Synthesis of Pd co-doped nano-TiO2–SO42– and its synergetic effect on the solar photodegradation of Reactive Red 120 dye

Pd co-doped TiO₂–SO₄^2– photocatalyst was synthesized by sol–gel, photodeposition methods and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and BET surface area measurements. Elements present in the catalyst are shown by X-ray photoelectron spectroscopy. X-ray diffraction analysis reveals that the photocatalyst has an anatase structure. Sulfation by sulfuric acid reduces agglomeration, inhibits the phase transformation and enhances the stability of TiO₂. The solar photocatalytic activity of the Pd–TiO₂–SO₄^2– is higher than that of the TiO₂–P25, Pd–TiO_2, bare TiO₂ and TiO₂–SO₄^2– at pH 7 for the mineralization of Reactive Red 120. The modification of palladium shows higher adsorption with synergistic effect and also enhances the separation of photogenerated electron–hole pairs, leading to higher photodegradation efficiency. The effects of operational parameters such as the amount of photocatalyst, initial pH on photo mineralization have been analyzed. A dual mechanism of degradation by Pd–TiO₂–SO₄^2– is proposed to explain its higher activity in solar light. The mineralization of Reactive Red 120 has also been confirmed by CV and COD measurements. The catalyst is found to be stable and reusable. Based on the degradation intermediates identified by GC–MS analysis, a reaction pathway is proposed.     

Synthesis,characterization, and antimicrobial activity of chitosan–zinc oxide/polyaniline composites

Organic–inorganic materials of chitosan–zinc oxide/polyaniline (CS–ZnO/PANI) composite were prepared via precipitation with a polymerization method and characterized by FT-IR, XRD, EDXS and TEM analysis, thereby providing evidence of composite formation. The size of the prepared CS–ZnO/PANI composite was found to be 100–200 nm, thereby rendering the morphology suitable for biomedical applications. Antibacterial activities of chitosan–ZnO (CS–ZnO), polyaniline (PANI) and CS–ZnO/PANI composites were determined against Gram-positive bacterium, Staphylococcus aureus (S. aureus), and Gram-negative bacterium, Pseudomonas aeruginosa (P. aeruginosa) and were tested in-vitro at 5–50 μg/mL. Results showed that CS–ZnO/PANI composite had broad-spectrum antibacterial activity that was greatly enhanced in comparison with CS–ZnO. In addition, CS–ZnO/PANI composite has tested fungal strains of Candida albicans (C. albicans) and relatively higher activities were observed than the known antibiotics. Finally, the antimicrobial activity of CS–ZnO/PANI composite against established biofilms was also examined and resulted in more than 95% inhibition in biofilm formation.     

First-principles calculations of electronic structure and optical properties of boron–phosphorus co-doped zinc oxide

This paper presents the electronic structure and optical properties of boron–phosphorus co-doped zinc oxide ((B, P) codoped ZnO) systems employing first principles calculations based on density functional theory. In the (B, P) codoped ZnO systems, dopants prefer to be located on the nearest-neighbor sites in the same (00l) plane forming B_Zn–P_O complex with binding energy of −1.92 eV; some hole sates appear above the valence band maximum. With increase in P concentration, P 3p states become more and more delocalized. The calculated optical properties indicate that strong optical transitions in lower energy region occur; the intensities and positions of these peaks are P concentration-dependent, which could be ascribed to the electronic transitions between P 3p and Zn 4s states. Moreover, the absorption coefficients and other optical constants of the (B, P) codoped ZnO systems, such as reflectivity, refractive index, and loss function, are also discussed.     

Experimental and first-principles DFT studies of electronic,optical and magnetic properties of cerium–manganese codoped zinc oxide nanostructures

Syntheses, structural, optical and magnetic characterizations of codoped ZnO nanoparticles have been reported. Nanoparticles of Zn_1−2xCe_xMn_xO (x=0.00, 0.01, 0.02, 0.03, 0.04, and 0.05) were synthesized using a microwave-assisted combustion method. Structural, optical and magnetic properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL) and a vibrating sample magnetometer (VSM). The observed shift in XRD peak position, change in peak intensity, cell parameters, volume and stress confirmed the substitution of cerium-manganese (Ce–Mn) dopants within ZnO lattice. The synthesized nanoparticles show different microstructure without changing the parent hexagonal wurtzite structure of zinc oxide (ZnO). The average crystallites size was decreased from 43 to 21 nm. Energy dispersive X-ray spectra confirmed the presence of Ce and Mn in ZnO system and the weight percentage was nearly equal to their nominal stoichiometry. DRS analysis showed a decrease in the energy gap with increasing dopants content. The observed luminescence in the green, violet and blue regions strongly depends on the nature of the doping elements and their concentration owing to the formation of different oxygen vacancy, zinc interstitial, and surface morphology. Our results demonstrate that Mn ions doping concentration play an important role in the observed room temperature ferromagnetism (RTFM) of Ce–Mn codoped ZnO nanoparticles. First- principles calculation results indicate that Ce governs the stability, while Mn adjusts the magnetic characteristics in codoped ZnO.     

Synthesis and characterization of nano Ag/Pt and methyl violet co-doped sol–gel porous material

Nano Ag/Pt and methyl violet (MV) co-doped sol–gel substrates have been prepared and characterized by spectral and microscopic techniques. MV was encapsulated in the sol–gel medium along with the bimetal nanoparticles and the resultant materials were compared. MV adsorbed on the surface of nanometal particles and encapsulated into the substrate of both is proposed as a scheme. Photodegradation of four different dyes (MV, methyl green, malachite green and Congo red) as probes, by prepared only bimetal doped substrate is examined and discussed to understand the mechanism.     

Synthesis and characterization of sub-micron sized copper–ruthenium–tantalum composites for interconnection application

Sub-micron sized ruthenium and tantalum reinforced copper composites as suitable material for electronic interconnection applications was synthesized using high temperature high pressure technique. High purity sub-micron starting powders were blended in a turbula mixer at varying compositions and consolidated at temperature of 850 °C and pressure of 30 MPa for 30 min. The density, phase composition, microstructure, hardness and electrical conductivity of the resulting materials were investigated. The addition of 2.5 vol% ruthenium improved the density of the pure sintered Cu from 97.20% of the theoretical to 99.89% and increased the Vickers hardness value from 114.2 HV to 127.8 HV. Tantalum addition was found to inhibit copper grain growth during sintering. The electrical resistivity of copper based composites remained relatively low with the addition of reinforcement materials.     

Mesoporous-assembled In2O3–TiO2 mixed oxide photocatalysts for efficient degradation of azo dye contaminant in aqueous solution

This work focuses on the improvement of the photocatalytic activity of mesoporous-assembled In₂O₃–TiO₂ mixed oxide photocatalysts for Congo Red (CR) azo dye degradation by varying the In₂O₃-to-TiO₂ molar ratio and calcination temperature. All of photocatalysts are synthesized by a sol–gel process with the aid of a structure-directing surfactant. The results show that the incorporation of In₂O₃ to the mesoporous-assembled TiO₂ can increase the specific surface area and total pore volume, inhibit the anatase-to-rutile phase transformation, and decrease the crystallite size of the resulting In₂O₃–TiO₂ mixed oxide photocatalysts. The mesoporous-assembled 0.05In₂O₃–0.95TiO₂ mixed oxide photocatalyst with an In₂O₃-to-TiO₂ molar ratio of 0.05:0.95 (5 mol% In₂O₃ incorporation) and calcined at 500 °C exhibits the highest CR dye degradation activity (with reaction rate constant of 0.86 h⁻¹), being considerably higher than that of the commercial P-25 TiO₂ powder.     

Synthesis and characterization of CuO–SnO2 nanocomposite and its application as liquefied petroleum gas sensor

Present paper reports the synthesis of CuO–SnO₂ nanocomposite via sol–gel route as a sensing material for a liquefied petroleum gas (LPG). X-ray diffraction analysis confirmed the formation of CuO–SnO₂ nanocomposite. Crystallite size was found 5 nm. The optical band gap of the nanocomposite was found 4.1 eV. The thin/thick films were fabricated using spin coating and screen printing technology respectively and investigated with the exposition of LPG at room temperature (25 °C). Surface morphology of the thin film exhibits that it has a number of gas adsorption sites. The sensitivities of the thick and thin film sensors were found 4.1 and 42 respectively. The response and recovery times of the fabricated film sensor were 180 and 200 s respectively. Maximum sensor response of thin film sensor was found 4100. Better sensitivity and percentage sensor response, small response and recovery times, and good reproducibility and stability recognize the fabricated thin film of CuO–SnO₂ as a challenging material for the detection of LPG.     

Synthesis of a novel organic nonlinear optical chromophore and the Testing for μgβ Value

Much attention has been devoted to nonlinear optica (NLO) materials over the past decade because of the poten tial applications in the field of telecommunications, optica signal processing, optical switching, and so forth. Organi NLO materials with high p…     

Synthesis of a novel organic nonlinear optical chromophore and the Testing for μgβ Value

A novel second-order nonlinear optical chromophore (DCDHF-2-V) was synthesized from 3-Hydroxy-3-methyl-2-butanae,propanedinitrile and 4-diethylaminobenzaldehyde by aldol condensation reaction. Molecular structural characterization was investigated by elemental analysis,FTIR,and 1H-NMR spectra. The melting point obtained from DSC thermogram was almost 251 ℃,and the compound shows a thermal stability up to 270 ℃. Second-order NLO properties of the chromophore were measured by solvatochromic method. From the quantum-mechanical two-level model,it can be obtained that the μgβ value of DCDHF-2-V is 6520 × 10-48 esu atthe wavelength of 1064 nm.     

Synthesis and characterization of a fluorinated oligosiloxane-containing encapsulation material for organic field-effect transistors,prepared via a non-hydrolytic sol–gel process

The operation of stable organic field-effect transistors (FETs) over long periods of time requires that organic FETs are encapsulated. We synthesized an inorganic–organic hybrid non-hydrolytic sol–gel material (TPDt) containing fluoroalkyl functional groups to encapsulate organic FETs. Fourier-transform infrared spectroscopy, atomic force microscopy, UV–Visible spectroscopy, and water contact angle measurements demonstrated that the TPDt films displayed smooth surfaces, good hydrophobicity, and optical transparency. The gas barrier properties of the TPDt films were tested by fabricating FETs using an organic semiconductor, poly[9,9-dioctylfluorenyl-2,7-diyl]-co-(bithiophene)]. The organic FETs were operated at 38 °C in the presence of a 90% relative humidity air atmosphere. The field-effect mobility of the organic FET decreased only negligibly, even after 2500 h operation under these conditions.     

Synthesis of phenylcarbazole–thiophene-based structural isomers as unipolar host materials for blue PHOLEDs and their device performance

New high triplet-energy host materials, which are symmetrically or asymmetrically designed by using phenylcarbazole and thiophene moieties, were synthesized by Suzuki–Miyaura cross-coupling reactions and their device performances of blue phosphorescent organic light-emitting diodes were also investigated. The synthesized compounds showed a high triplet energy (>2.84 eV) and good thermal stability. Highly efficient blue PHOLEDs were obtained when employing the symmetric compounds having C2 symmetry as the host material and bis[2-(4,6-difluorophenyl)pyridinato-C²,N](picolinato)iridium(III) (FIrpic) as the guest material. Their maximum external quantum efficiency of the device reached as high as 18.9% with blue color coordinate of (0.15, 0.35).     

NiTiO3/NiFe2O4 nanocomposites: Simple sol–gel auto-combustion synthesis and characterization by utilizing onion extract as a novel fuel and green capping agent

NiTiO₃/NiFe₂O₄ nanocomposites were prepared via a simple sol–gel auto-combustion route using onion extract as a novel fuel and green capping agent. The present work focused on the synthesis and characterization of NiTiO₃/NiFe₂O₄ nanocomposites for the first time. First, a sol of NiFe₂O₄ was obtained, from metal nitrates and onion extract as reductant. Second, a sol of titanat was prepared by mixing of tetra-n-butyl orthotitanate, diethanolamin and ethanol. Then obtained sol was added to the NiFe₂O₄ sol. The molar ratio of Ti to Ni had significant effect on morphology, magnetic properties, purity and phase of nanocomposites. Nanocomposites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV) and vibrating sample magnetometer (VSM). The magnetic properties of the samples were also investigated using an alternating gradient force magnetometer where the optimum condition was performed in the molar ratio Ti/Ni 1:1. The photocatalytic activity of the synthesized products has been compared with the photodegradation activity of methyl orange (MO).