Naslov
Titanate nanotubes modified with (3-aminopropyl)triethoxy silane and their temperature stability
(Titanatne nanocjevčice modificirane sa (3-aminopropil)trietoksi silanom i njihova temperaturna stabilnost)

Autori
Plodinec, Milivoj ; Gajović, Andreja ; Iveković, Damir ; Su, Dangsheng

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Internationa Symposium on Advanced Electron Microscopy for Catalysis and Energy Storage Materials - Booklet of Abstracts / D. S. Su, S. Wrabetz, D. Zhu - Berlin : Integrated Design of Catalytic Nanomaterials for a Sustainable Production, 2010, 21-21

Skup
Internationa Symposium on Advanced Electron Microscopy for Catalysis and Energy Storage Materials

Mjesto i datum
Berlin, Njemačka, 17.01.2010. - 20.01.2010

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Titanate nanotubes; surface modification; thermal stability; catalysts carrier
(Titanatne nanocjevčice; modifikacija površine; temperaturna stabilnost; nosači katalizatora)

Sažetak
Titanate nanotubes have wide field of applications ; as catalyst supports, for photo catalysis, as gas sensors, high efficiency solar cells, etc. Titanate nanotubes are particularly interesting due to its large surface area. We studied modified titanate nanotubes with application as catalysts carrier. With the aim to study their stability during further processing and during final catalytic reactions, we investigate temperature region in which the structure of modifier and nanotubes will be unchanged. Titanate nanotubes (TiNT-H) were synthesized by hydrothermal method. Chemical modification of TiNT-H was performed through the reaction of surface –OH groups with (3-aminopropyl)triethoxy silane (APTES) (Fig. 1a). The samples of surface- modified TiNT-H were marked as TiNT-x (x=20, 45, 90, 180), where x indicates the duration (in minutes) of the modification reaction. The structure and morphology of surface-modified nanotubes were studied by high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy (RS). High temperature behavior was examined by thermal gravimetric analysis and differential scanning calorimetry (TGA-DSC), while structural changes in situ at high temperature were studied by RS. HRTEM indicates that the morphology of the nanotubes was not changed during the modification, but the ends of the nanotubes become closed . Raman spectra show bands which can be assigned to TiNT-H crystal lattice vibrations in lower frequency region, while in the region higher than 1000 cm-1 the vibrations characteristic for 3- aminopropyl moiety were observed. Thus, very broad bands at about 2900 cm-1 can be assigned to CH stretching region, the broad band at about 1620 cm-1 may be assigned to the NH2 scissoring mode of vibrations, and the bands in region 1100-1450 cm-1 were assigned to the modes associated with CH2 group vibrations [1]. During in situ Raman spectroscopy of TiNT-x nanotubes we observed that hydrogen titanate crystal structure of modified nanotubes were stable up to 400 °C, which is much higher than the phase transition temperature of 175 °C for pure TiNT-H [2]. However, the degradation of organic groups attached to the nanotube surface started already at temperatures larger than 150 °C, while at temperature higher than 300° we did not observed any bands in higher wavenumbers spectral regions. High temperature RS and TGA-DSC results will be discussed considering (HR)TEM observations. By comparison of TiNT-x and TiNT-H [2] annealing we conclude that organic part which is built-in on the surface of TiNT nanotubes contribute to higher temperature stability of titanate nanotubes, while the recommended temperature region for further processing of modified nanotubes are below 150 °C. References: [1] L. Bistričić, V. Volovšek, V. Danačić, I. Movre Šapić, Spectrochimica Acta A 2006 ; 64: 327- 337. [2] A. Gajović, I. Friščić, M. Plodinec, D. Iveković, J. Mol. Struct. 2009 ; 924-926: 183-191.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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