Synthesis of the CdS nanoparticles in polymer networks

Summary CdS nanoparticles were synthesized in polymer networks. EDAX data show that the content of Cd²⁺ was about 3%wt. The particles size can be controlled by varying the amount of H₂S, and the absorption spectra indicated that the band edge shifts toward blue with decreasing the particles size. TEM and diffraction data show that the CdS nanoparticles with narrow size distribution were well assembled in polymer networks, and it has a hexagonal structure.     

Controlled growth of CdS nanoparticles in polyurushiol matrices

A method for fabrication of urushiol–cadmium coordination polymer was developed under UV irradiation, and then hybrid composites of CdS nanoparticles embedded in polyurushiol (PU) matrices were prepared by immersion the coordination polymer in thioacetamide (TAA). XPS measurements showed the coordination between cadmium ion and oxygen after UV irradiation. In the course of UV irradiation, the hydroxyl groups on the phenyl ring of urushiol were dissociated to urushiol semiquinone, and coordinated with cadmium ions to form complexes. The –OH groups on the phenyl ring of urushiol acted as the coordination sites for cadmium ion aggregations and the nanosized CdS particles were successfully grown in situ at these sites with the release of S²⁻ ions from TAA. The results from X-ray powder diffraction (XRD) analysis and the FT-IR spectra showed the formation of CdS nanoparticles and the polymerization of urushiol monomers. TEM showed that CdS nanoparticles were homogeneously dispersed in PU matrices. TG analysis showed that the PU/CdS nanocomposites had excellent thermo-stability. A possible formation mechanism of CdS nanoparticles in the PU matrices was also suggested based on the experimental results.     

Facile Bulk Synthesis of Homogeneous and Transparent Nanocrystals Hybrids via In Situ Transformation of Ionomers into CdS Quantum-Dot-Polymer

We systemically report on a method for fabricating bulk CdS QD-polymer hybrids nanocomposites with tunable control photoluminescence (PL) by using as-prepared ionomers. Firstly, we rationally designed to synthesize well-dispersed PMMA/Cd(AA)₂ (cadmium acrylate) ionomers containing different concentrations of Cd²⁺ ion clusters via free-radical polymerization. And then, we introduced H₂S gas into the ionomer solutions to obtain transparent PMMA/CdS QD-polymers in situ. Subsequently, we employed PMMA/CdS QD-polymers to further produce claviform CdS/PMMA hybrid nanocomposites via in situ bulk polymerization. The properties of as-prepared QD-polymers and their hybrid nanocomposites were thoroughly investigated by Ultraviolet–visible (UV-vis), transmission electron microscope (TEM), Fourier transform infrared spectra (FT-IR), photoluminescence (PL), thermogravimetric analyses (TGA) measurements. We have found that these QD-polymers exhibit uniform dispersity, good optical property and an obvious advantage on thermal stability, along with facilely producing bulk nanocrystal/polymer hybrid nanocomposites with a large scale.     

Visible Light-Induced Degradation of Methylene Blue in the Presence of Photocatalytic ZnS and CdS Nanoparticles

ZnS and CdS nanoparticles were prepared by a simple microwave irradiation method under mild conditions. The obtained nanoparticles were characterized by XRD, TEM and EDX. The results indicated that high purity of nanosized ZnS and CdS was successfully obtained with cubic and hexagonal crystalline structures, respectively. The band gap energies of ZnS and CdS nanoparticles were estimated using UV-visible absorption spectra to be about 4.22 and 2.64 eV, respectively. Photocatalytic degradation of methylene blue was carried out using physical mixtures of ZnS and CdS nanoparticles under a 500-W halogen lamp of visible light irradiation. The residual concentration of methylene blue solution was monitored using UV-visible absorption spectrometry. From the study of the variation in composition of ZnS:CdS, a composition of 1:4 (by weight) was found to be very efficient for degradation of methylene blue. In this case the degradation efficiency of the photocatalyst nanoparticles after 6 h irradiation time was about 73% with a reaction rate of 3.61 × 10⁻³ min⁻¹. Higher degradation efficiency and reaction rate were achieved by increasing the amount of photocatalyst and initial pH of the solution.     

Preferential interactions of poly(N-vinyl-2-pyrrolidone) in the binary mixture water/CdCl2

The poly(N-vinyl-2-pyrrolidone)(PVP)(2)/water(1)/CdCl₂(3) ternary system has been studied by viscometry, densimetry and atomic absorption spectrophotometry. In this system a preferential adsorption of Cd²⁺ at all solvent compositions studied and a conformational transition at 4mM of salt, the concentration at which a preferential adsorption minimum of Cd²⁺ in exhibited, are observed. The PVP/Cd²⁺ bound molar ratio is 0·23. CdCl₂ behaves as a salting-in agent for the macromolecule. The binary solvent mixture is thermodynamically more favourable at salt concentrations greater than 10 mM of CdCl₂.     

Preparation of Sn‐doped CdS/TiO2/conducting polymer fiber composites for efficient photocatalytic hydrogen production under visible light irradiation

Sn‐doped CdS/TiO₂ heterojunction was synthesized on the conducting polymer fiber mat by hydrothermal method. The conducting polymer fiber mat was made by electrospinning from polyvinylidene fluoride, styrene‐maleic anhydride copolymer, and nano‐graphites as conducting fillers. The Sn‐doped CdS/TiO₂ heterojunction was characterized by XRD, XPS, SEM, TEM, TGA, and UV–Vis absorption spectra. Under simulated solar light irradiation, a combination of Sn‐doped CdS/TiO₂/conducting polymer was found to be highly efficient for photocatalytic hydrogen evolution from splitting of water. The photocatalytic hydrogen production efficiency was up to 2885 μmol h^?1 g^?1cat. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42300.     

Tailoring of complex permittivity,permeability, and microwave-absorbing properties of CoFe2O4/NG/PMMA nanocomposites through swift heavy ions irradiation

In this study, the influence of swift heavy ions (SHI) [C⁶⁺ (80 MeV) and O⁷⁺ (100 MeV)] irradiation on microwave (MW) absorbing properties of cobalt ferrite nanoparticles/exfoliated nanographites/poly(methylmethacrylate) (CoFe₂O₄/NG/PMMA) nanocomposites was investigated in the frequency range of 2–18 GHz. This work is the first attempt to study the comprehensive effects of SHI irradiation on MW absorbing properties of polymer nanocomposites. The scanning electron micrographs of the nanocomposites reveal monotonic improvement in the dispersion of nanofillers (CoFe₂O₄ and NG) with an increase of irradiation dose. With an increase in the fluence of ions, the room temperature saturation magnetization was observed to decrease monotonically, whereas a reverse trend was detected for the coercivity. The SHI irradiated nanocomposites exhibited a relatively stronger MW absorption as well as a higher effective bandwidth of absorption. A minimum reflection loss (R_Lmin) of −36.7 dB (99.98% MW absorption) and a broad bandwidth (for R_L ≤ −10 dB) of ~7.1 GHz were detected in O⁷⁺ (100 MeV) SHI irradiated nanocomposite at the fluence of 1 × 10¹² ions/cm². The results demonstrate that SHI irradiation can used as an effective tool to tailor and enhance the MW absorption in light-weight CoFe₂O₄/NG/PMMA nanocomposites.     

Effect of electrical properties on gas sensitivity of polypyrrole/cds nanocomposites

In the present work, polypyrrole (PPy) nanocomposites were synthesized using ferric chloride (FeCl₃) as an oxidant by in situ polymerization at room temperature. Cadmium sulfide (CdS) nanoparticles were synthesized by ultrasonication technique with size ranging between 60 and 110 nm. The PPy/CdS nanocomposites were prepared by taking 1–3 wt % loading of CdS to measure the electrical conductivity. The PPy nanocomposites were characterized by using FTIR, X‐ray diffraction, UV, and SEM. Furthermore, these PPy/CdS nanocomposites were investigated to study their effect of electrical properties on gas sensitivity of ammonia and LPG. The nanocomposites showed improvement in conductivity and sensing response toward 250 ppm NH₃ was found to be maximum (4.2) compared with 100 and 500 ppm NH₃ gas, whereas in the case of LPG, it showed sensitive response. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42379.     

Colloidal Synthesis of ZnS,CdS and Zn x Cd1−x S Nanoparticles from Zinc and Cadmium Thiobiuret Complexes

ZnS, CdS and Zn _x Cd_1?x S nanoparticles were synthesised from the thermolysis of 1,1,5,5-tetra-iso-propyl-4-thiobiuret complexes of Zn and/or Cd in oleylamine. The influence of the different reaction parameters (precursor concentration, growth temperature, reaction time and injection solvent/capping agent combination) on the size, morphology and optical properties of the produced nanoparticles were studied. ZnS nanoparticles with size smaller than 4.3 nm had the cubic phase whereas the particles with size larger than 4.3 nm had a hexagonal crystal structure as suggested by the selected area electron diffraction. Transmission electron microscopy showed the formation of spherical ZnS nanoparticles in addition to few ZnS nanorods only at growth temperature of 280 °C. Powder X-Ray diffraction (p-XRD) showed that the obtained CdS nanoparticles were cubic under all reaction conditions except when dodecanethiol was used as an injection solvent which produced hexagonal CdS. The change in the crystal structure of the CdS nanoparticles was accompanied with a change in morphology from spherical to triangular. Cubic Zn _x Cd_1?x S nanoparticles were obtained under all reaction conditions. Lattice spacing of the Zn _x Cd_1?x S nanoparticles showed a very good agreement with Vegard’s law. The optical properties of the Zn _x Cd_1?x S nanoparticles were highly dependent on the ZnS to CdS precursor ratio and the solvents/capping agent combinations. This in detail study on the relationship of solvent systems (capping agents), thermolysis temperatures, time of reactions and precursors will help in understanding to control the morphology, size of the crystallites and phase of the materials.     

One‐pot synthesis of a few nanocomposites with poly(N‐vinylcarbazole) and CdS,Ag, Pd50–Ag50, and Pt50–Ru50 nanoparticles with γ irradiation

The one‐pot synthesis of nanocomposites of a conductive poly(N‐vinylcarbazole) (PVK) with CdS, Ag, Pd₅₀–Ag₅₀, and Pt₅₀–Ru₅₀ nanoparticles was performed with γ irradiation in a tetrahydrofuran–water mixture (3/1 vol %). For comparison, the CdS, Ag, Pd₅₀–Ag₅₀, and Pt₅₀–Ru₅₀ nanoparticles were also prepared with γ irradiation with polyvinylpyrrolidone as a stabilizer. Ultraviolet–visible spectroscopy, transmission electron microscopy, X‐ray diffraction analysis, and photoluminescence spectroscopy were used for the characterization of CdS, Ag, Pd₅₀–Ag₅₀, and Pt₅₀–Ru₅₀ nanoparticles and nanocomposites of PVK with CdS, Ag, Pd₅₀–Ag₅₀, and Pt₅₀–Ru₅₀ nanoparticles. The absorption spectrum of the CdS‐nanoparticle‐based composite revealed a quantum confinement effect. The emission spectrum of the composite with CdS nanoparticles and PVK indicated the block effect of PVK for surface recombination. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1809–1815, 2006     

Synthesis,characterization and photocatalytic activity of CdS–montmorillonite nanocomposites

Nanocomposites based on cadmium sulfide (CdS) and Na-montmorillonite (Na⁺-Mt) were prepared by a hydrothermal method using Cd[NH₂CSNH₂]SO₄ complex as precursor of CdS which was derived from cadmium sulfate and thiourea. These nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR) and X-fluorescence (XF). The nanocomposites consist of nanosized CdS pillars, which tend to increase in size as the amount of complex precursor increases. The CdS crystals have a hexagonal symmetry. The photocatalytic activity of the obtained CdS–Mt nanocomposites is improved significantly compared to that of the Mt and pure CdS. The resulting CdS–Mt nanocomposites could degrade methylene blue and rhodamine 6G under near UV–visible irradiation.     

Greenish-yellow emitting CdS: Sm3+ nanoparticles: Structural and optical analysis

Different concentrations of trivalent samarium (Sm³⁺) ions doped cadmium sulphide (CdS) nanoparticles were fabricated by one-step solid-state method at low temperature using C₁₀H₆(SO₃Na)₂ as surfactant for optoelectronic and solar cell applications. They were characterized through powder X-ray diffraction, Fourier transform infrared, Raman, scanning electron microscopy, transmission electron microscopy, UV–Vis absorption and photoluminescence studies. These nanoparticles establish cubic structure without any foreign phase and it was confirmed by Raman studies. The Raman spectrum of CdS nanoparticles shows first three longitudinal optical phonon orders. The adjacent lattice fringes were spaced about 0.30 nm. The direct band gap energy was found slightly higher than the bulk crystallites. The photoluminescence spectra of CdS: Sm³⁺ exhibits a broad peak at 563 nm with a shoulder at around 607 nm corresponding to Sm³⁺: ⁴G_5/2 → ⁶H_7/2 transition at 402 nm excitation. A luminescence quenching was noticed at higher Sm³⁺ ions concentration due to transfer of energy among the excited Sm³⁺ ions. The CdS: Sm³⁺ particles were fabricated with a size of the order of nanoscale and they can be used for efficient energy conversion. The studied CdS: Sm³⁺ nanoparticles are suitable for optoelectronic and solar cell applications.     

Preparation and optical properties of nanocomposite film of CdS:Cu with biomacromolecules

Nanocomposite films of CdS:Cu nanoparticles with chitosan and sodium alginate were prepared using spin‐coating method, and characterized by X‐ray diffraction, transmission electron microscopy, atomic force microscopy (AFM), ultraviolet–visible (UV–vis), and photoluminescent spectrum. The CdS:Cu nanoparticles have a cubic structure with an average crystal size of ∼2 nm, which show blue shift in UV–vis absorption spectra compared to bulk CdS. Furthermore, the CdS:Cu nanoparticles are formed steadily with increasing number of composite layers and homogeneously distributed between the chitosan and alginate layer. AFM measurement shows that the average height of a mono‐layered composite film is 25 nm. Emissions ascribed to the electron–hole recombination of CdS and the t₂‐like energy level of Cu was observed for the multi‐layered composite films. POLYM. COMPOS., 35:477–481, 2014. © 2013 Society of Plastics Engineers     

Synthesis of metal–cadmium sulfide nanocomposites using jingle-bell-shaped core-shell photocatalyst particles

Photocatalytic deposition of gold (Au) and silver (Ag) nanoparticles was investigated using jingle-bell-shaped silica (SiO₂)-coated cadmium sulfide (CdS) nanoparticles (SiO₂/CdS), which each had a void space between the CdS core and SiO₂ shell, as a photocatalyst. A size-selective photoetching technique was used to prepare the jingle bell nanostructure of SiO₂/CdS. Nanoparticles of Au and Ag were deposited by irradiation of the photoetched SiO₂/CdS in the presence of the corresponding metal complexes under deaerated conditions. Chemical etching of Au-deposited particles enabled the selective removal of CdS without any influence on the surface-plasmon absorption of Au. TEM analyses of the resulting particles suggested that some particles were encapsulated in hollow SiO₂ particles, while other Au particles were deposited on the outer surface of the SiO₂ shell. Emission spectra of the photoetched SiO₂/CdS showed that the metal deposition developed a broad emission with a peak around 650 nm originating from surface defect sites, the degree being dependent on the kind of metal nanoparticles and their amount of deposition. This fact can be explained by the formation of metal–CdS binary nanoparticles having defect sites at the interface between metal and CdS.     

Towards Monodisperse Semiconductor Clusters: Preparation and Characterization of ˜ 13-Å Thiophenolate-capped CdS Clusters

We report that two 10-Å [Cd₂₀S₁₃(SPh)₂₂]⁻⁸ clusters may be fused together to form a 13-Å CdS cluster, which shows a sharp absorption peak at 370 nm and a luminescence peak at 390 nm. This is supported by the concentration dependence of the absorption spectra, the luminescence-excitation spectra, the capillary zone electrophoresis separation, the electrochemical measurement, and the powder X-ray data. This cluster fusion process occurs naturally in solution at high concentrations of [Cd₂₀S₁₃(SPh)₂₂]⁻⁸. It can also be induced electrochemically by a two-electron oxidation process. We also show that capillary zone electrophoresis and electrochemical synthesis are two useful new techniques for obtaining monodisperse CdS clusters. Their potentials and limitations are discussed.     

Fabrication and characterization of CdS/BiVO4 nanocomposites with efficient visible light driven photocatalytic activities

Novel CdS/BiVO₄ nanocomposites were synthesized by simple solvothermal method. The as-prepared samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Raman spectroscopy, UV–vis diffuse reflectance spectra (DRS), Fourier transform infrared spectra (FT-IR) and photoluminescence (PL). In the nanocomposites, CdS particles were deposited on the surface of the BiVO₄. The photocatalytic tests showed that the CdS/BiVO₄ nanocomposites possessed a higher rate for degradation of malachite green (MG) than the pure BiVO₄ under visible light irradiation. The 1.5-CdS/BiVO₄ nanocomposite photocatalyst was found to degrade 98.3% of MG under visible light irradiation. Moreover, the photocatalytic mechanism of CdS/BiVO₄ nanocomposites was also discussed. The results showed that the nanocomposite construction between CdS and BiVO₄ played a very important role in their photocatalytic properties, which has the potential application in solving environmental pollution issues utilizing solar energy effectively.     

Bulk synthesis of homogeneous and transparent bulk core/multishell quantum dots/PMMA nanocomposites with bright luminescence

Core/multishell CdSe/CdS/CdS/Cd_0.75Zn_0.25S/Cd_0.5Zn_0.5S/Cd_0.25 Zn_0.75S/ZnS/ZnS QDs/PMMA bulk nanocomposites were successfully synthesized. To achieve a homogeneous and stable dispersion in MMA monomers, QDs were first modified with amphiphilic polymer of poly(ethylene glycol)‐oleate (PEG‐oleate). Subsequently, the transparent and homogeneous bulk composites were obtained by photopolymerization. The TEM analysis of ultramicrotome cut of composite demonstrates that QDs are well dispersed in the PMMA matrix. UV–vis transmission spectra show the nanocomposites still maintain high transmittance even with QDs content of up to 6 wt %. The thermogravimetric analysis (TGA) reveals the incorporation of the QDs significantly improves the thermal stability of composites, as evidenced by the retardation of a degradation initiation by 60°C. Photoluminescence spectra suggest that the nanocomposites exhibit bright fluorescence under UV excitation. X‐ray excited luminescence spectra show they have response to X‐ray. All of the experimental results indicate the great promising applications of core/multishell QDs/PMMA nanocomposites in optical communication devices and radiation detectors. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1548–1553, 2013     

Crystallographic,Energy Gap,Photoluminescence and Photo-Catalytic Investigation of Cu Doped Cd0.9Zn0.1S Nanostructures by Co-precipitation Method

In this work, the controlled synthesis of Cd_0.9Zn_0.1S, Cd_0.89Zn_0.1Cu_0.01S and Cd_0.87Zn_0.1Cu_0.03S nanostructures by chemical co-precipitation technique was reported. The XRD investigation confirmed the cubic structure on Zn/Cu-doped CdS without any secondary/impurity related phases. No modification in cubic structure was detected during the addition of Zn/Cu into CdS. The reduction of crystallite size from 63 to 40 Å and the changes in lattice parameter confirmed the incorporation of Cu into Cd_0.9Zn_0.1S and also the generation of Cu related defects. The shift of absorption edge along upper wavelength region and elevated absorption intensity by Cu doping can be accredited to the collective consequence of quantization and the generation of defect associated states. The enhanced optical absorbance and the reduced energy gap recommended that Cd_0.87Zn_0.1Cu_0.03S nanostructure is useful to enhance the efficiency of opto-electronic devices. The presence of Cd–S/Zn–Cd–S /Zn/Cu–Cd–S chemical bonding were confirmed by Fourier transform infrared investigation. The elevated green emission by Cu incorporation was explained by decrease of crystallite size and creation of more defects. Zn, Cu dual doped CdS nanostructures are recognized as the possible and also efficient photo-catalyst for the removal dyes like methylene blue. The enhanced photo-catalytic behavior of Zn, Cu dual doped CdS is the collective consequences of high density electron–hole pairs creation, enhanced absorbance in the visible wavelength, surface area enhancement, reduced energy gap and the formation of novel defect associated states. The stability measurement signified that Cu doped Cd_0.9Zn_0.1S exhibits superior dye removal ability and better stability even after 6 repetitive runs with limited photo-corrosion due to more charge carriers liberation, increased surface to volume ratio and creation of more defects.

     

新型CdS/TiO_2纳米复合材料的制备及其可见光催化性能研究

采用浸渍法和水热法相结合制备了新型的CdS/TiO_2纳米复合材料,并采用X射线衍射(XRD)、透射电子显微镜(TEM)、UV-Vis吸收光谱(UV- VIS)、电子自旋共振谱(ESR)等对样品进行了表征,XRD、TEM表明所制备的新型CdS/TiO_2粒径小、分散均匀,TiO_2以锐钛矿型存在,CdS以高分散的立方相和六方相存在,对比直接法制备的CdS/TiO_2,新型的CdS/TiO_2对活性艳红X-3B具有明显提高的可见光催化活性;大量的束缚单电子氧空位及电子之间强相互作用是新型CdS/TiO_2可见光催化活性提高的主要原因.     

Efficient preparation of hybrid nanocomposite coatings based on poly(vinyl alcohol) and silane coupling agent modified TiO2 nanoparticles

In the present investigation, at first, the surface of titanium dioxide (TiO₂) nanoparticles was modified with γ-aminopropyltriethoxy silane as a coupling agent. Then a new kind of poly(vinyl alcohol)/titanium dioxide (PVA/TiO₂) nanocomposites coating with different modified TiO₂ loading were prepared under ultrasonic irradiation process. Finally, these nanocomposites coating were used for fabrication of PVA/TiO₂ films via solution casting method. The resulting nanocomposites were fully characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), thermogravimetric analysis/derivative thermal gravimetric (TGA/DTG), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The TEM and SEM results indicated that the surface modified nanoparticles were dispersed homogeneously in PVA matrix on nanoscale and based on obtained results a possible mechanism was proposed for ultrasonic induced nanocomposite fabrication. TGA confirmed that the heat stability of the nanocomposite was improved. UV–vis spectroscopy was employed to evaluate the absorbance and transmittance behavior of the PVA/TiO₂ nanocomposite films in the wavelength range of 200–800 nm. The results showed that this type of films could be used as a coating to shield against UV light.