Novel titanate nanotubes-cyanocobalamin materials: Synthesis and enhanced photocatalytic properties for pollutants removal

New hybrid nanomaterials, with improved photocatalytic performance in pollutants removal, were obtained through the modification of titanate nanotubes (TNT) with a cobalt porphyrin, the cyanocobalamin, also knowing as vitamin B12 (B12). The nanocrystalline TNT were produced by hydrothermal treatment and after treated with cobalamin to produce B12-TNT materials. The characterization of the new hybrid material was performed by XRD, FTIR, TEM-EDS, DRS, XPS and ICP. The results show that the immobilization of the cobalt containing specie is dependent on the point of zero charge of the TNT and no modifications on the structure and morphology were observed. No significant changes in the optical band gap were observed after B12 incorporation, but an increasing in the visible light absorption, which arises from charge transfer and d–d transitions of the cobalt, was visualized. The samples photocatalytic performance was studied for the hydroxyl radical production and the highest catalytic ability was achieved by the B12-HTNT sample. The catalytic ability of these new hybrid nanomaterials for two model pollutants photodegradation, phenol and rhodamine B (RhB) was investigated. For both pollutants, the best results were achieved using B12-HTNT with a removal of 94% of a 10 ppm RhB and 87% of a 20 ppm phenol solution in 90 min of irradiation (150 mL, 0.2 g catalyst/L).     

Facile fabrication of porous pure and Ag nanoparticle-doped poly(4-vinylpyridine) films at the liquid-liquid interfaces

We reported an interfacial self-assembly of regularly layered porous poly(4-vinylpyridine)(P4VP) films at the interfaces of water-chloroform or -dichloroethane.The porous diameters were in the range from hundred nanometers to several micrometers.It was revealed that formation of such kind of porous materials was solvent dependent.Moreover,cyclic Ag nanoparticles could be grown in the porous P4VP films to form Ag-P4VP nanohybrids under radiation.     

Copper/Graphene/Clay Nanohybrid: A Highly Efficient Heterogeneous Nanocatalyst for the Synthesis of Novel 1,2,3‐Triazolyl Carboacyclic Nucleosides via ‘Click’ Huisgen 1,3‐Dipolar Cycloaddition

A very mild and highly efficient synthesis of some novel 1H‐1,2,3‐triazolyl carboacyclic nucleosides via a ‘Click’ Huisgen cycloaddition of N‐propargyl nucleobases and azido alcohols using Cu/aminoclay/reduced graphene oxide nanohybrid (Cu/AC/r‐GO nanohybrid) as nanocatalyst is described. The preparation and characterization of Cu/AC/r‐GO nanohybrid are discussed. This catalyst was characterized by X‐ray diffraction, FT‐IR, TEM, and energy‐dispersive analysis of X‐ray techniques. Cu/AC/r‐GO nanohybrid is a stable and highly efficient heterogeneous nanocatalyst that can be easily prepared, used, and restored from the reaction mixture by simple filtration, and reused for many consecutive trials without significant decrease in activity.     

Porous film fabricated by a thermoresponsive polymer poly(N-isopropylacrylamide-co-butylmethacrylate) with enhanced hydrophobicity

In this paper, two charge-neutral and poorly water-soluble bactericides (BC), hexaconazole and triadimenol, were first encapsulated in micelles derived from anionic surfactant, calcium dodecylbenzenesulfonate (DBS), and then were successfully intercalated into the gallery of Mg–Al layered double hydroxides (LDHs) by using ion exchange, coprecipitation and reconstruction methods, respectively, to obtain BC–LDHs nanohybrids. The loading amounts of hexaconazole-LDHs nanohybrids are obviously higher than those of triadimenol-LDHs nanohybrids. The release kinetics of bactericides from the nanohybrids was investigated. It was found that the bactericide release kinetic processes of the nanohybrids can be described with pseudo-second-order model. The initial release rates and equilibrium percent releases of the nanohybrids are obviously dependent of synthesis methods. The nanohybrids can well control the release of bactericides, showing they are a potential pesticide controlled-release formulation.     

Scanning transmission X-ray microscopy, X-ray photoelectron spectroscopy, and cyclic voltammetry study on the enhanced visible photocatalytic mechanism of carbon-TiO2 nanohybrids

Carbon-TiO₂ nanohybrids (CTs, 5-10 nm TiO₂ nanocrystals evenly dispersed on carbon film) have been successfully prepared via a mild, one-step hydrothermal approach. The interactions and electronic structures of carbon and TiO₂ nanoparticles and the enhanced visible photocatalytic mechanism were investigated by scanning transmission X-ray microscopy, X-ray photoelectron spectroscopy and cyclic voltammetry in detail. Meanwhile, it was demonstrated that the as-obtained CTs had a large BET specific surface area of 304.6 m²/g and showed excellent photocatalytic abilities towards organic (Rhodamine B, benzene) and inorganic pollutant (K₂Cr₂O₇) degradation in visible light. This work provided a new approach for the high performance catalyst design towards new energy sources and environmental issues.     

Synthesis and characterization of Naproxen intercalated Zn–Al layered double hydroxides

In this paper, naproxen was intercalated into Zn–Al layered double hydroxides (LDHs) by ion exchange method to obtain naproxen/LDHs nanohybrids. The effects of the contact time, the composition, and the structural charge density (σ _S,T ) and the specific surface area of LDHs, and pH value on the uptake of naproxen on LDHs, and the release of naproxen from the naproxen/LDHs nanohybrids were investigated. The adsorption isotherm curves of naproxen on the LDHs obey the Langmuir equation, and apparent monolayer capacity (A _m) in units of mmol m⁻² increases with the increase of the σ _S,T value of the LDHs samples. The release rate of naproxen from the naproxen/LDHs nanohybrids decreases with the increase of the σ _S,T value of the LDHs samples and is much lower than that of naproxen troche, indicating that the naproxen/LDHs nanohybrid is an efficient drug-controlled release system. In the pH range of 6~11.5, the uptake amount (A _eq) of naproxen on the LDHs decreases with the increase of pH value. The A _m values of LDHs(Cl⁻) are much higher than that of , which may contribute to that LDHs(Cl⁻), which has a stronger anion exchange ability than . The naproxen molecules are possibly adsorbed on each surface of the basal layer of LDHs. In other words, a bilayer is formed in the gallery of LDHs.     

羟基喜树碱-类水滑石纳米杂化的共组装制备及表征

采用共组装法在水溶液中制备羟基喜树碱(HCPT)-层状双金属氢氧化物(LDH)纳米杂化物.先利用微通道反应器通过共沉淀法制备了Zn₂Al-NO₃ LDH纳米片,然后与羧酸盐型HCPT在水介质中共组装,制备了HCPT插层LDH的纳米杂化物.利用酸处理,可将层间HCPT由非生物活性的羧酸盐型转化为生物活性的内酯型,这对高生物活性HCPT-LDH纳米杂化物的绿色制备具有重要意义.共组装法制备HCPT-LDH纳米杂化物,耗时短、载药量高、分散性好,且利用原料配比可方便地调控载药量. HCPT分子在LDH层间以其长轴倾斜于层板呈双层排列.所制备的HCPT-LDH纳米杂化物具有良好的药物缓释性能,颗粒内部扩散是药物释放过程的控速步骤.药物释放过程可用准二级动力学模型描述.可以用于构筑LDH基药物输送-控释体系.     

Chiral Recognition of Tryptophan Enantiomers Based on β‐Cyclodextrin‐platinum Nanoparticles/Graphene Nanohybrids Modified Electrode

The nanohybrids which based on β‐cyclodextrin, platinum nanoparticles and graphene (β‐CD‐PtNPs/GNs) were successfully synthesized and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FT‐IR) and electrochemical impedance spectroscopy (EIS). Then they were used to construct a simple and reliable chiral sensing platform to interact with tryptophan (Trp) enantiomers. Differential pulse voltammetry (DPV) was used to investigate the stereo selectivity of β‐CD‐PtNPs/GNs to Trp enantiomers. After interaction, the obvious difference of peak currents of L‐Trp and D‐Trp was obtained, indicating this strategy could be employed to chiral recognition of Trp enantiomers. Under the optimum conditions, the chiral sensor exhibited a good linear response to Trp enantiomers in a linear range of 5.0×10^?5 to 5.0×10^?3 M with a low limit of detection of 1.7×10^?5 M (S/N=3). This approach provided a new available platform to recognize and determine Trp enantiomers.     

Photoluminescent zinc oxide polymer nanocomposites fabricated using picosecond laser ablation in an organic solvent

Nanocomposites made of ZnO nanoparticles dispersed in thermoplastic polyurethane were synthesized using picosecond laser ablation of zinc in a polymer-doped solution of tetrahydrofuran. The pre-added polymer stabilizes the ZnO nanoparticles in situ during laser ablation by forming a polymer shell around the nanoparticles. This close-contact polymer shell has a layer thickness up to 30 nm. Analysis of ZnO polyurethane nanocomposites using optical spectroscopy, high resolution transmission electron microscopy and X-ray diffraction revealed that oxidized and crystalline ZnO nanoparticles were produced. Those nanocomposites showed a green photoluminescence emission centred at 538 nm after excitation at 350 nm, which should be attributed to oxygen defects generated during the laser formation mechanism of the monocrystalline nanoparticles. Further, the influence of pulse energy and polymer concentration on the production rate, laser fluence and energy-specific mass productivity was investigated.