Preparation of nanosized La 2CuO 4 perovskite oxide using an amorphous heteronuclear complex as a precursor at low-temperature

Abstract

The amorphous precursor of La 2Cu(DTPA) 1.6·6H 2O was synthesized by a simple inorganic reaction, and nanosized La 2CuO 4 cuprate oxide with a perovskite structure was prepared by the decomposition of the amorphous precursor at a low temperature in air. DTA and TGA analysis indicates that the precursor of La 2Cu(DTPA) 1.6·6H 2O can completely be decomposed into cuprate oxide at a temperature above 500°C. XPS reveals that the decomposed species is composed of La 2CuO 4 cuprate oxide after the precursor is calcined at 500°C for 2 h. XRD demonstrates that La 2CuO 4 cuprate oxide formed at 500°C is amorphous. Nanosized La 2CuO 4 crystalline powder with a perovskite structure is formed after the calcination temperature is increased to 650°C. TEM shows that the decomposed oxide has a plate texture when the calcination temperature is 500°C. After the calcination temperature is increased to 650°C, the La 2CuO 4 cuprate oxide exists as particles and the dispersion is homogenous. The average crystal size is about 28.7 nm and does not change too much with the increase of calcination time. The temperature also has few effects on the particle size after the crystal is formed above 650°C. The above results demonstrate that this is a useful way to synthesize nanosized perovskite oxides using an amorphous complex as the precursor.