Effects of heating atmosphere on formation of crystalline citrate-derived LaAlO 3 nanoparticles

Abstract

Crystalline LaAlO 3 nanoparticles were synthesized at relative low temperatures, using a citrate-precursor technique. La(NO 3) 3, Al(NO 3) 3, and C 3H 4(OH)(COOH) 3, in a molar ratio of 1:1:1, were dissolved in deionized water. NH 4OH was used to adjust the aqueous solution to pH 7. After drying, the citrate precursors were charred at 350 °C, followed by calcination at different temperatures, in air or oxygen atmosphere. The thermochemical properties of the resultant particles were analyzed using thermogravimetric and differential thermal analysis, X-ray diffractometry, infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. Effects of calcination temperature and heating atmosphere on the formation of crystalline LaAlO 3 nanoparticles were investigated. In O 2 atmosphere, clacining the citrate-derived charred solid precursor at 700 °C for 3 h can decompose all intermediates to produce pure LaAlO 3 nanoparticles (particle sizes ≤ 100 nm) with an average crystallite size of about 24 nm and possessing high sinterability.