Cobalt Ion Incorporation into Periodic Mesoporous Organosilica Materials Synthesized by Co-condensation of 1,2-Bistrimethoxysilylethane with 3-Glycidoxypropyltriethoxysilane

Bifunctional periodic mesoporous organosilica materials with and without cobalt ion incorporation were synthesized by co-condensation of 1,2-bistrimethoxysilylethane (BTME) with 3-glycidoxypropyltriethoxysilane (GPTS) in the presence of cetyltrimethylammonium bromide. Nitrogen gas adsorption on samples with varying ratios of BTME:GPTS revealed that increasing the amount of GPTS affects pore size, surface area and pore volume as well as shapes of the isotherms and hysteresis loops. The hysteresis loops of the Type IV isotherms obtained for GPTS-modified ethane silica materials (without cobalt ion) change from Type H3 to Type H4 with increasing GPTS content. There is a tendency for pore sizes to change from mesopore to micropore when the amount of GPTS is increased. Isotherms of cobalt ion incorporated GPTS-modified ethane silica materials change from Type IV to Type I with increasing GPTS content. The surface area, pore volume and pore diameter decrease with increasing loading of GPTS as well as after cobalt ion incorporation. Thermogravimetric analysis and differential thermal analysis show that the surfactant is removed by solvent extraction. Cobalt ion incorporation is confirmed by powder X-ray diffraction and Raman spectroscopy.     

One-pot synthesis to engineer a Co-KIT-6 catalyst for the ring opening of methylcyclopentane

Co-KIT-6 mesoporous materials with Ia3d symmetry and Si/Co ratios of 50, 25, and 10 were prepared using hydrothermal one-pot synthesis. The Co-KIT-6 mesoporous materials were characterized by X-ray diffraction, N₂ adsorption–desorption isotherms, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, and X-ray photoelectron spectroscopy. The physicochemical characterization results show that all of the samples have well-ordered cubic mesostructures and that the structural integrity is preserved for n_Si/n_Co ratios as high as 10. It was found that most of the cobalt ions exist as isolated framework species, but for Co-KIT-6 with an n_Si/n_Co ratio of 10, the presence of extra-framework species/small cobalt oxide clusters cannot be excluded. The ability of these catalysts was tested by examining the conversion of the reaction of methylcyclopentane with hydrogen at atmospheric pressure and temperatures between 200 and 450 °C. The catalytic results show that their catalytic activity increases significantly with increasing cobalt content. The active sites, tetrahedrally coordinated Co and isolated atomic Co sites, were responsible for the endocyclic CC bond rupture between substituted secondary–tertiary carbon atoms, whereas the small clusters serve as active sites for the successive CC bond rupture. The ring-opening selectivity can be improved by increasing the density of isolated cobalt atom sites at low reaction temperatures.     

Enhanced Electrochemical Capacitive Properties of Nickel‐Cobalt Oxide Nano‐flakes Materials

Nickel‐cobalt oxide nano‐flakes materials are successfully synthesized by a facile chemical co‐precipitation method followed by a simple calcination process. The studies show that the as‐prepared nickel‐cobalt oxides with different Ni/Co ratio are composed of NiO and Co₃O₄ compounds. The Co_0.56Ni_0.44 oxide material, which exhibits a mesoporous structure with a narrow distribution of pore size from 2 to 7 nm, possesses markedly enhanced charge‐discharge properties at high current density compared with the pure NiO and pure Co₃O₄. The Co_0.56Ni_0.44 oxide electrode shows a specific capacitance value of 1227 F/g at 5 mA/cm², which is nearly three times greater than that of the pure NiO electrode at the same current density.     

Synthesis of micro/mesoporous silica using poly(ethylene glycol) as a template

Analysis of isotherms of low-temperature nitrogen adsorption-desorption has revealed the formation of a micro/mesoporous structure in silica resulting from the sol-gel transition of SiO₂ in the presence of poly(ethylene glycol)s with different molecular masses used as templates. The specific surface area of pores has been determined by the BET and Langmuir methods; the volume and surface area of micropores have been estimated by the t-plot method; and the surface area and volume of pores, mesopore size distribution, and average pore diameter have been assessed using the Barrett-Joyner-Halenda method.     

中孔分子筛负载钴催化剂制备及其在费-托合成中的催化性能

 以HMS,MCM－41,AlHMS和ZrO2／HMS等中孔分子筛为载体,采用孔体积浸渍法制备了系列负载型钴催化剂．XRD测定结果表明,Co氧化物完全分散于分子筛内表面,载体仍保持中孔分子筛的特征;低温N2吸附测定结果表明,表面负载金属钴后,分子筛的比表面积和孔体积下降,孔径减小,孔壁增厚．比较了不同中孔分子筛负载Co催化剂在F－T反应中的催化性能,以短程六角对称的HMS为载体,有利于F－T反应中的链增长,烃类产物主要为微晶蜡;以ZrO2／HMS为载体可抑制CH4的生成,提高C5＋的选择性．     

Facile Synthesis of Ordered Mesoporous Zirconia for Electrochemical Enrichment and Detection of Organophosphorus Pesticides

Highly crystallized mesoporous ZrO₂ nanomaterials were synthesized by solvent evaporation induced self‐assembly approach. Ordered mesoporous ZrO₂ nanomaterials were characterized by TEM, SEM, BET, XRD and UV‐Vis spectroscopy. The obtained nanomaterials exhibit the close‐packing mesopores with average pore size of 7 nm and a highly crystallized framework with tetragonal phase. A non‐enzyme electrochemical sensor based on ordered mesoporous ZrO₂ is established for selective detection of methyl parathion (MP). The online extraction of MP is firstly achieved by ZrO₂ modified electrode at open‐circuit potential for 5 min., and the sensitive detection of MP is performed by differential pulse voltammetry (DPV) method. By comparison, DPV responses of mesoporous ZrO₂ are 40 times and 25 times larger than that of mesoporous silica and mesoporous carbon with the similar pore structure, implying the specific affinity advantage of zirconia to phosphoric group. The quantitative analysis result shows that the voltammetric currents are linear with concentrations of MP ranging from 1 ng/ml to 2 μg/ml with a detection limit of 0.53 ng/ml. The sensor also exhibits good stability and high selectivity against interfering species. The excellent analytical performances are owed to the accessible and uniform mesoporous structures, highly crystallized frameworks of ZrO₂ and its specific affinity to phosphate groups.     

Characterization Studies on the Ionic Liquid-Templated Mesoporous Silica with Wormlike Pores

This article reports a novel preparation of wormlike mesoporous silica with 1-hexadecane-3-methylimidazolium bromide (C₁₆MIM)Br, a kind of room-temperature ionic liquids (RTILs), as a template via a sol-gel nanocasting technique. The characterization studies were carried out in contrast with that of the mesoporous silica with cetyltrimethylammonium bromide (CTAB), a usually used template, which has the same alkyl chain length with (C₁₆MIM)Br. The structures of the silica materials have been characterized by Transmission electron microscopy (TEM), High-resolution TEM (HRTEM) and N₂ adsorption-desorption measurements. The results show that both the mesoporous materials prepared with different templates respectively can form regular wormlike mesopores with ca. 2 nm in pore diameter. They also have large BET surface areas with narrow size distribution. Compared to the CTAB-template mesoporous silica, the material with (C₁₆MIM)Br as a template has highly uniform pore size and larger surface area. In addition, the formation mechanism of the wormlike mesopores with RTIL has been proposed by an electrostatic charge matching assembly-pathway and steric factor.     

Pt-doped semiconductive oxides loaded on mesoporous SBA-15 for gas sensing

SBA-15-based solids combining semiconductive oxides (Sn and In) and noble metal (Pt) were prepared by an incipient wet impregnation method in order to obtain materials for gas sensing. The materials were characterized by XRD, BET adsorption, SEM, and TEM. The BET analysis allowed obtaining details about the specific surface areas, pore size, and modifications due to the indium and/or tin oxides followed by the Pt deposition. XRD data revealed that In₂O₃ did not enter the mesopores of SBA-15, preventing also the entrance of the Pt nanoparticles in the mesopores. On the other hand, SnO₂ nanoparticles further doped with Pt could enter the mesoporous network, affording a SBA-15 material loaded with SnO₂ and very small Pt nanoparticles with high dispersion. Tablets obtained by pressing the modified SBA-15 were tested as sensitive materials for propene and hydrogen detection.     

Aggregates and hydrogels prepared by self-assembly of amphiphilic copolymers with surfactants

Mesoporous carbons containing cobalt nanoparticles are synthesized by tri-or quad-constituent self assembly of Pluronic F127, phenol-formaldehyde oligomer (resol), cobalt acetylacetonate (acac), and optionally tetraethyl orthosilicate (TEOS, optional). Upon pyrolysis in N₂ atmosphere, the resol provides sufficient carbon yield to maintain the ordered structure, while decomposition of the Co(acac) yields cobalt nanoparticles. To provide increased surface area, the dispersed silicate from condensation of TEOS can be etched after carbonization to yield micropores, Without silica templated micropores, the surface area decreases as the cobalt content increases, but there is a concurrent increase in the volume-average pore diameter (BHJ) and a dramatic increase in the adsorption capacity of methylene green with the equilibrium adsorption capacity from 2 to 90 mg/g with increasing Co content. Moreover, the surface area and pore size of mesoporous composites can be dramatically increased by addition of TEOS and subsequent etching. These composites exhibit extremely high adsorption capacity up to 1151 mg/g, which also increases with increases in the Co content. Additionally, the inclusion of cobalt nanoparticles provides magnetic separation from aqueous suspension. The in situ synthesis of the Co nanoparticles yields to a carbon shell that can partially protect the Co from leaching in acidic media; after 96 h in 2 M HCl, the powders remain magnetic.     

Preparation of a kind of mesoporous carbon and its performance in adsorptive desulfurization

Carbon materials were prepared using mesoporous silica HMS with different pore sizes as the hard templates and water-soluble phenolic resin as the carbon source. The obtained materials were characterized by powder X-ray diffraction, transmission electron microscopy and N₂ physical adsorption, and were used in adsorptive desulfurization. It has been shown that the carbon material prepared using HMS with larger pore size (>3 nm) presented uniform wormlike mesopore of 2.3 nm and large BET surface area (1903 m²/g). The mesoporous carbon was an excellent adsorbent to remove the refractory sulfur compound in diesel, especially dibenzothiophene and 4, 6-dimethyldibenzothiophene.     

CoPd Nanoalloys with Metal–Organic Framework as Template for Both N-Doped Carbon and Cobalt Precursor: Efficient and Robust Catalysts for Hydrogenation Reactions

In this work, a series of metal–organic framework (MOF)-derived CoPd nanoalloys have been prepared. The nanocatalysts exhibited excellent activities in the hydrogenation of nitroarenes and alkenes in green solvent (ethanol/water) under mild conditions (H₂ balloon, room temperature). Using ZIF-67 as template for both carbon matrix and cobalt precursor coating with a mesoporous SiO₂ layer, the catalyst CoPd/NC@SiO₂ was smoothly constructed. Catalytic results revealed a synergistic effect between Co and Pd components in the hydrogenation process due to the enhanced electron density. The mesoporous SiO₂ shell effectively prevented the sintering of hollow carbon and metal NPs at high temperature, furnishing the well-dispersed nanoalloy catalysts and better catalytic performance. Moreover, the catalyst was durable and showed negligible activity decay in recycling and scale-up experiments, providing a mild and highly efficient way to access amines and arenes.     

仿生光催化剂的优化制备、介孔特性表征及其在催化降解苯酚废水中的应用

以十二胺(DDA)或十八胺(ODA)为模板剂,采用焙烧或萃洗法去除模板剂制备中孔分子筛(HMS).X射线粉末衍射(XRD)及氮吸附表征结果说明,以十二胺为模板剂且采用焙烧法去除模板剂制备的分子筛具有明显的XRD介孔衍射峰,而且其氮吸附曲线具有典型的IV类等温线特征及H1型脱附滞后环,这属于典型的介孔材料特征.以此分子筛为载体,通过F—C反应将磺酸铁酞菁(FePcS)修饰在HMS上,得到新型光催化剂.催化剂的BET比表面积为675.1m2·g-1,平均孔径为5.78nm,孔容为0.587cm3·g-1,且仍保持着鲜明的介孔特征.最后在模拟可见光照射下应用催化剂处理浓度高达1000mg·L-1的模拟苯酚废水,反应400min后,苯酚的转化率达到85%以上,反应溶液pH值也由4.52降到2.65,表明有酸类降解中间产物生成,反应最终苯酚转化率接近100%,总有机碳(TOC)的去除率达81%以上.催化剂表现出了良好的催化降解有机废水的性能.     

基于长链离子液体模板合成Fe(Co、Ni)-MCM-48

以两亲长链离子液体(氯化-1-十六烷基-3-甲基咪唑)为模板剂,采用水热合成方法,分别合成了含铁、钴和镍的立方介孔分子筛MCM-48。通过XRD、TEM、ICP-AES、FTIR、UV-Vis和N₂吸附/脱附实验对其结构和形态进行了表征,并考察了钴掺杂量和模板剂用量对合成立方相结构的影响。结果表明,用该方法合成的试样具有较高的比表面积和规则的立方介孔孔道结构等特征;相对于铁和镍的掺杂试样,钴物种能以四面体的结构稳定地存在于立方介孔分子筛骨架中。     

Synthesis of Superacid‐Functionalized Mesoporous Nanocages with Tunable Pore Diameters and Their Application in the Synthesis of Coumarins

Here we demonstrate for the first time the preparation of a triflic acid (TFA)‐functionalized mesoporous nanocage with tunable pore diameters by the wet impregnation method. The obtained materials have been unambiguously characterized by XRD, N₂ adsorption, FTIR spectroscopy, and NH₃ temperature‐programmed desorption (TPD). From the characterization results, it has been found that the TFA molecules are firmly anchored on the surface of the mesoporous supports without affecting their acidity. We also demonstrate the effect of the pore and cage diameter of the KIT‐5 supports on the loading of TFA molecules inside the pore channels. It has been found that the total acidity of the materials increases with an increase in the TFA loading on the support, whereas the acidity of the materials decreases with an increase in the pore diameter of the support. The acidity of the TFA‐functionalized mesoporous nanocages is much higher than that of the zeolites and metal‐substituted mesoporous acidic catalysts. The TFA‐functionalized materials have also been employed as the catalysts for the synthesis of 7‐hydroxy‐4‐methylcoumarin by means of the Pechmann reaction under solvent‐free conditions. It has been found that the catalytic activity of the TFA‐functionalized KIT‐5 is much higher than that of zeolites and metal‐substituted mesoporous catalytic materials in the synthesis of coumarin derivatives. The stability of the catalyst is extremely good and can be reused several times without much loss of activity in the above reaction.     

Adsorption and structural properties of channel-like and cage-like organosilicas

Channel-like and cage-like mesoporous silicas, SBA-15 (P6mm symmetry group) and SBA-16 (Im3m symmetry group), were modified by introducing single ureidopropyl surface groups, mixed ureidopropyl and mercaptopropyl surface groups, and single bis(propyl)disulfide bridging groups. These hexagonal and cubic organosilicas were prepared under acidic conditions via co-condensation of tetraethyl orthosilicate (TEOS) and proper organosilanes using poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) amphiphilic block copolymer templates, P123 (EO₂₀PO₇₀EO₂₀) and F127 (EO₁₀₆PO₇₀EO₁₀₆). The modified SBA-15 and SBA-16 materials were synthesized by varying the molar ratio of organosilane to TEOS in the initial synthesis gel. The removal of polymeric templates, P123 and F127, was performed with ethanol/hydrochloric acid solution. In the case of SBA-15 the P123 template was fully extracted, whereas this extraction process was less efficient for the removal of F127 template from the SBA-16-type organosilicas; in the latter case a small residue of F127 was retained. The adsorption and structural properties of the resulting materials were studied by nitrogen adsorption-desorption isotherms at −196^∘C (surface area, pore size distribution, pore volumes), powder X-Ray diffraction, CHNS elemental analysis and high-resolution thermogravimetry. The structural ordering, the BET specific surface area, pore volume and pore size decreased for both channel-like and cage-like mesoporous organosilicas with increasing concentration of incorporated organic groups.     

Preparation of amino-functionalized mesoporous silica thin films with highly ordered large pore structures

Highly ordered amino-functionalized mesoporous silica thin films have been directly synthesized by co-condensation of tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES) in the presence of triblock copolymer Pluronic P123 surfactant species under acidic conditions by sol-gel dip-coating. The effect of the sol aging on thin films organization is systematically studied, and the optimal sol aging time is obtained. The amino-functionalized mesoporous silica thin films exhibit a long-range ordering of 2D hexagonal (p6mm) mesostructure with a large pore size of 8.3 nm, a large Brunauer–Emmett–Teller (BET) specific surface area of 680 m² g⁻¹ and a large pore volume of 1.06 cm³ g⁻¹ following surfactant extraction as demonstrated by X-ray diffraction (XRD), Transmission electron microscope (TEM), and physical adsorption techniques. Based on BET surface area and weight loss, the surface coverage of amino-groups for the amino-functionalized mesoporous silica thin films is calculated to be 3.2 amino-groups per nm². Moreover, the functionalized thin films display improved properties for immobilization of cytochrome c in comparison with pure-silica mesoporous thin films.     

Needle-like calcium carbonate assisted self-assembly of mesostructured hollow silica nanotubes

Mesostructured hollow silica nanotubes (MHSNTs) were successfully produced via the self-assembly of C₁₆TMABr and silica species on the surface of needle-like calcium carbonate nanoparticles in an alkaline medium at room temperature. The characterization of MHSNTs by transmission electron microscopy (TEM), scanning electron microscopy (SEM), pore size distribution (PSD) and Brunauer-Emmett-Teller (BET) indicated that MHSNTs had uniform tubular hollow structures with big openings, a length of 1.5-2.0 μm, an inner diameter of 150-200 nm at the open end and 50-60 nm at the closed end, and a wall thickness of 20-30 nm, as well as a narrow PSD around 2.3 nm in the shells and a BET surface area as high as ∼975.3 m²/g. By small-angle X-ray diffraction (XRD), BET and pore structure analysis, it was found that more uniformly structured mesopores could be formed by the method of removing the double templates simultaneously through a solvent extraction process, as compared to the separate removal of the double templates by calcinating and then etching in an acidic solution, and the amount of C₁₆TMABr affected the mesoporous structures of MHSNTs greatly. The formation processes of MHSNTs were also studied with XRD and FTIR.     

Facile synthesis and characterization of copper oxalate/cobalt oxalate/manganese oxalate and copper oxide/cobalt manganese oxide/manganese oxide as new nanocomposites for efficient photocatalytic degradation of malachite green dye

Scientists seek to synthesize new catalysts with simple methods to treat water pollution from organic dyes using photocatalytic degradation technology. In this technology, when light falls on the catalyst, the produced hydroxyl free radicals convert the dye into non-toxic gases such as CO₂ and H₂O. So, in this work, copper oxalate/cobalt oxalate/manganese oxalate (Abbreviated as P₁) and copper oxide/cobalt manganese oxide/manganese oxide (Abbreviated as P₂) new nanocomposites were fabricated via precipitation of Cu²⁺/Co²⁺/Mn²⁺ solution using oxalic acid and ignition of precipitate at 550 °C for 4 hrs, respectively. Some tools, involving X-ray diffraction (XRD), UV–vis spectrophotometer, energy dispersive X-ray spectroscopy (EDX), nitrogen gas sorption analyzer, transmission electron microscope (TEM), and field emission scanning electron microscope (FE-SEM), were used for characterizing the fabricated nanocomposites. The EDX spectra confirmed that the P₁ composite consist of C (26.28 %), oxygen (46.66 %), manganese (7.27 %), cobalt (7.59 %), and copper (12.20 %). Also, the P₂ composite consist of oxygen (8.23 %), manganese (31.34 %), cobalt (27.19 %), and copper (33.24 %). A transmission electron microscope shows that the P₁ and P₂ composites consist of polyhedral and spherical shapes with an average diameter of 28.13 and 14.37 nm, respectively. The BET surface area, average pore size, and total pore volume of the P₁ composite are 29.0725 m²/g, 2.0749 nm, and 0.0302 cc/g, respectively. Besides, the BET surface area, average pore size, and total pore volume of the P₂ composite are 58.1088 m²/g, 1.6087 nm, 0.0467 cc/g, respectively. 60 mg of the synthesized nanocomposites completely decompose 60 mL of 15 mg/L of malachite green dye solution within 20 min in the presence of hydrogen peroxide and UV light. The synthesized catalysts outperformed many other catalysts published in previous studies.     

Highly ordered Ti-SBA-15: Efficient H2 adsorbent and photocatalyst for eco-toxic dye degradation

Highly ordered 2D-hexagonal mesoporous titanium silicate Ti-SBA-15 materials (space group p6mm) have been synthesized hydrothermally in acidic medium employing amphiphilic tri-block copolymer, Pluronic F127 as structure directing agent. Samples are characterized by powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, FT IR spectroscopy, UV-visible diffuse reflectance measurements, N₂ adsorption/desorption and TG-DTA analysis. XRD and TEM results suggested the presence of highly ordered mesophase with hexagonal pore arrangements. BET surface area for Ti-SBA-15 (924 m² g⁻¹) is considerably higher than the pure silica SBA-15 (611 m² g⁻¹) prepared following the same synthetic route. UV-visible and FT-IR studies suggested the incorporation of mostly tetrahedral titanium (IV) species, along with some six-coordinated sites in the silicate network. This material shows very good H₂ adsorption capacity at higher pressure and excellent catalytic activity in the photocatalytic degradation of ecologically abundant dye methylene blue.     

Rapid Synthesis of Mesoporous TiO2 for the Photoanodes in Dye Sensitized Solar Cells

Mesoporous TiO₂ microspheres with high specific surface areas were synthesized by means of a facile one‐step microwave hydrothermal process without using any template. The mesoporous materials were rapidly achieved using TiCl₄, urea and ammonium sulphate at comparatively low microwave power (400 W) for 8 min irradiation. The morphology and microstructure of the as‐prepared products were characterized by field emission scanning electron microscopy (FESEM), X‐ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer‐Emmett‐Teller (BET) surface area analysis. Structural characterization indicates that the TiO₂ microspheres display mesoporous structure. The average pore sizes and BET surface areas of the spheres were 5.3 nm and 222 m²g^?1, respectively. The mesoporous nanocrystals synthesized at 160 °C for 8 min were then used to prepare the photoanode for dye sensitized solar cells (DSSCs). A high power conversion efficiency of 5.72% was achieved from the mesoporous TiO₂ based photoanode, representing about 25.7% improvement over the efficiency of P25 photoanode.