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

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