SBA-15:TiO2 nanocomposites: II. Direct and post-synthesis using acetylacetone

Jardim, Alice A.M.L.F.; Bacani, Rebeca; Gonçalves, Norberto S.; Fantini, M.C.A.; Martins, Tereza Silva

doi:10.1016/j.micromeso.2016.10.009

Cited by 20 publications

(15 citation statements)

References 55 publications

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“…To control the catalytic functions, the state, the size, and the shape of the TiO 2 particles as well as their location in the mesopore are key factors. The TiO 2 species have been immobilized in PMSs as isolated molecular species and oxide nanoparticles in the silica wall and on the mesopore using several molecular precursors and with varied synthetic conditions (both direct synthesis and postsynthetic immobilization); − however, the size and shape of the TiO 2 particles as well as their location (on the external surface or in the mesopore) are still difficult to be controlled precisely. Although the size-controlled synthesis of TiO 2 particles has been a topic of interest in materials chemistry to adapt the wide range of applications of TiO 2 and to optimize the performances of materials, − the size-controlled synthesis of TiO 2 using PMSs as a template is still challenging.…”

Section: Introductionmentioning

confidence: 99%

Size-Controlled Synthesis of Anatase in a Mesoporous Silica, SBA-15

2017

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The preparation of anatase in the cylindrical mesopore of SBA-15 (pore size of 8 nm) was done by the impregnation of tetraisopropyl orthotitanate and its subsequent crystallization. The impregnation was done without a solvent. Hydrolysis and condensation were promoted by the HCl vapor to encapsulate a larger amount of titanium oxo species in the mesopore and to suppress the desorption of the titanium oxo species during crystallization to anatase. After the reaction, the shape of the N adsorption isotherm changed significantly, indicating the decrease of the Brunauer-Emmett-Teller surface area from 743 to 283 m/g and of the pore volume from 1.27 to 0.26 cm/g, respectively. After the crystallization to anatase, the TiO content in the product was estimated to be 62 mass %, filling 30% of the pore volume of SBA-15. The homogeneous distribution of titanium in the SBA-15 sample was confirmed by elemental mapping based on scanning electron microscopy/energy-dispersive X-ray spectrometry. The crystal size of the anatase was determined to be ca. 8.1 nm, which is consistent with the pore size of the used SBA-15 (8.0 nm, derived from the Barrett-Joyner-Halenda analysis of the nitrogen adsorption isotherm). The zeta potential measurements showed the absence of anatase as isolated particles or on the surface of SBA-15 particles. All of these characterizations confirmed the successful size-controlled synthesis of anatase in the mesopore of SBA-15.

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Section: Introductionmentioning

confidence: 99%

Size-Controlled Synthesis of Anatase in a Mesoporous Silica, SBA-15

2017

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“…There were no significant displacements of these bands in the nanocomposites, suggesting little interaction between the metal and the silanol groups. Evidence of the presence of zinc comes from the wider bands observed in the region of 400-700 cm -1 in the SBAZn nanocomposites spectra compared to SBA-15 [19,28,29]. The stretching modes of Zn-O appear around 460, 550 and 600 cm -1 , but these bands could be covered by the stretching bands (δ[O-Si-O], around 500 cm -1 ) of silica appearing in the same region [29][30][31][32][33].…”

Section: Fourier Transform Infrared Spectroscopymentioning

confidence: 99%

“…One such OMS is Santa Barbara Amorphous-15 (SBA-15), which has a two-dimensional hexagonal structure, a pore size distribution of around 10 nm and surface area of around 800 m 2 . g -1 [15,17,19]. In this work, nanometric commercial ZnO was incorporated into SBA-15, with the aim of developing an effective sunscreen formulation.…”

Section: Introductionmentioning

confidence: 99%

“…In this work, nanometric commercial ZnO was incorporated into SBA-15, with the aim of developing an effective sunscreen formulation. While there are many reports describing the production and efficacy of composite silicon dioxide (SiO 2 ):ZnO using the post-synthesis method, the combination of OMS and ZnO for use in cosmetics and sunscreens is novel and has not been explored previously [19][20][21][22][23]. 20 ; Sigma Aldrich) was solubilized in 30 mL of distilled water and 120 mL of 2 mol/L HCl (Alphatec).…”

Section: Introductionmentioning

confidence: 99%

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ZnO:SBA-15 Nanocomposites for Potential Use in Sunscreen: Preparation, Properties, Human Skin Penetration and Toxicity

Vieira

Grice

Roberts

et al. 2018

Skin Pharmacol Physiol

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Aim: We evaluated the effects of the incorporation of zinc oxide (ZnO) nanoparticles in a mesoporous matrix, aiming to improve the textural, structural and morphological properties and verify their safety so that they can be applied in sunscreen cosmetics. Materials and Methods: ZnO nanoparticles were incorporated into an ordered mesoporous silica matrix known as Santa Barbara Amorphous-15 (SBA-15), using post-synthesis methodology. The resulting nanocomposites were characterized using X-ray diffraction, small angle X-ray scattering, N₂ adsorption-desorption isotherms, Fourier transform infrared spectroscopy, scanning electron microscopy and predicted in vitro sun protector factor (SPF) estimation. Effectiveness and safety were evaluated by antimicrobial activity, in vitro cell toxicity and non-invasive multi-photon tomography with fluorescence lifetime imaging. Results: The structure of the nanocomposites was similar to that of SBA-15, with little perturbation caused by ZnO incorporation. Nanocomposites had an increased in vitro SPF, reduced cytotoxic activity and favourable antimicrobial properties compared to ZnO. ZnO:SBA-15 nanocomposites exhibited no measurable toxicity when applied to human skin in vivo. Conclusion: Due to their suitable physicochemical properties and improved safety compared to bare ZnO nanoparticles, the ZnO:SBA-15 nanocomposites show promise for use in cosmetic applications.

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“…More recently, SBA-15 mesoporous silica used as photocatalyst support is widely researched due to ultraviolet transparent, high specic surface area (600-1100 m 2 g À1 ), adjustable pore diameter (2-30 nm), and uniform mesoporous hexagonal pore size distribution. 15,16 Jardim et al 17,18 studied the inuence of reaction media and synthesis routes on the physical properties of TiO 2 /SBA-15 nanocomposites, and they found that the post-synthesis method is more conducive to the formation of single crystal anatase. Conceição et al 19 prepared commercial anatase TiO 2 /SBA-15, wherein the activity for photocatalytic degradation of pesticide amicarbazone under UVA blacklight increased with increase in TiO 2 contents.…”

Section: Introductionmentioning

confidence: 99%