Enhanced photoactivity effect of Ag metal loading on Zr4+ doped N-TiO2 obtained by microwave assisted method

618-626Herein, we report the fabrication of Ag metal loading on Zr-doped-N-TiO2 (AgZrT) nanocomposites (NCs) via microwave-assisted impregnation reduction method. The main objective of the work is to study the effect of Ag loading on structural, chemical and photoactivity of Zr-doped-N-TiO2(ZrT). The obtained NCs were characterized using XRD, HRTEM, EDS, XPS etc. Obtained AgZrT NCs showed the existence of metastable anatase phase with an average crystallite size of about 10 nm supported by HRTEM. The presence of Ti, Zr and Ag is confirmed by EDS while the metallic state of Ag and oxidation state of Ti and Zr (+4) is confirmed by using XPS. The Ag loading effect on photoactivity of ZrT NPs was studied under UV and direct sunlight using model dye Methyl Orange (MO). The positive impact of Ag metal loading is supported by the enhanced photoactivity of ZrT. The degradation kinetics for MO and its plausible mechanism under sunlight is proposed

Nanostructured ZrO2 Thick Film Resistors as H2-Gas Sensors Operable at Room Temperature

Nanostructured ZrO2 powder was synthesized by microwave assisted sol-gel method. The material was characterized by XRD and SEM techniques. X-Ray diffraction studies confirm that a combination of tetragonal and monoclinic zirconia nanoparticles is obtained by using microwave-assisted method. The nanopowder was calcined at an optimized temperature of 400 °C for 3 h. The prepared powder had crystalline size about 25 nm. Thick films of synthesized ZrO2 powder were prepared by screen printing technique. The gas sensing performances of these films for various gases were tested. Films showed highest response to H2 (50 ppm) gas at room temperature with poor responses to others (1000 ppm). The quick response and fast recovery are the main features of this sensor. The effects of microstructure, operating temperature and gas concentration on the gas response, selectivity, response time and recovery time of the sensor in the presence of H2 gas and others were studied and discussed

Magnetite–Silica–Gold Nanocomposite: One-Pot Single-Step Synthesis and Its Application for Solvent-Free Oxidation of Benzyl Alcohol

A simple and innovative method for a single-step–one-pot room temperature synthesis of magnetite–silica–gold nanocomposite has been demonstrated. This simple process involves a combination of different reactions occurring simultaneously. Specifically, coprecipitation of iron salts, reduction of gold chloride, and formation of silica, all at one instance, result in a unique nanocomposite of iron oxide, silica, and gold. The well-known method of coprecipitation of iron salts to form iron oxide nanoparticles has been modified suitably to include sodium silicate (silica source) instead of an alkali (for coprecipitation). Gold chloride premixed in sodium silicate, prior to reaction, gives the third and important functionality: gold nanoparticles, which can act as a catalyst. The nanocomposite so formed is stable due to the silica network, is magnetically separable, has high surface area, and is catalytically active. The composite has been characterized by a host of different techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive analysis using X-rays, X-ray photoelectron spectroscopy, transmission electron microscopy, zeta potential measurements, dynamic light scattering, BET surface area measurements, and magnetic measurements. The catalytic feature of this composite was verified by a model reaction involving oxidation of benzyl alcohol to benzaldehyde by molecular oxygen. The nanocomposite was found to show high conversion efficiency with excellent selectivity and recyclability. High surface area of the nanocomposite and efficient surface passivation by silica framework coupled with facile access to catalytic gold nanoparticles make the current nanocomposite highly efficient. The existing material and the process are innovative and can be extended to incorporate other active materials of interest. More importantly, the synthesis approach is “greener” (one-pot, single-step, aqueous, room temperature, avoiding toxic chemicals and harsh reducing agents, scalable, and industrially economic process). The composite was further found to be catalytically active, magnetically separable, and reusable for the solvent-free oxidation of benzyl alcohol at atmospheric pressure and without the use of harsh oxidizing agents, thereby making our approach extremely promising for industrial applications

Synthesis and characterization of cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II) and mercury(II) complexes with 2-hydroxyimino-3-(2' -imino-4-phenylthiazolyl)-butane and 2-hydroxyimino-3-[2' -imino-4' (<i>p-</i>tolulylthiazolyl)]-butane

1145-1149The complexes of the composition [M(HL)2(H2O)2].Cl2 [HL = 2-hydroxyimino-3-(2'-imino-4-phenylthiazolyl)butane(HL1), 2-hydroxyimino-3-[2'-imino-4-(p-tolulylthiazolyl)]-butane(HL2)]; M=Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)] have been synthesised and characterised by elemental analysis, magnetic susceptibility, molar conductance, TGA, X-ray diffraction and spectral studies. HL1 and HL2 acts as neutral bidenate ligands and the complexes appear to be octahedral. Antibacterial activities of ligands and their metal complexes have been determined against Escherichiacoli, Bacillus substilis; Klebsiella pbeumoniae, Pseudomonas aerogens, Salmonalla paratyphi B, Staphylococcus aureus, and Proteus vulgaris.</i

Photoelectrochemical and photocatalytic activity of nanocrystalline TiO2 thin films deposited by chemical bath deposition method

The thin films of nanocrystalline TiO2 were synthesized using titanium isopropoxide as a source of Ti on fluorine-doped tin oxide (FTO) and commercial glass substrates by chemical bath deposition method. The resultant films were annealed at different temperatures (300, 400 and 500 °C) for 3 h. The annealed nanocrystalline thin films were thoroughly characterized by XRD, SEM, UV–Vis. DRS, PL, FT-IR, Raman and TEM. The XRD study shows the average crystallite size of TiO2 is 15 nm having anatase phase, while as temperature increases crystallite size increases. SEM and TEM results show elongated spherical shape of TiO2 nanocrystals. Optical absorption spectra show the band gap energy decreases from 3.2 to 3.1 eV as annealing temperature increases. From the PL spectra, an emission peak observed at 600 nm is due to the indirect band gap and defects present in the material. The FT-IR spectrum of TiO2 thin film annealed at 400 °C shows the band at 532 cm−1 due to O–Ti–O stretching vibrations confirms the formation of anatase TiO2. The Raman spectrum shows an intense peak at 149 cm−1 and four weaker peaks are characteristics of anatase phase of TiO2. The photodegradation efficiency of methyl orange (MO) was observed to be 92% by using TiO2 thin film within 90 min under UV–Vis. light. It shows enhanced photoconversion efficiency of 1.02% under UV light.</p

Synthesis and X-ray diffraction studies of 4-[2'-hydroxy salicylidene-5' (2"-thiazolylazo)] methoxy benzene

817-820<span style="font-size: 15.0pt;mso-bidi-font-size:8.0pt;font-family:" times="" new="" roman","serif""="">The new compounds having azo Schiff base characteristics have been synthesized by condensing 5-(2'-thiazolylazo) salicylaldehyde with para-substituted aniline and subjected for structural characterization. X-ray diffraction study has been carried out for 4-[2'-hydroxy salicylidene-5'-(2'-thiazolylazo)]methoxy benzene. The structure of compound is found to be <span style="font-size: 15.0pt;mso-bidi-font-size:8.0pt;font-family:" times="" new="" roman","serif""="">tetragonal, belonging to non-primitive system. The strain broadening effects are also examined and discussed. </span

Fabrication of M@Cu_<i>x</i>O/ZnO (M= Ag, Au) Heterostructured Nanocomposite with Enhanced Photocatalytic Performance under Sunlight

We report a biogenic method for the design and characterization of three different composite nanomaterials, Cu_<i>x</i>O/ZnO, Ag@Cu_<i>x</i>O/ZnO, and Au@Cu_<i>x</i>O/ZnO (x = I and II), with the surface plasmon resonance (SPR) effect and p–n heterojunction for photocatalysis. The crystal structure of the material was scrutinized by XRD, DRS, PL, XPS, FT-IR, EDS, and TEM analysis. To make the composite efficient, we have sensibly introduced plasmonic Ag and Au on Cu_<i>x</i>O/ZnO individually by using Ziziphus jujuba leaf extract. The widened light incorporation, effectual conveyance of photogenerated carriers, and incidence of brawny SPR effect makes the composites sensitive under visible light. The synthesized ternary composites, Ag@Cu_<i>x</i>O/ZnO and Au@Cu_<i>x</i>O/ZnO, exhibit much higher photocatalytic activity than ZnO and Cu_<i>x</i>O/ZnO for the degradation of industrial textile effluent and methyl orange under sunlight as well as UV light. Using effortless comet assay practice, the genotoxicity of TE prior to and past photodegradation was assessed