Polymerized Complex Synthesis of Perovskite Lead Titanate at Reduced Temperatures: Possible Formation of Heterometallic (Pb,Ti)-Citric Acid Complex

Perovskite PbTiO 3 powders were prepared by a polymerized complex technique at relatively low temperatures, viz. 400−600 °C. Heating of a mixed solution of citric acid (CA), ethylene glycol (EG), and Pb and Ti ions with a molar ratio of Pb/Ti/CA/EG = 1/1/10/40 at 130 °C produced a yellowish transparent polymeric gel without any precipitation, which after pyrolysis at 300 °C was converted to a powder precursor for PbTiO 3 . We suggest, based on the results of Raman and 13 C NMR spectroscopies, that a heterometallic (Pb,Ti)−CA 3 chelate complex formed in a starting Pb/Ti/CA/EG solution and it was thermally stable upon polymerization at 130 °C. Chemical analyses showed no PbO loss during calcination of powder precursors at 400−700 °C, which led to the conclusion that a solid-state reaction between isolated PbO and TiO 2 particles was not responsible for PbTiO 3 formation, but PbTiO 3 formed directly by thermal decomposition of the powder precursor above 400 °C.