IR@CGCRI - Central Glass and Ceramic Research Institute (CSIR)
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Integration of oxygen vacancy rich-TiO2 with BiOI and Ag6Si2O7: Ternary p-n-n photocatalysts with greatly increased performances for degradation of organic contaminants
No full textPhotocatalysis process is a prominent approach for the degradation of organic contaminants. However, the swift recombination of charge carriers commonly limits the photoactivity. Hence, to create a suitable nanocomposite for removal of pollutants, BiOI and Ag6Si2O7 particles were anchored on the oxygen vacancy rich-TiO2 (abbreviated as OVs-TO) through a simple approach to construct the OVs-TO/BiOI/Ag6Si2O7 nanocomposites. Then, various structural features of the systems were assayed with different characterization tools. It was found that the photocatalyst with 20 wt% and 30 wt% of BiOI and Ag6Si2O7 exhibits the excellent performance in removal of RhB, which are about 194, 18.1, and 9.59-times higher than the TiO2 (abbreviated as TO), OVs-TO, and OVs-TO/BiOI (20 %) nanomaterials, respectively. This supreme improved photodegradation activity was allocated to the formed p-n-n heterojunctions between the semiconductors, impressive segregation of charges, significant visible-light absorption of OVs-TO, BiOI, and Ag6Si2O7, and textural enhancement. A suitable mechanism was also offered through the outcomes of Mott-Schottky and the quenching experiments. This research work illustrated that the ternary p-n-n photocatalyst could be efficacious for ameliorating the visible-light photocatalytic ability for environmental and energy applications
Microwave and Conventional Preparation of P2O5-ZnO-Al2O3-Na2O Glass/Eu3+ Ion as Luminescent Probe
No full textGlass comprising of P2O5-Al2O3-Na2O-ZnO is melted in microwave (MW) heating as an alternate energy efficient heating method. Properties of glasses obtained from MW heating are compared with that of glasses prepared adopting resistive heating. Glass transition temperature (T-g) in MW melted glass is found similar to 15-20 degrees C lower compared to the glass prepared in resistance furnace. XPS O1s spectra indicate less non-bridging oxygen (NBO) formation in glass obtained from MW melting. This may be due to less evaporation as well as less leaching of alumina from crucible wall during melting. Photoluminescence spectra of Eu3+-doped glass indicate higher asymmetric ratio in the conventional glass. MW melting requires 2 h 20 min, whereas it is similar to 6 h in resistive heating. Comparison of power consumption analysis depicts maximum MW forward power < 1.5 kW with similar to 1 kW average power during melting of glass. Maximum power in resistive heating furnace is recorded 4 kW for identical melting
Understanding the correlation between orbital degree of freedom, lattice-striction and magneto-dielectric coupling in ferrimagnetic Mn1.5Cr1.5O4
No full textDielectric anomaly observed in cubic Mn1.5Cr1.5O4 around ferrimagnetic ordering temperature (T (N)) suggests a possible magneto-dielectric coupling in the system. This report confirms the presence of a weak but significant magneto-dielectric coupling in the system. The ab initio calculations show a band gap of around 1.2 eV, with Fermi-level closer to the conduction band. The major features of conduction band nearest to the Fermi-level correspond to d ( xz ) and d (3z ) (2) (-r ) (2) orbitals of Mn3+ ion. Temperature-dependent neutron diffraction results show a rapid decay in structural parameters (lattice-striction and transition metal-oxygen bond length) around T (N.) We confirmed that these changes in structural parameters at T (N) are not related to structural transition but the consequences of orbital-ordering of Mn3+. The rapid decay in transition metal-oxygen bond length under internal magnetism of the system shows that magnetism could certainly manipulate the electric dipole moment and hence the dielectric constant of the system. Magneto-striction acts as a link between magnetic and dielectric properties
Integration of oxygen vacancy rich-TiO2 with BiOI and Ag6Si2O7: Ternary p-n-n photocatalysts with greatly increased performances for degradation of organic contaminants (vol 613, 126101, 2021)
No full textCharacterization and thermal analysis of laser metal deposited gamma-TiAl thin walls
No full textThe present work focuses on investigating the effect of process variables (power, travel speed, powder flow rate) on microstructure and mechanical properties of Laser Metal Deposited (LMD) gamma-TiAl thin walls. To this end, LMD technique was used to deposit gamma-TiAl thin walls at different processing conditions. Microstructures of as-deposited samples were investigated using both optical and scanning electron microscopy. X-ray diffraction (XRD) technique was used to determine the phases present. Microhardness measurements were carried out along both longitudinal and build directions. Microstructural analysis of as deposited samples revealed a fine lamellar structure comprising of gamma and alpha(2) phases. Colony size of 30-60 mu m and lamellar spacing between 0.1 and 0.7 mu m were observed. XRD analysis confirmed the presence of gamma and alpha(2) phases. Comparison of elemental analysis results on both powder and as-deposited samples revealed a negligible loss of Al and no oxygen pick up in the deposited thin walls. Hardness values were found to decrease with an increase in wall height, and hardness values increased marginally (5%) with an increase in travel speed. Further, 3D transient thermal analysis was also carried out to complement the LMD of thin walls in terms of melt pools and cooling rates. It was found that the melt pool depth (MPDc = 0.266 mm) is smaller at the centre than the edge (MPDe = 0.513 mm) of the wall. A higher cooling rate of 1.05 x 10(5) degrees C/s near the wall substrate was found for 200-12. (c) 2021 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Antimicrobial activity study of Ag-ZnO nanoflowers synthesised from neem extract and application in cotton textiles
No full textZinc oxide has gained a tremendous attention from materials researchers owing to its availability, ease of synthesis, biocompatibility, low cytotoxicity and widespread applications. A few green synthesis methods are available in the literature for making hierarchically structured ZnO (ZO)/metal doped ZnO. In this work, a green synthesis of Ag-ZnO flowers (AZO) has been performed from neem extract (Azadiracta indica) by low temperature solution method. Material properties of the samples such as crystallinity/crystal phase, morphology and optical property have been investigated systematically. In addition, the effect of AZO upon the growth of gram positive/negative bacteria has been studied. As prepared AZO along with a biocompatible and chitosan having antimicrobial property has been used for deposition of a robust coating on commercial cotton fabric. The morphology, chemical bond vibrations and antimicrobial activity of the coated fabric against E. coli, S. aureus and fungi C. albicans have been studied. The coated fabric shows excellent antibacterial and antifungal activities. Thus, the material can be used as medical textile in research laboratory and/or other health sectors
Efficient carbon counter electrodes for BaSnO3-based dye-sensitized solar cells
No full textNatural source derived carbon materials make them ideally suited alternative to costly Pt counter electrode for their good catalytic activity, resistance to iodine corrosion, and high stability of the device. Apart from the extensively acclaimed photoanode TiO2, BaSnO3 (BSO) has been projected as an efficient alternative to it. In this study, remarkable efforts have been endeavoured to establish BSO-carbon-based dyesensitized solar cell (DSSC) device. Investigation on the adequate performance of natural source derived carbon-based counter electrodes for BSO-based DSSCs, explored as a significant alternative to costly Pt and TiO2, respectively, which could elucidate better photo-stability and more extended device performance compared to TiO2-Pt-based DSSCs. (c) 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the Second International Symposium ``Functional Nanomaterials in Industrial Applications: Academy-Industry Meet''
Hydroxylated BiFeO3 as efficient fillers in poly(vinylidene fluoride) for flexible dielectric, ferroelectric, energy storage and mechanical energy harvesting application
No full textHere we report the effect of surface hydroxylation of BiFeO3 fillers on the dielectric, ferroelectric, energy storage and mechanical energy harvesting performance of poly(vinylidene fluoride). Surface hydroxylation helped to improve the interfacial interaction between the filler and PVDF matrix by introducing a strong hydrogen bonding between the -OH group of the hydroxylated BiFeO3 filler surface and the -CF2 dipole of PVDF in place of electrostatic interfacial interaction between non-hydroxylated BiFeO3 and the -CH2 dipole of PVDF. The amount of polar phase increased to around 91% for a 7 wt% hydroxylated BiFeO3 loaded PVDF film (7BFOH) by this new type of interfacial interaction. The dielectric, ferroelectric, energy storage and mechanical energy harvesting performance of the PVDF based composite films also improved by the above said technique. Upon repeated human finger tapping, the 7BFOH film delivered similar to 18 V output peak to peak open circuit ac voltage (V-OC). After rectification, the V-OC of the 7BFOH film was able to charge a 10 mu F capacitor up to similar to 3 V which was able to light up some LEDs (connected in parallel) together instantaneously, which proved the real life applicability of the composite films in low power consuming self-powered electronic devices
Magnetron configurations dependent surface properties of SnO2 thin films deposited by sputtering process (vol 177, 109353, 2020)
No full textA highly sensitive cobalt chromite thick film based trace acetone sensor with fast response and recovery times for the detection of diabetes from exhaled breath
No full textAcetone is known as the breath biomarker of diabetes. In this paper we have reported on a highly sensitive, stable cobalt chromite (CoCr2O4) thick film-based trace acetone sensor with quick response and recovery times promising for the detection of diabetes from exhaled breath. CoCr2O4 nanoparticles were prepared by a cost-effective and easy sol-gel method. The as prepared nanoparticles were well characterized by sophisticated characterization techniques, such as, XRD, FESEM. TEM, HRTEM, XPS, and BET. Further these nanoparticles were exploited to fabricate a Taguchi type chemoresistive sensor using a customized drop coater. The developed sensor was characterized by I-V measurement. The developed sensor exhibited high p-type response towards 1 ppm of acetone vapor (similar to 3.81 folds), and appreciable resolution between 1 ppm, 2 ppm (response = similar to 4.82 folds), and 5 ppm (response = similar to 6.64 folds) acetone vapor at 300 degrees C. Further, the sensor exhibited fast response and recovery times of similar to 1.65 s and similar to 62 s, respectively. Also, the response of the sensor to 1 ppm acetone vapor is appreciably higher than that of 0.2 ppm ethanol, 0.25 ppm ammonia vapor, and saturated moisture. Finally, the sensor is stable for at least 6 months and exhibits repeatable measurements