Preparation of nanosized La2CuO4 perovskite oxide using an amorphous heteronuclear complex as a precursor at low-temperature

The amorphous precursor of La2Cu(DTPA)(1.6). 6H(2)O was synthesized by a si mple inorganic reaction, and nanosized La2CuO4 cuprate oxide with a perovsk ite structure was prepared by the decomposition of the amorphous precursor at a low temperature in air. DTA and TGA analysis indicates that the precur sor of La2Cu(DTPA)(1.6). 6H(2)O can completely be decomposed into cuprate o xide at a temperature above 500 degrees C. XPS reveals that the decomposed species is composed of La2CuO4 cuprate oxide after the precursor is calcine d at 500 degrees C for 2 h. XRD demonstrates that La2CuO4 cuprate oxide for med at 500 degrees C Is amorphous. Nanosized La2CuO4 crystalline powder wit h a perovskite structure is formed after the calcination temperature is inc reased to 650 degrees C. TEM shows that the decomposed oxide has a plate te xture when the calcination temperature is 500 degrees C. After the calcinat ion temperature is increased to 650 degrees C, the La2CuO4 cuprate oxide ex ists as particles and the dispersion is homogenous. The average crystal siz e is about 28.7 nm and does not change too much with the increase of calcin ation time. The temperature also has few effects on the particle size after the crystal is formed above 650 degrees C, The above results demonstrate t hat this is a useful way to synthesize nanosized perovskite oxides using an amorphous complex as the precursor. (C) 2000 Elsevier Science S.A. All rig hts reserved.