聚乙烯吡咯烷酮修饰的CdS纳米晶：多元醇合成、表征和可见光活性

采用溶剂热法合成了具有不同晶粒尺寸的聚乙烯吡咯烷酮（PVP）修饰的CdS纳米晶,并运用XRD,N₂物理吸附,TEM,IR,UV-Vis等手段进行表征。结果表明,所制得的样品均为聚乙烯吡咯烷酮(PVP)修饰的CdS纳米晶;添加四甲基氢氧化铵(TMAH)有利于获得晶粒尺寸较小的CdS纳米晶;受纳米晶粒尺寸的影响,CdS纳米晶的吸收边发生蓝移且可见光催化活性明显提高。     

Preparation and characterization of polyaniline microwires containing CdS nanoparticles

Polyaniline(PANI) microwires containing CdS nanoparticles have been prepared by introducing hydrogen bonding and/or electrostatic interaction between mercaptocarboxylic acid capped CdS nanoparticles and PANI. SEM and TEM proved them to be wire-like structures. PL spectra of the PANI/CdS complex is blue-shifted by 14 nm compared to CdS nanoparticles in N-methylpyrrolidinone(NMP).     

Electrochemically synthesized CdS nanoparticle-modified TiO2 nanotube-array photoelectrodes: Preparation,characterization, and application to photoelectrochemical cells

A novel electrodeposited CdS nanoparticle-modified highly-ordered TiO₂ nanotube-array photoelectrode and its application to photoelectrochemical cells is reported. Results show formation of a thin, nanoparticulate CdS layer, comprised of sphere-like 10–20 nm diameter nanoparticles, on the anodic synthesized TiO₂ nanotube-array (inner diameter of 70 nm, wall thickness 25 nm and ca. 400 nm length) electrode. The resulting CdS–TiO₂ photoelectrode has an as-fabricated bandgap of 2.53, and 2.41 eV bandgap after sintering at 350 °C in N₂ ambient. Photoelectrochemical properties are described in detail.     

Synthesis and characterization of CdS nanoparticles prepared by precipitation in the presence of span 20 as surfactant

Cadmium sulfide nanoparticles with average size of ≈16 nm have been synthesized using chemical precipitation reaction of CdCl₂ and Na₂S in the presence of nonionic surfactant stabilized reverse emulsions. Sorbian monolaurate (Span 20) is used for the stabilization of emulsions. The influence of Span 20 on controlling the size and properties of CdS nanoparticles were studied. The obtained CdS nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy-dispersive x-ray (EDX), and X-ray diffraction (XRD). The optical properties of CdS nanoparticles are investigated systematically by UV-visible absorption spectroscopy. The blue shift in the absorption region and increase in the bandgap to the larger value (2.77 eV) are attributed to the nanosize of the obtained particles.     

Sorption of thallous ion from acidic aqueous solutions onto ETS-10 titanosilicate

The sorption of the thallous ion from aqueous acidic solution (pH = 1.5) onto as-synthesized and modified ETS-10 titanosilicates was studied by using an isotope dilution method and a batch-mode technique. The present results show that the thallium(I) sorption was effective onto all three considered materials and is enhanced by the porosity and acidity modification of the ETS-10 titanosilicate. The best uptake performance was achieved by the meso-ETS-10. This behavior is explained based on the newly created additional mesoporous system and enriching the external surface with silanol groups. Also, the presence of phosphorus enhanced the inherent porosity allowing thus better internal diffusion properties of crystalline material. However, the chemically modified surface seems to have a negative contribution to the kinetic uptake of thallous ion as shown by the positive value of the activation energy E _a, in comparison with the processes more favorable energetically for ETS-10 and meso-ETS-10 materials.     

Optical properties of core/shell typed PMMA/CdS nanoparticles prepared by in situ and ex situ surfactant-free emulsion polymerization

Core/shell poly(methyl methacrylate)/cadmium sulfide (PMMA/CdS) nanoparticles were prepared by surfactant-free emulsion copolymerization with 2-(dimethylamino)ethyl methacrylate (DMAEMA) auxiliary monomer. According to the addition time of Cd²⁺ ions, the synthesis of the hybrid nanoparticles was conducted in in situ and ex situ techniques. The core/shell PMMA/CdS nanoparticles synthesized by the post-addition (ex situ) of Cd²⁺ ions showed a wide size distribution and interference fringes in the photoluminescence (PL) spectrum. However, these results were improved when the PMMA/CdS nanoparticles were synthesized in the presence of Cd²⁺ ions (in situ method). The in situ method made it possible to obtain monodisperse hybrid nanoparticles and fairly narrow band-gap emission.     

The CdS nanoparticle with capped surface and its nonlinear optical properties studied by hyper-Rayleigh scattering

The CdS nanoparticles synthesized in AOT (bis(2-ethylhexyl) sulfosuccinate, disodium salt) reverse micelle in addition of the electric neutral surface-capping agent of pyridine are characterized by XPS, TEM and the absorption spectra. The values of the first-order hyperpolarizability β for two kinds of nanoparticles, CdS/AOT^- and CdS/pyridine/AOT^-, have been experimentally measured in solution by the newly developed hyper-Rayleigh scattering technique. The values of β are larger than 10^-27 esu, which are among the largest values reported for solution species.     

Preparation and electrorheological characteristic of CdS/Polystyrene composite particles

Cadmium sulfide/polystyrene (CdS/PS) hybrid particles were synthesized and their physical characteristics including electrorheology were examined. Monodisperse CdS/PS nanocomposite particles with diameters of 2 μm were obtained via dispersion polymerization. To form cadmium sulfide nanoparticles onto the PS surface, 2-(dimethylamino)ethyl methacrylate was used as a functional monomer for coordinating with Cd²⁺ ions. Finally, cadmium sulfide nanoparticles with size < 10 nm were formed with the release of S²⁻ ions from thioacetamide. The morphology of the as-prepared CdS/PS nanocomposite particles clearly showed that the CdS particles are present on the surface of the PS. The optical properties were also studied. In addition, their electrorheological characteristics were confirmed by using optical microscopy with applied electrical field. Recently, dielectric properties of CdS nanoparticles were already reported; however, electrorheological characteristics of CdS/PS nanocomposite particles were investigated for the first time.     

A Covalent Organic Framework–Cadmium Sulfide Hybrid as a Prototype Photocatalyst for Visible‐Light‐Driven Hydrogen Production

CdS nanoparticles were deposited on a highly stable, two‐dimensional (2D) covalent organic framework (COF) matrix and the hybrid was tested for photocatalytic hydrogen production. The efficiency of CdS‐COF hybrid was investigated by varying the COF content. On the introduction of just 1 wt % of COF, a dramatic tenfold increase in the overall photocatalytic activity of the hybrid was observed. Among the various hybrids synthesized, that with 10 wt % COF, named CdS‐COF (90:10), was found to exhibit a steep H₂ production amounting to 3678 μmol h^?1 g^?1, which is significantly higher than that of bulk CdS particles (124 μmol h^?1 g^?1). The presence of a π‐conjugated backbone, high surface area, and occurrence of abundant 2D hetero‐interface highlight the usage of COF as an effective support for stabilizing the generated photoelectrons, thereby resulting in an efficient and high photocatalytic activity.     

CdS-containing nano-assemblies of double hydrophilic block copolymers in water

Two samples of poly(sodium(sulfamate-carboxylate)isoprene)-block-poly(ethylene oxide) copolymer (SCIEO-1 and SCIEO-2) differing in molecular weight and relative length of polyelectrolyte blocks have been used as templates for the synthesis of cadmium sulfide (CdS) nanoparticles in aqueous media. The double-hydrophilic copolymer SCIEO has very high 1D charge density, and its polymer chain structure mimics that of polysaccharide heparin. It is soluble in aqueous media, but the addition of cadmium acetate (Cd(Ac)₂) to its aqueous solution causes the formation of micellar aggregates with Cd²⁺containing insoluble cores above the threshold Cd²⁺ concentration. The trapped Cd²⁺ ions can be chemically transformed to CdS nanoparticles. The stability of hybrid SCIEO/CdS micelles depends on the ratio of PEO-to-SCI lengths: it was found that the SCIEO-2 copolymer with sufficiently long PEO block behaves as an effective stabilizer for the synthesis of CdS nanoparticles embedded in micelles, while SCIEO-1 does not. The morphology of aggregates varies with the Cd-to-SCI ratios and ranges from spherical to mixture of spherical and necklace-like micellar aggregates. A number of experimental techniques including static and dynamic light scattering, fluorescence correlation spectroscopy, atomic force and transmission electron microscopy, UV-vis, and fluorescence spectroscopy were employed for the characterization of both CdS containing hybrid micelles and embedded CdS nanoparticles.     

The influence of the nanofiller on thermal properties of thermoplastic polyurethane elastomers

Pure Fe₃O₄ and Mn-doped Fe₃O₄ nanoparticles were synthesized by simple wet chemical reduction technique using nontoxic precursors. Manganese doping of two concentrations, 10 and 15%, were employed. All the three synthesized nanoparticles were characterized by stoichiometry, crystal structure, and surface morphology. Thermal studies on as-synthesized nanoparticles of pure ferrite (Fe₃O₄) and manganese (Mn) doped ferrites were carried out. The thermal analysis of the three as-synthesized nanoparticles was done by thermogravimetric (TG), differential thermogravimetric, and differential thermal analysis techniques. All the thermal analyses were done in nitrogen atmosphere in the temperature range of 308–1233 K. All the thermocurves were recorded for three heating rates of 10, 15, and 20 K min^?1. The TG curves showed three steps thermal decomposition for Fe₃O₄ and two steps thermal decompositions for Mn-doped Fe₃O₄ nanoparticles. The kinetic parameters of the three as-synthesized nanoparticles were evaluated from the thermocurves employing Kissinger–Akahira–Sunose (KAS) method. The thermocurves and evaluated kinetic parameters are discussed in this paper.     

The sorption of some radiocations on microporous titanosilicate ETS-10

The microporous titanosilicate ETS-10 synthesized from gel with following molar composition: 1.0 Na₂O: 1.49 SiO₂ : 0.2 TiO₂ : 0.6 KF : 1.28 HCl : 39.5 H₂O was subjected to sorption of radioactive cations ¹¹⁵Cd²⁺, ²⁰⁴Hg²⁺, ⁶⁰Co²⁺ and ¹³⁷Cs⁺ (M) from aqueous solution, in the absence of ionic competition. The uptake of these cations on the ETS-10 was compared by means of the distribution coefficient (K_d) versus contact time and sorption capacity (R) at equilibrium. The FT-IR spectra of M-ETS-10 sorption products exhibit a modification of the absorption band, principally at 381 cm^-1.     

Effect of the method of production of TiO<Subscript>2</Subscript>/CdS nanohetero film structures on the effectiveness of photoinduced charge separation

The properties of TiO₂/CdS nanohetero structures produced by the chemical and photocatalytic deposition of CdS nanoparticles on the surface of nanocrystalline films of TiO₂ under the conditions of laser pulse photolysis were studied. It was shown that in the case of photocatalytically formed TiO₂/CdS nanocomposites the spatial separation of the photogenerated charges between the components of the hetero structure, leading to the formation of intermediates of the photochemical transformations (Ti^III centers in the TiO₂ nanoparticles and S^– radical-anions in the CdS nanoparticles), is an order of magnitude more effective.     

Ultrasensitive mercury(II) ion detection by europium(III)-doped cadmium sulfide composite nanoparticles

With the biomolecule glutathione (GSH) as a capping ligand, Eu³⁺-doped cadmium sulfide composite nanoparticles were successfully synthesized through a straightforward one-pot process. An efficient fluorescence energy transfer system with CdS nanoparticles as energy donor and Eu³⁺ ions as energy accepter was developed. As a result of specific interaction, the fluorescence intensity of Eu³⁺-doped CdS nanoparticles is obviously reduced in the presence of Hg²⁺. Moreover, the long fluorescent lifetime and large Stoke's shift of europium complex permit sensitive fluorescence detection. Under the optimal conditions, the fluorescence intensity of Eu³⁺ at 614 nm decreased linearly with the concentration of Hg²⁺ ranging from 10 nmol L⁻¹ to 1500 nmol L⁻¹, the limit of detection for Hg²⁺ was 0.25 nmol L⁻¹. In addition to high stability and reproducibility, the composite nanoparticles show a unique selectivity towards Hg²⁺ ion with respect to common coexisting cations. Moreover, the developed method was applied to the detection of trace Hg²⁺ in aqueous solutions. The probable mechanism of reaction between Eu³⁺-doped CdS composite nanoparticles and Hg²⁺ was also discussed.     

Interaction of water‐soluble tetrakis‐(1‐methyl‐4‐pyridiniyl)‐porphyrin and CdS naonoparticles

The interaction between positively charged porphyrin TMPyP(4) (tetrakis‐(1‐methyl‐4‐pyridiniyl) porphyrin) and negatively charged surface of colloidal CdS nanoparticles has been studied by absorption spectrum, fluorescence spectroscopy, and time‐correlated single‐photon‐counting methods. Addition of CdS colloid to a TMPyP(4) solution leads to TMPyP(4) adsorption onto the surface of CdS colloid with an apparent association constant of 4643 L/mol. This adsorption results in distinct changes in absorption spectrum of TMPyP (4) and the quenching of its′ fluorescence, but the biexponential fluorescence decay changes hardly. Nearly 90% of the fluorescence of 5 × 10^?6 mol/L TMPyP(4) can be quenched with 1.5 × 10^?4 mol/L CdS colloid. These spectral changes are attributed to the formation of a certain form complex TMPyP(4)‐CdS.     

An Electrochemical Aptasensor for Detection of Thrombin based on Target Protein‐induced Strand Displacement

A sensitive electrochemical aptasensor for detection of thrombin based on target protein‐induced strand displacement is presented. For this proposed aptasensor, dsDNA which was prepared by the hybridization reaction of the immobilized probe ssDNA (IP) containing thiol group and thrombin aptamer base sequence was initially immobilized on the Au electrode by self‐assembling via Au? S bind, and a single DNA labeled with CdS nanoparticles (DP‐CdS) was used as a detection probe. When the so prepared dsDNA modified Au electrode was immersed into a solution containing target protein and DP‐CdS, the aptamer in the dsDNA preferred to form G‐quarter structure with the present target protein resulting that the dsDNA sequence released one single strand and returned to IP strand which consequently hybridized with DP‐CdS. After dissolving the captured CdS particles from the electrode, a mercury‐film electrode was used for electrochemical detection of these Cd²⁺ ions which offered sensitive electrochemical signal transduction. The peak current of Cd²⁺ ions had a good linear relationship with the thrombin concentration in the range of 2.3×10^?9–2.3×10^?12 mol/L and the detection limit was 4.3×10^?13 mol/L of thrombin. The detection was also specific for thrombin without being affected by the coexistence of other proteins, such as BSA and lysozyme.     

Development and characterization of a titanosilicate ETS-10-coated optical fiber reactor towards the photodegradation of methylene blue

An optical fiber reactor (OFR) system containing uniformly distributed quartz fibers coated with titanosilicate ETS-10 crystals was investigated. Optimum ETS-10 film thickness (～1.5 μm) and coating length (15 cm) were determined from the light propagation analysis in a single ETS-10-coated fiber. The nearly constant value of the attenuation coefficient (α ≈ 0.10 cm^?1) for films with different thickness indicated uniform fiber surface coverage with these films. The extinction coefficient, ?, decreased from ～1.6 to ～1.0 μm^?1 with ETS-10 film thickness increasing from ～0.5 to ～1.5 μm, which suggested less contact per unit film thickness between light and ETS-10 crystals inside thicker films, likely due to their lower crystal packing density. Photodegradation of methylene blue (MB) conducted in the OFR showed higher photocatalytic activity for thicker ETS-10 films. Although higher MB photodegradation rates were obtained at higher light intensity, the apparent quantum efficiency, Φ, decreased with increasing light intensity. This is consistent with the charge separation mechanism for MB photodegradation in the UV light range investigated. All ETS-10 samples investigated showed ～4–5 times higher Φ values in the OFR than in the slurry reactor, likely due to the unique light/photocatalyst/reactant contact and high fiber packing density in the OFR.     

普鲁士蓝/CdS纳米复合物电致化学发光及其H2O2传感应用

通过一定体积比的CdS和普鲁士蓝(PB)胶体纳米溶液的简单混合,制备了PB/CdS纳米复合物。在共反应剂存在条件下,PB纳米粒子含量较低时,在ITO电极上CdS纳晶的电致化学发光(ECL)强度可以增强3倍左右。PB纳米粒子含量较高时,CdS纳晶的ECL强度则显著降低。详细讨论了PB纳米粒子对CdS纳晶ECL影响的机理。PB纳米粒子对CdS纳晶的ECL增强可用于H2O2传感。该传感器对H2O2响应的线性范围为3.3×10-8～6.5×10-3 mol.L-1(R=0.999 2),检测限为12 nmol.L-1(S/N=3),传感器具有良好的稳定性和重现性。     

Enhanced Visible‐Light‐Induced Photoelectrocatalytic Degradation of Methyl Orange by CdS Sensitized TiO2 Nanotube Arrays Electrode

In this work, CdS sensitized TiO₂ nanotube arrays (CdS/TiO₂NTs) electrode was synthesized with the CdS deposition on the highly ordered titanium dioxide nanotube arrays (TiO₂NTs) by sequential chemical bath deposition method (S‐CBD). The as‐prepared CdS/TiO₂NTs was characterized by field‐emission scanning electron microscopy (FE‐SEM) and X‐ray diffraction (XRD). The results indicated that the CdS nanoparticles were effectively deposited on the surface of TiO₂NTs. The amperometric I‐t curve on the CdS/TiO₂NTs electrode was also presented. It was found that the photocurrent density was enhanced significantly from 0.5 to 1.85 mA/cm² upon illumination with applied potential of 0.5 V at the central wavelength of 253.7 nm. The photoelectrocatalytic (PEC) activity of the CdS/TiO₂NTs electrode was investigated by degradation of methyl orange (MO) in aqueous solution. Compared with TiO₂NTs electrode, the degradation efficiencies of CdS/TiO₂NTs electrode increased from 78% to 99.2% under UV light in 2 h, and from 14% to 99.2% under visible light in 3 h, which was caused by effective separation of the electrons and holes due to the effect of CdS, hence inhibiting the recombination of electron/hole pairs of TiO₂NTs.     

An ultrasensitive hydrogen peroxide biosensor based on electrocatalytic synergy of graphene–gold nanocomposite, CdTe–CdS core–shell quantum dots and gold nanoparticles

We first reported an ultrasensitive hydrogen peroxide biosensor in this work. The biosensor was fabricated by coating graphene–gold nanocomposite (G–AuNP), CdTe–CdS core–shell quantum dots (CdTe–CdS), gold nanoparticles (AuNPs) and horseradish peroxidase (HRP) in sequence on the surface of gold electrode (GE). Cyclic voltammetry and differential pulse voltammetry were used to investigate electrochemical performances of the biosensor. Since promising electrocatalytic synergy of G–AuNP, CdTe–CdS and AuNPs towards hydrogen peroxide was achieved, the biosensor displayed a high sensitivity, low detection limit (S/N = 3) (3.2 × 10⁻¹¹ M), wide calibration range (from 1 × 10⁻¹⁰ M to 1.2 × 10⁻⁸ M) and good long-term stability (20 weeks). Moreover, the effects of omitting G–AuNP, CdTe–CdS and AuNP were also examined. It was found that sensitivity of the biosensor is more 11-fold better if G–AuNP, CdTe–CdS and AuNPs are used. This could be ascribed to improvement of the conductivity between graphene nanosheets in the G–AuNP due to introduction of the AuNPs, ultrafast charge transfer from CdTe–CdS to the graphene sheets and AuNP due to unique electrochemical properties of the CdTe–CdS, and good biocompatibility of the AuNPs for horseradish peroxidase. The biosensor is of best sensitivity in all hydrogen peroxide biosensors based on graphene and its composites up to now.