ZnO nanopowders and their excellent solar light/UV photocatalytic activity on degradation of dye in wastewater

Low-cost and scalable preparation,high photocatalytic activity,and convenient recycle of Zn O nanopowders(NPs)would determine their practical application in purifying wastewater.In this contribution,ZnO NPs were scalably synthesized via the simple reaction of Zn powder with H_2O vapor in autoclave.The structural,morphological and optical properties of the samples were systematically characterized by X-ray diffraction,scanning electron microscopy,Fourier transform infrared spectra,transmission electron microscopy,Micro-Raman,photoluminescence,and ultraviolet-visible spectroscopy.The as-prepared Zn O NPs are composed of nanoparticles with 100–150 nm in diameter,and have a small Brunauer-Emmett-Teller surface area of 6.85 m~2/g.The formation of Zn O nanoparticles is relative to the peeling of H_2 release.Furthermore,the product has big strain-stress leading to the red-shift in the band gap of product,and shows a strong green emission centered at 515 nm revealing enough atomic defects in Zn O NPs.As a comparison with P25,the obtained dust gray Zn O NPs have a strong absorbance in the region of 200–700 nm,suggesting the wide wave-band utilization in sunlight.Based on the traits above,the Zn O NPs show excellent photocatalytic activity on the degradation of rhodamine B(Rh-B)under solar light irradiation,close to that under UV irradiation.Importantly,the Zn O NPs could be well recycled in water due to the quick sedimentation in themselves in solution.The low-cost and scalable preparation,high photocatalytic activity,and convenient recycle of Zn O NPs endow themselves with promising application in purifying wastewater.     

Synthesis and Characterization of CdS Nanoparticles via Cyclic Microwave from Cadmium Oxalate

The present study reports synthesis and characterization of CdS nanoparticles prepared by cyclic microwave route with the use of [Cd(C₂O₄)·3H₂O] powder as a precursor. The products, with an average size ~15 nm, were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray microanalysis, thermogravimetric analysis, transmission electron microscopy and Fourier transform infrared spectroscopy. Optical property of obtained product was investigated by photoluminescence spectroscopy. The prepared nanostructures displayed a very strong luminescence at 528 nm (2.34 eV) at room temperature.     

Graphene enhanced electrochemiluminescence of CdS nanocrystal for H2O2 sensing

Graphene-CdS (G-CdS) nanocomposites were successfully prepared by CdS nanocrystals (CdS NCs) formed in situ on the surface of graphene sheets, using graphene oxide (GO) sheets with rich negatively charged carboxylic acid groups as starting materials. Compared with pure CdS NCs, the presence of the graphene doped in G-CdS nanocomposites could facilitate the electrochemical redox process of CdS NCs; further, the as-prepared G-CdS nanocomposite can react with H₂O₂ to generate strong and stable electrochemiluminescent (ECL) emission, which not only enhances its ECL intensity by about 4.3-fold but also decreases its onset potential for about 320 mV. The as-prepared solid-state ECL H₂O₂ sensor shows acceptable linear response from 5 μM up to 1 mM with a detection limit of 1.7 μM (S/N = 3). The ECL H₂O₂ sensor exhibits excellent reproducibility and long-term stability. Such a property would promote the potential application of the graphene as enhanced materials in fabricating sensors for chemical and biochemical analysis.     

Activation of CdS nanoparticles by metallic ions and their selective interactions with PAMAM dendrimers

CdS nanoparticles (NPs) in colloidal dispersion were activated by metallic ions [Mn(II) and Cu(II)], employing a simple method under mild conditions. These metallic ions on the surface of the CdS NPs quench the red-shifted defect emission, and efficiently promote near band gap emission; they also enhance the photo stability and dispersability of the suspensions. Taking advantage of the chemical affinity of Mn(II) and Cu(II) for the CdS surface, we carried out a study of the interaction between [CdS-M(II) _n ] NPs and polyamidoamine dendrimers of 1 and 2.5 generations (G₁=8 amino, and G_2.5=32 carboxylic end-groups, respectively). The strong interaction between these two chemical species results in the formation of new [CdS-M(II) _n G _n ] nanocomposites. All colloidal systems were monitored by UV-visible electronic absorption and emission spectroscopies, and electronic paramagnetic resonance. The crystal structures of the nanocomposites, as well as their average diameters (2.0–3.3 nm), were determined by high-resolution transmission electron microscopy images.     

Assembly of Pt nanoparticles on electrospun In2O3 nanofibers for H2S detection

In this paper, we presented a simple and effective solution route to deposit Pt nanoparticles on electrospun In₂O₃ nanofibers for H₂S gas detection. The morphology and chemical structure of the as-prepared samples were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectra (XPS). The results showed that large quantities of In₂O₃ nanofibers with diameters about from 60 to 100 nm were obtained and the surface of them was decorated with Pt nanoparticles (5–10 nm in size). The In₂O₃ nanofibers decorated by Pt nanoparticles exhibited excellent gas sensing properties to H₂S, such as high sensitivity, good selectivity and fast response at relatively low temperature.     

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。     

Photochemical preparation of CdS hollow microspheres at room temperature and their use in visible-light photocatalysis

CdS hollow microspheres have been successfully prepared by a photochemical preparation technology at room temperature, using polystyrene latex particles as templates, CdSO₄ as cadmium source and Na₂S₂O₃ as both sulphur source and photo-initiator. The process involved the deposition of CdS nanoparticles on the surface of polystyrene latex particles under the irradiation of an 8 W UV lamp and the subsequent removal of the latex particles by dispersing in dichloromethane. Photochemical reactions at the sphere/solution interface should be responsible for the formation of hollow spheres. The as-prepared products were characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. Such hollow spheres could be used in photocatalysis and showed high photocatalytic activities in photodegradation of methyl blue (MB) in the presence of H₂O₂. The method is green, simple, universal and can be extended to prepare other sulphide and oxide hollow spheres.     

Photocatalytic Oxidative Coupling of Methane over Au1Ag Single-Atom Alloy Modified ZnO with Oxygen and Water Vapor: Synergy of Gold and Silver

C−H dissociation and C−C coupling are two key steps in converting CH₄ into multi-carbon compounds. Here we report a synergy of Au and Ag to greatly promote C₂H₆ formation over Au₁Ag single-atom alloy nanoparticles (Au₁Ag NPs)-modified ZnO catalyst via photocatalytic oxidative coupling of methane (POCM) with O₂ and H₂O. Atomically dispersed Au in Au₁Ag NPs effectively promotes the dissociation of O₂ and H₂O into *OOH, promoting C−H activation of CH₄ on the photogenerated O⁻ to form *CH₃. Electron-deficient Au single atoms, as hopping ladders, also facilitate the migration of electron donor *CH₃ from ZnO to Au₁Ag NPs. Finally, *CH₃ coupling can readily occur on Ag atoms of Au₁Ag NPs. An excellent C₂H₆ yield of 14.0 mmol g⁻¹ h⁻¹ with a selectivity of 79 % and an apparent quantum yield of 14.6 % at 350 nm is obtained via POCM with O₂ and H₂O, which is at least two times that of the photocatalytic system. The bimetallic synergistic strategy offers guidance for future catalyst design for POCM with O₂ and H₂O.     

Reaction of Perrhenate with Phthalocyanine Derivatives in the Presence of Reducing Agents and Rhenium Oxide Nanoparticles in Biomedical Applications

A novel alternative route to access rhenium(V)−phthalocyanine complexes through direct metalation of metal-free phthalocyanines (H₂Pcs) with a rhenium(VII) salt in the presence of various two-electron reducing agents is presented. Direct ion metalation of tetraamino- or tetranitrophthalocyanine with perrhenate (ReO₄⁻) in the presence of triphenylphosphine led to oxidative decomposition of the H₂Pcs, giving their respective phthalonitriles. Conversely, treatment of H₂Pcs with ReO₄⁻ employing sodium metabisulfite yielded the desired Re^VO−Pc complex. Finally, reaction of H₂Pcs with ReO₄⁻ and NaBH₄ as reducing agent led to the formation of rhenium oxide (Re_xO_y) nanoparticles (NPs). The NP synthesis was optimised, and the Re_xO_y NPs were capped with folic acid (FA) conjugated with tetraaminophthalocyanine (TAPc) to enhance their cancer cell targeting ability. The cytotoxicity profile of the resultant Re_xO_y−TAPc−FA NPs was assessed and found to be greater than 80 % viability in four cell lines, namely, MDA−MB-231, HCC7, HCC1806 and HEK293T. Non-cytotoxic concentrations were determined and employed in cancer cell localization studies. The particle size effect on localization of NPs was also investigated using confocal fluorescence and transmission electron microscopy. The smaller NPs (≈10 nm) were found to exhibit stronger fluorescence properties than the ≈50 nm NPs and exhibited better cell localization ability than the ≈50 nm NPs.     

Preparation of single-phase α-Fe(III) oxide nanoparticles by thermal decomposition. Influence of the precursor on properties

In this research, we present an experimental procedure to prepare single-phase α-Fe(III) oxide nanoparticles by thermal decomposition of five different precursors including: iron(III) citrate; Fe(C₆H₅O₇), iron(III) acetylacetonate; Fe(C₅H₇O₂)₃, and iron(III) oxalate; Fe(C₂O₄)₃, iron(III) acetate; Fe(C₂H₃O₂)₃, and the thermal curves obtained were analyzed. The influence of the thermal decomposition of precursors on the formation α-Fe₂O₃ was studied by differential thermal gravimetry and thermogravimetry. The synthesized powders were characterized by using X-ray diffraction and scanning electron microscopy. High quality iron oxide nanoparticles with narrow size distribution and average particle size between ca. 2 and 30 nm have been obtained. It was found that the iron precursors affect the temperatures of the pure α-Fe₂O₃ nanoparticle formation with different diameters; iron(III) citrate (29 nm), iron(III) acetylacetonate (37 nm), and iron(III) oxalate (24 nm).     

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。     

同轴静电纺丝技术制备Y2O3:Eu3＋@SiO2豆角状纳米电缆与表征

采用同轴静电纺丝技术, 以氧化钇、氧化铕、正硅酸乙酯(C₈H₂₀O₄Si)、无水乙醇、PVP和DMF为原料, 成功制备出大量的Y₂O₃:Eu^3＋@SiO₂豆角状纳米电缆. 用TG-DTA, XRD, SEM, TEM和荧光光谱等分析技术对样品进行了系统地表征． 结果表明, 得到的产物为Y₂O₃:Eu^3＋@SiO₂豆角状纳米电缆, 以无定型SiO₂为壳层, 晶态Y₂O₃:Eu^3＋球为芯, 电缆直径约为200 nm, 内部球平均直径约150 nm, 壳层厚度约为25 nm, 电缆长度＞300 μm. 纳米电缆内部为球状结构, 沿着纤维长度方向有序排列, 形貌均一. Y₂O₃:Eu^3＋@SiO₂豆角状纳米电缆在246 nm紫外光激发下, 发射出Eu^3＋离子特征的波长为614 nm的明亮红光. 对其形成机理进行了初步讨论.     

Coordination mechanism,characterization, and photoluminescence properties of spinel ZnAl<Subscript>2</Subscript>O<Subscript>4</Subscript> nanoparticles prepared by a modified polyacrylamide gel route

Single-phase ZnAl₂O₄ nanoparticles with the spinel structure were successfully synthesized using a modified polyacrylamide gel method according to the atomic ratio of Zn to Al = 1: 1.8. The as-prepared samples were characterized by means of X-ray powder diffraction (XRD), thermogravimetric analysis (TG), differential scanning calorimetry analysis (DSC), field-emission scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and photoluminescence (PL) spectra. XRD patterns show that the pure phase of ZnAl₂O₄ is obtained after heating the xerogel at 900°C for 5 h in air. The SEM images reveal that the ZnAl₂O₄ nanoparticles have a narrow particle size distribution and the average particle size is around 45 nm. Photoluminescence (PL) spectra demonstrate the single phase ZnAl₂O₄ nanoparticles have an emission peak located at 469 nm when excited by 350 nm light. The phase structure, coordination mechanism, and luminescence properties have been discussed on the basis of the experimental results.     

Fabrication of Hemoglobin/Ionic Liquid Modified Carbon Paste Electrode Based on the Electrodeposition of Gold Nanoparticles/CdS Quantum Dots and Its Electrochemical Application

A novel H₂O₂ amperometric biosensor based on the electrodeposition of gold nanoparticles (AuNPs) and CdS quantum dots (CdS QDs) onto a carbon paste electrode (CPE) and immobilizing hemoglobin (Hb) with ionic liquid (IL), is presented in this article. The modification process of the electrode was monitored by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Due to synergistic effects of AuNPs, CdS QDs and IL, the biosensor exhibited high stability and good bioelectrocatalytic ability to H₂O₂ with a linear concentration range from 10 to 750 µM and a detection limit of 4.35 µM (S/N=3).     

Bimetallic palladium–gold nanoparticles synthesized in ionic liquid microemulsion

The palladium and gold precursors were dissolved in dispersive and continuous phase of ionic liquid microemulsion (H₂O/Triton X-100 (TX-100)/1-butyl-3-methylimidazolium hexafluorophosphate), respectively. [PdCl₆]^2? ions were reduced in situ by TX-100 in dispersive phase (H₂O) to prepare Pd nanoparticles (NPs) and then [AuCl₄]^? crossed through the interface film and reacted with the as-prepared Pd NPs to form Pd₄Au NPs. The as-prepared Pd₄Au NPs were characterized by transmission electronic microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and ultraviolet–visible spectroscopy. The as-prepared Pd₄Au NPs suspension and carbon nanotubes (CNTs) suspension were vigorously stirred to prepare the electrocatalyst supported on the CNTs with a total metal loading of 20?wt.% (denoted by Pd₄Au/CNTs). Cyclic voltammetry and chronoamperometry tests show that the Pd₄Au/CNTs are very promising for the oxidation of ethanol in alkaline medium. The result can be attributed to the synergistic effect between Pd and Au during the catalytic process.     

Thermolysis characteristics of salts of <Emphasis Type="Italic">o</Emphasis>-phthalic acid with the formation of Fe,Co, Ni,Cu metal particles

Studies of the thermolysis of ortho-[Ni(H₂O)₂(C₈H₄O₄)](H₂O)₂, [Cu(H₂O)(C₈H₄O₄)], and acid [M(H₂O)₆](C₈H₅O₄)₂ (M(II) = Fe(II), Co(II), and Ni(II)), [Cu(H₂O)₂(C₈H₅O₄)₂] phthalates reveal that the solid products of their decomposition are composites with nanoparticles embedded in carbon–polymer matrices. Metallic nanoparticles with oxide nanoparticle impurities are detected in iron/cobalt polymer composites, while nickel/copper composites are composed of only metallic particles. It is found that nickel nanoparticles with the diameters of 6–8 nm are covered with disordered graphene layers, while the copperbased composite matrix contains spherical conglomerates (50–200 nm) with numerous spherical Cu particles (5–10 nm).     

Novel Cellulose Derivatives Containing Metal (Cu,Fe, Ni) Oxide Nanoparticles as Eco-Friendly Corrosion Inhibitors for C-Steel in Acidic Chloride Solutions

Novel environmentally-friendly corrosion inhibitors based on primary aminated modified cellulose (PAC) containing nano-oxide of some metals (MONPs), for instance iron oxide nanoparticles (Fe₃O₄NPs), copper oxide nanoparticles (CuONPs), and nickel oxide nanoparticles (NiONPs), were successfully synthesized. The as-prepared PAC/MONPs nanocomposites were categorized using Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and selected area diffraction pattern (SAED) techniques. The data from spectroscopy indicated that successful formation of PAC/MONPs nanocomposites, as well as the TEM images, declared the synthesized PAC/Fe₃O₄NPs, PAC/CuONPs, and PAC/NiONPs with regular distribution with particle size diameters of 10, 23 and 43 nm, respectively. The protection performance of the as-prepared PAC and PAC/MONPs nanocomposites on the corrosion of C-steel in molar HCl was studied by the electrochemical and weight-loss approaches. The outcomes confirmed that the protection power increased with a rise in the [inhibitor]. The protection efficiency reached 88.1, 93.2, 96.1 and 98.6% with 250 ppm of PAC/CuONP, PAC/Fe₃O₄NPs, and PAC/NiONPs, respectively. PAC and all PAC/MONPs nanocomposites worked as mixed-kind inhibitors and their adsorption on the C-steel interface followed the isotherm Langmuir model. The findings were reinforced by FT-IR, FE-SEM and EDX analyses.     

Synthesis of CdS, ZnS and Ag2S nanoparticles stabilized by sodium bis(2-ethylhexyl)sulfosuccinate and polyoxyethylenesorbitan monooleate in aqueous medium

The effect of synthesis conditions (molar ratio between precursors, concentration of surfactants, synthesis temperature) on the size of CdS, ZnS and Ag₂S nanoparticles (NPs) stabilized by sodium bis(2-ethylhexyl)succinate and polyoxyethylenesorbitan monooleate was studied. It was established that stabilization by polyoxyethylenesorbitan results in formation of smaller NPs (～8 nm) as compared to that in the presence of sodium bis(2-ethylhexyl)sulfosuccinate (14–60 nm), which is due to the difference between the adsorption rates of these surfactants onto the surface of synthesized NPs. The resulting aqueous dispersions of CdS, ZnS and Ag₂S NPs exhibit long-term stability to sedimentation. The nanoparticle size increases insignificantly with temperature increasing to 65–70°C and rises abruptly at higher temperatures. The increase in the ratio between concentrations of precursors (sulfide and metal ions) also results in an increase in NP size, allowing one to synthesize nanoparticles of prescribed sizes. The optical properties of the resulting nanoparticles were studied. The positions of the exciton peaks and the luminescence intensity peaks of the dispersions of synthesized CdS and ZnS NPs were determined.     

无定形硒纳米粒子的交联酶模板法合成及其在生物传感器中的应用

本文以戊二醛交联的辣根过氧化物酶(HRP)为模板合成了均匀分散的无定形硒纳米粒子(粒径10~20 nm)，以所得合成产物为载体构建了HRP生物传感器。研究结果表明，无定形硒纳米粒子具有良好的生物相容性和吸附性，所得传感器灵敏度高，对测定底物的生物亲和性好。     

Exploring the interactions between gold nanoparticles and analytes through surface‐assisted laser desorption/ionization mass spectrometry

Surface‐assisted laser desorption/ionization mass spectrometry (SALDI‐MS) is applied to provide strong evidence for the chemical reactions of functionalized gold nanoparticles (Au NPs) with analytes – Hg²⁺ ions induced MPA?Au NPs aggregation in the presence of 2,6‐pyridinedicarboxylic acid (PDCA) and H₂O₂ induced fluorescence quenching of 11‐MUA?Au NDs. PDCA‐Hg²⁺‐MPA coordination is responsible for Au NPs aggregation, while the formation of 11‐MUA disulfide compounds that release into the bulk solution is responsible for H₂O₂‐induced fluorescence quenching. In addition to providing information about the chemical structures, SALDI‐MS is also selective and sensitive for the detection of Hg²⁺ ions and H₂O₂. The limits of detection (LODs) for Hg²⁺ ions and H₂O₂ by SALDI‐MS were 300 nM and 250 µM, respectively. The spot‐to‐spot variations in the two studies were both less than 18% (50 sample spots). Our results reveal that SALDI‐MS can be used to study analyte‐induced changes in the surface properties of nanoparticles. Copyright © 2010 John Wiley & Sons, Ltd.