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Microporous and mesoporous materials are used as catalyst carriers, adsorbents, and ion exchangers. In this study, mesoporous molecular sieves were prepared through the rapid reaction of Na 2 SiO 3 and H 2 SiF 6 in a water solution containing surfactants. Mesoporous silica (MS) precipitates were produced within 5 s and X-ray diffraction (XRD) analysis of the MS samples indicated the formation of mesoporous molecular sieves owing to the appearance of well-defined peaks at intervals of 3.8–5.2 nm. The specific surface area was 371 m2 g−1 when using a cationic surfactant and in the range of 959–1135 m2 g−1 in nonionic surfactants. The pore-size distribution of MS samples showed a constant value of 2.5–3.1 nm. The shape of the silica particles observed via scanning electron microscopy was spherical with a uniform size of ∼0.7 μm. Transmission electron microscopy images of the samples obtained using the nonionic surfactant showed worm-hole-shaped pores, whereas those obtained using the cationic surfactant had regular honeycomb-shaped pores. MS samples synthesized using nonionic surfactants were thermally very stable in the light of their XRD peaks being maintained at 900 °C. The intensity of Q3 and Q4 signals for the MS obtained by nonionic surfactant is double than that of cationic surfactant, proving that silicate network of MS-PL15 is lots thicker than that of MS-CTAB. MS synthesized by nonionic surfactant can be used as a catalyst support at high temperatures because they has a large specific surface area and excellent thermal stability. Schematic showing the formation of MS samples via cationic and nonionic surfactant templating. Image 1 • Mesoporous silica was formed via the rapid reaction of Na 2 SiO 3 and H 2 SiF 6. • A constant pore-size distribution of 2.5–3.1 nm was obtained. • Mesoporous silica formed using nonionic surfactants showed high thermal stability. • Well-defined XRD peaks at 3.8–5.2 nm showed the formation of mesoporous sieves. [ABSTRACT FROM AUTHOR]

Highlights: [•] Mesoporous-titanosilicate was prepared by hydrolysis of tetraethylorthosilicate. [•] Mesoporous-titanosilicate exhibited gallery height of 3.60nm, and specific surface area of 435–542m2/g. [•] CH4 conversion (>90%) and H2 yield (>90%) over Ni/SPT and Rh/SPT were higher than that (>80%) of commercial catalyst. [•] CO yield was very low due to from the formation of carbon nanotubes. [•] SPT catalyst was it an oxidation site, uniform dispersion of metal, ordered pore structure and heat stability. [Copyright &y& Elsevier]

Abstract: Carboxylated graphene–ZnO (G-COOZn) composites were grown as ZnO nanoparticles onto graphene sheets by a one-step thermal method using carboxylated graphene (G-COOH) and Zn(NO3)2. G-COOH sheets were synthesized from graphene oxide (GO) and chloroacetic acid (Cl–CH2–COOH). GO was used as the starting material, as prepared by the Hummers’ method using graphite flakes. GO, G-COOH, and G-COOZn were characterized by XRD, AFM, SEM, TEM, FT-IR, 13C-NMR, and Raman spectroscopy. The electrochemical properties of the G-COOZn supercapacitor were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge tests. The results show that the asymmetric supercapacitor has electrochemical capacitance performance within the potential range of 0–1V. The supercapacitor delivered a specific capacitance of ∼238Fg−1 at a current density of 50mAcm−2. This method provides an easy and straightforward approach to deposit ZnO nanoparticles onto graphene sheets, and may be readily extended to the preparation of other classes of hybrids based on GO sheets for specific technological applications. [Copyright &y& Elsevier]

Abstract: Titanosilicate was modified by interlayer surface silylation using octyltriethoxysilane (OTES) and dodecylamine (DDA) in ethanol without a pre-swelling step. The introduction of silyl groups into the interlayer region was confirmed by XRD, FT-IR, RAMAN, SEM, TGA, 29Si NMR and TEM. DDA acts as a gallery expander and silylation catalyst. The evaporation of ethanol from the dispersion yields well-ordered silylation. Layered titanosilicate silicate with large basal spacings between 2.95 and 3.87nm were investigated. The layered structures of the silylated products were confirmed by swelling behavior upon attachment of alkylsilyl groups. Solid-state 29Si MAS NMR of the silylated samples showed Q3 and Q4 signals as well as T2 signals. The increase in the relative intensity of Q4 for Q3 and the appearance of a T2 signal was attributed to the grafting of OTES to the interlayer surface silanol groups. This method provides a promising route for the preparation of new functional nanomaterials to bond a variety of functional groups to the interlayer surface of layered materials. [Copyright &y& Elsevier]

Abstract: Highly ordered mesoporous silica-pillared kenyaite (SPK) and magadiite (SPM) were prepared by the hydrolysis of tetraethylorthosilicate (TEOS) through the catalytic effects of dodecylamine (DDA) in the interlayer space. SPM and SPK exhibited regular gallery heights of 3.0 and 3.4nm, narrow pore size distributions of 2.5 and 3.0nm and large specific surface areas of 877 and 1029m2/g, respectively. The sharpness of the d 00 l peak for SPK was well-preserved even after heating up to 800°C in air, while the peak for SPM collapsed between 700 and 800°C. A uniform spacing of 2–3nm between the layers were obtained from the TEM images of SPM and SPK. SPK and SPM impregnated with 5wt% of Ni and Pd were examined as potential catalysts in the partial oxidation of methane at 750°C. The Ni/SPK, Ni/SPM and Pd/SPK catalysts showed higher methane conversions, which remained stable for almost 100h of heating. Especially, the Pd/SPK catalyst exhibited high selectivity and stability to H2. The results indicate that the SPK and SPM products are highly applicable as catalytic supports in high temperature reactions. [Copyright &y& Elsevier]

Abstract: H+-titanosilicate (H4Ti2Si8O22 ·4H2O), formed by proton ion exchange of layered titanosilicate JDF-L1 (Na4Ti2Si8O22 ·4H2O) produced intercalation compounds in DDA (dodecylamine)–TEOS (tetraethylorthosilicate) solution. H+-titanosilicate/DDA/TEOS intercalation compounds rapidly hydrolyzed in pure water to form siloxane-pillared H+-titanosilicates. Calcination of siloxane-pillared H+-titanosilicates for 5h at 500°C in air resulted in the formation of mesoporous silica-pillared H+-titanosilicate (SPT) derivatives. SPT derivatives exhibited refractions corresponding to a basal spacing of 4.16–4.32nm, a uniform pore size of 2.8–3.4nm, and a large surface area of 535–618m2/g. The structures and physical properties of SPT derivatives remained stable after heating for 5h at 700°C in air. These results indicate that DDA molecules have a decisive role in pore formation within SPT derivatives, because they act as a base catalyst and as a template, like surfactant micelles, during the hydrolysis of TEOS. [Copyright &y& Elsevier]