La2O3 Nanoplates Prepared by Heat-Treatment of Electrochemically Grown La(OH)3 Nanocapsules from Nitrate Medium

Cathodic electrodeposition of La(OH)(3) was successfully carried out from low-temperature nitrate bath at current density of 1 mA cm(-2) without any templates and surfactants. To obtain oxide product, the prepared hydroxide sample heat treated at 700 degrees C for 2 hours in dry air atmosphere. The XRD results showed that the obtained hydroxide and oxide samples have hexagonal phase of La(OH)(3) and pure single crystalline of La2O3, respectively. Mechanism of La(OH) 3 deposition from nitrate bath at the applied conditions was proposed. CHN and FT-IR analyses showed that nitrate intercalation in the deposit during the electrodeposition process and confirmed the proposed mechanism. Morphological characterization revealed that La(OH)(3) has compact morphology with capsule-like structures having approximately an average diameter of 15 nm and the length of up to 50 nm. After heat treatment, formation of plate-like structures of La2O3 with different size at nanoscale was confirmed by SEM and TEM. Mechanism of La(OH)(3) cathodic deposition from nitrate bath, and the Mechanism of La(OH)(3) nanocapsules formation and growth and their conversation to La2O3 nanoplates during the heat treatment have been proposed and discussed. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.057112jes] All rights reserved.