Very high titanium content mesoporous silicas

Titanium content in mesoporous titanosilicate catalysts has been modulated up to a minimum Si/Ti value of 1.9 by using complexing agents able to coordinate both Si and Ti atoms and harmonize the reactivity of the resulting precursors avoiding subsequent phase segregation and leading to chemically very homogeneous materials.El Haskouri, Jamal, [email protected] ; Beltran Porter, Aurelio, [email protected] ; Beltran Porter, Daniel, [email protected] ; Amoros del Toro, Pedro Jose, [email protected]

Large monolithic silica-based macrocellular foams with trimodal pore system

Silica-based materials with hierarchical pore systems at three different length scales (small mesopores–large mesopores–macropores) have been prepared through a nanotectonic approach by using mesoporous nanoparticles as building blocks; the resulting materials present a highly accessible foam-like architecture and can be prepared as large monoliths.Huerta Morillo, Lenin Jose, [email protected] ; Latorre Saborit, Julio, [email protected] ; Beltran Porter, Aurelio, [email protected] ; Beltran Porter, Daniel, [email protected] ; Amoros del Toro, Pedro Jose, [email protected]

Supramolecular self-assembling in mesostructured materials through charge tuning in the inorganic phase

Supramolecular self-assembling of organic CTA+ micelles and inorganic [VO(H2O)PO4]n^q-2 2D-anions for the isolation of hexagonal mesostructured materials can be reached by charge tuning in the inorganic phase through the adjustment of the vanadium mean oxidation state.El Haskouri, Jamal, [email protected] ; Cabrera Medina, Saul, [email protected] ; Beltran Porter, Aurelio, [email protected] ; Alamo Serrano, Jaime, [email protected] ; Beltran Porter, Daniel, [email protected] ; Amoros del Toro, Pedro Jose, [email protected]

Tuning the pore size from micro- to meso-porous in thermally stable aluminophosphates

Thermally stable porous aluminophosphates (ICMUV-3) with P/Al molar ratios in the range 0.15 <= P/Al <= 0.75 and showing continuously adjustable pore sizes from 13 to 37 Å have been prepared through a surfactant-assisted procedure without changing the surfactant length and/or addition of organic expansors.Cabrera Medina, Saul, [email protected] ; El Haskouri, Jamal, [email protected] ; Beltran Porter, Aurelio, [email protected] ; Beltran Porter, Daniel, [email protected] ; Amoros del Toro, Pedro Jose, [email protected]

Towards the Loewenstein limit (Si/Al = 1) in thermally stable mesoporous aluminosilicates

The use of complexing agents to generate polynuclear precursor species containing both Al and Si allows the synthesis of thermally stable mesoporous aluminosilicates including solely tetrahedrally coordinated aluminium, in which the Si/Al ratio can be modulated down to a minimum Si/Al value of 1.06(4).Cabrera Medina, Saul, [email protected] ; El Haskouri, Jamal, [email protected] ; Latorre Saborit, Julio, [email protected] ; Beltran Porter, Aurelio, [email protected] ; Beltran Porter, Daniel, [email protected] ; Amoros del Toro, Pedro Jose, [email protected]

Nanostructured alumina from freeze-dried precursors

Nanocrystalline alumina has been obtained on the 100-g scale by thermal decomposition of precursors resulting from the freeze-drying of aqueous solutions of different aluminium-containing products,namely aluminium acetate and aluminium L-lactate. Samples prepared at different temperatures (from 873 to 1573 K in steps of 100 K) were characterized by X-ray powder diffraction, scanning and transmission electron microscopy, and surface area measurements. In the acetate case, the transformation sequence involves the formation of q-Al2O3 as an intermediate phase between g- and a-Al2O3, whereas this q phase is not observed in the lactate case. TEM and SEM images show the nanoparticulate character of the aluminas obtained at relatively low temperatures, with typical particle size in the 5 to 10 nm range. Progressive grain growth occurs as temperature increases. Otherwise, the precursor characteristics have a clear influence on the microstructure of the resulting aluminas , as reflected also by the measured BET surface area values. Whereas long aluminium acetate fibres results in open arrays of low aggregated alumina particles, large aluminium lactate sheets lead to comparatively compact alumina microstructures. Nanostructured alumina obtained from the lactate precursor has been to reconstituted in a granulated powder with sufficient consistence and flowability to allow it to be thermal sprayed and deposited on a stainless steel substrate. X-ray powder diffraction data show that g-Al2O3 is the major phase in the coating, which includes also a-Al2O3 particles. SEM results offer evidences on the nanostructured character of the coating

Large scale synthesis of nanostructured zirconia-based compounds from freeze-dried precursors

Nanocrystalline zirconia powders have been obtained at the multigram scale by thermal decomposition of precursors resulting from the freeze-drying of aqueous acetic solutions. This technique has equally made possible to synthesize a variety of nanostructured yttria or scandia doped zirconia compositions. SEM images, as well as the analysis of the XRD patterns, show the nanoparticulated character of those solids obtained at low temperature, with typical particle size in the 1015 nm range when prepared at 673 K. The presence of the monoclinic, the tetragonal or both phases depends on the temperature of the thermal treatment, the doping concentration and the nature of the dopant. In addition, Rietveld refinement of the XRD profiles of selected samples allows detecting the coexistence of the tetragonal and the cubic phases for high doping concentration and high thermal treatment temperatures. Raman experiments suggest the presence of both phases also at relatively low treatment temperatures

Silica-based powders and monoliths with bimodal pore systems

Porous pure and doped silicas with pore sizes at two length scales (meso/macroporous) have been prepared and shaped both as powders and monoliths through a one-pot surfactant assisted procedure by using a simple template agent and starting from atrane complexes as inorganic precursors.El Haskouri, Jamal, [email protected] ; Latorre Saborit, Julio, [email protected] ; Beltran Porter, Aurelio, [email protected] ; Beltran Porter, Daniel, [email protected] ; Amoros del Toro, Pedro Jose, [email protected]