2,859 publications from this institution
Strontium oxide nanoparticle decorated carbon nanotube nanocomposites (SrO·CNT NCs) were prepared in alkaline medium using a wet-chemical technique at low temperature.
Purpose The purpose of this paper is to evaluate the photochromic performance of photochromic compounds in polymer matrices. Design/methodology/approach The polystyrene films doped with photochromic fulgide were prepared and the effect of UV irradiation were studied using spectrophotometer. The reversible reaction was effected using white light. The effect of heat was also determined. Findings A film of the green coloured fulgide 2‐E doped in polystyrene polymer was irradiated with UV light (366 nm), the film turned blue. The latter colour was partially switched back to the original green colour when the film was irradiated with a white light. Increasing the annealing temperatures, increases the percentage conversion of 2‐C to 2‐E . The observed large bathochromic shifts in λ max of 2‐C and the partial conversion of 2‐C to 2‐E were rationalised on the bases of electronic and steric effects. It was found that both isomers 2‐C and 2‐E absorbed white light and they interconvert. The kinetics of photocoloration and photobleaching processes were followed spectrophotometrically by monitoring the absorbance of the ring closed product 2‐C at its λ max of 620 nm. The apparent first‐order rate constants for both processes were determined. It was found that there was slight variation in the rate constant for photocoloration reaction with annealing temperature. On the other hand, the apparent first‐order rate constant of the photobleaching reaction decreases with increasing the annealing temperature. Research limitations/implications The polystyrene polymer doped photochromic fulgides described in the present paper was prepared and studied. The principle of study established can be applied to any type of polymer or to any type of photochromic compounds. Practical implications The photochromic materials developed can be used for different applications, such as coatings and holography. Originality/value The method developed may be used to enhance the performance of photochromic materials.
In the molecule of the title compound, C20H13BrN2O, the tetrahydrobenzo[h]quinoline fused-ring system is buckled owing to the ethylene –CH2CH2– fragment, the benzene ring and the pyridine ring being twisted by 17.7 (1)°. The 4-substituted aromatic ring is bent away from the pyridine ring by 82.3 (1)° in order to avoid crowding the cyanide substituent. Two molecules are linked by a pair of N—H⋯O hydrogen bonds to form a centrosymmetric dimer.
In this article, a ternary WO3/g-C3N4@ BiVO4 composites were prepared using eco-friendly hydrothermal method to produce efficient hydrogen energy through water in the presence of sacrificial agents. The prepared samples were characterized by scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet-visible (UV-vis), Brunauer-Emmett-Teller (BET) surface area, and photoluminescence spectroscopy (PL) emission spectroscopy. The experimental study envisages the formation of 2-D nanostructures and observed that such kinds of nanostructures could provide more active sites for photocatalytic reduction of water and their inherent reactive-species mechanism. The results showed the excellent photocatalytic performance (432 μmol h−1 g−1) for 1.5% BiVO4 nanoparticles in WO3/g-C3N4 composite when compared with pure WO3 and BiVO4. The optical properties and photocatalytic activity measurement confirmed that BiVO4 nanoparticles in WO3/g-C3N4 photocatalyst inhibited the recombination of photogenerated electron and holes and enhanced the reduction reactions for H2 production. The enhanced photocatalytic efficiency of the composite nanostructures may be attributed to wide absorption region of visible light, large surface area, and efficient separation of electrons/holes pairs owing to synergistic effects between BiVO4 and WO3/g-C3N4. The prepared samples would be a precise optimal photocatalyst to increase their suppliers for worldwide applications especially in energy harvesting.
A polymeric hybrid nanocomposite, namely polythiophene tin(IV)phosphate (PTh–SnP), was expediently synthesized by incorporating polythiophene (PTh) in tin phosphate (SnP) to enhance the conducting behavior and sorption of heavy metal ions by porous polymeric cation exchanger. Composite was characterized by Fourier Transform-Infra Red and Transmission Electron Microscopy. The dc electrical conductivity studies carried out on the composite, showed conductivity within the range of 4.0 × 10−2–1.0 × 10−3 S/cm−1; measured by a 4-in line-probe dc electrical conductivity measuring technique. Ion-exchange kinetics for few divalent metal ions was evaluated by particle diffusion-controlled ion-exchange phenomenon at four different temperatures. The particle diffusion mechanism is confirmed by the linear τ (dimensionless time parameter) vs t (time) plots. The exchange processes thus controlled by the diffusion within the exchanger particle for the systems studies herein. Some physical parameters like self-diffusion coefficient (D0), energy of activation (Ea) and entropy (ΔS°) have been evaluated under conditions favoring a particle diffusion-controlled mechanism.
Al2O3 doped Mn3O4 nanomaterial was synthesized by low-temperature stirring method and applied as a catalyst for the degradation of organic pollutants under solar light for prospective environmental applications. The morphological and physiochemical structure of the synthesized solar photocatalyst was investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). FESEM showed a mixture of nanowires and aggregated nanoparticles. This Al2O3 doped Mn3O4 nanomaterial exhibited high solar photocatalytic degradation in a short time when applied to brilliant cresyl blue (BCB). Thus, the synthesized nanoparticles can be used as an efficient solar photocatalyst for the degradation of BCB.
In the title mol-ecule, C(18)H(12)N(2)OS, the dihedral angle between the two fused-ring systems is 7.2 (1)°. The hydr-oxy group forms an intra-molecular hydrogen bond with the imino group.
