Microfibrous TiO2−sepiolite and TiO2/SiO2−sepiolite nanocomposites were prepared following a colloidal route based on the controlled hydrolysis of alkoxides in the presence of cetyltrimethylammonium−sepiolite gel. In this way, titanium(IV) isopropoxide and tetramethoxysilane were used as titania and silica precursors, respectively, being incorporated within the organophilic layer developed on the surface of the silicate microfibers and further hydrolyzed in this region. The hydrolysis of the precursor gives highly viscous colloidal systems leading to a spontaneous heterocoagulation process of the colloidal system. Drying and thermal treatments of the resulting gels ensure the elimination of water and organic matter, driving to the formation of TiO2 nanoparticles homogeneously distributed on the surface of the sepiolite microfibers. The nanocomposites were characterized by chemical analyses, transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction, thermogravimetric/differential thermal analysis, and N2 adsorption. They were tested as photocatalysts in the photo-oxidation of phenol in an aqueous medium, showing the efficiency of the anatase containing nanocomposites in the removal of this selected pollutant model molecule. Thiourea was incorporated to increase the TiO2 anatase phase stability, improving in this manner the photocatalytic activity of the TiO2−sepiolite nanocomposites. It has been shown that sepiolite has a positive synergistic effect on the TiO2 photocatalysis.

The 3D polymeric terephthalate of scandium has been synthesized and its structure solved by single-crystal XRD. It was obtained as a single phase and characterized and tested as a hydrogen and nitrogen adsorbent and heterogeneous catalyst as a redox agent in the oxidation of sulfides. The compound shows a BET area of 721 m2 g-1 with a high C BET = 7000. The high chemical and thermal stability and excellent hydrogen sorption properties make this compound a useful material for hydrogen storage.

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Under soft conditions, it is possible to cause the irreversible delamination of organoclays (long‐chain alkylammonium cation‐exchanged smectites, and vermiculite‐layered silicate derivatives) via a sol–gel process that involves alkoxysilanes (e.g., tetraethoxysilane) and that finally gives silica–clay heteromaterials. These intermediate silica–organoclay nanocomposites facilitate the diffusion of the alkoxides which, in the presence of water, are hydrolyzed and subsequently polymerized. This process is a heterocoagulation that gives homogeneous gels in which the order in the layer stacking of clays is partially or completely lost, depending on the nature of the layered silicate. After calcination to eliminate the organic moiety, that is, the alkylammonium chains, the gel is irreversibly transformed into a silica–clay material in which the silicate layers are fully separated by the silica network generated by the alkoxide. The resulting solids are inorganic–inorganic nanocomposites which could be compared to polymer–clay nanocomposites, but in the present case the inorganic silica network is the continuous phase and the individual layers the corresponding disperse phase of the nanocomposite. These materials are solids of high specific surface area (> 400 m2 g–1), which exhibit micro‐ and mesoporosity, and also have properties inherent to both components, the pristine clay (e.g., a cation‐exchange capacity) and the silica network (e.g., an ability to be functionalized).

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