Preparation of pure perovskite-type BaSnO 3 powders by the polymerized complex method at reduced temperature

Abstract

Cubic perovskite-type pure barium stannate, BaSnO 3, powders were prepared using the polymerized complex technique at the relatively low temperature of 600°C. SnCl 4· xH 2O was first dissolved in ethylene glycol (EG) and anhydrous citric acid (CA) was then added. After complete dissolution, BaCO 3 powder was added and the mixture was stirred at 80°C for several hours until the solution became transparent, demonstrating the presence of Ba 2+- and Sn 4+–citric acid complexes. This solution, with molar ratio Ba/Sn/CA/EG=1:1:10:40, was heated at 130°C to produce a yellowish transparent resin without any precipitation via polymerization with citric acid and ethylene glycol including the complexes. Pyrolysis of the resin at 350°C yielded a powder precursor of BaSnO 3. X-ray diffraction and Raman analysis indicated the formation of pseudo-cubic BaSnO 3 when the barium–tin precursor was heat treated in air at ≥600°C for 2 h. The product was identified as pseudo-cubic BaSnO 3 with lattice parameter a 0=0.4118±0.0003 nm. The powder formed at 800°C consisted of faceted microcrystals 80–100 nm in size.