Surface Enhanced Raman Spectroscopy of 4-Mercaptopyridine Molecules on Pb_3O_4 Nanoparticles

The surface enhanced Raman scattering （SERS） technique has been developed greatly since its first discovery nearly twenty-nine years ago. It is a very attractive technique for the detection of various organic and inorganic molecules due to its sensitivity and selectivity. However, the most critical aspect for performing a SERS experiment is the choice and fabrication of the substrates. For many yeas, SERS has been still restricted primarily to the usage of detecting analytes adsorbed onto coinage（Au, Ag or Cu） or alkali（ Li, Na or K） rough metallic surfaces. Recently, Quagliano reported SERS from molecules adsorbed on InAs/GaAs semiconductor quantum dots for the first time. Until now, few reports on semiconductor materials as the SERS substrates have been noted. Herein, we report our successful attempt to gain high signal-to-noise ratio （S/N） SERS spectra of 4-mercaptopyridine （ 4-Mpy ） adsorbed on Pb3O4 nanopaticles.

Research on PbS Nanoparticles Coated with 2,6-O-Diallyl-β-CD

PbS nanoparticles coated with 2.6-O-dial1yl-β-CD were prepared successfully and characterized by transmission electron microscope (TEM), X-ray photoelectron spectrometer (XPS). The sample shows a very rapid induced absorption

Enhancement of photocatalytic and photoelectrochemical properties of TiO_(2) nanotubes sensitized by SILAR-Deposited PbS nanoparticles

The aim of this work is to improve the photocatalytic and photoelectrochemical properties of TiO_(2) nanotubes(TiO_(2)-NTAs)by sensitizing them with PbS nanoparticles(NPs)prepared by the Successive Ionic Layer Adsorption and Reaction method(SILAR).The Microstructure,surface morphology,phase composition and optical properties of the prepared structure were characterized using X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM and High-resolution mode HRTEM)and X-ray photoelectron spectroscopy(XPS).The TiO_(2) NTAs were loaded by PbS NPs,which contents increase by increasing the number of SILAR cycles.The PbS NPs,which have a size in the order of ~20 nm,were found to be uniformly distributed in the TiO_(2) NTAs without damaging the tubular ordered structure.The photocatalytic activity of the PbS/TiO_(2) NTAs system,toward Amido Black(AB),showed significant enhancement compared to the bare untreated TiO_(2) NTs.At 30 SILAR deposition cycles the PbS-NPs/TiO_(2) NTAs structure is able to remove 75% of BA under simulated solar light,considerably higher than the 40% removal obtained with unloaded TiO_(2) NTAs.A significant improvement of the Photoelectrochemical(PEC)efficiency has been also demonstrated for the PbS-NPs/TiO_(2) NTAs hybrid system.This improvement is mainly related to visible-light harvesting and reduced recombination of photo-generated electron-hole pairs due to the synergistic effect of the heterojunction and to the wellorganized morphology of the TiO_(2) NTAs.

Self-assembling Behavior of Amphiphilic Copolymer Containing Cross-linked Hydrophilic Block in Ethanol

The self-assembly behavior of the amphiphilic block copolymer poly（ methyl methacrylate） -block-poly（ lead dimethacrylate） （PMMA-b-PLDMA） with cross-linked hydrophilic block（PLDMA） in ethanol was investigated. The results show that the size and morphology of the resulting micelle or micellar aggregates are ascribed to the content of ethanol and the nature of the solvent mixture. PbS nanoparticles were formed in the micelle by in situ reaction with H2S gas. The morphology and size of the self-assembly objects were investigated using scanning electron microscopy （SEM） and transmission electron microscopy（TEM）.

Synthesis of novel magnetic sulfur-doped Fe_3O_4 nanoparticles for efficient removal of Pb(Ⅱ)

In this work, we report the synthesis of magnetic sulfur-doped Fe_3O_4 nanoparticles (Fe_3O_4:S NPs) with a novel simple strategy,which includes low temperature multicomponent mixing and high temperature sintering. The prepared Fe_3O_4:S NPs exhibit a much better adsorption performance towards Pb(Ⅱ) than bare Fe_3O_4 nanoparticles. FTIR, XPS, and XRD analyses suggested that the removal mechanisms of Pb(Ⅱ) by Fe_3O_4:S NPs were associated with the process of precipitation (formation of PbS), hydrolysis,and surface adsorption. The kinetic studies showed that the adsorption data were described well by a pseudo second-order kinetic model, and the adsorption isotherms could be presented by Freundlich isotherm model. Moreover, the adsorption was not significantly affected by the coexisting ions, and the adsorbent could be easily separated from water by an external magnetic field after Pb(Ⅱ) adsorption. Thus, Fe_3O_4:S NPs are supposed to be a good adsorbents for Pb(Ⅱ) ions in environmental remediation.

From Two-Dimensional Metal Organic Coordination Networks to Near-Infrared Luminescent PbS Nanoparticle/Layered Polymer Composite Materials

Two-dimensional(2-D)layered metal-organic coordination(lead methacrylate(LDMA))networks have been prepared in aqueous solution under mild conditions and their structure determined by single crystal diffraction.As the ligand used in our experiments is easily polymerized,these metal-organic coordination layers are therefore employed as precursors to fabricate cross-linked polymer layered materials throughγ-irradiated polymerization.The stabilities of the samples are signifi cantly improved afterγ-irradiation.To our knowledge,this is the fi rst time that covalent bonded polymer layered structures have been fabricated without the assistance of added surfactant or template.Such layered polymer materials cannot only act as alternatives to layered inorganic materials in some caustic environments,but also allow the generation of PbS nanoparticles(NPs)without aggregation in the polymer matrix.By exposing the polymer layer to H2S gas at room temperature,uniform PbS nanoparticles with an average size of about 6 nm are generated in situ.In addition,the resulting PbS NPs exhibit near-infrared(NIR)luminescent properties,which suggests the composite materials may be useful as active optical elements at communication wavelengths from 1300 to 1550 nm.

In-situ interaction of nano-PbS with gelatin

Water-soluble gelatin-PbS bionanocomposites （BNCs） were synthesized via a facile one-pot chemical reaction method at pH 7.40. The samples were characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, UV-vis absorption spectra （UV-vis）, Fourier transform infrared spectra （FT-IR） and circular dichroism （CD）. FT-IR data were used to envis- age the binding of PbS particles with oxygen atoms of carbonyl groups of gelatin molecule. The possible integration mechanism between gelatin and PbS was discussed in detail. The effect of Pb2＋ and PbS on the conformations of gelatin has also been analyzed by means of UV-vis, CD and FT-IR spectra, resulting in less c^-helix content and more open structures （[3-sheet, r-turn, or expanded）. A new formula to calculate the association constant was proposed according to the relationship between the absorbance of gelatin-PbS BNCs and the free concentration of PbS, and apparent association constants K （298/303/308 K： 3.11/2.00/1.60 × 10^6 tool/L） at three different temperatures were calculated based on this formula. Thermodynamic parameters such as AG^θ, △Hθ and △S^θ were also determined. The results of the thermodynamic investigations indicated that the reaction was spontaneous （AG^θ 〈 0）, and enthalpy-driven （△H^8 〈 0）.