- Kolkata, West Bengal, India
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Hierarchical TiO2 hollow spheres with a coating of functionalized C dots show a very fast and selective dye adsorption, and the TiO2 hollow spheres obtained after calcination of the dye adsorbed CF@THS can be useful as an efficient... more
Hierarchical TiO2 hollow spheres with a coating of functionalized C dots show a very fast and selective dye adsorption, and the TiO2 hollow spheres obtained after calcination of the dye adsorbed CF@THS can be useful as an efficient photoanode and a photocatalyst.
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Exploring new electrode materials is the key to realize high performance energy storage devices for effective utilization of renewable energy. Natural clays with layered structure and high surface area are prospective materials for... more
Exploring new electrode materials is the key to realize high performance energy storage devices for effective utilization of renewable energy. Natural clays with layered structure and high surface area are prospective materials for electrical double layer capacitors (EDLC). In this work, a novel hybrid composite based on acid-leached montmorillonite (K10), multi-walled carbon nanotube (MWCNT) and manganese dioxide (MnO2) was prepared and its electrochemical properties were investigated by fabricating two-electrode asymmetric supercapacitor cells against activated carbon (AC) using 1.0M tetraethylammonium tetrafluroborate (Et4NBF4) in acetonitrile (AN) as electrolyte. The asymmetric supercapacitors, capable of operating in a wide potential window of 0.0-2.7V, showed a high energy density of 171Whkg(-1) at a power density of ∼1.98kWkg(-1). Such high EDLC performance could possibly be linked to the acid-base interaction of K10 through its surface hydroxyl groups with the tetraethylammonium cation [(C2H5)4N(+) or TEA(+)] of the ionic liquid electrolyte. Even at a very high power density of 96.4kWkg(-1), the cells could still deliver an energy density of 91.1Whkg(-1) exhibiting an outstanding rate capability. The present study demonstrates for the first time, the excellent potential of clay-based composites for high power energy storage device applications.
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ABSTRACT Anatase TiO2 nanofibers (200–300 nm diameter) with 3-dimensionally (3D) ordered pore structure and high surface area were synthesized by electrospinning technique. Unique combinations of partially acetylacetone chelated... more
ABSTRACT Anatase TiO2 nanofibers (200–300 nm diameter) with 3-dimensionally (3D) ordered pore structure and high surface area were synthesized by electrospinning technique. Unique combinations of partially acetylacetone chelated Ti-alkoxide, viscosity controlling cum high positive charge balancing agent PVP and the structure director F127 yielded nanofibers with ordered mesoporosity similar to the Pm3¯m structure. Dynamic heating of the fibers in the temperature range 350–540 °C and simultaneous XRD studies revealed that the amorphous to anatase transformation initiated at about 400 °C with retention of 3D mesoporosity up to the final heat-treatment stage. TEM studies also confirmed this. During amorphous to anatase conversion, the surface area decreased from 165 (350 °C) to 90 m2g‒1 (540 °C). The crystalline mesoporous nanofibers showed enhanced photocatalytic activity with reusability.
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Photocatalytic water splitting is of significant interest due to the potential utilization of renewable solar energy for production of clean and green H2 fuel. Among various metal oxide based photocatalysts, perovskite oxides are... more
Photocatalytic water splitting is of significant interest due to the potential utilization of renewable solar energy for production of clean and green H2 fuel. Among various metal oxide based photocatalysts, perovskite oxides are promising. In a ABO3 perovskite structure, changing stoichiometry or creating A or B site defects by incorporating cations with different valency and size facilitates interesting properties. Moreover, exsolution of light absorbing nanoparticles from the perovskite lattice can result in improved photocatalysts. The aim of this neutron diffraction study is to explore and improve understanding of the substitution and exsolution mechanism in the perovskite lattice and therefore its influence on photocatalysis can be correlated. Furthermore, this will enable us to optimize and develop a new class of photocatalyst materials with enhanced energy conversion efficiency.
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A Ni-based ternary nanocomposite, Ni–rGO–zeolite, has been developed as an efficient and recyclable heterogeneous catalyst for on-water regioselective azide alkyne cycloaddition.
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An environment-friendly synthesis of highly porous spherical carbon nanostructures (PSCN), in situ doped with N and S, from mustard seed waste has been accomplished. The synthesised PSCN has an interconnected...
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We observed that the hydrolysis-condensation reaction of precursors makes a significant difference in constructing ordered mesopores in electrospun ZrO2 nanofibers. Transmission-SAXS studies confirm the generation of uniform clusters of... more
We observed that the hydrolysis-condensation reaction of precursors makes a significant difference in constructing ordered mesopores in electrospun ZrO2 nanofibers. Transmission-SAXS studies confirm the generation of uniform clusters of size ∼1.44 nm in the ZrOCl2·8H2O (inorganic salt) derived sol due to its relatively slow hydrolysis-condensation process. These initial -Zr-O-Zr- clusters acted as building blocks to form uniform 3D ordered cubic (Pm3[combining macron]m) mesopores in the presence of Pluronic F127 surfactant. In contrast, the commonly used Zr-alkoxide (zirconium n-propoxide) precursor, which is highly hydrolysable even after the use of a controlling agent, generates larger clusters with broad size distributions due to the uncontrolled hydrolysis-condensation of alkoxy groups. Accordingly, in the presence of F127, the alkoxide derived sol yielded disordered mesopores in the resultant fibers. XRD under dynamic heating conditions (up to 900 °C) and the corresponding TEM ...
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Ti1−xZrxO2−y single crystals with exposed high energy facets and defects show co-catalyst free solar water splitting and high solar energy conversion in DSSCs.
Crystalline cubic zirconia nanocoating on cpTi with enhanced surface hardness, durability and biocompatibility, useful as an advanced oral implant was fabricated by applying layer-by-layer dip-coating at low annealing temperature.
A unique, extremely fast alloy–dealloy phenomenon of Au–Ag nanoparticles inside transparent SiO2 film associated with large plasmonic modifications is observed.
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Low temperature fabrication of durable photoactive anatase TiO 2 coatings (on glass and plastic substrates) has been accomplished using the synthesized water and water-EtOH dispersible organic-free TiO 2 nanopowder. This nanopowder has... more
Low temperature fabrication of durable photoactive anatase TiO 2 coatings (on glass and plastic substrates) has been accomplished using the synthesized water and water-EtOH dispersible organic-free TiO 2 nanopowder. This nanopowder has been synthesized by refluxing the mixture of Ti(OiPr) 4 , EtOH, and H 2 O in the presence of excess NO 3 − ion as a stabilizer at 80 °C for 24 h. The nanopowder has a small crystallite size (∼5 nm) and a high specific surface area of about 268 m 2 g −1. It is highly dispersible in water (up to 20 wt %), and the water−EtOH mixture (10 wt %) and the resulting dispersions are very stable. The water−EtOH (1:3 w/w) dispersion of the TiO 2 nanopowder (4−5 wt %) has been used to prepare transparent coatings on glass and flexible plastic (polypropylene and polycarbonate) substrates with a surface hardness of ∼2−3 and 1−2 H, respectively, and good adhesion (5B; high quality). The reasons behind good adhesion and hardness of these coatings have been discussed. Such coatings on plastic and glass substrates have been used as reusable photocatalysts for degradation of toxic dye (methylene blue) to show the self-cleaning property under UV (365 nm) and visible light (Xenon source; 1 sun) sources. Further, by using this TiO 2 powder, a fluorescent ZnS:Mn/TiO 2 phosphor can be easily prepared at a much lower temperature.