd O and O Al O bonds were observed from the FTIR spectrum of the composite. Photocatalytic activity confirmed that the CdO Al2O3 nanocomposite exhibits a maximum degradation efficiency of 82.09% against MY dye which was found to be better than pure CdO and Al2O3 nanoparticles due to the synergistic effect, high surface area and the formation of p-n junction at the interface of CdO and Al2O3. The CdO Al2O3 composite catalyst synthesized via precipitation method seems to be more stable and definitely it will be a potential candidate in photocatalysis related field.

Molybdenum substituted PbS (PbS:Mo) nanoparticles has been synthesized by a cost effective precipitation method. The undoped and doped nanoparticles exhibit face-centered cubic structure. The presence of Mo in the doped samples is confirmed from the EDX spectra. Band gap value of pure PbS decreases with Mo doping. Photosensitivity seems to decrease with Mo doping. Photocatalytic tests performed show that the photodegradation efficiency of PbS increases with Mo substitution and the 5 wt.% Mo-doped sample exhibits a maximum efficiency of 90.24% and 83.95% against the degradation of congo red and rhodamine B dyes, respectively. The PbS:Mo nanoparticles exhibit better antifungal activity against A. niger fungus. The obtained results confirm that the PbS:Mo nanoparticles are well suited as an efficient photocatalyst for the degradation of organic dyes and a potential antimicrobial agent.

This paper outlines the synthesis and characterization of NiO, CdO and NiO-CdO nanocomposites prepared by a simple soft chemical route. The thermal behavior, structure, surface morphology, elemental composition of the synthesized samples was characterized by TG-DTA, XRD, SEM, EDX and XPS analyses. The various functional groups present in the samples were identified by FTIR analysis. Photoconductive and antibacterial studies were performed to find the suitability of the composite in photoconductive sensor and pharmaceutical applications. Thermal studies confirm that the thermal decomposition of NiO, CdO and NiO-CdO nanocomposites occur at 332.9 °C, 325.8 °C and 334.5 °C, respectively. XRD studies confirm that the NiO and CdO nanopowders exhibit cubic crystal structure and diffraction peaks related to NiO and CdO were observed in the composite. The EDX and XPS spectra confirmed the presence of Ni, Cd and O in the composite. The optical and photoconductive results confirmed that the composite has properties intermediate between NiO and CdO nanopowders. The NiO, CdO and NiO-CdO nanocomposites showed enhanced antibacterial activities against S. aureus and K. pneumonia bacteria strains.

This paper reports the role of bioactive elements in inducing ferromagnetism in CdO nanopowder. CdO nanopowder was synthesized by a soft chemical method using aloe vera gel extract as solvent. XRD studies confirm the presence of diffraction peaks related to cubic crystal structure of CdO. Weak peaks related to the oxides of Cu, Fe, Mg, Zn, Ni and Mn were also observed. Nanosized grains were observed from the TEM image. EDX and XPS spectra confirm the presence of bioactive magnetic elements in the synthesized sample. Magnetic studies confirm that the paramagnetic nature of CdO becomes ferromagnetic due to the presence of magnetic ions in the aloe vera gel extract.

A comparative study has been performed in this paper on the photocatalytic activity and third order NLO properties of NiO-CdO and NiO-CuO nanocomposites green synthesized using Psidium guajava leaf extract. Under visible light illumination for about 90 min, the NiO-CdO nanocomposite degraded 86 % and the NiO-CuO nanocomposite degraded 91.5% of rhodamine B dye. Decreased crystallite size, larger specific surface area, enhanced visible light absorbing ability, least band gap value and greater dispersibility of CuO are responsible for the better degradation ability of the NiO-CuO nanocomposite than the NiO-CdO nanocomposite. The occurrence of reverse saturable absorption (RSA) effect from the Z-scan studies confirmed that both the composites are well suited for nonlinear optical and photonic devices. The high value of NLO susceptibility possessed makes the NiO-CuO nanocomposite highly polarized than the NiO-CdO nanocomposite.

Proper disposal of fiber waste products is a major problem faced by the FRP industries and hence needs a sustainable solution for its reuse and recycling. The present paper deals with the performance of concrete using waste fiber reinforced polymer powder (FRP), as a partial replacement for fine aggregate in the concrete. Field emission scanning electron microscopy (FESEM) analysis along with energy dispersive X-Ray (EDX) is carried out to find out the elements present in the FRP powder used in the present study. Partial replacement of 5%, 10% and 15% are carried out in the fine aggregate content of control mixture of M30 grade. The workability, compressive strength, split tensile strength, flexural strength, impact and abrasion resistance are measured to observe the effect of waste FRP powder on the concrete. From the study it is observed that workability decreased with increase in percentage of FRP substitution with a considerable increase in strength properties for 10% replacement of fine aggregate content by waste fiber reinforced polymer powder. Also better performance is observed for impact and abrasion resistance

Zirconium doped SnS 2 (SnS 2 :Zr) nanopowders were synthesized by a simple soft chemical route using SnCl 2 •2H 2 O, thiourea (SC(NH 2 ) 2 ) and zirconium oxychloride (ZrOCl 2 •8H 2 O) as precursor salts. The thermal behavior, structural, morphological, magnetic and antifungal properties of the synthesized nanopowders was studied and the results obtained are reported in this paper. TG-DTA analysis confirms that both the undoped and doped samples become well crystallized above 377 °C. The undoped and doped samples exhibit hexagonal crystal structure with a strong (1 0 1) preferential growth. The metal sulfide (M-S) stretching frequency is observed from the presence of the peaks at 583 and 538 cm −1 in the FTIR spectra. Increased band gap values have been observed for the doped samples. Ferromagnetic orderings in the form of S-shaped loops are observed for the doped samples. Improved antibacterial efficiency was observed with Zr doping.

Sr-doped SnS2 nanopowders with 0, 5, 10 and 15 wt.% Sr concentrations were synthesized by a simple soft chemical route. XRD studies confirm the polycrystalline nature of the samples. The undoped and doped SnS2 nanopowders exhibit hexagonal crystal structure with a strong (1 0 1) preferential orientation. The 2θ values of the (1 0 1) plane of the undoped SnS2 shift towards lower angle with Sr doping. Nanoneedles are evinced for all the samples from the SEM images. EDX spectra confirm the presence of Sr in the doped samples. The optical band gap of pure SnS2 decreases with Sr doping. Peaks related to SnS2 are evinced at 572 nm in the PL spectra and at 313 cm−1 and 203 cm−1 in the Raman spectra. Improved ferromagnetic orderings in the form of S-shaped loops were observed for the doped samples. Antibacterial studies show that the zone of inhibition of SnS2 increases with Sr-doping. The obtained results infer that Sr2+, a cationic dopant ion strongly enhanced the physical properties of SnS2 nanopowders.

Semiconductor nanocomposites containing two metal oxides with different functionalities have gained significant attention as they exhibit improved optical, electrical, magnetic and catalytic properties better than their single entities. The present work aims to synthesize NiO-CuO nanocomposite and to study its suitability for photoconductive sensor, soft magnetic materials applications and as antimicrobial agent. NiO, CuO and NiO-CuO nanoparticles were synthesized by precipitation method. X-ray diffraction (XRD) studies reveal the existence of cubic and monoclinic structured peaks of NiO and CuO in the nanocomposite. Ni-O and Cu-O related bands were observed from the Fourier Transform Infrared (FTIR) spectrum of the nanocomposite. The nanocomposite exhibits band gap between NiO and CuO. Photosensitivity of NiO improves when coupled with CuO. The nanocomposite possess enhanced ferromagnetic behaviour due to increased point defects, uncompensated spins and exchange coupling between Cu2+ and Ni2+ ions. CuO improved the antifungal ability of NiO against Aspergillus terreus (A. Terreus) fungi.

CdO nanopowders were synthesized by a simple soft chemical method using cadmium acetate as the precursor salt. The as-synthesized nanopowders were characterized by XRD, SEM, EDX and TEM analysis. Polycrystalline nature with a (1 1 1) preferential orientation is revealed by the XRD analysis, which was confirmed from the SAED pattern. The presence of Cd and O in the nanopowders is confirmed from the EDX spectrum. The presence of peaks at 417, 499, 620 and 669 cm−1 observed in the FTIR spectrum corresponds to the bonding between Cd and O. Antimicrobial activities were performed against three bacteria and fungi strains by the agar well diffusion method, and from the observed zones of inhibition, it is confirmed that the as-synthesized CdO nanopowders act as an effective antimicrobial agent against pathogenic microorganisms.

Nano needle structured Cu-doped Sn 2 S 3 thin films with different Cu concentrations (0, 1, 2 and 3 wt.%) were prepared by spray pyrolysis technique on glass substrates maintained at 400 °C. XRD analysis showed that the undoped and doped Sn 2 S 3 films exhibit orthorhombic crystal structure with a preferential orientation along the (2 1 1) plane. SEM images confirm the presence of nano needles in both the undoped and doped films. Optical band gap is red shifted from 1.96 eV to 1.86 eV with increase in Cu concentration in the films which may be attributed to Moss-Burstein effect. All the films have resistivity in the order of 10 −1 Ω-cm and the Sn 2 S 3 film coated with 2 wt.% Cu concentration exhibit a minimum resistivity of 0.335 × 10 −1 Ω cm. The obtained results infer that Sn 2 S 3 film coated with 2 wt.% Cu concentration exhibit better physical properties.

Nanostructured ternary CdZnO thin films with zinc concentrations (0, 2, 4, 6 and 8 wt%) were prepared by spray pyrolysis technique using perfume atomizer on glass substrates at 375 °C. The effect of doping concentration on the structural, morphological, optical and electrical properties of the films was studied and from the results obtained it is observed that the CdZnO film with 6 wt% Zn doping concentration has better physical properties and this film is subjected to post annealing in air at different temperatures. The effect of thermal annealing on the properties of the deposited films was systematically studied. The XRD patterns reveal that the films are polycrystalline in nature with cubic structure and are highly textured along (1 1 1) preferential orientation. The SEM and AFM images confirmed these results and showed more crystallization up to 300 °C annealing temperature. Film transparency decreases with annealing temperature. Analysis of the absorption edge revealed that the optical band gap energies of the films was red shifted with annealing temperature. The annealed films have a resistivity in the order of 101 Ω cm. Increased transparency and reduced resistivity observed for the CdZnO films make them suitable for optoelectronic device applications especially as window layer in solar cells.

The present work focuses on the synthesis of pure SnS2 nanopowder, pure CdO nanopowder and SnS2-CdO nanocomposite by a cost effective chemical method using tin (II) chloride, thiourea and cadmium acetate as the precursor salts. The synthesized samples were characterized by using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy dispersive X-ray spectroscopy(EDS), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), Fourier Transmission Infrared Spectroscopy (FTIR), UV–Vis diffuse reflectance spectroscopy, Photoluminescence (PL) Spectroscopy and Electron spin resonance (ESR). Diffraction peaks related to both SnS2 and CdO was observed in the XRD pattern of the composite. Photocatalytic studies established that the composite exhibit a photodegradation efficiency of nearly equal to 86.11% against rhodamine B and 92.86% against congo red dyes. Also, the SnS2-CdO nanocomposite exhibited enhanced photocatalytic H2 evolution activity, from visible light water splitting.

The present work reports the improvement in the structural, optical, electrical and photocatalytic properties of molybdenum doped CdO (CdO:Mo) thin films deposited on glass substrates by spray pyrolysis technique. XRD patterns reveal a strong (1 1 1) preferential orientation for the CdO:Mo thin films. Cauliflower shaped nanostructures were evinced with Mo doping. EDX and XPS analyses confirmed the presence of Mo in the doped films The doped films exhibit better transparency with the band gap being varied from 2.46 eV to 2.56 eV with increase in Mo doping concentration. The doped films exhibit better photodegradation efficiencies against the decolorization of metanil yellow due to enhanced energy transfer. Among the doped films, a remarkable efficiency of 87.3 % was observed for the 2 wt% Mo-doped CdO catalyst. Also, the more stable and reusable nature makes CdO:Mo catalysts suitable for practical applications for the degradation of toxic dyes.

Visible light mediated photocatalytic activity of Ni-doped Al2O3 nanoparticles synthesized via precipitation method has been reported in this paper. Ni doping concentration in Al2O3 is varied as 0, 2, 4 and 6 wt%. The presence of diffraction peaks related to monoclinic crystal structure of θ- Al2O3 is evinced from the XRD patterns of the undoped and doped samples. The diffraction peak (0 0 2) appears to be dominant for all the samples and crystallite size decreased from 41 nm to 33 nm with Ni doping. A shift towards higher wavelength in the absorption edge of pure Al2O3 is evinced with Ni doping. PL spectra confirm the presence of peaks related to oxygen vacancies in the samples. Photocatalytic activity tests performed against metanil yellow dye confirmed that the doped samples exhibit better degradation efficiency than the undoped sample. The 4 wt% Ni-doped Al2O3 catalyst exhibits a maximum degradation efficiency of 86.84% after 90 min visible light irradiation which was well acknowledged from its decreased crystallite size, band gap values and improved surface morphology. The results obtained confirmed that the Ni-doped Al2O3 nanoparticles are well suited as visible light mediated catalysts for the degradation of toxic organic dyes.

Using γ spectrometry, the concentration of the naturally occurring radionuclides (226)Ra, (232)Th and (40)K has been measured in soil, sand, cement, clay and bricks, which are used as building materials in Tiruvannamalai, Tamilnadu, India. The radium equivalent activity (Raeq), the criterion formula (CF), indoor gamma absorbed dose rate (DR), annual effective dose (HR), activity utilization index (AUI), alpha index (Iα), gamma index (Iγ), external radiation hazard index (Hex), internal radiation hazard index (Hin), representative level index (RLI), excess lifetime cancer risk (ELCR) and annual gonadal dose equivalent (AGDE) associated with the natural radionuclides are calculated to assess the radiation hazard of the natural radioactivity in the building materials. From the analysis, it is found that these materials used for the construction of dwellings are safe for the inhabitants. The radiological data were processed using multivariate statistical methods to determine the similarities and correlation among the various samples. The frequency distributions for all radionuclides were analyzed. The data set consisted of 15 measured variables. The Pearson correlation coefficient reveals that the (226)Ra distribution in building materials is controlled by the variation of the (40)K concentration. Principal component analysis (PCA) yields a two-component representation of the acquired data from the building materials in Tiruvannamalai, wherein 94.9% of the total variance is explained. The resulting dendrogram of hierarchical cluster analysis (HCA) classified the 30 building materials into four major groups using 15 variables.

The natural level of radioactivity in building materials is one of the major causes of external exposure to γ-rays. The primordial radionuclides in building materials are one of the sources of radiation hazard in dwellings made of these materials. By the determination of the radioactivity level in building materials, the indoor radiological hazard to human health can be assessed. This is an important precautionary measure whenever the dose rate is found to be above the recommended limits. The aim of this work was to measure the specific activity concentration of (226)Ra, (232)Th and (40)K in commonly used building materials from Namakkal, Tamil Nadu, India, using gamma-ray spectrometer. The radiation hazard due to the total natural radioactivity in the studied building materials was estimated by different approaches. The concentrations of the natural radionuclides and the radium equivalent activity in studied samples were compared with the corresponding results of different countries. From the analysis, it is found that these materials may be safely used as construction materials and do not pose significant radiation hazards.