Preparation and characterization of polythiophene/molybdenum disulfide intercalation material

Utilizing the solvothermal synthesis technique, lithium intercalated molybdenum disulfide Li_xMoS₂ was expediently obtained, which was allowed to react with water to the formation of single-molecule-layer suspension. The intercalation of polythiophene into MoS₂ was achieved by means of in situ polymerization of the intercalated monomers. The nanocomposite was characterized by X-ray powder diffraction, thermogravimertic analysis and differential scanning calorimetry. It was revealed that the intercalated polymer chain favors the monolayer arrangement with the thiophene rings lying parallel with the host layers. The optimum conditions were explored to prepare the single-phase product with a composition of Li_0.12(PTP)_0.54MoS₂. The nanocomposite exhibits enhanced electrical conductivity in the order of 10⁻² S cm⁻¹ at ambient temperature, resulted from the incorporation of the electronically conductive polythiophene between the semiconducting host layers and the coupling between the guest conjugated π-orbits and the host layers.     

Preparation of nanocomposite materials from mercaptoacetate-modified platinum nanoparticles and a layered nickel hydroxyacetate salt

Nanocomposites were prepared by a very simple route from preformed platinum particles and a nickel layered hydroxide salt (LHS), these compounds being first synthesized separately by the polyol process. The nanoparticles were treated with mercaptoacetate before being brought into contact with the lamellar compound. XPS and IR spectroscopies give clear evidence for interactions between the platinum nanoparticles and the mercaptoacetate species. XRD, TEM and magnetic characterizations show that the structure of the nickel hydroxide layers is retained and that some of the LHS sheets contain incorporated nanoparticles.     

Effect of the SiO2/TiO2 ratio on the solid acidity of SiO2-TiO2/montmorillonite composites

SiO₂-TiO₂/montmorillonite composites with varying SiO₂/TiO₂ molar ratios were synthesized and the effect of the SiO₂/TiO₂ ratio on the solid acidity of the resulting composites was investigated. Four composites with SiO₂/TiO₂ molar ratios of 0, 0.1, 1 and 10 were synthesized by the reaction of colloidal SiO₂-TiO₂ particles prepared from alkoxides with sodium-montmorillonite at room temperature. The composites showed slight expansion and broadening of the XRD basal reflection, corresponding to the intercalation of fine colloidal SiO₂-TiO₂ particles into the montmorillonite sheets and incomplete intercalation to form disordered stacking of exfoliated montmorillonite and colloidal SiO₂-TiO₂ particles. The colloidal particles crystallized to anatase in the low SiO₂/TiO₂ composites but remained amorphous in the high SiO₂/TiO₂ composites. The specific surface areas (S_BET) of the composites measured by N₂ adsorption ranged from 250 to 370 m²/g, considerably greater than in montmorillonite (6 m²/g). The pore size increased with decreasing SiO₂/TiO₂ molar ratio of the composites. The NH₃-TPD spectra of the composites consisted of overlapping peaks, corresponded to temperatures of about 190 and 290 °C. The amounts of solid acid obtained from NH₃-TPD were 186-338 μmol/g in the composites; these values are higher than in the commercial catalyst K10 (85 μmol/g), which is synthesized by acid-treatment of montmorillonite. The present sample with SiO₂/TiO₂ = 0.1 showed the highest amount of acid, about four times higher than K10.     

Titanium phosphate surfactants intercalation compounds: Thermal and structural characterization

Titanium phosphate containing long chain surfactants can be synthesized either by batch using the inorganic ion-exchanger γ-titanium phosphate and surfactant solutions or via sol-gel by direct intercalation. The resulting content of the surfactants after being exchanged depends on the length of the chain and is greater in the case of the material obtained by direct intercalation. All of the material obtained has a layered structure and an increased interlayer distance. The longer the chain is the greater the increase in distance. The layered structure is maintained up to 300 °C. The pyrophosphate formation occurs at 900 °C in the case of material by direct intercalation, whereas in the case of batch material it occurs at a higher temperature. The surfactant loss occurs in three or more distinct stages. As far as the batch material is concerned the last loss occurs at a high temperature of ∼800 °C. Thermal treatment is carried out in air or nitrogen atmosphere for the better characterization of the processes.     

Synthesis and magnetic properties of layered MnPSxSe3−x (0 < x < 3) and corresponding intercalation compounds of 2,2′-bipyridine

In this work, we synthesize a series of new MnPS_xSe_3−x (0 < x < 3) compounds by high temperature solid-state reaction and also obtain the corresponding intercalation compounds (Mn_1−yPS_xSe_3−x(bipy)_4y, x = 1.2, 1.8 and 2.4) via the intercalation of 2,2′-bipyridine with MnPS_xSe_3−x. XRD results confirm that MnPS_xSe_3−x compounds show the layered structure and can be regarded as the solid solution of MnPS₃ and MnPSe₃. Magnetic measurements indicate that MnPS_xSe_3−x compounds exhibit paramagnetism with negative Weiss constant in the paramagnetic temperature region, and an antiferromagnetic phase transition occurs at the Neel temperature. It is found that the magnetic properties of MnPS_xSe_3−x slab are dramatically changed after the intercalation of 2,2′-bipyridine, which is close related to the relative ratio of S and Se atom as well as the intralayered Mn²⁺ vacancies of MnPS_xSe_3−x slab.     

Effect of preparation method on structure and adsorption capacity of aluminum pillared montmorillonite

Aluminum pillared montmorillonites (Alpill-MMTs) were prepared by two different methods, i.e. conventional intercalation and ultrasonic assisted intercalation, in order to study the effects of preparation methods on their structures and adsorption abilities. In the conventional intercalation, a base-hydrolyzed solution of [AlO₄Al₁₂(OH)₂₄(OH₂)₁₂]⁷⁺, Al₁₃⁷⁺, was firstly prepared and then mixed with a suspension of sodium montmorillonite (Na⁺-MMT) for 24 h with vigorous stirring, resulting in the cation exchange between Al₁₃⁷⁺ and Na⁺ balancing ions in the MMT interlayers. On the other hand, the high power ultrasonic was used in the second method for creating the Al₁₃⁷⁺ ions and then in situ intercalating into the MMT suspension, in which the reaction was performed for 20 min. Both Al₁₃⁷⁺ intercalated MMTs were calcined at 500 °C for 2 h in order to obtain the Alpill-MMTs. The ultrasonic could not only shortening the intercalation process, but also increasing the amount of intercalated Al₁₃⁷⁺ in the MMT. The ultrasonic synthesized Alpill-MMT (Alpill-MMT-ultra) consisted of mesoporous structure with multiple pore sizes ranging from 3 to 30 nm; therefore, it possessed higher specific surface area and pore volume than the conventionally synthesized Alpill-MMT (Alpill-MMT-str). Adsorption capacities of Alpill-MMTs were investigated using cationic adsorbate, i.e. Basic Yellow 1 (BY1). The highest adsorption capacities were respectively about 95 and 81 mg/g for the Alpill-MMT-ultra and Alpill-MMT-str, when using initial BY1 concentration of 2000 mg/L. The Alpill-MMT-ultra showed higher efficiency for BY1 removal than the Alpill-MMT-str even after thermal regeneration. The adsorption kinetics of both Alpill-MMTs for BY1 removals were found to follow a pseudo-second-order model, while their adsorption data corresponded to Langmuir isotherm. These results indicated the competency of Alpill-MMTs as the adsorbents for treatment of wastewater containing cationic dye.     

Preparation and properties of UV-cured acrylated silane intercalated polymer/LDH nanocomposite

A novel UV-cured polymer/layered double hydroxide (LDH) nanocomposite was prepared by modifying the LDH with sodium dodecyl sulfate (SDS) and [3-(methyl-acroloxy)propyl]trimethoxysilane (KH570) followed by UV irradiation after blended into a acrylate system. From the XRD analyses, the SDS-modified LDH-DS presented the basal spacing of 2.67 nm, whereas the further KH570-intercalated LDH-KH showed a slight decrease to 2.41 nm. After UV irradiated the exfoliated microstructure was formed, and observed by TEM and HR-TEM, showing the fine dispersion and random orientation of LDH in the polymer matrix. The storage modulus and glass transition temperature of the nanocomposite containing 5% LDH-KH increased to 47.5 MPa and 67.8 °C, respectively, from 39.7 MPa and 66 °C of the pure polymer from DMTA measurements. The tensile strength and Persoz hardness were enhanced to 10.6 MPa and 111 s, respectively, from 7.7 MPa and 85 s of the pure polymer.     

Synthesis, spectroscopic and structural characterization of poly-o-methoxyaniline and poly-o-methylaniline intercalated into layered vanadyl phosphate

We present the spectroscopic and structural characterization of poly-o-methoxyaniline and poly-o-methylaniline intercalated into oxovanadium phosphate. The influence of synthesis conditions was also investigated. Furthermore, for comparison purpose intercalation reactions between polyaniline (PANI) and the matrix also have been performed. Infrared spectra (infrared bands near 1610 and 1500 cm⁻¹ characteristic of CC stretching from quinoid and benzenic rings, respectively) suggest that the organic polymers are present in an intermediate oxidation state of emeraldine, which are in agreement with UV-Vis spectra. Under soft reaction conditions (room temperature), only aniline undergoes intercalation reaction, whereas o-methoxyaniline and o-methylaniline react under refluxing by exfoliation-reconstruction process. These different synthetic procedures (topotactic mechanism and exfoliation-reconstruction) result materials with different arrangements of polymeric species into the interlayer space.     

Topotactic route for new layered perovskite oxides containing fluorine: Ln1.2Sr1.8Mn2O7F2 (Ln = Pr, Nd, Sm, Eu, and Gd)

A series of fluorine intercalated Ruddlesden-Popper layered perovskites, Ln_1.2Sr_1.8Mn₂O₇F₂ (Ln = La, Pr, Nd, Sm, Eu, and Gd) were synthesized from the parent oxides, Ln_1.2Sr_1.8Mn₂O₇, with the organic reagent, poly(vinylidene fluoride), as the fluorine source. Oxidative intercalation readily occurred by decomposition of the organic fluoride immediately adjacent to the parents.     

Layered inorganic/organic mercaptopropyl pendant chain hybrid for chelating heavy cations

Heavy metal sorbents with uptake capacities for divalent cadmium and lead cation removal from aqueous solutions have been synthesized by grafting mercaptopropyltrimethoxysilane onto the surface of two different precursors obtained from lamellar ilerite, its acidic and the cetyltrimethylammonium exchanged forms. The organofunctionalization was carried out by two different procedures: reflux and solvent evaporation methodologies. Elemental analysis data based on carbon content gave 1.37 and 3.53 mmol of organic pendant groups per gram of hybrid by the reflux method, when starting from acidic ilerite and the surfactant form. X-ray diffraction corroborated the maintenance of the original crystallinity. Infrared spectroscopy and nuclear magnetic resonance for ²⁹Si and ¹³C nuclei are in agreement with the success of the proposed method. The sulfur basic centers attached to the lamellar structure are used to coordinate both cations at the solid/liquid interface. The isotherms were obtained through the batchwise process and the experimental data were adjusted to the Freundlich model. The maximum sorption capacities of 5.55 and 5.12 mmol g⁻¹ for lead and 6.10 and 7.10 mmol g⁻¹ for cadmium were obtained for organofunctionalized ilerite and its surfactant form, synthesized by reflux methodology. This behavior suggested that these hybrids could be employed as promising sorbents with a polluted system.