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Highlights: [•] Sol–gel synthesis of hierarchically porous Ni/C composite monolith is studied. [•] Poly(acrylic acid) induces the phase separation and also acts as the network former. [•] Effects of starting compositions on the morphologies are investigated. [•] Carbothermal reduction by the heat-treatment in Ar produces Ni/C composite. [•] The Ni/C material possesses hierarchical pores and high specific surface areas. [Copyright &y& Elsevier]

Monolithic aluminum phosphate (AlPO4) with a macro–mesoporous structure has been successfully prepared via the sol–gel process accompanied by phase separation in the presence of poly(ethylene oxide) (PEO). Gelation of the system has been mediated by propylene oxide (PO), while PEO induces a phase separation. The dried gel is amorphous, whereas the crystalline tridymite phase precipitates upon heating above 1000 °C. Heat treatment does not spoil the macroporous morphology of the AlPO4 monoliths. Nitrogen adsorption–desorption measurements revealed that the skeletons of the dried gels possess a mesostructure with a median pore size of about 30 nm and a surface area as high as 120 m2 g−1. Hydrothermal treatment before heat treatment can increase the surface area to 282 m2 g−1. [ABSTRACT FROM AUTHOR]

Abstract: Using macroporous alumina as an aluminum source as well as structural support, high- and low-silica zeolites with trimodal pores have been fabricated in a monolithic form. Trimodally porous zeolites are obtained by the hydrothermal treatment of a monolithic alumina support impregnated with a mixture of AEROSIL 200, H2O, and sodium hydroxide or tetrapropylammonium hydroxide. The results of XRD measurement and 27Al NMR analysis reveal the formation of zeolites and the incorporation of Al into zeolite frameworks in tetrahedrally-coordinated environment. Low-silica zeolites, such as PHI- and ANA-type zeolites are formed when sodium hydroxide is utilized as a base and a structure directing agent (SDA). On the other hand, MFI-type zeolites are crystallized from highly supersaturated solutions with the use of tetrapropylammonium hydroxide. High alkaline resistance of alumina support enables the choice of wide range of OH−/SiO2 ratio, and moreover, the choice of desirable degree of supersaturation. As a result, the homogeneous crystallization of zeolites onto the alumina support has been successfully achieved. [Copyright &y& Elsevier]

Abstract: Detailed nanostructures have been investigated for hierarchically porous alumina aerogels and xerogels prepared from ionic precursors via sol–gel reaction. Starting from AlCl3·6H2O and poly(ethylene oxide) (PEO) dissolved in a H2O/EtOH mixed solvent, monolithic wet gels were synthesized using propylene oxide (PO) as a gelation initiator. Hierarchically porous alumina xerogels and aerogels were obtained after evaporative drying and supercritical drying, respectively. Macroporous structures are formed as a result of phase separation, while interstices between the secondary particles in the micrometer-sized gel skeletons work as mesoporous structures. Alumina xerogels exhibit considerable shrinkage during the evaporative drying process, resulting in relatively small mesopores (from 5.4 to 6.2nm) regardless of the starting composition. For shrinkage-free alumina aerogels, on the other hand, the median mesopore size changes from 13.9 to 33.1nm depending on the starting composition; the increases in PEO content and H2O/EtOH volume ratio both contribute to producing smaller mesopores. Small-angle X-ray scattering (SAXS) analysis reveals that variation of median mesopore size can be ascribed to the change in agglomeration state of primary particles. As PEO content and H2O/EtOH ratio increase, secondary particles become small, which results in relatively small mesopores. The results indicate that the agglomeration state of alumina primary particles is influenced by the presence of weakly interacting phase separation inducers such as PEO. [Copyright &y& Elsevier]

Mullite monoliths with well-defined macropores and mesostructured skeletons have been prepared via the sol–gel process accompanied by phase separation in the presence of poly(ethylene oxide) (PEO). Gelation of Al2O3–SiO2 binary system with chloride salts as an additional precursor has been mediated by propylene oxide (PO) as an acid scavenger, while PEO worked as a phase-separation inducer. The dried gel and that heat-treated at 800°C are amorphous, and γ-Al2O3 or Si–Al spinel phase nanocrystals are crystallized at 900–1000°C. After heat-treated at and above 1100°C for 5h, the complete crystalline mullite is generated, and the macroporous monoliths in large dimensions of more than 15mm×15mm×10mm are obtained. Heat-treatment at 200–1400°C does not basically spoil the macroporous structure of monoliths, while decreases the macropore size and significantly alters the phase compositions and micro-mesoporous structure. [ABSTRACT FROM AUTHOR]

We report the application of hierarchically porous zirconium phosphate monoliths with high surface area as acidic heterogeneous catalysts for the dehydration of xylose into furfural. Analyses by NH 3 -temperature programmed desorption and 31 P solid state NMR reveal the presence of both Lewis and Brønsted acid sites in the as-synthesized zirconium phosphate monolith and that calcined at 600 °C. High accessibility and availability of the acidic sites and easy separation of the monolith from the liquid medium result in good catalytic activity (initial reaction rate for furfural production as 8.7 mmol g cat − 1 h − 1 ) with easy handling of the catalyst. [ABSTRACT FROM AUTHOR]

Abstract: We studied an applicability of a silica monolithic membrane as separation medium for high-performance liquid chromatography (HPLC). We prepared porous monolithic silica membranes having a three-dimensional network structure to cut and shape into a membrane separation medium. We evaluated chromatographic properties of a variety of solutes using a column containing the membranes with HPLC to elucidate summable property of the membrane separation media. In addition, we made brief study on separation of HbA1c in whole blood with the “stacked” membranes having different surface characteristics in one column, which is a membrane column. We confirmed that the membrane column was able to separate HbA1c from other matrix in whole blood to some extent, and it also had an excellent ability for hydrophobic and ion exchange adsorption. [Copyright &y& Elsevier]