Preparation of gas sensing CoTiO3 nanocrystallites using EDTA as the chelating agent in a sol–gel process.

CoTiO 3 nanocrystallites with an average diameter of 40 nm were prepared by the sol–gel method using C 10 H 16 N 2 O 8 (EDTA) as the chelating agent. The thermal decomposition process and chemical bonding of the precursor were studied by thermogravimetric-differential scanning calorimetry and fourier transform infrared spectra, respectively. The as-prepared nanocrystallites were characterized by X-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy. The effects of calcination temperature, sol pH and chelating agent on the formation of CoTiO 3 were investigated. The results show that calcination temperature is a key factor controlling the composition of the products. Acid sol is the optimum condition for hydrolysis and polycondensation of Ti(OC 4 H 9 ) 4 . Co 2+ and Ti 4+ were bonded together by EDTA, and pure CoTiO 3 nanocrystallites were obtained due to this chelating effect. The chelating mechanism and the formation process of CoTiO 3 in the sol–gel process were proposed. Furthermore, the nano-CoTiO 3 was applied to make a gas sensor, and the response value to 104 ppm ethanol was 17.9, response time and the recovery time were 13 s and 10 s, respectively. [ABSTRACT FROM AUTHOR]