Sol–gel synthesis and structural characterization of niobium-silicon mixed-oxide nanocomposites

Silica-alumina-niobia (SiO2/Al2O3/Nb2O5) matrix obtained by the sol-gel processing method: new material for online extraction of zinc ions

“…The two spectra are very similar, although the bands recorded for SiAlNb are somewhat broader and some of them shift toward lower frequencies. This behavior is consistent with the infrared spectra obtained by Aronne et al 40 …”

Flow injection on-line minicolumn preconcentration and determination of trace copper ions using an alumina/titanium oxide grafted silica matrix and FAAS

“…The band, broad and strong, around 3420 and 3448 cm −1 is attributed to OH stretching vibrational mode [25]. The absorption band around 1640 cm −1 is assigned to the mode of deformation connections of hydroxyl and molecular water adsorbed (δ O-H ) on the adsorbents [25]. For SiO 2 / Al 2 O 3 /TiO 2 , a shoulder and more intense peak was verified being an evidence of the modification of silica surface by the mixed oxides.…”

“…The infrared spectra of the material SiO 2 / Al 2 O 3 /TiO 2 exhibited a similar pattern to the silica in the location of the peaks. The band, broad and strong, around 3420 and 3448 cm −1 is attributed to OH stretching vibrational mode [25]. The absorption band around 1640 cm −1 is assigned to the mode of deformation connections of hydroxyl and molecular water adsorbed (δ O-H ) on the adsorbents [25].…”

“…For SiO 2 / Al 2 O 3 /TiO 2 , a shoulder and more intense peak was verified being an evidence of the modification of silica surface by the mixed oxides. The absorption bands observed in approximately 1219 cm −1 is stretching from Si-O from the silica support (ν -Si-O ) [25,26], 1074 cm −1 can be assigned to Si-O stretch in linear Si-O-Si or Si-O-Al and the absorption around 940 cm −1 is related to stretching and bending modes of the same bond of the Si-OH group or Si-O-Ti bonds [27]. The absorption band Preconcentration procedure optimization using Doehlert design and response surface methodology…”

Desenvolvimento de materiais nanoestruturados à base de óxido de nióbio para aplicação em fotônica

“…A espectroscopia vibracional na região do infravermelho tem sido reportada na literatura como uma ferramenta útil na investigação da microestrutura de géis, vidros e filmes de sílica e sistemas binários de sílica com metais de transição WACHS, 1996;INNOCENZI, 2003;FERRARI, J. L. et al, 2011 Na literatura INNOCENZI, 2003;ARONNE et al, 2007) A análise das outras bandas indica a presença de óxido de nióbio. Orel et al (OREL et al, 1998) (POLMAN, 1997;GONCALVES et al, 2002;TANABE, 2002;GONÇALVES et al, 2004; POLMAN e VAN VEGGEL, 2004;ZAMPEDRI et al, 2007;GONÇALVES, GUIMARÃES, et al, 2008;GONÇALVES, MESSADDEQ, et al, 2008;FERRARI et al, 2010;FERRARI, J. L. et al, 2011 Assim, ao contrario do reportado na literatura em outros sistemas preparados pela metodologia sol gel, não foi necessário um tratamento térmico posterior para densificação completa dos guias de onda (ZAMPEDRI et al, 2003;ZAMPEDRI et al, 2004;GONÇALVES, GUIMARÃES, et al, 2008;GONÇALVES, MESSADDEQ, et al, 2008).…”