The influence of water–organic solvent composition on the morphology and luminescent properties of CdS nanoparticles obtained by chemical precipitation

Cadmium sulfide (CdS) nanoparticles have been obtained by chemical precipitation onto the surface of single-crystalline silicon from an aqueous solution of ammonia, cadmium chloride (CdCl₂), and thiourea, as well as from water–DMSO and water–DMF mixtures with the same concentrations of the reagents. According to data of atomic force microscopy, the samples obtained from the aqueous solution consist of individual nanoparticles and agglomerates thereof with sizes of no larger than 1 µm. Materials obtained from the water–organic mixtures are distinguished by the aggregation of CdS nanoparticles into threadlike chains. The length of the formed curved chains and the size of CdS nanoparticles composing them depend on the nature and amount of an organic component of a mixture. Atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy data have shown that the average size of CdS nanoparticles is 2–2.5 nm depending on solvent composition.     

Mesoporous cadmium sulfide nanoparticles derived from a new cadmium anthranilato complex: Characterization and induction of morphological abnormalities in pathogenic fungi

A cadmium complex of the general formula Cd(C₁₃H₉O₂NCl)₂(H₂O)₂ {C₁₃H₉O₂NCl = 2-(4-chlorophenylamino)benzoate} was synthesized and characterized regarding its CHN data, solution molar conductivity and spectroscopic (UV–Vis. and IR) properties. Cadmium sulfide nanoparticles (CdS NPs) were grown form the microcrystalline complex and thiourea via a hydrothermal route. The as-prepared NPs were assigned based on X-ray powder diffraction (PXRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and Brunauer – Emmett – Teller (BET) surface area measurements. The CdS absorption and emission spectra were also recorded that revealed an energy gap of 2.47 eV and large Stokes shift of 130 nm. For the as-prepared NPs, the measurements have also indicated a mesoporous structure and an average particle size of 20–28 nm associated with an average pore diameter of 11.21 nm. The as-synthesized CdS NPs acted as antifungal controlling agent against human and plant pathogenic fungi of serious environmental and health concerns. The NPs at concentration of 200 ppm inhibited several fungi with inhibition efficiency of 100% against Aspergillus ustus Au-28. The nanoparticles induced morphological abnormalities in fungal mycelia, conidia and vesicle. Additionally, they inhibited the conidia septum formation, accelerated the chlamydospores generation and enlarged the yeast cells.     

全固态Z-型CdS/Au/Bi2MoO6异质结的构筑及其光催化性能

采用简单的化学还原沉积和二次水热的方法成功制备了CdS和Au共同修饰Z型CdS/Au/Bi2MoO6(CdS/Au/BMO)光催化剂。通过X射线粉末衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)等测试技术对其组成、形貌、光吸收特性和光电化学性能等进行系统表征。实验结果表明,CdS/Au/BMO-2复合材料在可见光照射下表现出最佳的降解效率,其降解RhB的速率常数约为BMO的8.8倍和CdS的20倍。Au NPs作为固态电子媒介,为光生电子的传输和转移提供了一个通道,同时Au NPs的表面等离子体共振(SPR)效应和CdS纳米粒子显著拓宽了催化体系对可见光的响应范围;通过对催化剂的组成、结构和光电性能表征,确定了CdS/Au/BMO的能带结构,进而探讨了CdS/Au/BMO活性增强机制。     

Fe3O4/PEI/Au@CdSe/CdS多功能复合材料的制备与表征

以共沉淀法制备出Fe₃O₄纳米粒子,通过聚乙烯亚胺(PEI)修饰Fe₃O₄纳米粒子,再原位复合上Au纳米粒子,制得Fe₃O₄/PEI/Au纳米颗粒微球。再将Fe₃O₄/PEI/Au纳米颗粒与巯基乙酸修饰的量子点CdSe/CdS连接,成功制备了Fe₃O₄/PEI/Au@CdSe/CdS多功能复合微球。经过傅里叶变换红外光谱仪(FTIR)、荧光分光光度计、荧光显微镜、X射线衍射(XRD)、透射电子显微镜(TEM)及振动样品磁强计(VSM)的表征。结果表明:多功能复合微球的粒径在40nm左右,具有超顺磁性,剩磁,矫顽力近似等于零,饱和磁化强度为28.83A·m₂·kg^-1,同时兼有优越的荧光性能和金纳米粒子的特性。     

Fe3O4/PEI/Au@CdSe/CdS多功能复合材料的制备与表征

以共沉淀法制备出Fe₃O₄纳米粒子,通过聚乙烯亚胺(PEI)修饰Fe₃O₄纳米粒子,再原位复合上Au纳米粒子,制得Fe₃O₄/PEI/Au纳米颗粒微球。再将Fe₃O₄/PEI/Au纳米颗粒与巯基乙酸修饰的量子点CdSe/CdS连接,成功制备了Fe₃O₄/PEI/Au@CdSe/CdS多功能复合微球。经过傅里叶变换红外光谱仪(FTIR)、荧光分光光度计、荧光显微镜、X射线衍射(XRD)、透射电子显微镜(TEM)及振动样品磁强计(VSM)的表征。结果表明:多功能复合微球的粒径在40 nm左右,具有超顺磁性,剩磁,矫顽力近似等于零,饱和磁化强度为28.83 A·m²·kg^-1,同时兼有优越的荧光性能和金纳米粒子的特性。     

Preparation and Optoelectronic Property of a SnO2/CdS Nanocomposite Based on the Flowerlike Clusters of SnO2 Nanorods

A SnO₂/CdS nanocomposite based on the flowerlike clusters of SnO₂ nanorods was prepared and characterized with x-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and EDX analysis. The SEM and TEM images show the nanocomposite is composed of CdS nanoparticles and flowerlike clusters of SnO₂ nanorods. The UV–vis spectrum of the nanocomposite displays a new absorption band in the region of 350 to 530 nm, compared with that of the flowerlike clusters of SnO₂ nanorods. The measurement of optoelectronic property indicates that the photoresponse of the composite is extended into the visible region and the incident photon-to-current conversion efficiency (IPCE) of the composite is up to 6.5 in the range of 400 to 440 nm. These phenomena ought to be ascribed to the special nanostructure of the SnO₂/CdS composite obtained.     

Study of the effect of formamide and N,N-dimethylformamide on the synthesis of CdS nanoparticles in a SiO2 matrix by sol-gel method

The influence of formamide (F) and N,N-dimethylformamide (DMF) in drying and firing of CdS nanocrystals in SiO₂ glasses by a sol-gel method has been studied. It has been established that pore size distribution and surface area are different with the use of DMF and that influences the quality of the final product. The presence of CdS semiconductor nanoparticles has been demonstrated by transmission electronic microscopy (TEM), and the quantum confinement effect due to the size of nanoparticles is denoted by a blue shift in the visible absorption spectra. From the results obtained in this paper, it is clear that DMF has an influence on final material microstructure.     

Understanding the role of surfactants on the preparation of ZnS nanocrystals

We have synthesized surface modified ZnS nanoparticles of size 2-3 nm using non-ionic surfactant-stabilized reverse emulsions. The non-ionic surfactants in the Span series, i.e. sorbitan monolaurate (Span 20) and sorbitan monooleate (Span 80) of hydrophilic-lipophilic balance (HLB) values of 8.6 and 4.3, respectively, have been used for the stabilization of emulsions. The role of these surfactants in controlling the size and properties of the ZnS nanoparticles has been discussed. The triethylamine (TEA) has been proved to be the effective surface modifying (capping) agent for the preparation of free-standing ZnS nanoparticles. The Span 20 with the higher HLB value of 8.6 has been found to be highly suitable in synthesizing TEA-capped ZnS nanoparticles of smaller size and higher photophysical characteristics compared to that of the Span 80 of lower HLB value of 4.3. A mechanism for the formation of TEA-capped ZnS nanoparticles from the surfactant-stabilized reverse emulsions has been proposed.     

Physicochemcial characteristic of CdS-anchored porous WS2 hybrid in the photocatalytic degradation of crystal violet under UV and visible light irradiation

In this work, we report the synthesis of CdS-incorporated porous WS₂ by a simple hydrothermal method. The structural, morphological, and optical properties of the samples were examined by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), high resolution X-ray photoelectron spectroscopy (XPS) and UV–visible spectrometry. The photocatalytic activities were established for degradation of crystal violet (CV) under UV and visible light irradiation. The CdS-incorporated porous WS₂ hybrid demonstrated high photocatalytic activity for degradation of CV pollutant compared to pure CdS nanoparticles and porous WS₂ sheets. This result implies that the CdS-incorporated porous WS₂ promoted more electron-hole pair transformation under UV and visible light irradiation. This significant enhancement of photocatalytic efficiency of CdS-incorporated porous WS₂ photocatalyst under visible light can be ascribed to the presence of CdS nanospheres on the meshed-like WS₂ sheets which potentially improves absorption in the visible range enabled by surface plasmon resonance effect of CdS nanospheres. The photostability and reusability of the CdS-porous WS₂ were examined through recycling experiments.     

Photocatalytic reduction of nitro aromatic compounds to amines using a nanosized highly active CdS photocatalyst under sunlight and blue LED irradiation

A variety of aromatic nitro compounds were chemoselectively reduced to the corresponding anilines using conveniently prepared nanosized CdS as a photocatalyst under the sunlight and blue LED irradiation. The results demonstrated that synthesized CdS nanostructures have the potential to provide a promising visible light driven photocatalyst for chemoselective reduction of nitro aromatics in the presence of nitrile and carbonyl groups to the corresponding amines under both sunlight and blue LED irradiation. Photoreduction of nitro aromatics by the prepared nanosized CdS with high surface area was faster than when using the commercially available CdS under both sunlight and LED irradiation. Nanosized CdS photocatalyst was prepared by a simple method without any capping agent. X-ray diffraction (XRD), energy dispersive spectrometry (EDAX), transmission electron microscopy (TEM), scanning electron microscopy (SEM), N₂ absorption—desorption, diffuse reflectance spectroscopy (DRS), and flat band potential methods were employed for the characterization, which revealed that the prepared CdS nanoparticles have a well-resolved cubic structure with the size of around 10–30 nm and a band gap of 2.37 eV.     

Controllable synthesis of functionalized CdS nanocrystals and CdS/PMMA nanocomposite hybrids

We reported controllable synthesis of CdS nanocrystal-polymer transparent hybrids by using polymethylmethacrylate (PMMA) as a polymer matrix. In a typical run, the appropriate amounts of cadmium chloride (CdCl₂) and sodium sulfide (Na₂S) in the presence of 2-mercaptoethanol (ME) as the organic ligand are well dispersed in H₂O/DMF solution without any aggregation. From a combination of transmission electron microscopy (TEM) and a computing method of Brus’s model according UV-vis absorption spectra, the particle size of as-prepared hydroxyl-coated CdS nanocrystal was determined to be about 5 nm. Then, with the surface treatment with methacryloxypropyltrimethoxysilane (MPS), CdS-PMMA hybrids were obtained via free radical polymerization in situ. FT-IR characterization indicates the formation of robust bonding between CdS nanocrystals and the organic ligand and the formation of double-bond functional CdS nanocrystals. The TGA measurement displays CdS-PMMA hybrids possess better thermal stability compared with pure PMMA polymer. The fluorescence measurement shows that CdS nanocrystals and CdS-PMMA hybrids exhibit good optical properties. Also, the luminescent photographs taken under ultraviolet light prove the luminescence properties.     

Controllable incorporation of CdS nanoparticles into TiO<Subscript>2</Subscript> nanotubes for highly enhancing the photocatalytic response to visible light

A constant current electrochemical deposition was employed to incorporate CdS nanoparticles into the TiO₂ nanotube arrays (TiO₂NTs). The size and amount of CdS nanoparticles in TiO₂NTs (CdS@TiO₂NTs) were controllable via modulating current, deposition time and electrolyte concentration. It was revealed, from the scanning electron microscopy (SEM) images and X-ray photoelectron spectroscopy (XPS) in depth profile, that CdS nanoparticles were filled into TiO₂ nanotubes. A shift of the absorption edge toward the visible region under the optimal electrodeposition condition was observed with the diffuse reflectance spectroscopy (DRS). A 5-fold enhancement in the photocurrent spectrum for TiO₂NTs was observed and the photocurrent response range was significantly extended into the visible region because of the CdS incorporation. Compared with pure TiO₂NTs, under a visible light irradiation, CdS@TiO₂NTs exhibited a 3.5-fold improvement of photocatalytic activity, which was demonstrated by the photocatalytic decomposition of Rhodamine B (RhB).     

CdS/TiO2纳米管复合结构的制备与光电性能研究

利用阳极氧化法在钛金属基体表面制备一层TiO₂纳米管阵列薄膜, 然后通过水热反应在TiO₂纳米管上负载CdS纳米粒子, 形成CdS/TiO₂纳米管的复合结构。利用SEM、XRD、XPS、UV-Vis等手段对其形貌和结构进行表征。进一步考察了CdS/TiO₂纳米管的光电性能和光催化活性, 结果表明, 相比于TiO₂纳米管, CdS/TiO₂纳米管复合结构在紫外光和可见光下都具有更好的光催化活性及光电性能。     

CdS/TiO2纳米管复合结构的制备与光电性能研究

利用阳极氧化法在钛金属基底表面制备一层TiO2纳米管阵列薄膜,然后通过水热反应在TiO2纳米管上负载CdS纳米粒子,形成CdS/TiO2纳米管的复合结构。利用SEM、XRD、XPS、UV-Vis等手段对其形貌和结构进行表征。进一步考察了CdS/TiO2纳米管的光电性能和光催化活性,结果表明,相比于TiO2纳米管,CdS/TiO2纳米管复合结构在紫外光和可见光下都具有更好的光催化活性及光电性能。     

离子交换膜中CdS单分散纳米晶的合成及其光学性质

以硫代乙酰胺(TAA)为前驱体, 采用液相反应在全氟磺酸离子交换膜(Nafion)中自组装得到了均匀分布、单分散的纳米CdS晶体；与文献报道的前驱体如Na₂S和H₂S不同, TAA可以在全氟磺酸离子膜中均匀扩散, 最终在Nafion薄膜中得到均匀分布的纳米CdS晶体. 利用高分辨电子显微镜(HRTEM)、X射线衍射仪(XRD)和能量散射X射线分析(EDXA)研究了Nafion薄膜模板中CdS纳米晶体的形成机理、晶粒大小和分布；采用紫外- 可见吸收光谱和荧光光谱分析了Nafion薄膜中单分散纳米CdS晶体的光学性质. 结果表明, 随CdS纳米晶体尺寸的减小, 量子尺寸效应明显增强；在紫外吸收谱中表现为吸收边明显蓝移, 而在光致发光谱中, 表现为带边发射的蓝移.     

Synthesis and characterization of CdS nanoparticles embedded in a polymethylmethacrylate matrix

CdS nanopowder capped with sodium bis(2-ethylhexyl)sulfosuccinate was synthesized by using water-in-oil microemulsions. The CdS nanoparticles of about 5 nm obtained were embedded in polymethylmethacrylate matrix by a photocuring process. The transparent yellow solid compound was characterized by optical absorption and emission spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The properties of this compound were compared with those of the nanopowder dispersed in heptane and in methylmethacrylate. The results obtained indicate that the nanoparticles are homogeneously dispersed in the matrix and do not change in size during the embedding process. Even if the surface slightly changes its luminescence properties, as a consequence of the different new chemical environment, the final product seems to be suitable for practical applications.     

S/Cd物质的量比对微波水热制备CdS微晶的形貌影响及光学性能研究

采用微波水热法,以CdCl2·H2O和Na2S2O3·5H2O为镉源和硫源,在不同的S/Cd物质的量比条件下合成了CdS微晶。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、场发射扫描电子显微镜(FE-SEM)、EDS、透射电子显微镜(TEM)等对样品的物相、形貌和元素组分进行了分析。结果表明:随着S/Cd物质的量比的增大,产物CdS的形貌发生规律性变化,由四面体结构逐渐转变为准球形结构;准球形结构具有分级结构,是由更小的纳米晶组装而成;光致发光性质研究结果表明,所得的CdS微晶具有较好的蓝光发射性能。     

Synthesis, structural and photocatalytic studies of Mn-doped CdS nanoparticles

Mn-doped CdS nanoparticles (Cd_1?x Mn _x S; where x = 0.00–0.10) were synthesized by a chemical precipitation method. The synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscope, transmission electron microscope (TEM), and UV–Vis spectrometer. The XRD and TEM measurements show that the size of crystallites is in the range of 10–40 nm. Optical measurements indicated a red shift in the absorption band edge upon Mn doping. The direct allowed band gaps of undoped and Mn-doped CdS nanoparticles measured by UV–Vis spectrometer were 2.3 and 2.4 eV at 400 °C, respectively. Photocatalytic activities of CdS and Mn-doped CdS were evaluated by irradiating the solution to ultraviolet light and taking methyl orange (MO) as organic dye. It was found that 5 mol% Mn-doped CdS bleaches MO much faster than undoped CdS upon its exposure to the ultraviolet light. The experiment demonstrated that the photo-degradation efficiency of 5 mol% Mn-doped CdS was significantly higher than that of undoped CdS.     

Simple and low temperature preparation and characterization of CdS nanoparticles as a highly efficient photocatalyst in presence of a low-cost ionic liquid

A simple and low temperature method is proposed for preparation of CdS nanoparticles in presence of 1-ethyl-3-methylimidazolium ethyl sulfate, [EMIM] [EtSO₄], a room-temperature ionic liquid (RTIL). The powder X-ray diffraction (XRD) studies display that the products are excellently crystallized in the form of cubic structure and size of the nanparticles prepared in presence of the RTIL is smaller than that prepared in water. Energy dispersive X-ray spectroscopy (EDX) investigations reveal that the products are very pure and nearly stoichiometric. The results obtained by scanning electron microscopy (SEM) demonstrate that the CdS nanoparticles prepared in presence of the RTIL have lower tendency for aggregation relative to the prepared sample in water. Diffuse reflectance spectra (DRS) of the product prepared in the neat RTIL, shows 1.52 eV blue shift relative to bulk CdS, which can be attributed to quantum confinement effect of the CdS nanoparticles. A possible formation mechanism for CdS nanoparticles in presence of the RTIL is presented. Photocatalytic activity of the CdS nanoparticles towards photodegradation of methylene blue (MB) using UV and visible lights was performed. The results demonstrate that observed firstorder rate constant for photodegradation of MB on CdS nanoparticles prepared in the neat RTIL are about 20 and 6 times greater than the prepared sample in water using visible and UV lights, respectively.     

CdS/TiO2 composite films for methylene blue photodecomposition under visible light irradiation and non-photocorrosion of cadmium sulfide

Cadmium sulfide/titanium dioxide (CdS/TiO₂) composite films were grown on glass by the chemical bath deposition (DBQ) and sol-gel/dip coating methods, respectively, in order to increase the photocatalytic activity of TiO₂ in photodegradation processes. The influence of the CdS deposition time on the morphology, optical absorption, and phononic modes of the composites were examined. Scanning electron microscopy (SEM) images showed clearly the CdS deposit on the TiO₂ surface. The absorbance spectra indicated that the absorption of composites depends on the CdS deposition time and the absorption edges are shifted to the visible range. Micro Raman spectra exhibited the phonons associated with the TiO₂ anatase and the longitudinal optic (LO) phonon of CdS whose intensity increases with the CdS deposition time. Photodegradation of methylene blue (MB) under visible light irradiation was observed in all films and the results were compared with those obtained with TiO₂ films. The decomposition is higher for the composite with the CdS deposition time of 15 min. This optimal deposition time allows maximal enhancement of the charge carriers transfer to TiO₂ involved in the photocatalysis. No signal associated with cadmium was detected by the atomic absorption spectroscopy (AAS), which means that the CdS photocorrosion does not occur since trap centers such as OH-Cd-S and Cl^?, which trap holes and inhibit the photocorrosion, are produced during the growth process.