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This work reports the synthesis of mesoporous MCM-41 nanoparticles by applying microwave radiation (MWR) in the range of 400–1000 W. Silica nanoparticles were produced at short time (10 min) and low power radiation (400 W) which showed large surface area (S BET ∼1000 m2g-1) and a suitable chemical surface composition. Both, scanning and transmission electron microscopies (SEM and TEM) revealed that the mesoporous silica had a nanometric size close to 100 nm with a predominant spherical morphology. Also, it was found that the particles were smaller and agglomerated at higher microwave radiation power (>600 W) and longer heating time (>10 min). On the other hand, low microwave radiation power (400 W) was sufficient to obtain MCM-41 with high surface area (1182 m2g-1) keeping the same particle size. Under MWR synthesis, pore diameters slightly expanded up to ∼4.00 nm which are larger for those obtained by the hydrothermal method (∼2.0 nm). According to the FTIR results, the surface of the sample labeled as MCM 400W10 exhibited a number of free silanol groups (α ΟΗ) of ∼4.08 per nm2 which could improve their surface modification for being used in diverse biomedical applications including drug delivery. [ABSTRACT FROM AUTHOR]

Mesoporous silica‐based materials are used as sorbents and supports in many fields. The ordered pore architecture of MCM‐41, and the absence of interconnections, make it suitable as a model system. The surface is natively functionalized by many silanol groups, endowing the material with a polar surface to directly interact with the target species or to mount additional functional groups. Either bare or functionalized, surface silanol arrangement is crucial to material performance. In the case of CO2 capture with amine‐functionalized silica, silanol groups are responsible for fundamental H‐bonds during chemisorption, but they also modulate the effect and weight of humidity on the material performance. In addition, the silanol groups can also tune the weight of physisorption over chemisorption. The relationship between these aspects and the textural features of mesostructured silica has not been addressed in detail. In this study, computer models are employed to investigate the adsorption capacity and selectivity of bare mesostructured silica with three different pore sizes. Results are rationalized in terms of silanol surface density and pore curvature. The importance of the energetic inequivalence between Q3 and Q2 sites on the silica surface is emphasized, as this causes adsorption behavior to deviate from ideality. [ABSTRACT FROM AUTHOR]

Santa Barbara Amorphous-15 (SBA-15) is a mesoporous molecular sieve with a large surface area and is extensively applied in purification, separation, and catalytic procedures. In this study, an SBA-15 was prepared from a sodium silicate precursor, and pentaethylene hexamine was anchored to its surface. A composite named N-SBA-15 was characterized using several experimental techniques. FTIR and XPS measurements confirmed that amino groups were conjugated on the surface of SBA-15. XRD and TEM confirmed that N-SBA-15 comprised highly ordered, hexagonal mesopore structures, which were not destroyed by the addition of amino groups. After functionalization, the surface area, pore volume, and pore size of the composite were 188 m2/g, 0.303 cm3/g, and 5.0 nm, respectively. N-SBA-15 was applied in the adsorption of aromatic acids, namely tannic acid (TA), acid red 1 (AR-1), and acid blue 40 (AB-40). The influence of various adsorption conditions such as dye concentration, adsorbent dosage, solution pH, and solution temperature was investigated. For AB-40 dye, the N-SBA-15 composite exhibited 40 times higher adsorption capacity than pure SBA-15. The highest adsorption capacities of N-SBA-15 for TA, AB-40, and AR-1 were 869, 818, and 308 mg/g, respectively. Thermodynamic studies were conducted to evaluate the exothermic property of the adsorption process and spontaneous behavior. The adsorptive data fitted well with pseudo-second-order and Langmuir isotherm models. Results confirmed that amino-modified SBA-15 material is a promising adsorbent for the elimination of aromatic acids form aqueous solution.

Abstract Mesoporous silica‐based materials are used as sorbents and supports in many fields. The ordered pore architecture of MCM‐41, and the absence of interconnections, make it suitable as a model system. The surface is natively functionalized by many silanol groups, endowing the material with a polar surface to directly interact with the target species or to mount additional functional groups. Either bare or functionalized, surface silanol arrangement is crucial to material performance. In the case of CO2 capture with amine‐functionalized silica, silanol groups are responsible for fundamental H‐bonds during chemisorption, but they also modulate the effect and weight of humidity on the material performance. In addition, the silanol groups can also tune the weight of physisorption over chemisorption. The relationship between these aspects and the textural features of mesostructured silica has not been addressed in detail. In this study, computer models are employed to investigate the adsorption capacity and selectivity of bare mesostructured silica with three different pore sizes. Results are rationalized in terms of silanol surface density and pore curvature. The importance of the energetic inequivalence between Q3 and Q2 sites on the silica surface is emphasized, as this causes adsorption behavior to deviate from ideality.

Among mesoporous ordered silica‐based materials, MCM‐41 is widely employed in both experimental and computational investigations of gas adsorption. Specific surface area and pore size distribution are typically obtained by analyzing the N2 adsorption isotherm. To this aim, different models and theories are available, and which one is more accurate is under debate. On the computational side, the in silico model ought to match the characteristics of real samples and reproduce the macroscopic performance. While the typical hexagonal symmetry is usually considered, the tetragonal one is sometimes applied without any explained rationale. Interestingly, during the last decade, the preparation of mesoporous silica‐based materials with rare tetragonal symmetry is reported, indeed, but these are never tested as gas sorbents. In the present work, computer models with different symmetry are compared for their ability to reproduce the available experimental data from real samples. The combination of grand‐canonical Monte Carlo and molecular dynamics simulations is used to probe the differences at the microscopic level. The surface‐adsorbed gas molecules are differently ordered and a different type of N2 adsorption isotherm is correspondingly found. [ABSTRACT FROM AUTHOR]

We report the synthesis of a hybrid nanocatalyst obtained through the immobilization of bio-inspired [{Mn(bpy)(H2O)}(µ-2-MeC6H4COO)2(µ-O){Mn(bpy)(NO3)}]NO3 compound into functionalized, monodispersed, mesoporous silica nanoparticles. The in situ dual functionalization sol–gel strategy adopted here leads to the synthesis of raspberry-shaped silica nanoparticles of ca. 72 nm with a large open porosity with preferential localization of 1,4-pyridine within the pores and sulfobetaine zwitterion on the nanoparticles' periphery. These nano-objects exhibit improved catalase-mimicking activity in water thanks to the encapsulation/immobilization of the catalytic active complex and high colloidal stability in water, as demonstrated through the dismutation reaction of hydrogen peroxide. [ABSTRACT FROM AUTHOR]

We report the synthesis of a hybrid nanocatalyst obtained through the immobilization of bio-inspired [{Mn(bpy)(H2O)}(µ-2-MeC6H4COO)2(µ-O){Mn(bpy)(NO3)}]NO3 compound into functionalized, monodispersed, mesoporous silica nanoparticles. The in situ dual functionalization sol–gel strategy adopted here leads to the synthesis of raspberry-shaped silica nanoparticles of ca. 72 nm with a large open porosity with preferential localization of 1,4-pyridine within the pores and sulfobetaine zwitterion on the nanoparticles’ periphery. These nano-objects exhibit improved catalase-mimicking activity in water thanks to the encapsulation/immobilization of the catalytic active complex and high colloidal stability in water, as demonstrated through the dismutation reaction of hydrogen peroxide.

In recent years, health authorities have become increasingly concerned about preventing consumer exposure to opium alkaloids present in Papaver somniferum L. poppy seeds. In this study, a simple, rapid and efficient method has been optimised to determine all main opioids in poppy seeds (morphine, codeine, thebaine, papaverine, noscapine and oripavine) by UHPLC-QqQ-MS/MS. For this purpose, solid-liquid extraction (SLE) of samples was optimised and six magnetic adsorbent materials with a core of Fe3O4 coated with amorphous and mesostructured silica, both functionalised with octadecyl-silane or octyl-silane were characterised and evaluated for magnetic solid-phase extraction (MSPE). The material with the best results was non-functionalised mesostructured silica and, with it, the MSPE procedure was optimised. This method was validated and used to quantify six opioids in 14 edible seed samples (eleven poppy seeds and three seed mixes). Considerable amounts were found (1.5–249.0 mg/kg morphine, Papaver rhoeas L. seeds were declared on the product label.

The Nozaki Ir‐based CO2 hydrogenation catalyst was successfully immobilized on post‐functionalized silica beads (d=200 μm) through click chemistry. This material hydrogenates CO2 into formic acid with turnover numbers reaching 2.8×104 in a batch reactor within 24 hours, paving the way towards the design of efficient heterogeneous catalysts for this transformation. [ABSTRACT FROM AUTHOR]

Highlights • Functionalized mesostructured silica helps in developing promising sensors. • Simultaneous determination of pindolol, acebutolol and metoprolol by DPV is reported. • Factors affecting the detection of the target β-blockers were investigated. • Portable sensor for in situ simultaneous analysis of β-blockers. • God recovery values for β-blockers analysis in drinking, environmental and wastewaters. Abstract In this work, hexagonal mesoporous silica (HMS) and amino-functionalized HMS (HMS-NH 2) were prepared and incorporated into carbon paste electrodes (CPEs) to obtain electrochemical sensors for pindolol (Pin), acebutolol (Ace) and metoprolol (Met) determination in waters by voltammetric techniques. The materials were characterized and they showed high specific surface area, large pore volume and a quasi-spherical morphology. Firstly, the electrochemical behaviour of the modified CPEs was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Then, the dependence of the current intensity with the electrolyte support (type and pH) and the accumulation time was investigated to optimize the experimental conditions for simultaneous β-blockers determination by DPV. Results showed that the sensor modified with functionalized silica (NH 2 -HMS-CPE) exhibited strong adsorption activity, showing three well-defined peaks in the differential pulse voltammograms, that appeared at about +0.85 V (Pin), +1.11 V (Ace) and +1.45 V (Met). This fact can be attributed to the high surface area of the material, with a 3 D wormhole-like channel structure that favoured excellent pore accessibility, and the synergistic effect produced by the grafted amino groups producing hydrogen bond interactions with the oxygen atoms of the target β-blockers. The prepared sensor exhibits good reproducibility, wide linear ranges and very low detection limits (0.1, 0.046 and 0.23 μmol L−1 for Pin, Ace and Met, respectively). Moreover, the NH 2 -HMS-CPE was successfully applied for the simultaneous determination of Pin, Ace and Met in tap, mineral, river and sewage effluent waters with simple sample treatment (recoveries 97–112%). [ABSTRACT FROM AUTHOR]

The hydrogenation of CO2 to formic acid can be carried out by numerous homogenous catalysts, while efficient heterogeneous catalysts are rare. In this work, we successfully synthesize an immobilized lutidine‐derived pincer‐type N‐heterocyclic carbene ruthenium complex based on a mesoporous organo‐silica hybrid material using sol‐gel direct synthesis in the presence of structure directing agents and click chemistry as the two key pillars of this strategy. This material efficiently catalyzes the hydrogenation of CO2 into formate with turnover numbers reaching 18′000 within 24 hours, surpassing the performance of the corresponding homogeneous complexes. Searching for stability: A new Immobilized pincer‐type NHC Ru catalyst is successfully synthesized based on an organo‐silica hybrid material with a simple strategy. This material is characterized at molecular level, and it catalytically hydrogenates CO2 into formic acid with turnover numbers reaching 18′000 in a batch reactor within 24 hours, surpassing its homogeneous analogues (ca. 9000). [ABSTRACT FROM AUTHOR]

Santa Barbara Amorphous-15 (SBA-15) is a mesoporous molecular sieve with a large surface area and is extensively applied in purification, separation, and catalytic procedures. In this study, an SBA-15 was prepared from a sodium silicate precursor, and pentaethylene hexamine was anchored to its surface. A composite named N-SBA-15 was characterized using several experimental techniques. FTIR and XPS measurements confirmed that amino groups were conjugated on the surface of SBA-15. XRD and TEM confirmed that N-SBA-15 comprised highly ordered, hexagonal mesopore structures, which were not destroyed by the addition of amino groups. After functionalization, the surface area, pore volume, and pore size of the composite were 188 m2/g, 0.303 cm3/g, and 5.0 nm, respectively. N-SBA-15 was applied in the adsorption of aromatic acids, namely tannic acid (TA), acid red 1 (AR-1), and acid blue 40 (AB-40). The influence of various adsorption conditions such as dye concentration, adsorbent dosage, solution pH, and solution temperature was investigated. For AB-40 dye, the N-SBA-15 composite exhibited 40 times higher adsorption capacity than pure SBA-15. The highest adsorption capacities of N-SBA-15 for TA, AB-40, and AR-1 were 869, 818, and 308 mg/g, respectively. Thermodynamic studies were conducted to evaluate the exothermic property of the adsorption process and spontaneous behavior. The adsorptive data fitted well with pseudo-second-order and Langmuir isotherm models. Results confirmed that amino-modified SBA-15 material is a promising adsorbent for the elimination of aromatic acids form aqueous solution. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus, which is commonly found in hospitals, has become a major problem in infection control. In this study, Ag/80S bioactive ceramics used for enhanced antibacterial applications have been developed. An in vitro bioactivity test of the Ag/80S bioactive ceramic powders was performed in a phosphate-buffered saline (PBS). To explore the antibacterial activity of the Ag/80S bioactive ceramic powders, the Kirby-Bauer susceptibility test, the kinetics of microbial growth analysis and the colony-forming capacity assay were used to determine their minimum inhibitory concentration (MIC) against methicillin-resistant Staphylococcus aureus (MRSA). The results confirmed that the Ag/80S bioactive ceramic powders have antibacterial activity against MRSA (ATCC 33592) and MRSA (ATCC 49476).

Prosthetic joint infection (PJI) is one of the main factors that causes joint replacement surgery failure, of which hip joint infection is the most serious. Staphylococcus aureus accounts for more than 50% of the infections caused by pathogenic microorganisms. Unfortunately, antibiotics have long been used to kill bacteria, but increasingly, multiple drug resistant pathogens (MDRP), such as methicillin-resistant Staphylococcus aureus (MRSA), have appeared and are causing a significant reduction in the efficacy of traditional antibiotics. In this study, silver nanoparticles (AgNP) confined to mesostructured silica (MS-Ag) powders were prepared to evaluate their antibacterial activity against MRSA. According to the results of thermogravimetric analysis (TGA), there was no weight loss when the temperature was greater than 600 °C. This result showed that the water, alcohol, non-ionic surfactant F127 and PUF in the silicone-containing colloid were completely removed. These results indicated that the calcination temperature for total dehydration was at least 600 °C. The as-synthesized precursor samples of MS-Ag1 were calcined directly at 400 °C, 500 °C, 550 °C and 600 °C for 2 h. The specific surface area increased over the range of 400–500 °C, and the non-ionic surfactant F127 and PUF were removed over this temperature range. Further, a transition occurred from an amorphous state to a crystalline state, and the thickness of the pore wall increased with the increasing calcination temperature over the range of 500–600 °C. Thus, the specific surface area and pore volume decreased from 526.7 m 2 /g and 0.84 cm 3 /g to 384.7 m 2 /g and 0.67 cm 3 /g, respectively. The antibacterial activity of MS-Ag powders against MRSA was verified by the disk diffusion method and time-killing curves. The minimum inhibitory concentrations (MIC) of the MS-Ag powders against MRSA were between 2.5 mg/mL and 5 mg/mL. [ABSTRACT FROM AUTHOR]

Hyperpolarization by dynamic nuclear polarization relies on the microwave irradiation of paramagnetic radicals dispersed in molecular glasses to enhance the nuclear magnetic resonance ( NMR) signals of target molecules. However, magnetic or chemical interactions between the radicals and the target molecules can lead to attenuation of the NMR signal through paramagnetic quenching and/or radical decomposition. Here we describe polarizing materials incorporating nitroxide radicals within the walls of the solids to minimize interactions between the radicals and the solute. These materials can hyperpolarize pure pyruvic acid, a particularly important substrate of clinical interest, while nitroxide radicals cannot be used, even when incorporated in the pores of silica, because of reactions between pyruvic acid and the radicals. The properties of these materials can be engineered by tuning the composition of the wall by introducing organic functionalities. [ABSTRACT FROM AUTHOR]

The UV excited emission properties of mesoporous silica in the blue and UV range are modified by the adsorption and desorption of oxygen molecules at the two defect sites. To interpret the experimental purging cycles we model the oxygen-silica interaction at thermodynamic level, succeeding in explaining the interaction mechanism and the trend of UV centre to undergo photo-bleaching when excited under vacuum conditions. The analysis called for the presence of two different set of defects for both the centres, pinpointed as defects liable to interact with O 2 and non-interacting isolated defects. To support the thermodynamic analysis, we simulated the O 2 adsorption and desorption processes within the first principles DFT cluster framework. The calculated atomic configurations and the potential energy curves along selected probable reaction paths allow suggesting the kinetics of molecular oxygen interaction on examined surface silica defects and pointing at an oxygen vacancy E’-like defect as the possible result of the UV centre photo-bleaching. [ABSTRACT FROM AUTHOR]

Highly efficient polyamine-modified mesostructured silica adsorbents fabricated invoking a facile one-pot process under microwave-assisted heating show superior CO 2 uptake capacity up to 4.43 mmol g −1 comparable to polyamine-immobilized mesoporous SBA-15 silicas prepared by the conventional post-synthesis route is reported. Solid adsorbents modified with various alkanolamines were examined. The influences of type and loading of polyamines, surfactant template, textural and surface properties of the support on CO 2 uptake performance, efficiency, and recyclability of the adsorbents were explored by adsorption/desorption kinetics as well as various solid-state 1D multinucleus and 2D heteronucleus correlation spectroscopy techniques. The results so obtained afford detailed information regarding to the interactions among the guest amines, surfactant template, silica surfaces, and adsorbed CO 2 , which are helpful for verification of adsorption structures and assessment of adsorption performances to render future design and fabrication of amine-based solid adsorbents for efficient and prospective applications in CO 2 capture. [ABSTRACT FROM AUTHOR]

[Display omitted] • CO 2 capture and methanation were carried out employing materials from rice husks. • CO 2 capture was carried out at high temperature using lithium silicate as sorbent. • CO 2 conversion to CH 4 was performed employing Ni5/MCF as catalyst. • A single reactor with two beds in series proved to be a promising option. The CO 2 capture was carried out at high temperature using lithium silicate as sorbent and its subsequent conversion to CH 4 was performed employing Ni5/MCF as catalyst. Different operating variables such as temperature, time and H 2 concentration were studied to maximize the performance of both the sorbent and the catalyst in the coupled processes. Three different configurations were adopted and implemented for the disposition of the sorbent and catalyst. The gases from the capture and regeneration stage were quantified by chromatography with an FID detector and mass spectrometry. The characterization of the used materials by XRD was carried out to verify their stability under operating conditions. The arrangement that consisted of a single reactor with two beds in series proved to be a promising option since it allowed achieving a high production of CH 4 (0.76 mol CH4 kgcat−1). [ABSTRACT FROM AUTHOR]

Amplified spontaneous emission (ASE) in dye‐doped mesostructured silica films, deposited directly over fused silica substrates, is demonstrated with low thresholds. Due to functionalization of the silica network with phenyl groups, the refractive index of the active layer is sufficiently increased to impart waveguiding properties that lead to highly efficient ASE. Such functionalization eliminates the need for a separate low‐refractive‐index layer between the active film and the substrate, as is often used to achieve waveguiding properties with silica mesostructured materials, though which is typically accompanied by significant optical losses that reduce overall ASE performance. By forming a high‐quality waveguide without the need for a separate low‐refractive‐index layer, significantly improved properties are obtained, with ASE thresholds as low as 8 kW cm−2. Solid‐state 2D NMR spectroscopy measurements establish the compositions and structures of the active mesostructured film at a molecular level, in particular that phenyl functionalization of the mesochannel surfaces promotes the homogeneous dispersion of the laser dye species over nanoscale dimensions in the materials. [ABSTRACT FROM AUTHOR]

Abstractt In this work, mesostructured silica nanoparticles (MSN) were modified by the pore expander 3-aminopropyl triethoxysilane (APTES) via the sol–gel method before impregnation with a colloidal α-FeOOH-ionic surfactant (IS-FeOOH) to produce IS-FeOOH/MSN APTES . Its properties were characterized using X-ray diffraction, Fourier-transform infrared and surface area analysis, and compared with pristine MSN, MSN APTES and IS-FeOOH/MSNs. The results suggest that IS-FeOOH was located on the outer surface of MSN but in the pores when loaded onto MSN APTES , while retaining its colloidal structure on both supports. It was found that the photoactivity of the catalysts toward photo-Fenton-like degradation of 2-chlorophenol (2-CP) under visible light irradiation was in the following order: IS-FeOOH/MSN (92.2%) > IS-FeOOH/MSN APTES (77.6%) > MSN APTES (38.7%) > MSN (17.5%). The results indicate that the presence of colloidal IS-FeOOH on the outer surface of MSN plays important role in enhancing photoactivity. Photokinetic analysis also supported this result by showing that the surface and bulk reaction was the rate-limiting step for IS-FeOOH/MSN and IS-FeOOH/MSN APTES , respectively. The operating conditions of 2-CP degradation over IS-FeOOH/MSN were further optimized using response surface methodology. The optimum conditions were found to be 9.09 wt% of IS-FeOOH loading with 0.14 mM H 2 O 2 at pH 5.11 and 49.9 °C to give 99.9% of the predicted value of photodegradation. [ABSTRACT FROM AUTHOR]

A pore expanded MCM-41 mesostructured silica (PE-MCM-41) was modified by double-functionalization with molecules containing amino groups in order to obtain CO 2 adsorbents for industrial post-combustion applications. PE-MCM-41 was modified by grafting with aminopropyl (AP), ethylenediamino (ED) and diethylenetriamino (DT) organosilanes, by impregnation with polyethyleneimine (PEI), pentaethylenehexamine (PEHA) and tetraethylenepentamine (TEPA), and by double functionalization, impregnating PEI, PEHA and TEPA over samples previously grafted with AP and DT. CO 2 adsorption properties of these materials were found to depend on the kind, amount and viscosity of the organic compound loaded. Grafted samples showed amine efficiencies in CO 2 capture up to 0.38 mol CO 2 /mol N, leading to CO 2 uptakes ranging from 38.2 to 76.9 mg CO 2 /g ads (pure CO 2 , 45 °C, 1 bar). Impregnation yielded adsorbents with higher organic content but lower efficiency (between 0.20 and 0.25 mol CO 2 /mol N), and with a net CO 2 adsorption capacity up to 96.9 mg CO 2 /g ads. By using the double-functionalization technique, the nitrogen content was increased while maintaining high amine efficiency (0.37 mol CO 2 /mol N) and consequently exhibiting higher CO 2 adsorption capacity, up to 104 mg CO 2 /g ads. Thus, this functionalization route was proven successful. However, at high organic loading a sharp drop in the amine efficiency was observed, being ascribed to the blocking of the MCM-41 pores by amines. [ABSTRACT FROM AUTHOR]

Isolated and purified organosolv eucalyptus wood lignin was depolymerized at different temperatures with and without mesostructured silica catalysts ( i.e. , SBA-15, MCM-41, ZrO 2 -SBA-15 and ZrO 2 -MCM-41). It was found that at 300 °C for 1 h with a solid/liquid ratio of 0.0175/1 (w/v), the SBA-15 catalyst with high acidity gave the highest syringol yield of 23.0% in a methanol/water mixture (50/50, wt/wt). Doping with ZrO 2 over these catalysts did not increase syringol yield, but increased the total amount of solid residue. Gas chromatography–mass spectrometry (GC–MS) also identified other main phenolic compounds such as 1-(4-hydroxy-3,5-dimethoxyphenyl)-ethanone, 1,2-benzenediol, and 4-hydroxy-3,5-dimethoxy-benzaldehyde. Analysis of the lignin residues with Fourier transform-infrared spectroscopy (FT-IR) indicated decreases in the absorption bands intensities of OH group, C O stretching of syringyl ring and aromatic C H deformation of syringol unit, and an increase in band intensities associated with the guaiacyl ring, confirming the type of products formed. [ABSTRACT FROM AUTHOR]

Mesostructured cellular foam (MCF) silica spheres with different textual parameters were synthesized using a triblock copolymer as a template. The effects of acid concentration and aging time on the window size and morphology were discussed. Besides, the adsorption performances of lysozyme and bovine serum albumin on the blank MCF with different window size and aminopropyl-modified MCFs were studied. The adsorption capacity and rates were shown to be dependent on the window size and surface chemical properties of the adsorbents. In particular, the MCF with window size of 15.2 nm showed fast adsorption for lysozyme with an adsorption capacity of 500 mg/g in 10 min. Furthermore, it has been shown that MCF spheres are potential materials in the separation of biomolecules because of their chemical tunable surface and molecular sieve properties. [ABSTRACT FROM AUTHOR]

Highlights: [•] The molybdenum complex anchored to SBA-15 by covalent binding through the ligand. [•] High-efficiency catalyst for the selective oxidation of olefins. [•] The catalyst exhibited remarkable recyclability for five consecutive cycles. [ABSTRACT FROM AUTHOR]

Abstract: Colloidal gold nanoparticles were synthesized by different procedures affording suspensions with two different mean sizes (2 and 5nm). Au catalysts were prepared by sol immobilization onto several silica frameworks with different 2D and 3D mesoporosities. The catalysts were tested in styrene oxidation reactions showing excellent efficiency and selectivity. The effect of nanoparticle size and mesoporous framework on the physical and catalytic properties of the final materials was studied. The most selective catalyst was prepared from the 5nm Au nanoparticles and the more interconnected silica framework (3D mesoporosity). [Copyright &y& Elsevier]

Abstract: Glycerol was converted to liquid fuels through a one-pot process catalyzed by mesostructured Ir–Re–W/SiO2. The reaction was performed over 0.4g of catalyst suspended in an aqueous solution of glycerol (4.72mmol/ml) at 553K under a hydrogen pressure of 6.0MPa for 50h. A hydrocarbon-enriched organic phase was self-separated from the aqueous solution after the reaction. The total yield of oil products was greater than 40%, and the selectivity toward hydrocarbons was approximately 90%. The conversion proceeds through a complicated mechanism that involves a Cg reaction and hydrodeoxygenation. Doped tungsten oxide species in a silica matrix are active acidic sites for acid-catalyzed dehydration. Supported iridium species are catalytic active sites for hydrodeoxygenation and Cg reactions. The evolution of their chemical states during the catalytic process was detected by X-ray photoelectron spectroscopy. Rhenium species are important co-catalysts for iridium species. These active catalytic species work together to achieve the direct conversion of glycerol in aqueous solution to liquid fuels under a hydrogen atmosphere. [Copyright &y& Elsevier]

Abstract: Highly dispersed mesostructured cellular foam silica spheres of relatively uniform micrometer size (3.5–4.5μm) were successfully prepared using a triblock copolymer EO20PO70EO20 as the structure-directing agent accompanied by TMB and K2SO4. Both two additives have effective influence and K2SO4 have better performance than other inorganic salts such as KCl and NaCl. The pore size and surface area were tuned by TMB and NH4F. The resultant S-MCFs were modified with C18 group before being used as the HPLC stationary phase for effective separation of aromatic compounds and phthalic acid esters. The perfect spherical morphology and large pore volume gave rise to low and stable back pressure. High surface area, ultralarge pore size and unique pore structure would permit high flow rates and afford the possibility for fast separation. [Copyright &y& Elsevier]

Abstract: The distribution of amino groups on amino-functionalized SBA-15 materials for CO2 adsorption was studied by transmission electron microscopy (TEM) in combination with a staining technique using RuO4 in order to analyze the influence of the aminated organic chains location on the CO2 adsorption properties. Mesostructured amino-functionalized SBA-15 materials were obtained by co-condensation, grafting and impregnation using aminopropyl, AP(N), ethylene-diaminepropyl, ED(NN), diethylene-triaminepropyl, DT(NNN) and polyethyleneimine, PEI, as functionalizing agents. CO2 adsorption isotherms of functionalized samples at 45°C showed that both the adsorption capacity (mgCO2/g ads) and the efficiency of amino groups (mol CO2/mol N) depend on the functionalization technique and the amount of organic compound used. While samples synthesized by co-condensation showed negligible CO2 uptake and efficiency, adsorbents prepared by grafting and impregnation presented significant CO2 adsorption capacities but a dissimilar efficiency. Key differences in the location of aminated chains explained the performance of CO2 capture for every adsorbent, being grafted samples the adsorbents where amino groups were better distributed, favouring CO2 diffusion trough the whole structure. [Copyright &y& Elsevier]

Abstract: We report here on the first one-pot synthesis of mesoporous silica SBA-16 containing aluminum. This material was successfully synthesised using poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) Pluronic F-127 (PEO106PPO70PEO106) as structure directing agent, butanol as co-surfactant and specifically adjusting the pH during the synthesis (i.e. adopting the so called “pH-adjusting method”). The structural and porosity properties of the novel [Al]-SBA-16 were studied by X-ray diffraction, 27Al-MAS–NMR and N2 adsorption at 77K. The acidity was monitored by infrared spectroscopy of CO adsorption at 100K. [Copyright &y& Elsevier]

Abstract: The oxidation of naphthalene by immobilized laccase from Trametes versicolor has been performed using diverse immobilization strategies on mesostructured silica materials. Laccase was immobilized by physical adsorption on several SBA-15 with different textural properties and by covalent attachment on functionalized SBA-15 prepared by co-condensation method (direct synthesis). The adsorption of laccase was partially reversible and showed some degree of lixiviation. However, covalently attached laccase to aminopropyl and aminobutyl functionalized SBA-15 exhibited important activity for the degradation of naphthalene with, respectively, 35% and 39%wt of removal in 5h. The aminopropyl biocatalyst retained higher activity after repeated uses than the corresponding aminobutyl. [ABSTRACT FROM AUTHOR]

Abstract: The regeneration of thiol-functionalized SBA-15 adsorbents of mercury is presented in this article. The influence of temperature and pH on the adsorption process was studied. The effect due to the presence of complexing agents in aqueous solution on the desorption step was also evaluated. Hg(II) maximum adsorption capacities at different temperatures ranging from 20°C to 60°C were obtained and it was found that temperature does not affect the adsorption process. Mercury adsorption capacity was also determined in the presence of HNO3 and HCl up to 3M concentration. The comparison of the results showed that whereas hydrochloric acid exhibits an appreciable capacity to regenerate the thiol-functionalized SBA-15 adsorbent, the nitric acid results inefficient. The difference was attributed to the mercury complexing ability of chloride anion. Four complexing compounds, KBr, KSCN, (NH2)2CS, and HBr were tested for desorbing mercury in regeneration experiments. All agents were able to remove significant amounts of adsorbed mercury, being hydrobromic acid the complexing compound that yields the best results. [Copyright &y& Elsevier]

Abstract: Different iron-containing catalysts have been tested for the oxidation of phenol aqueous solutions in a catalytic fixed bed reactor in the presence of hydrogen peroxide. All the catalysts consist of iron oxide, mainly crystalline hematite particles, over different silica supports (mesostructured SBA-15 silica and non-ordered mesoporous silica). The immobilization of iron species over different silica supports was addressed by direct incorporation of metal during the synthesis or post-synthesis impregnation. The synthesis conditions were tuned up to yield agglomerated catalysts with iron loadings between 10 and 15wt.%. The influence of the preparation method and the type of silica support was evaluated in a catalytic fixed bed reactor for the continuous oxidation of phenol in terms of catalysts activity (phenol and total organic carbon degradation) as well as their stability (catalyst deactivation by iron leaching). Those catalysts prepared by direct synthesis, either in presence of a structure-directing agent (Fe2O3/SBA-15(DS)) or in absence (Fe2O3/SiO2(DS)), achieved high catalytic performances (TOC reduction of 65% and 52%, respectively) with remarkable low iron leaching in comparison with their silica-based iron counterparts prepared by impregnation. Catalytic results have demonstrated that the synthesis method plays a crucial role in the dispersion and stability of active species and hence resulting in superior catalytic performances. [Copyright &y& Elsevier]

Abstract: A study on the phase behavior and structure of the alkanolamine salts of the dimeric amphiphile 3,4-bis-dodecyloxycarbonyl-hexanedioic acid (GS-H) is presented for the first time. Data are compared to those of the corresponding monomeric surfactant (lauric acid, LA). The alkanolamine salts of GS-H show very low Krafft points (<0°C) and form hexagonal liquid crystals at concentrations lower than its monomeric counterpart, indicating that aggregation is favored for dimeric surfactants. The minimum concentration for liquid crystal formation increases for bulky alkanolamines with a structure-disrupting effect, such as triethanolamine (TEA). However, the specific surface areas per molecule in the liquid crystals derived from small-angle X-ray scattering (SAXS) are similar for monoethanolamine (MEA) and TEA salts; the same can be said when comparing monomeric (LA) and dimeric (GS-H) salts. GS-H can also form hexagonal and lamellar liquid crystals with organic aminosilanes acting as reactive counterions, as revealed by solvent penetration experiments with polarized optical microscopy (POM). Consequently, mineralization with silica and alumina was carried out by a sol–gel method using GS-H as a possible structure-directing agent. Both silica and alumina samples possessed a lamellar structure, which disappears on calcination; however, calcined alumina has indeed a high surface area coming mainly from micropores. It was found that the surfactant/aminosilane ratio is critical for obtaining structured silica before calcination. [Copyright &y& Elsevier]

Abstract: A drug delivery system using mesostructured silica as a reservoir has been developed for the storage and controlled release of a drug with a cell-penetrating peptide (CPP) as a vector. We use fluorescein isothiocyanate (FITC) as the drug model and octaarginine (R8) as a vector to endow the drug with cell-penetrating property. The mesostructured silica reservoir system was prepared by using a one-pot liquid–crystal templating method, which is suitable for the encapsulation of intact FITC-R8 conjugates and sustained release of drugs without hampering their properties. The hydrophobic poly(propyl oxide) (PPO) shell of the pore-filling Pluronic F127 and the electrostatic interaction between R8 and siloxide ions on the pore walls act as the diffusion-limiting factors of the FITC-R8 conjugate. A sigmoidal in vitro release of FITC-R8 from mesostructured silica into phosphate buffered saline (PBS, pH 7.4) was observed and the typical release duration was 5days at 37°C. Release from the reservoir yielded significant elongation in duration of the FITC signals in DU145 cells by confocal microscopic analysis, compared with a single administration of FITC-R8. [Copyright &y& Elsevier]

Abstract: A combination of laser-based top-down and chemical bottom-up processes to prepare hierarchical (pore) structures is presented. Polymer templates with dimensions in the micrometer regime are fabricated by two-photon polymerization of an acrylate monomer and are subsequently infiltrated with mesostructured silica using the liquid crystal templating approach. Calcination, which removes both the macro-templating polymer and the nano-templating surfactant molecules, can be carried out so that the morphology of the sample is preserved, delivering SBA-15-type mesoporous constructs which correspond to a replica (or an inverse copy) of the initial polymer structure. This is shown here on simple line structures and on woodpile structures as examples. As the two-photon polymerization allows the controlled construction of various imaginable shapes, mesoporous materials can be constructed with practically any desired morphology on the micrometer scale. The dual pore system of macro- and mesopores classifies these materials as hierarchical pore systems with applications in catalysis and sorption. In addition, the versatility of silica surface chemistry opens new venues for the fabrication of photonic crystals and the general biocompatibility of silica allows the construction of scaffolds for biomedical applications. [Copyright &y& Elsevier]

Abstract: We have investigated the effect of methanol addition on the RF 8(EO)9 and RF 7(EO)8 surfactant-based systems. While upon the addition of methanol the L1 micellar phase grows, the direct hexagonal (H1) and the lamellar (L α ) liquid crystals progressively melt with the increase of alcohol content. Phase behavior and SAXS measurements proved that methanol molecules interact with the oxyethylene units of the surfactant. This involves a folding up of the hydrophobic chains in the liquid crystal phases. Moreover, for the RF 7(EO)8 surfactant, the cloud point curve is shifted to high temperatures upon addition of alcohol. Starting from these systems, we have prepared mesoporous materials. Results show that due to the hydrogen bonds between the alcohol and the EO groups, the hexagonal structure of the mesostructured silica obtained from RF 8(EO)9 is lost when the content of CH3OH is increased. In contrast, for the compounds prepared from the RF 7(EO)8-based system, the pore ordering occurs in the presence of alcohol. This phenomenon has been related to the moving of the cloud point curve toward high temperatures with the addition of methanol. Our study reveals also that under our conditions the methanol released during the hydrolysis of the silica precursor does not affect the self-assembly mechanism in a positive or negative way. [Copyright &y& Elsevier]

Abstract: Mesoporous forms of silica with wormhole framework structures prepared from tetraethylorthosilicate (denoted MSU-J-TEOS) or from sodium silicate (denoted MSU-J-SS) and an amine surfactant as the structure-directing porogen are highly effective reinforcing and toughening agents for rubbery and glassy epoxy polymers. The improvements in tensile strength and modulus provided by MSU-J silicas with a large average framework pore size (e.g., 5.9 and 21.3nm) are superior to those provided by the corresponding silicas made from the same TEOS or SS precursors but with smaller framework pore sizes (e.g., 4.2 and 5.2nm). The improved performance of the larger pore structures is realized even though the surface areas (∼670m2/g) are substantially lower than the surface areas of the smaller pore analogs (812–1025m2/g), most likely, because of more efficient polymer impregnation of the particle mesopores. In comparison to the MSU-J-TEOS silica assembled from TEOS, MSU-J-SS silica made from SS exhibits a more uniform pore distribution and smaller particles. These latter textural features lead to improved tensile strength and modulus without compromising the strain-at-break for both rubbery and glassy epoxy polymers. The exceptional strength and toughness provided by MSU-J-SS silica in comparison to MSU-J-TEOS silica are correlated with the high degree of dispersion of the mesophase particles in the epoxy matrix for the more effective distribution of stress and the deflection of microcracks. [Copyright &y& Elsevier]

Carbon nanotubes (CNT5)/mesostructured silica core-shell nanowires with a carbon nanotube core and controllable highly ordered periodic mesoporous silica shell are syntheiszed via the interfacial surfactant template. The core-shell nanowires are characterized by transmission electron microscope (TEM), X-ray diffraction pattern (XRD) and nitrogen sorption/desorption. The results indicate that the core-shell nanowires have highly ordered periodic mesoporous silica shell (space group p6mm), high BET surface area and narrow pore size distribution. Moreover, the morphology of core-shell nanowires can be controlled by the pH value. The core-shell nanowires have promising applications in biosensors, nanoprobes and energy storage due to their good dispersibility in polar solvents. [ABSTRACT FROM AUTHOR]

Abstract: Mesoporous SBA-15 silica materials have been functionalized with perfluorosulfonic acidic Nafion resin using a post-synthetic impregnation method. The remarkable physicochemical properties of hexagonally ordered SBA-15 silicas (high surface area, large and narrow pore size distribution and thermal stability) make them particularly attractive for the immobilization of strongly acidic perfluorosulfonic sites. The loading of Nafion resin was varied between 10wt.% and 20wt.%. The synthesized Nafion/SBA-15 hybrid materials were evaluated in the Friedel-Crafts acylation of anisole. The optimum catalytic performance of Nafion/SBA-15 hybrid material with a resin loading around 13wt.% was compared with other perfluorosulfonic acid-based catalysts either commercially available or prepared following recipes reported in the literature. The influence of several variables on the acylation of anisole, such as the reaction temperature and the anisole/acylating agent ratio, has also been assessed by means of a factorial design of experiments. The catalytic activity of Nafion-modified SBA-15 materials is strongly affected by the reaction temperature, whereas a lesser effect was evidenced for the reaction mixture composition in the range under study. The optimal operation conditions in terms of anisole conversion were achieved at 150°C and equimolar anisole/acetic anhydride mixture. The deposition of poly-acetylated by-products on the catalytic acid sites is mainly responsible for the catalyst deactivation, whereas the leaching of sulfonic groups and their contribution in the anisole acylation via homogeneous catalysis has been ruled out. Finally, the recovery of the catalytic activity by regeneration of the spent catalyst by refluxing in nitric acid solution was demonstrated. The characterization of the regenerated catalyst indicates that the regained activity is likely related to the displacement of the deactivating by-products out of the perflurorosulfonic acid sites during the nitric acid regeneration. [Copyright &y& Elsevier]

Abstract: A novel SBA-16-related synthesis of mesostructured silica containing framework aluminum is reported here. This material was successfully synthesized using aluminum sulphate and the pH-adjusting method. The structural and porosity properties of this novel material were studied by X-ray diffraction and N2 adsorption at 77K. The Al insertion was determined by 27Al-MAS-NMR and the acidity was monitored by infrared spectroscopy of CO adsorption at 100K. [Copyright &y& Elsevier]

Abstract: Local differences in surface hydrophilicities/hydrophobicities of propyl- and arene-sulfonic-acid modified mesoporous silica and organosilica catalysts have been compared and correlated with their bulk catalytic properties for aqueous-sensitive organic reactions. Syntheses of propyl- and arene-SO3H-modified mesoporous silicas and organosilicas yield materials with different hydrophilicities, especially when ethylsiloxane moieties are incorporated into the silica frameworks. Solid-state two-dimensional (2D) 13C{1H} and 29Si{1H} heteronuclear correlation (HETCOR) NMR spectra prove that the incorporation of hydrophobic ethylsiloxane groups into functionalized mesoporous silica frameworks result in reduced interactions of adsorbed water with the silica framework in general and, importantly, in the immediate vicinities of the SO3H active sites. The hydrophilic/hydrophobic character of the surface, as well as the active site properties depend on the functional species attached. Propyl-sulfonic acid moieties are less acidic but more hydrophobic than arene-SO3H species, leading to superior overall activities for water-mediated acid-catalyzed organic reactions. The etherification of vanillyl alcohol (4-hydroxy-3-methoxybenzylalcohol) with 1-hexanol to yield 4-hydroxy-3-methoxybenzyl-1-hexyl ether is shown to proceed significantly more effectively on SO3H-modified mesoporous organosilicas, compared to wholly siliceous mesoporous supports. The correlation of macroscopic adsorption and reaction results with 2D NMR measurements allows the hydrophilic/hydrophobic surface properties of the mesoporous support to be optimized with respect to water-retention capacities and activities for water-sensitive organic reactions. [Copyright &y& Elsevier]

Abstract: Using diethyl ether as a co-solvent, a non-stable interface of biphasic oil–water system (the so-called oil–water two-phase (OWTP) system) was employed in the preparation of mesostructured silicas with diversified particle morphologies. By adjusting the molar ratios of H2O:C2H5OC2H5:NH3 ·H2O and the alkalinity of the OWTP system, several product morphologies could be obtained under different reaction conditions. On the other hand, different product morphologies with distinct structural properties could be obtained at a specific reaction condition, indicating that product morphology varied upon intrinsic characteristics of non-equilibrium processes in the system as well. There are six kinds of product morphologies in our results. In the biphasic region the morphotypes such as vesicles, slices, and spheres were widely distributed. Multi-lamellar fragments were formed under relatively strong alkaline conditions and at a high proportion of diethyl ether (>41%). bi-continuously phased fragments were observed in the weak alkaline conditions and medium proportion between diethyl ether and water. In the single-phase region, hexagonally ordered MCM-41, plain sheets of MCM-48, as well as smooth and plain slices with worm-like pore structures were formed with bi-modal pore-size distribution structure. Based on HRTEM analysis, these structural features were rationalized being derived from fragments that originated from the oil/water interface. Apparently, the product morphosynthesis resulted from a combination of fluid rheological distortions and reconstructive reaction fields. With a systematic approach we have established the reaction phase diagram of the system, which enabled us to define the structural properties and to classify the morphology of the products for nomenclatural purposes in studying OWTP systems. [Copyright &y& Elsevier]

Abstract: In this study doped-silicon polymers were synthesized using the non-ionic surfactant Tween 80 as template. The obtained material was compared with silicates doped with the cationic surfactant CTAB. Both materials were synthesized by sol–gel process with tetraethoxysilane (TEOS) as silicon source. In the synthesis procedure reported herein the main difference to previous reports is that the obtained solids were dried smoothly at 55°C avoiding surfactant calcination. The aim of this work is to obtain new biomaterials appropriate to be used for encapsulation devices in which the surfactant kept within the silica network has two roles: (1) to improve the mechanical resistance in drying–swelling processes preventing crack formation, (2) to hold and protect the encapsulated molecules keeping intact their bioactivity during TEOS polymerization. Structural features such as pore size and surface topology were studied by means of N2 adsorption, X-ray diffraction and AFM microscopy. The influence of surfactant net charge and molecular shape on the materials obtained is discussed. [Copyright &y& Elsevier]

Abstract: A series of well-ordered mesoporous silicas SBA-15 was prepared under various experimental conditions and characterized by N2 physisorption, small-angle X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effect of the synthesis conditions on the textural and structural properties of SBA-15 materials was studied using a statistical model built from a full 23 factorial design at two levels. The variables chosen were temperature of the reaction of gel formation (synthesis stage), as well as temperature and time of the following hydrothermal treatment of the formed gel (aging stage). Within the experimental conditions, the response equations for surface area, micropore area, total pore volume, mesopore diameter, unit-cell parameter and pore wall thickness show good agreement with the experimental data. The statistical analysis showed that both, synthesis and aging temperatures had a significant influence on the textural and structural properties of SBA-15 materials. Their increase affected in a positive way the BET surface area, total pore volume, pore diameter and unit-cell parameter, producing simultaneously a decrease of micropore area and pore wall thickness. The effect of the gel aging time on the responses studied was not so strong with the exception of micropore area, which continued decreasing with the increase of aging time. Textural and structural differences induced by change in the synthesis conditions are discussed in terms of the mechanism of SBA-15 formation in presence of Pluronic P123. [Copyright &y& Elsevier]

Abstract: An effective method for dispersing NiO onto ordered mesoporous silica, SBA-15, is described. The procedure involves the use of polyethylene oxide (PEO) as an encapsulating agent. It can be expected that encapsulation between PEO and Ni2+ ions mainly involves complexes between PEO and Ni2+ ions. Both N2 adsorption/desorption isotherm and TEM analyses indicate that a 2-dimensionally hexagonal pore structure with a distinct pore symmetry (space group P6mm) is maintained throughout the procedure, even though both Ni2+ ions and PEO are present in the middle of the self-assembly of mesostructured silica. The particle size of the NiO increases slightly as a function of PEO concentration. When the ratio of PEO to the templating agent (triblock copolymer, polyethylene oxide–polypropylene oxide–polyethylene oxide) reaches a value of 4.5, ordered mesoporous silica with NiO is hardly formed. [Copyright &y& Elsevier]

Abstract: The Cs-salt of heteropolyacid with stoichiometry Cs2.5H0.5PW12O40 (CsHPW) was deposited selectively at the external surface of the SBA-15 silica microcrystals, inside its mesoporous channels and simultaneously at both location modes. The structure, texture and performance of these CsHPW/SBA-15 composites were compared with that of a reference bulk salt of the same composition. Location of CsHPW salt on the external surface of SBA-15 microcrystals leads to disintegration of its agglomerates increasing acidity of the catalytic phase. A novel preparation strategy consisting of grafting the basic Cs-species at the internal pores surface of SBA-15 stabilized the CsHPW phase inside the channels in form of 5–8nm nanocrystals at 30–70wt.% loadings. The catalytic tests demonstrated that insertion of the CsHPW catalytic phase inside the nanotubular channels of SBA-15 in combination with location of an additional amount of this phase at the external surface of SBA-15 microcrystals allows to increase the specific activity of this phase in MTBE synthesis, propionylation of anisole and alkylation of catechol with t-butanol by a factor of 1.5–3. This level of specific activity in combination with high total loading of catalytic phase >60wt.% permit to get composite catalytic materials with catalytic activity higher by a factor of 1.2–1.5 with respect to the bulk CsHPW catalyst and stabilizing the catalytic phase against colloidization in polar media. [Copyright &y& Elsevier]

Abstract: The assembling mode of transition metal oxides and metallic guest phases (GP) embedded in nanotubular pores of ordered mesostructured silicas (OMS) hosts was evaluated based on N2 adsorption–desorption data. The corresponding isotherms were measured for sample sets of composite materials MoO3/Al-MCM-41, WO3/SBA-15, TiO2/SBA-15, ZrO2/SBA-15, NiO/SBA-15 and Ni°/SBA-15 with GP loadings in the range of 20–80wt%. The materials were also characterized by XRD, HRTEM and local/total EDS. It was shown that a combination of composite surface area values normalized per gram of OMS with pore size distribution (PSD) derived from the adsorption or desorption branch of the isotherm distinguishes the ensemble of small nanoparticles with a size of less than an OMS mesopore diameter and single nanoparticles of a size comparable with OMS mesopore diameter. It also discerns amorphous layer at the surface of OMS pore walls from the ensemble of amorphous nanoparticles. At high GP loadings the PSD derived from the adsorption branch of the N2-adsorption isotherm more reliably reflects the filling of OMS mesopores with crystalline or amorphous guest nanoparticles. [Copyright &y& Elsevier]

Abstract: TiO2 (30–80wt.%) and ZrO2 (48–75wt.%) were inserted inside the pores of SBA-15 mesostructured silica host by chemical solution decomposition (CSD) or internal hydrolysis (IH) of the corresponding alkoxides. Both methods yielded composites with 85–94% TiO2 crystallinity (anatase). In case of ZrO2, CSD yielded >95% crystallinity (tetragonal phase), while IH gave an amorphous ZrOx-phase that does not crystallize up to 1073K. The guest Ti(Zr)-oxide phases did not block the SBA-15 pores, and their surface was fully accessible for nitrogen adsorption. Calcination in air of TiO2/SBA-15 and ZrO2/SBA-15 (CSD) composites up to 1073K did not change the nanocrystals structure and slightly increased the domain size derived from XRD data from 5.0–8.5 to 6–10nm for TiO2 (IH and CSD) and from 4.5 to 6.5nm for ZrO2 (CSD). After the same treatment the crystals domain size of bulk reference TiO2 increased to >100nm with full conversion to rutile polymorph and of reference bulk ZrO2––to 20–25nm with partial conversion to monoclinic modification. Thorough characterization of the texture, structure, location and dispersion by HRTEM, SAXS, EDS, SEM, XRD, N2-adsorption methods allowed evaluation of the assembling mode of TiO2 and ZrO2 inside SBA-15 nanotubes: amorphous layer, ensemble of small 4–5nm crystals (TiO2-IH and ZrO2-CSD) or single large 8.5nm crystals (TiO2-CSD). [Copyright &y& Elsevier]

Abstract: Heteropoly acid of Keggin structure tungstovanadogermanic (H5GeW11VO40) has been chemically anchored to the modified SBA-15 surface. The material was characterized by solid-state 29Si MAS NMR, FT-IR spectroscopy, XRD, TG-DTA and N2 adsorption experiments. The preservation of the structure of the HPA and dispersion of the cluster on the support were verified. On the bases of the spectroscopic evidences, HPA clusters were attached firmly to the surface. [Copyright &y& Elsevier]