Naslov
Synthesis and characterization of nanocrystalline zinc aluminate spinel by sol–gel technique using modified alkoxide precursor

Autori
Kurajica, Stanislav ; Tkalčec, Emilija ; Šipušić, Juraj ; Matijašić, Gordana ; Brnardić, Ivan ; Simčić, Ivan

Izvornik
Journal of sol-gel science and technology (0928-0707) 46 (2008), 2; 152-160

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
zinc aluminate spinel ; nanoparticles ; sol–gel synthesis ; crystallization ; surface area

Sažetak
Nanosized zinc aluminate spinel (gahnite, ZnAl2O4) powders were prepared by sol– gel technique at low sintering temperatures. Aluminium-sec-butoxide [Al(OsBu)3] and zinc nitrate hexahydrate [Zn(NO3)2.6H2O] were used as starting materials. Gels with and without chelating agent were prepared. Ethyl-acetoacetate (C6H10O3) was used as a chelating agent in order to control the rate of hydrolysis of Al(OsBu)3. The dried gels and thermally treated samples were characterized by means of Differential Thermal Analysis and Thermo- Gravimetric Analysis (DTA, TGA), X-Ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR) and Transmission Electron Microscopy (TEM). The surface area was measured by Brunauer-Emmet- Teller (BET) adsorption-desorption isotherms. It has been established that chelation enables to obtain a transparent gel. The thermal evolution of gels was characterized by two crystallization processes in the range 200-400 °C and 600-700 °C. Both processes yielded pure ZnAl2O4 as evidenced by XRD, i.e. zinc aluminate spinel powders were produced by gel heat-treatment at temperatures as low as 300 °C. The average gahnite crystallite size for the samples sintered in the temperature range of 400– 1000 °C has been calculated from the broadening of XRD lines revealing that nanocrystalline powders were prepared. The surface areas measured for the samples fired at 700 °C for 2 h were 43.1 m2g-1 and 62.6 m2g-1, for sample without and with the chelating agent, respectively. TEM micrographs confirmed the nano- scale size of particles.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija, Kemijsko inženjerstvo

Napomena
Glavni autor: Stanislav Kurajica

POVEZANOST RADA