Integrated chemical systems built using nanoporous glass/ceramics as substrates

Size controlled synthesis of highly dispersed anatase/rutile nanoparticles with photocatalytic activity toward salicylic acid degradation

“…For both the rutile and anatase phases, the results obtained by the Scherrer equation suggest that the titania present in the SBA-15-xTiO 2 samples is under the nanometric regime. Also, increases in the crystallite size with sequential IDCs are observed, which are already described for similar systems [19][20][21] and are explained by the fact that nanoparticles exceeding the interfacial free energy are expected to be minimized by their growth. Therefore, instead of forming new nucleation sites, consecutive IDCs preferentially promote the coverage of the preformed titania nanoparticles, causing their increase in size.…”

“…The larger band-gap values observed for the SBA-15-xTiO 2 samples submitted to lower numbers of IDCs may be related to the well-known size-induced effect observed for semiconductors under a nanometric regime, 29 which supports the assumption of the increase in size of the TiO 2 nanoparticles with successive ICDs. Some authors 30,31 have also suggested that changes in band-gap could be related to the support effect, since it is known that Ti-O-Si bonds in titania-silica oxides strongly modify the [19][20][21] electronic structure of the Ti atom by increasing its effective positive charge. 32,33 Therefore, it seems that the extraordinarily high band gap values observed for the SBA-15-xTiO 2 samples should not be attributed to one or other effect, but to a combination of both the quantum size effect (which is supported by the Raman and XRD results) and an electronic semiconductor support interaction.…”

Slow Magnetic Relaxation in CoIICuII Coordination Oligomer Built into Mesoporous Material

“…In fact, this glass has been successfully used to produce nanocomposites of a great variety of compounds such as complexes, semiconductors, oxides, and polymers. [31][32][33][34] Otherwise, the porous materials employed for the incorporation of magnetic molecules are the functionalized and nonfunctionalized SBA-15 [26] or MCM-41-type ordered mesoporous silica with pore sizes ranging from 2 to 15 nm. These materials are mesostructured with channels in highly ordered two-dimensional hexagonal arrays.…”

γ -Fe 2 O 3 nanoparticles dispersed in porous Vycor glass: A magnetically diluted integrated system

“…The volume of pores represents approximately 28% of the total volume. 20 The porous surface contains silanol groups, with acidic hydrogen atoms ͑pK a ϳ 9͒, which can be used as active sites for incorporation of several compounds, [14][15][16][17][18] such as the metallo-organic compound employed in this paper.…”

“…In particular, an interesting synthesis technique for nanostructured materials has been labeled the single-source precursor ͑SSP͒ approach and has been increasingly employed in the preparation of semiconductor nanocrystals and thin films. [16][17][18] A major challenge for this research field is to achieve a fine-controlled synthesis of nanostructures and to assemble them into chemically integrated systems where their performance can be engineered.…”