Synthesis and characterization of zirconia- and silica-doped zirconia nanopowders by oxalate processing

Synthesis and characterization of novel ZrO2-SiO2 mixed oxides

“…The increase in pore diameter can be linked to the presence of sulfate ions on the micropore walls, causing tension and rupture, followed by increased micropore volume and diameter 42 . The spectra in the infrared region shown in Figure 5 indicate the presence of a band at 1630 cm -1 that corresponds to scissor bending vibration of the H-O-H bond of the physisorbed molecular water 27,42,46,47 . The samples showed bands centered at 1078 cm -1 with a shoulder at ~ 1220 cm -1 due to the asymmetric Si-O-Si stretching vibrations of transverse-optical (TO 3 ) mode and the longitudinal-optic (LO 3 ) part stretching vibrations, respectively 47 .…”

“…Above 700 °C, the loss of mass is associated with the dehydroxilation of the surface 27 . The usually characteristic band of Si-C at 1276 cm -1 for the ZrO 2 -SiO 2 -Me catalyst in the FTIR analysis ( Figure 5) could not be verified due to the small amount of MeSi(OEt) 3 used for synthesis.…”

“…Owing to these properties, the acidic mixed oxides play an important role in applications such as the cyclization of citronellal to isopulegol 16,17 , isomerization of α-pinene and dehydration of 4-methyl-2-pentanol 18 , Fischer-Tropsch process 19 , ammonia oxidation 20 , hydrogenation of alkenes 21 , synthesis of alcohols 22 , and biodiesel production 23 . Among the most frequently employed methods for the synthesis of mixed oxides are the coprecipitation 24 , hydrothermal routes 25 , sonochemical processes 26 , the oxalate route 27 , and the sol-gel process 28 . From all these processes, the sol-gel process (SGP) has attracted attention due to its versatility in the development of new materials, owing to the simplicity and flexibility of the synthesis, which permits the preparation of highly pure and homogeneous products with controlled porosity 29 .…”

“…In this context, silica-supported zirconium oxide has emerged as catalyst because of its thermal and chemical stability, its higher resistance to deactivation compared to the isolated oxides, and its higher acidity 27,[31][32][33] . Based on the above considerations, the objective of this work was the synthesis and characterization of the mixed oxide ZrO 2 -SiO 2 as well as the modification of its acid force and its hydrophilic character, followed by an preliminary assessment of the catalyst in the esterification of oleic acid with methanol, aiming at a future application in the production of biodiesel from high free fatty acid feedstocks.…”

Structure property relations in multicomponent oxide systems with additions of TiO2 and ZrO2 for glaze applications

“…In the case of ZrO 2 addition, based on the literature data indicates the 574 and 732cm −1 bands as being characteristic of the monoclinic phase of zirconia [14], the band at 555 cm −1 could be ascribed to this component in these samples [15]. The band of the monoclinic zirconia phase that occurs at 732 cm 1 overlaps the symmetric Si-O-Si stretching vibrations of the SiO 4 units.…”