Characterization and Dehydration Behavior of a Natural,Ammonium Hydroxide,and Thermally Treated Zeolitic Tuff

Aqueous NH₄OH-treated and subsequently calcined forms of local natural zeolitic tuff were characterized by different techniques including scanning electron microscopy (SEM), X-ray powder diffraction, inductively coupled plasma–atomic emission spectroscopy (ICP-AES), volumetric N₂ adsorption at ?196°C, thermogravimetry (TG), differential scanning calorimetry (DSC), and transmittance infrared spectroscopy. The dehydration behavior of the samples was investigated using an in situ temperature-programmed diffuse reflectance Fourier transform infrared spectroscopy (TP-DRIFTS) method under vacuum. The DRIFTS spectra recorded yielded information about the effect of the NH₄OH treatment and subsequent calcination on the dehydration behavior of the natural zeolite. Changes in the infrared bands corresponding to vibrations of the O–H and N–H bonds upon in situ heating under vacuum were analyzed.     

Synthesis and characterization of Y (In,Mn) O3 blue pigment using the complex polymerization method (CPM)

In this paper, a new synthetic pathway is proposed for the system YIn_1-xMn_xO₃, a bright blue inorganic pigment, discovered in 2009. Blue pigment samples with increasing concentration of Mn³⁺ (x?=?0.08, 0.12 and 0.16) were prepared using the complex polymerization method (CPM) and compared with those synthesized via solid state reaction. All powders, the amorphous precursor from CPM and the starting materials for solid state method, were calcined at 1000, 1100, 1200 and 1300?°C for 12?h, and the resulting blue pigments were characterized by X-ray diffraction (XRD), colorimetric system CIE L*a*b* and Near infrared (NIR) reflectance measurements. XRD patterns and Rietveld Refinement show that the lowest temperature at which single hexagonal phase (isostructural to YInO₃) is formed is 1000?°C for CPM method and 1300?°C for conventional solid state method, respectively. The L*a*b* values demonstrate that the coloration of powders prepared by CPM exhibit temperature dependence below 1300?°C, a color shade shift from grayish blue to intense deep blue is observed when heating the samples from 1000 to 1300?°C. Blue pigments obtained by CPM have smaller particle size due to low temperatures and excellent near-infrared reflectance comparable to those by solid state method. Thus, providing advantages for application process and energy efficiency.     

Effects of Cerium and Aluminum in Cerium-Containing Hierarchical HZSM-5 Catalysts for Biomass Upgrading

We report the synthesis of multifunctional, hierarchical, cerium-containing HZSM-5 catalysts with various aluminum and cerium contents using a dry-gel, dual templating method. The catalysts were characterized by X-ray diffraction, N₂ physisorption, scanning electron microscopy, diffuse reflectance UV?CVisible spectroscopy, diffuse reflectance Fourier transform infrared spectroscopy, Fourier transform Raman spectroscopy, NH₃ temperature programmed desorption and X-ray photoelectron spectroscopy. At low theoretical Si:Al ratios (15 and 20), the formation of amorphous silica?Calumina materials was observed. However, at higher theoretical Si:Al ratios (30, 40, and 50), crystalline materials were formed. Furthermore, with Si:Al ratios of 50, cerium incorporation as high as 2.2?wt% was obtained using this procedure. To understand the role of aluminum and cerium in the catalyst, the crystalline materials were studied in the catalytic fast pyrolysis of glucose at 600?°C. The catalysts with cerium incorporated showed an increase in the production of oxygenated chemicals as well as CO, compared with their non-cerium containing analogs.     

Waste-free Soft Reactive Grinding Synthesis of High-Surface-Area Copper–Manganese Spinel Oxide Catalysts Highly Effective for Methanol Steam Reforming

Cu–Mn spinel oxides with a high specific surface area were prepared by a simple and waste-free soft reactive grinding (SRG) technique involving the use of clean precursor salts as the starting materials. The samples were characterized by means of N₂ adsorption, X-ray diffraction (XRD), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and temperature-programmed reduction (H₂-TPR). The results show that the catalysts obtained from the SRG route exhibited much higher catalytic activity in methanol steam reforming as compared to their wet-chemically synthesized counterparts prepared by conventional coprecipitation. The superior performance of the SRG-derived Cu–Mn materials was attributed to the favorable formation of Cu_1.5Mn_1.5O₄ spinel phase leading to the creation of much smaller copper nanoparticles with enhanced stability in the working catalyst.     

Carbon-modified TiO2 for photocatalysis

ABSTRACT: Here we present a method to produce TiO2 nanocrystals coated by thin layer of graphitic carbon. The coating process was prepared via chemical vapor deposition (CVD) with acetylene used as a carbon feedstock with TiO2 used as a substrate. Different temperatures (400°C and 500°C) and times (10, 20, and 60 s) of reaction were explored. The prepared nanocomposites were investigated by means of transmission electron microscopy, Raman spectroscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy/diffuse reflectance spectroscopy and ultraviolet-vis (UV-vis)/diffuse reflectance spectroscopy. Furthermore, photocatalytic activity of the materials was investigated under visible and UV-vis light irradiation in the process of phenol decomposition. It was found that TiO2 modification with carbon resulted in a significant increase of photoactivity under visible irradiation and decrease under UV-vis light irradiation. Interestingly, a shorter CVD time and higher process temperature resulted in the preparation of the samples exhibiting higher activity in the photocatalytic process under visible light irradiation.     

镍掺杂铝酸镧涂层的制备及其红外辐射性能

采用溶胶?凝胶法合成了Ni2+掺杂的LaAlO3基红外辐射材料LaAl0.6Ni0.4O2.89 (LANO),以其为辐射基料,利用喷涂工艺在氧化铝陶瓷片表面制备红外辐射涂层,考察了磷酸二氢铝、铝溶胶、硅溶胶和钠水玻璃4种粘结剂对涂层物相组成、热稳定性和红外辐射性能的影响. 结果表明,以LANO为辐射基料、铝溶胶为粘结剂时,涂层红外辐射性能最佳,3?5 ?m波段红外发射率达0.93;所制涂层具有良好的抗热震性能,50次热震后涂层未明显剥落失效;涂层具有显著的强化辐射传热效果,节能率达31.7%.     

Ordered mesoporous sulfated silica-zirconia materials with high zirconium contents in the structure

A series of mesoporous sulfated silica-zirconia materials with various Si/Zr molar ratios (2.0–5.0) have been prepared using tri-block copolymer as a template, which were characterized by X-ray diffraction, TEM, nitrogen adsorption, UV-Vis diffuse reflectance spectroscopy, infrared spectroscopy, thermal gravimetric analysis, and catalytic reactions. XRD patterns displayed that ordered mesoporous sulfated silica-zirconia materials were obtained when the molar ratio of Si/Zr was not less than 4.0 (ZrSiS-4 and ZrSiS-5). When the molar ratio of Si/Zr was less than 4.0, the samples had a separated phase of amorphous sulfated zirconia (ZrSiS-2 and ZrSiS-3). Furthermore, TEM images (ZrSiS-4 and ZrSiS-5) revealed that the mesostructure of these materials were highly ordered. N₂ adsorption (ZrSiS-4 and ZrSiS-5) exhibited typical IV adsorption isotherms and uniform pore distribution. UV-Vis reflectance and IR spectra suggested (ZrSiS-4 and ZrSiS-5) that Zr atoms were incorporated into the walls of mesoporous silica. Cracking reactions of cumene and 1,3,5-triisopropylbenzene (TIPB) showed that, the ordered mesoporous sulfated silica-zirconia materials were very active in acidic catalytic reactions, especially for the cracking of large molecules.     

Fabrication and high-temperature structural characterization study of porous anodic alumina membranes

Porous anodic alumina (PAA) membranes with highly ordered array of nanopores were prepared by two-step anodization process. Studies on structural and thermal properties and the thermal stability of the prepared PAA membranes were carried out. Investigation using scanning electron microscopy, atomic force microscopy, X-ray diffraction, thermal analysis and infrared spectroscopy was performed on the prepared PAA membranes at room temperature and in the temperature range 600?C1,400?°C. The as-prepared PAA membranes revealed the amorphous nature. Polycrystalline PAA membranes were obtained by annealing carried out at different temperatures. Annealing study confirmed that the heat treatment transformed the amorphous PAA membranes to their crystalline phases, namely, ??-alumina at about 870?°C and then to ??-alumina around 1,250?°C.     

Characterization and catalytic behaviors of methylamine modified FAU zeolites

The methylamine (MA) modified FAU zeolites with 5.8 and 80 of silica alumina molar ratio were successfully prepared by the treatment of original FAU zeolites with MA. The obtained materials were investigated with diffuse reflectance infrared Fourier transform spectroscopy, X-ray diffraction, magic-angle spinning nuclear magnetic resonance, thermogravimetry, temperature-programmed desorption of CO₂ and NH₃ (CO₂-TPD and NH₃-TPD), nitrogen content analysis, and specific surface area analysis. The formations and thermal stabilities of different Si–N–C groups in the MA modified FAU zeolites were confirmed. The changing of aluminium species due to the interaction of MA and framework/extraframework aluminium (FAL/EFAL) in the modified samples was discovered. The acidity and basicity of the MA modified FAU zeolites were correlated to the hybrid aluminium species and variation of Si–N–C groups, respectively. The catalytic behaviors of the MA modified FAU zeolites were explored by Knoevenagel condensation reaction of benzaldehyde and malonic acid.     

磷酸酯改性纳米氢氧化镁的研究

以六水硝酸镁和氢氧化钠为原料,磷酸酯为改性剂,采用直接沉淀法一步合成改性纳米氢氧化镁,通过沉降体积实验,确定改性剂的较佳用量为1.0%,并用红外光谱(FHR)、X射线衍射(XRD)、透射电镜(TEM)、堆密度对改性前后的样品进行表征.结果表明,该方法可以使磷酸酯吸附在氢氧化镁颗粒表面,改变氢氧化镁的表面性质,从而提高在有机介质中的分散稳定性,与未改性的氧氧化镁样品相比,改性后纳米氢氧化镁XRD衍射峰主峰强度提高,团聚程度和堆密度减少.     

Synthesis of high surface area nanocrystalline MgO by pluronic P123 triblock copolymer surfactant

Nanocrystalline magnesium oxide with high surface area was prepared by a simple precipitation method using pluronic P123 triblock copolymer (Poly(ethylene glycol)-block, Poly(propylene glycol)-block, Poly(ethylene glycol)) as surfactant. The prepared samples were characterized by X-ray Diffraction (XRD), N₂ adsorption (BET), Fourier transform infrared spectroscopy (FTIR), Thermal, differential thermal gravimetric and differential thermal analyses (TG/DTG/DTA) and Scanning electron microscopy (SEM). The obtained results revealed that the addition of surfactant is effective to prepare magnesium oxide with high surface area and affects the morphology of the prepared samples. The results showed that the magnesium oxide calcined at different temperatures ranging from 600 to 800 °C possessed a high surface area in the range of 133.9–78.1 m² g^?1. In addition, the magnesium oxide prepared with the addition of surfactant showed a narrower pore size distribution compared to the sample prepared without the addition of a surfactant.     

Ammonium complex of niobium as a precursor for the preparation of Nb2O5/Al2O3 catalysts

Ammonium oxalate complex of niobium was investigated as an aqueous precursor for the preparation of x% Nb₂O₅/Al₂O₃ (x=5, 10, 20 and 30 wt.%) samples. Catalysts with the same Nb₂O₅ contents were also prepared from the traditional niobium oxalate/oxalic acid aqueous solution. The catalysts were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), temperature-programmed reduction (TPR), infrared spectroscopy of chemisorbed pyridine and X-ray photoelectron spectroscopy (XPS). A comparison with the preparation method using the niobium oxalate salt was performed. The results showed that the niobium precursor influence the species growing leading to phases with different reducibility. The XPS revealed the presence of multilayers of niobium oxide on the Nb₂O₅/Al₂O₃ samples prepared by using niobium ammonium oxalate complex, while the ones obtained from niobium oxalate led to Nb₂O₅ particles islands. The addition of niobium oxide decreased the fraction of Lewis acid sites and increased the fraction of Brønsted acid sites, independent of the precursor salt. However, the creation of BAS was more pronounced on the Nb₂O₅/Al₂O₃ samples prepared from niobium oxalate.     

Effect of Lubricant on the Surface Structure of Aluminosilicate Fibers

Commercial aluminosilicate fibers of the nominal composition 45 wt% Al₂O₃, 54 wt% SiO₂ have similar bulk properties but different surface chemistries, depending on whether they were formed with (WL) or without (NL) the aid of a mineral-oil lubricant. Both fiber samples are X-ray amorphous as formed; they have similar crystallization temperatures and have activation energies for crystallization of 751 and 854 kJ/mol for samples NL and WL, respectively. Fiber surface properties differ markedly, as indicated by diffuse reflectance infrared transmission spectroscopy and X-ray photoelectron spectroscopy. These techniques show that carbon from the lubricant degradation and/or combustion is incorporated into the melt, whereupon it reacts with nonbonding oxygens in the Al-O network to form network carbonates.     

Synthesis andcharacterisation of nanocrystalline MgAl2O4 ceramic powders by use of molten salts

Abstract

Nanocrystalline MgAl₂O₄ powders were prepared by a thermal decomposition method, i.e. by use of molten salts. This method involves co-melting stoichiometric amounts of magnesium nitrate hydrate Mg(NO₃)₂.6H ₂O and aluminium nitrate hydrate Al(N O₃) ₃.9H₂O at 500°C. The spinel content of the co-melted and calcined powders at different firing temperatures up to 1000°C was determined by chemical analysis and the powders were characterised with respect to spinel formation, crystallite and particle sizes by X RD, T EM , and IR spectroscopy. The results obtained revealed that the co-melted materials were amorphous. After heat treatment of the amorphous materials at up to 1000°C, pure spinel powder was obtained, reaching over 98% spinel content. During calcination at different firing temperatures up to 1000°C the amorphous material progressively crystallised, forming nanocrystalline spinel with a maximum crystallite size of about 10 nm and particle size of around 300 nm. Bands in IR spectra were observed corresponding to the ex istence of AlO₆ groups prior to magnesium spinel formation, which was the only crystalline phase at 1000°C.     

Influence of Mg concentration on structural,morphological and optical properties of nanoceria

Nano crystalline pure and Mg doped ceriaparticles were synthesized by simple chemical co-precipitation method using cerium nitrate hexahydrate as a source material and magnesium nitrate as doping precursor at room temperature. The effect of doping were investigated by X-ray diffraction pattern(XRD), FT-Raman,fourier transform infrared spectroscopy(FTIR), Ultraviolet spectroscopy(UV), photoluminescence spectroscopy(PL), field emission scanning electron microscope(FESEM) and high resolution transmission electron microscopy with energy dispersive spectroscopy (HRTEM &EDS). The X-ray diffraction pattern and FT-Raman studies showed that the prepared samples were nano particulates with cubic fluorite structure. The XRD pattern analysis showed that the size of the particles ranged from 13 to 20?nm, however 4?wt% Mg doping results in reduction of particle size compared with other doping concentrations. The effects of Mg concentration on various structural parameters of the prepared samples were also determined. The slight blue shift observed upon doping in UV–Vis absorption region around 330–360nmrecorded for reduction in particle size. The FTIR unveils the presence of Metal oxygen bonds below 700?cm^?1in the prepared samples. All samples showed a broad emission band at 430?nm with linearly increasing intensity with respect to dopant concentrations. The Spherical morphology with weak agglomeration was identified through FESEM and HRTEM analysis. The elemental analysis of Ce, O and Mg were confirmed through EDS analysis.     

Direct synthesis of Ti-SBA-15 in the self-generated acidic environment and its photodegradation of Rhodamine B

A series of Ti-containing SBA-15 samples were firstly prepared in the self-generated acidic condition. The samples were characterized by powder X-ray diffraction, N₂-adsorption, transmission electron microscopy, inductively coupled plasma, Fourier-transform infrared spectroscopy, UV–vis diffuse reflectance spectra (UV–vis) and X-ray photoelectron spectroscopy. All the samples possessed well-ordered hexagonal arrays of mesopores and Ti ions could be incorporated into the framework of SBA-15. Catalytic performances of the obtained materials were evaluated in the photodegradation of Rhodamine B (RhB). Catalytic tests indicated that Ti-SBA-15 showed much higher photodegradation ability towards RhB than pure TiO₂.     

Novel partially bio-based fluorinated polyimides from dimer fatty diamine for UV-cured coating

A series of novel partially bio-based fluorinated polyimides with double-bond end groups (BGPIs) from 4,4′-(hexafluoroisopropylidene) diphthalic anhydride, 4,4′-(hexafluoroisopropylidene) dianiline, Priamine 1074, 4-aminobenzoic acid, and glycidyl methacrylate were synthesized via a copolycondensation method in m-cresol. The chemical structure and performances of BGPIs were fully characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography, solubility test, X-ray diffraction, and differential scanning calorimetry. It was determined that the prepared BGPIs were in the amorphous phase and readily soluble in conventional aprotic polar solvents. Additionally, the properties of as-prepared UV-cured coatings based on BGPIs were also evaluated by real-time Fourier transform infrared, thermogravimetric analysis, UV–Vis spectroscopy, and so on. Results revealed that all coatings exhibited satisfactory curing, higher adhesion, lower water uptakes, outstanding optical transparency, and fairly favorable thermal stability under a high content of biomass up to 48.9%. Therefore, these bio-based polymers could be considered as a potential sustainable candidate for high-temperature UV-curable coatings in the microelectronic field.     

Crystallinity in PPS–carbon composites: A study using diffuse reflection FT-IR spectroscopy and differential scanning calorimetry

A method based on diffuse reflection Fourier transform infrared (FT-IR) spectroscopy has been developed for determining the state of crystallinity in composite materials made from poly(phenylene sulfide) (PPS) reinforced with carbon fibers. Using this technique, good-quality spectra can be obtained directly from the surface of prepreg or molded composite; thus the method is rapid and nondestructive. Several peaks in the spectrum are sensitive to the crystallinity and can be used for quantitative characterization purposes. The recommended indicator is the ratio of the heights of the peaks at 1075 and 1093 cm^?1. Using a range of samples of varying crystallinity prepared by annealing amorphous prepreg, it has been shown that there is a very good correlation between this ratio and the enthalpy of crystallization as determined by differential scanning calorimetry. The effects of such annealing, as well as heating in air at high temperatures, have been investigated.     

FTIR-OMNI采样器快速分析材料表面涂层聚合物成分

采用傅里叶变换红外光谱(FTIR)仪的衰减全反射(ATR)附件——OMNI采样器,对45#钢、山羊皮革、易拉罐内壁、空白光盘等4种材料表面的聚合物涂层进行了ATR-FTIR分析。结果表明,该方法无需对样品进行前处理,适用于生产、科研、质检等部门快速分析材料表面涂层的聚合物成分,具有简便、准确、无损的特点。     

Poly(ethylene) glycol-modified,amphiphilic, siloxane–polyurethane coatings and their performance as fouling-release surfaces

Amphiphilic siloxane–polyurethane (AmSiPU) coatings were prepared using a series of polyisocyanate prepolymers modified with polydimethyl siloxane (PDMS) and poly(ethylene glycol) (PEG). Fouling-release performance of the AmSiPU coatings was evaluated through laboratory biological assays using several representative marine organisms. First, polyisocyanate prepolymers with compositional variation in PDMS and PEG were synthesized and characterized using Fourier transform infrared spectroscopy (FTIR) and isocyanate titrations. Then, the prepolymers were incorporated into coatings. Surface wettability of the coatings was evaluated using contact angle and surface energy measurements. Coatings’ surfaces were also characterized using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). ATR-FTIR and XPS experiments revealed that both PDMS and PEG moieties were present on the surface suggesting amphiphilic character. AFM phase images show microphase separation. AmSiPU coatings show excellent fouling-release performance toward bacteria (Cellulophaga lytica), the diatoms (Navicula incerta), and the green algae (Ulva linza), demonstrating comparable or superior performance to many commercial amphiphilic fouling-release coatings. Despite the incorporation of hydrophilic PEG, AmSiPU coatings show good macrofouling release which is often challenging with amphiphilic coating systems. AmSiPU coatings are a nontoxic and tough fouling-release solution with comparable performance to benchmarks in the fouling-release coatings market.